This blog was authored by Don Shulsinger, Vice President, Sales and Marketing, Immedia

1.TI: What is Blink Home Monitoring? 

Blink is a one-of-a-kind, battery-powered, ultra-affordable, whole home-monitoring system that’s simple to set up and use, and is equally perfect for both renters and homeowners. Its compact, totally wire-free design houses innovative HD video technology, plus motion and temperature sensors, to deliver instant home insight to your mobile device via the Blink App.

2. TI: What makes Blink stand out from its competitors?

Blink is a unique entry into the home monitoring space: a wire-free HD home monitoring and alert system that aims to make smartphone-based home insight easy and affordable for the masses--whether they rent or own. How? By building a product around three tenets that translate into real-life benefits for its rapidly-growing community.

• Make it affordable. With no monthly fees, users can create a whole-house system for far less than the cost of traditional home monitoring and security products, with the flexibility to affordably expand their system as necessary.
• Make it easy to set up. Blink offers simple, DIY set-up that requires little technical or toolbox know-how. Its battery-powered, wire-free design makes it uniquely appealing, in that users can truly place it anywhere - on a bookshelf or desk, flush on the wall, or in a corner--without having to worry about the nearest outlet, or unsightly wires draped across their home or apartment.
• Make it simple to customize and manage. Blink allows users to create a system that suits their lifestyle. Want to make sure your garage is safe? Arm Blink’s motion detection, and receive an alert and video clip if a door or window opens. Prefer to check in on your furry friend a few times a day? Activate Live View for a glimpse of what’s happening at home. Worried about a break-in? Add the optional, 105db alarm unit to ward off intruders. Want to keep an eye on your home while you’re away on vacation? Blink’s batteries last a year, giving you the flexibility to check in as much as you want.
• Users can also choose from two video storage options: free cloud-based storage (which holds 1440 5-second clips) or local USB storage (which holds over 40,000 5-second clips), and temperature and status alerts round out a rich feature set that’s scheduled to expand further in 2016.

3. There are many wireless connectivity technologies on the market. Why did you choose to integrate Wi-Fi^® in Blink?   

In an increasingly wireless world, convenience and flexibility are key. Through the use of Wi-Fi, we are able to provide the broadest possible number of consumers the power to move, operate, and use their system anytime and from anywhere. With its Wi-Fi-based technology, Blink makes access to one’s home and peace of mind just a tap away.

4.Why did you choose TI’s SimpleLink™ Wi-Fi CC3100 connectivity technology for your product?

TI's SimpleLink Wi-Fi technology is a cost effective, easy to integrate, low-power, small footprint solution which is ideally suited for Blink. By utilizing the SimpleLink device’s ability to support intermittent connection mode – in which the device goes into low power mode for extended periods of time, and then upon a sensor trigger indicates activity in the room – the device performs a highly optimized fast wake up, reconnection and transmission of visual data to the cloud. This low-power technology enables extended battery life of the product for a better overall consumer experience.

5.Where do you see your technology/solution going in the next five years?

With the advanced technology Blink already has in place, and the possibilities available in today’s fast-paced market, there is significant potential for our already one-of-a-kind system to continue to grow. As wire-free design is one of our primary differentiators, we are highly aware of the demand for outdoor-compatibility, and this may very easily be what our consumers see in the next generation of Blink. Another highly-requested feature is smart-home integration, and with convenience to our users being one of our top priorities, this is certainly a feature we are excited about implementing in the future.

For more information visit:

• SimpleLink Wi-Fi CC3100 wireless network processor
• Blink Home Monitoring

It’s day one of the International Consumer Electronics Show (CES) in Las Vegas, and we’re at the TI Village technology area surrounded by more than 100 product demos showcasing the next generation of innovation in automotive, IoT, smart homes, personal electronics and more.

You could easily spend hours taking it all in; but if you’re at the show, and you’ve only got 30 minutes – or if you are living vicariously through our online coverage – here are five things in the TI Village you really don’t want to miss (hint: think amazing ultra-high definition for your home theater, next-generation intelligence for your car and real-time, remote health monitoring, to name a few).

1) DLP® 4K UHD solution

Why you should see it

You have to see it to believe it. From home theater to the boardroom to the classroom, our new 4K UHD chip is going to rock your viewing world. The DLP® 4K UHD solution uses the fast speed of the chip with advanced image processing to deliver more than 8 million pixels to the screen using 4 million tiny mirrors. Each mirror is capable of switching over 9,000 times per second, creating two distinct and unique pixels on the screen during every frame to deliver full 4K UHD resolution. The chipset offers customers access to an affordable 4K solution for large screen projection displays.

Where you can find it in the TI Village

TI Village – ECD Theater space

How you can experience it online

Get more information about our 4K UHD chip here in our Enlightened blog post.

2)     EvoCar

Why you should see it

Consumers want the car of the future, now. As they call for a quicker evolution of the in-vehicle experience, the automotive cockpit is in the midst of an overhaul to modernize information, entertainment and safety options available to drivers and passengers.

The Evolution Car – or “EvoCar” – showcases the breadth of our automotive portfolio, demonstrating technologies that enable automotive manufacturers to make the driving experience more enjoyable and informative than ever.

EvoCar features the following TI technology: DLP® chipset for head-up display (HUD), advanced driver assistance systems (ADAS), infotainment, haptics and audio.

Where you can find it in the TI Village

N115 behind the front desk and automotive technology area.

How you can experience it online

Hop into the front seat with us! Watch our Periscope video live at 9:30 a.m. PST on Thursday, Jan. 7. We’ll walk step-by-step through key technologies featured in the EvoCar. If you miss the Periscope video (only available for 24 hours), check it out on YouTube.

For more information about EvoCar, check out our blog post on Behind the Wheel.

3)     Real-time, remote health monitoring with DynoSense

Why you should see it

Forget visiting the doctor to monitor your vital signs. DynoSense is a cloud-based, real-time health-scanning system that utilizes 12 integrated sensors to seamlessly capture and analyze 50+ different health metrics and upload the data. It can integrate with weight scales, activity trackers and medication schedules. DynoSense also sets individualized health parameter alerts and enables communication with family, care-providers, trainers, pharmacists and physicians.

Where you can find it in the TI Village

Enter the TI Village and take a right past the welcome desk to the Wearables area.

How you can experience it online

Watch for the live Periscope broadcast today and find it later on TI’s YouTube channel.

4)     Wireless charging

Why you should see it

See how personal electronics and industrial and medical systems can be wirelessly charged from a small, 5-W Qi-compliant wireless power transmitter. The demo features the recently released bq500511 power management and bq50002 analog front end chipset.

Where you can find it in the TI Village

Power Island near the Wearables section. Take a hard right after you enter the TI Village.

How you can experience it online

Get charged up with us! Tune into Periscope on Thursday, Jan. 7 at 11 a.m. PST to catch this demo live. If you miss the Periscope video (only available for 24 hours), check it out on YouTube.

Also, read our blog post on Fully Charged: Your secret weapon to integrated 5W wireless charging, or start designing with the wireless power transmitter reference design.

5)     Our Real-Time News Center

Why you should see it

Stay informed on the latest announcements, trends and happenings at CES through our real-time news center. Our multi-screen display shows you what types of technology are most talked about at the show, what some of the most influential leaders in tech are seeing at the show and all the announcements at CES throughout the day.

Where you can find it in the TI Village

Enter TI Village and take a right.

How you can experience it online

Get all the live updates from our real-time news center on our CES microsite here.

Want to stay connected during the entire show? You can also follow our coverage of #CES2016 on Twitter, Facebook and LinkedIn.

Recent projections from a research firm[1] indicate 2015 will likely be a record year with 25 percent growth for solar installations; and the amount of energy capacity generated from solar will grow to 50 GW worldwide compared to 40 GW in 2014. One of the key end equipments in each of these solar energy harvesters is a solar inverter. A solar inverter, or any kind of inverter for that matter, will take a direct current (DC) input and convert it to an alternating current (AC) output that can be used to power standard appliances and electronics in a home or business. While just about any high power DC source can be used, the largest sector of inverter growth is in renewables, particularly solar energy.

When installed in a home or business, the solar inverter can connect to the electricity grid to offset consumption, or in some cases even provide energy back to the utility. To do this, it must be able to synchronize its AC output with the grid voltage and comply with certain safety requirements such as shutting off the AC output when the grid voltage disappears. We wouldn’t want to be energizing the grid when workers are trying to repair high voltage lines after a big storm.

Traditionally, a series of solar panels are connected to a string inverter. These inverters take approximately 600V DC (in case of residential string) input, which equates to a few kilowatts of solar capacity. An inverter for a solar farm will need to be sized appropriately, but centralizes (central inverter) the conversion and makes the overall solar harvester system cheaper to install when designed correctly. Another topology is a solar micro-inverter that is sized to match a single panel, or about 200 W to 300 W. By distributing the inversion process, the solar array can accommodate much more complex rooftops and enable smaller arrays to be installed that wouldn’t typically reach the input voltages of the string inverter.

At the core of each of these different types of solar inverters are a few core sub-systems:

Digital controller

A typical solar inverter consists of a full bridge for the DC-AC which connects to the grid and a DC-DC stage which connects to the panel to boost the voltage for the inverter to be able to feed power into the grid. The goal of solar inverters is to extract the maximum power from the panel and feed clean power into the grid. To ensure this the power stage voltages and currents must be accurately sampled, and pulse width modulation (PWM) for the power switches in the DC-AC and DC-DC accurately generated. A digital controller can be more efficient by sensing line load changes faster, have greater power density due to higher operating frequencies and offer up some additional features for system level integration since we have a full central processor unit core to work with.

Isolation

Overcoming voltage limitations is a huge problem in any power electronics design. In order to sense and control these voltages, we use capacitive isolation devices. These devices allow high frequency signals to cross power boundaries, but block the high voltage DC. This isolation technology has a long life expectancy and low electro-magnetic emissions, making it well suited for industrial applications.  In the inverters, we also use isolated power supplies so that we can power the electronics on the other side of the isolation boundary effectively and high voltage MOSFETs and IGBTs to control the power paths.

Gate drivers

For the power path control, we use MOSFETs and IGBTs. These devices are designed to be able to switch very high voltages and currents, which makes them a great fit in the digital buck converters in an inverter. The real key with using these devices is driving them properly. The input acts as a capacitor that must be charged and discharged each time the FET is switched. When switching these devices at the high speeds required by the inverter, several amps can be required to properly drive them. If they aren’t switched fast enough, the conversion stage can suffer huge efficiency losses. To do this properly, dedicated drivers are used, which translate the digital PWM from the controller to the current required by the FET.

One of the upcoming trends is the ability to monitor and control energy production statistics of residential/commercial solar installations. Adding low-power wireless connectivity standards like ZigBee®, 6LowPAN or wired communication such as power line communication (PLC) is becoming a common place in solar harvester systems. Once connected to a backhaul network, getting the data onto the cloud for the user to view anywhere is just a step away. Additionally, the communications systems can be used to monitor the system and alert the owner of any potential upcoming maintenance

Several new TI Designs reference designs help engineers accelerate time to market for solar inverter designs. Be sure to check out Solar Inverter page for solar inverter system solutions. Also, check out our new “Systems Made Simple” training series for a deeper systems discussion on building your next solar inverter. 

Additional resources:

• Watch our Systems Made Simple video series.
• Visit our Solar String Inverters page for more information.
• See our Solar Micro Inverters block diagram.
• Check out these TI Design reference designs:
  • C2000™ Solar DC/AC Single Phase Inverter
  • C2000™ Solar DC/DC Converter with Maximum Power Point Tracking (MPPT)
  • Grid-tied Solar Micro Inverter with MPPT
  • Single-Phase Inverter with Voltage Source and Grid Connected Mode

Guest blog by Matt Johnson, CTO, Bluvision

The expectations of Real-Time Locating Systems (RTLS) have been on the rise in recent years. The driving factor for growth has been the promise of precise asset tracking. However, most RTLS solutions aren’t equipped to scale, at least not without significant investment and cost of ownership. Bluvision, a complete Internet of Things (IoT) ecosystem provider, has managed to solve the challenge of scalability without compromising on accuracy, revolutionizing RTLS.

A RTLS solution that scales

Bluvision’s RTLS solution uses Bluetooth® low energy and Wi-Fi® technology along with sophisticated algorithms in the cloud to enable tracking and monitoring of assets. The combination of Bluzone – our cloud solution – and our Bluetooth-to-Wi-Fi gateway called “BluFi,” gives our customers the ability to track and monitor assets (equipment or people) without the need for a smartphone applications or expensive hardware.  In minutes, you can quickly install and connect our BluFi gateways to our IoT Cloud and start your RTLS project.  Our “install and go” solution gives enterprises the ability to quickly manage thousands of devices/assets and gain visibility into their precise location, at scale. Capabilities like REST APIs, cutting-edge sensors and hardware, cloud-based location policies, drawing small to complex geofences, and handling big data, gives Bluvision the ability to handle complex and fluid RTLS environments like airports, manufacturing facilities, etc.

Example of the Bluvision RTLS demo

Accuracy under three feet

The fact that Bluvision is using Bluetooth Smart sensors, Bluetooth to Wi-Fi gateways and the cloud means that we are able to provide high accuracy – down to under three feet with minimal footprint, even in harsh RF conditions. Using TI’s leading SimpleLink™ Bluetooth Smart CC2640 wireless microcontroller (MCU), enables us to provide superior accuracy at a fraction of the cost compared to competing technologies like RFID and GPS. This apart, RFID and GPS also come with a high cost of ownership and serious infrastructure costs. Our solution uses minimum hardware that is fast and easy to implement.

Making sense of complex data

The advanced algorithms that we use are capable of converting complicated configurations into human readable format. Bluzone has various RTLS components built into it that promises unprecedented accuracy and range. One of the key features of the solution is the ability to create unique geofences with ease. Enterprises can not just monitor when an asset enters the geofences, but are also capable of recording history of movement of these assets that enable predictive analysis.

With new wireless technologies, the scope and reach of RTLS promises to grow. We aim to continue to redefine how technology can be used for indoor location. To see a live demo of our RTLS solution, stop by the TI Village (#N115-N118) at CES 2016.

For more information about TI at CES 2016 visit www.ti.com/ces2016

Are you at the International Consumer Electronic Show (CES) in Las Vegas? Make sure you stop by the TI Village (#N115-N118) for a first-hand experience of our numerous demos. Learn how we have created the world's lowest power capacitive touch solution, and how we are using energy harvesting to change the way you energize sensor networks from ambient power sources.

Not able to make it to Las Vegas? Here is a quick synopsis of the MSP demos being shown:

MSP430™ MCU with CapTIvate™ technology

(Please visit the site to view this video)

MSP MCUs with CapTIvate technology are the world's lowest-power capacitive touch microcontroller, and the most noise immune. These FRAM-based MCUs are glove friendly, can reject moisture and offer support for metal touch.

Energy Harvesting Watering System Utilizing MSP430FR5949, bq25570 and DRV8838

(Please visit the site to view this video)

Automated systems are becoming common. Providing line-power to thousands of sensors in these systems can be challenging, to say the least. One solution is to use energy harvesting to energize sensor networks from ambient power sources.

In my last post, I provided an introduction to body-diode reverse recovery. Now we will take a look at a method for measuring reverse recovery in an actual circuit.

Measuring reverse recovery in a synchronous buck converter is a challenge. Current probes are fairly large and would add significant inductance to the power-stage loop. The bandwidth of current probes is also inadequate.

How about a shunt resistor? That sounds promising, but you’ll need to make sure that it doesn’t introduce significant loop inductance. I found a few that are 10mΩ and “low inductance.”

I’m tempted to put this in the source of the synchronous FET, but there are two problems:

• The shunt may see the gate-drive current as well as the recovery and load current.
• The shunt will add inductance that may affect the lower gate drive due to the high di/dt currents.

One solution is to put the shunt resistor in the drain of the upper MOSFET so that there is no chance of it interfering with the gate drives. The Vishay VCS1625/Y08500R01000F9R worked – it is built with Kelvin connections and constructed to reduce inductance. See Figure 1.

Figure 1: Shunt resistor (from Vishay)

Silicon MOSFET recovery measurement

To get a baseline Qrr measurement with a silicon MOSFET bridge, I got out a cutting knife, cut an island for the shunt resistor on the TPS40170EVM-597, and placed the shunt resistor. I used a 50Ω SMA-to-BNC cable to run the signal to the scope (terminated with 50Ω). I placed a 50Ω resistor in series so I get one-half the signal, but no ringing. Be sure to use skew adjustments when mixing probe types!

Note that with the shunt in the top, the scope is grounded to the positive input rail. This means that the power-supply positive output is grounded (negative supply to the buck converter) and any other test equipment like load banks must not short out the supplies through the scope connections. Figure 2 shows the modified evaluation module (EVM) schematic.

Figure 2: Modified silicon bridge for reverse-recovery measurements

 Figure 3 shows the TPS40170 EVM after inserting the shunt.

Figure 3: EVM probing technique

Figure 4 shows the switch-node and shunt waveforms at 300kHz, 24V_IN, 5V_OUT and 4A_OUT.

Figure 4: Silicon bridge-switching waveforms

In Figure 4, yellow is the software node and purple is the top FET drain current. The average of the current “triangle” waveform matches well with the 4A load -> 20mV = 4A.

In Figure 5, the highlighted reverse-recovery charge for the TPS40170/silicon MOSFET is shown in red (using the CSD185363A). The peak recovery current is ~ 18A (90mV) and I estimate Qrr ~ <100nC for a loss of 24V*300KHz*100nC = <720mW. Note that some of the current in the “red zone” goes to the load after the switch node rises, so my estimate may be a little high for Qrr.

Figure 5: Silicon bridge reverse recovery

Think about that! An 18A, 12ns-wide current pulse is being drawn from the input supply every 3.33µs. The high –di/dt will cause voltages to develop in any loop inductance in the power stage and possibly cause operational problems. Fortunately, the TPS40170EVM-597 has a very good layout to mitigate problems – it’s not always that way in practice.

Enter GaN – where is the recovery?

I used the same technique to measure the LMG5200 GaN (Gallium Nitride) EVM. I first grabbed a reference scope shot of the switch-node voltage of the LMG5200EVM while it drove 24V -> 5V at a 4A load. I used an Agilent 33220A to drive a fixed ~21% duty cycle at 300kHz to the LMG5200 PWM input. See Figure 6 – Channel 1 shows the switch-node waveform.

Figure 6: LMG5200 GaN switching waveforms

 I included the high/low drive signals for reference (Channels 3 & 4). The “body diode” conduction has a higher drop than the MOSFET counterpart – I see ~2.5V during this time instead of ~0.6V. I grabbed this scope shot because I’m going to add a resistor/inductance to the input loop that will cause a bit more ringing.

Figure 7 shows the change when I added the shunt resistor in the drain of the upper GaN device.

Figure 7: GaN switching-waveform probe technique

Note that I had to implement a level-shift circuit (simple PNP and resistor) to level shift the 300kHz 21% duty-function generator signal from “ground” (which is now the positive side of the 24V supply) to the PWM input at -24V. Without that, I’d have a ground contention (otherwise known as a blown fuse) when putting the scope sensing on the positive rail. Figure 8 shows the switch node (yellow) and top GaN current (purple).

Figure 8: LMG5200 GaN switching waveforms with shunt inserted

 Zooming in on Figure 9, the recovery current has disappeared (no red area). There is a little additional ringing due to the added inductance from the sense resistor, but no recovery losses or associated complications. You’ll still see switching and switch-node capacitance losses, but GaN does not show the reverse recovery that causes issues in silicon MOSFET-based converters – a welcome relief!

Figure 9: GaN Qrr measurements

Additional Resources:

• Get to know the user-friendly interface of the LMG5200
• Learn to use the LMG5200 with the GaN Half-Bridge Power Stage EVM User’s Guide
• Explore more GaN blogs

Picture yourself driving the car of the future: You take your place in the driver’s seat. You connect your phone, pull up the map to your destination and cue your music using a touchscreen control panel with colorful 3-D graphics that can be customized to your preferences at the swipe of your finger and sound of your voice. This integrated infotainment console leverages the “Jacinto” DRAx family of infotainment processors.

As you shift into reverse, your head never turns. Your eyes remain fixed on the windshield, where you see a crisp, colorful display providing a bird’s-eye view of the car – including both side mirror views and real-time pedestrian and object detection. This augmented reality experience – made possible by our advanced driver assistance system (ADAS) using the TDA family of ADAS processors– conveys critical information in real-time through a head-up display (HUD), powered by our DLP® chipset.

Ready to go, you shift into drive. Traffic is stopped up ahead, so you signal a lane change and begin to steer to the right.

Buzz! The steering wheel and the right side of your seat vibrate, alerting you to an obstacle on the right-hand side of the road. You also see a warning in the windshield display. You are experiencing haptics technology – providing tactile feedback to alert you of potential driving hazards – and driver alerts through the HUD. You slow down and stay in your lane, confident in the state-of-the-art technology that is helping create a safer driving experience.

As you continue to your destination, you effortlessly adjust your music playlist from the 3-D infotainment console in the center of your car. Meanwhile, your passengers are continually entertained. Right before their eyes in the passenger windshield is another display, a passenger HUD, powered by DLP® Products technology. The visual experience provides front-seat passenger infotainment in the form of movies, web browsing, books and more – all without distracting you from your very important job at the wheel.

Driving can be monotonous, and it’s easy to feel comfortable in this car of the future. But if you begin to feel sleepy, the ADAS system right before your eyes is monitoring your face, analyzing your head motion while two dots follow each eye to gauge activity level and potential sleepiness. When your eyelids droop slightly and your head bobs, the haptics-enabled steering wheel and seat vibrate while the HUD could provide immediate visual alerts, prompting your full attention to the road.

From driver monitoring to passenger entertainment – complete with hazard warnings, advanced information delivery, effortless infotainment and overall comfort – you’ve just experienced EvoCar. This featured product demo is on display this week in the TI Village at the International Consumer Electronics Show in Las Vegas.

For an even more lifelike experience, check out our Periscope video tour of EvoCar on Friday, Jan. 8 or watch it on YouTube.

Applications engineers tend to overlook printed circuit board (PCB) layout during circuit design. It is often the case that a circuit’s schematic is correct, but does not work, or perhaps works with reduced performance. In this post, I will show you how to properly lay out an operational amplifier (op amp) circuit PCB to ensure functionality, performance, and robustness.

An intern and I were recently working on a design together using the OPA191 op amp in a noninverting configuration with a gain of 2V/V, a 10kΩ load, and a supply voltage of +/-15V. Figure 1 shows the design schematic.

Figure 1: Schematic of the OPA191 in a noninverted configuration

I tasked the intern with laying out the PCB for this design. I gave him some general guidelines for laying out PCBs – keep traces as short as possible and keep components close together to minimize board space – and sent him on his way. How hard could it be? It’s just a few resistors and a couple of capacitors, right? Figure 2 shows the first attempt at the layout. The red lines are traces routed on the top layer and the blue lines are traces routed on the bottom layer.

Figure 2: First layout attempt

That’s when I realized that PCB layout isn’t as intuitive as I thought; I should have been a little bit more detailed with the guidelines. He did everything I recommended, keeping the traces relatively short and the components close together. The layout could be improved, however, to reduce PCB parasitic impedances and optimize performance.

The first improvement we made is moving R1 and R2 next to the inverting pin (pin 2) of the OPA191; this will help reduce stray capacitance on the inverting pin. The inverting pin of an op amp is a high-impedance node and is therefore “sensitive.” Long traces can act as antennas, which allow high-frequency noise to couple into the signal chain. PCB capacitance on the inverting pin can cause stability issues. Therefore, the connections on the inverting pin should be kept as small as possible.

Moving R1 and R2 next to pin 2 allows R3, the load resistor, to rotate 180 degrees, which then allows the decoupling capacitor, C1, to move even closer to the positive supply pin (pin 7) of the OPA191. It is extremely important to place decoupling capacitors as close to the supply pins as possible. Having long traces between the decoupling capacitor and the supply pin adds inductance on the supply pin, which can degrade performance.

Another improvement we made concerns the second decoupling capacitor, C2. The via connecting –VCC and C2 should never be put between the capacitor and the supply pin; it should be in a place where the supply voltage must pass through the capacitor before entering the supply pin of the device.

Figure 3 shows how to move each component and via to improve the layout.

Figure 3: Location of components for improved layout

Even after moving the components to new locations, it’s still possible to make additional improvements. You could make the traces as wide as possible to reduce the inductance of the trace – about the size of the pad to which the trace will connect. Another is to pour a ground plane on the top and bottom layer. This will create a solid, low-impedance path for return currents.

Figure 4 shows our final layout.

Figure 4: Final layout

The next time you are laying out a PCB, make sure to follow all of these layout practices:

• Make the connections to the inverting pin as short as possible.
• Place decoupling capacitors as close to the supply pins as possible.
• If using multiple decoupling capacitors, place the smallest decoupling capacitor closest to the supply pin.
• Do not place vias between decoupling capacitors and supply pins.
• Make traces as wide as possible.
• Do not route traces with 90-degree angles.
• Pour at least one solid ground plane.
• Do not sacrifice good layout to label a component with silkscreen.

Additional resources

• Learn more about stability in our TI Precision Labs – Op Amps training series on stability.
• Read about issues related to decoupling capacitors in amplifier expert Art Kay’s blog, “The decoupling capacitor … is it really necessary?”
• Find commonly used analog design formulas in our wildly popular and free Analog Engineer’s Pocket Reference e-book (myTI login required).
• Read more blogs about precision amplifiers.

Power over Ethernet (PoE) offers a convenient approach to deliver electrical power through Ethernet cables, eliminating the need for other external power sources and separate power cabling for equipment connected in an Ethernet network.

One limitation of the current IEEE802.3at standard is that the powered device (PoE PD) is not allowed to consume more than 25.5W. Another is that power can be delivered only over two pairs, which results in cable loss and low overall system efficiency. As a result, many applications have so far been out of reach for PoE, including the lighting market.

However, once released, the IEEE802.3bt standard will be able to fix these shortcomings, while adding many more features that will enable the use of PoE for LED lighting applications.

Let’s first review why you should consider PoE for LED lighting applications:

• Lowinstallation costs. At less than 60V, you may not need a licensed electrician.
• Easy plug and play. Because the light automatically turns on when the fixture is connected through a network cable, there’s no need to turn off breakers before installation, and you can check cabling/interconnections immediately.
• Flexibility. Easily install and relocate network lighting devices.
• Connected lighting. Each lighting fixture has an IP address, with intelligent lighting control capability. This enables the use of various sensors (occupancy, light detection) in each fixture.
• Achievable low standby power.
• The fixture’s electronic ballast is small. The ballast operates from centralized driver, which is the power sourcing equipment (PSE), providing isolated low voltage. This enables the use of a simple buck topology in the ballast.

What PoE luminaires will be most common? Troffers, downlights and many others.

Now, let me give you some details on the IEEE802.3bt standard. As an active member of this committee, I can give you a short summary of the major changes from the current standard that will directly impact PoE lighting.

A first change concerns the maximum power that the load can consume. To address this, the committee created two new types, type 3 and type 4, to allow the PSE to source up to 60W and 90W (52V-57V), respectively. Combining these new types with power delivery over four pairs will result in even more power available at the PD end of the cable.The committee is also introducing a new concept called “extended power.”

What is it exactly and why is it useful?  An issue with the current standard is that the allocated PD input power is based on a worst-case maximum cable length, which is 100 meters. See figure 1 below. The extended power concept solves this by allowing the PD to go beyond this limit, as long as it does not cause the PSE to source more than it allocated. This implies that the PD “knows” the cable resistance. System architectures where the Ethernet cables are very short can take advantage of this feature.

Figure 1: Long cable vs. short cable: efficiency comparison

A second change to the standard is about the standby power, which is related to the power signature that a PD must generate in order to maintain the PSE power. The maintain power signature (MPS) consists of a specific DC current amplitude, time duration and duty cycle. The big change with the next standard is about reducing the time duration and duty cycle considerably, which will dramatically reduce the average standby power, while the lights are off and data communication remains active. See figure 2.

Figure 2: Maintain Power Signature

A third change to the standard is about ensuring that lighting remains operational (or can quickly turn back on) independent of data communication. This results in more reliable operation. To achieve this, the committee has defined a new requirement for type 3 and type 4 PSEs to support the physical layer classification for any power level the PSE can support.

Fourth, the Autoclass feature will allow better power optimization by the PSE. Basically, it allows the PSE to set the power budget to the maximum PoE PD power through a power measurement, including the cable losses.

I’m seeking feedback from lighting industry leaders, system integrators, LED ballast manufacturers and potential PSE lighting switch manufacturers (endspan and midspans).

What do you think? Do any of the new features mentioned above pique your interest and why? Please comment below to share your thoughts.

Additional resources about:

• Tool download: PoE PD Efficiency Calculator tool
• System block diagram: Power-over-Ethernet (PoE)
• Power products: PoE Powered device (PD) products and PoE Power sourcing equipment (PSE) products

Dorothy said it in the Wizard of Oz: there truly is no place like home. And we’d like our homes to be as smart as they are sweet.

Here in Las Vegas, it’s day three of the International Consumer Electronics Show. We’d like to show you some of the hottest smart home technology on display in the TI Village – tools designed to help take some of the heavy lifting out of everyday home maintenance – and bring back some of the simple joys of home ownership.

Home security is paramount. The Blink smart home monitoring system, enabled by the SimpleLink™ Wi-Fi®CC3100 wireless network processor, allows you to easily monitor your home with wireless cameras throughout the house.

Control access to your garage from inside your house or from miles away with the Wi-Fi-equipped Genie Aladdin Connect™ smart garage door controller, enabled by the low‐power SimpleLink Wi‐Fi CC3200 wireless microcontroller (MCU). This smart device also instantly lets you know when someone is operating your garage door, and whether that person is an authorized user or not. Anyone who downloads the Aladdin Connect app on their smartphone can be invited by you to access your garage. This enables you to empower others to gain entry to your garage, and you can delete access soon after. Or you can open it remotely for deliveries or guests – from your couch or while you’re at work.

Tired of mowing your lawn? Cue the robotic lawn mower. Who needs an expensive weekly lawn subscription when you have a Husqvarna robotic lawnmower? This autonomous mower grooms your lawn without you ever stepping foot outside. As you might imagine, battery life and management is key to operation. The Husqvarna Automower® 450X lawnmower uses a variety of our analog products, including battery management with the bq77908A and the LM25011 wide vin, non-synchronous buck regulator with adjustable current limit.

Be alerted to fires or carbon monoxide in your home with a low-power, cloud-connected fire alarm – FirstAlert OneLink. You can test FirstAlert OneLink and silence alarms from the app on your phone – at home or away. This product isbased on our SimpleLink Bluetooth® Smart CC2640 wireless MCU.

Who needs keys? The Schlage Sense™ Smart Deadbolt allows you to enter your home remotely by utilizing your iOS smartphone and a few home kit apps. You can assign user-specific codes for different people, and they can unlock your door using smart locks and numeric keypads. You can also set parameters for when each code can work to let dog walkers or handymen inside your home. Paramount to the Schlage Sense is the ability to order Siri to lock and unlock your doors, no matter where you are in your house. And she’ll do so without missing a beat. Knowing beauty is as important as brains, Schlage Sense Smart Deadbolt is available in a variety of finishes and is easy to use. It is enabled by the SimpleLink Bluetooth Smart CC2640 wireless MCU.

Remotely adjust the temperature of your home. Manual thermostat control is a thing of the past. The Venstar is a low-power, Internet-connected, monitored and controlled thermostat with the MSP430™ microcontroller and SimpleLink Wi-Fi C3100 wireless network processor.

Never miss a moment of your favorite song regardless of what room you’re in with multi-room audio speaker synchronization. The WiLink™ 8 audio multi-room cape reference design extends the standard TI Sitara™ processor-based BeagleBone Black with Wi-Fi and Bluetooth combo connectivity from our WiLink 8 module.

Learn more about our smart home tech and other demos at the show on our CES homepage.

This blog was authored by Guy Cohen, Director of Electronics Engineering, simplehuman

One of simplehuman’s philosophies is that if we can make a product better and more efficient, then we do. When we looked around for a well-designed, well-lit vanity mirror, we realized that there was nothing adequate available in the existing beauty market, so we decided to design our own. We added a few of our signature touches including sensor activation and upgrading the light quality, among other improvements. Now, with the introduction of our wide-view sensor mirror, we’ve added another enhancement – Wi-Fi® connectivity.

1. What is the simplehuman wide-view sensor mirror? 

The simplehuman wide-view sensor mirror is a lighted vanity mirror that has adjustable side panels, enabling users to view themselves from any angle.  It has LED light strips that automatically illuminate as your face approaches with a tru-lux light system that simulates natural sunlight – which is proven to be the best kind of lighting to view makeup in.  This way, the user can make sure their makeup is color-correct as well as applied evenly.

The mirror is also app-enabled – the first of its kind. Through the companion simplehuman app, users can adjust the lighting on the mirror with a variety of preset light settings or capture ambient light from different locations to recreate the same color temperature and intensity on your mirror. This allows the user to get a preview of their makeup in less than ideal light settings and therefore be able to make adjustments before going out in that light.

2. What makes the wide-view sensor mirror stand out from its competitors?

The wide-view sensor mirror is truly the first “smart mirror” designed with useful Wi-Fi-connected features that enhance the product. There is no other mirror like it on the market. The tru-lux light that we developed for our entire line of sensor mirrors has 600 lux and 90 CRI (color-rendering index), more than twice that of our competitors’, and is as close natural sunlight as you can get. It’s a better, brighter, clearer light. But, if you wish to adjust the lighting to your liking or view yourself under less than ideal light settings, you can do that as well. Users can take a photo through the app, which grabs relevant information, such as light brightness or color temperature, and transfers data through our cloud-based server to reflect the same light onto the mirror. The optics design of the mirror ensures that light will illuminate evenly across the mirror so there’s no light loss or hot spots.

3. There are many wireless connectivity technologies on the market. Why did you choose to integrate Wi-Fi in the wide-view sensor mirror?

We wanted to give the user more control over the way they could use a vanity mirror. Offering one kind of light can be limiting, especially if you want to see how you might look in less than ideal lighting situations. Connecting them through the app and Wi-Fi gives the user this flexibility in a seamless, user-friendly way – and it’s easy to control from almost anywhere in the world. Wi-Fi also allowed us to maintain our product clean button-less aesthetic while giving the user total control.

We chose to implement the SimpleLink™ Wi-Fi CC3200 wireless MCU in the wide-view sensor mirror due to its superiority as a single-chip solution.  The CC3200 device provided us with the optimal balance between performance, development time and cost while maintaining a small footprint. Compared to other Wi-Fi processors we evaluated, we immediately saw that the CC3200’s SDK is very well documented and included a lot of different examples and protocol libraries which would help expediting the evaluation and development time significantly. All this made the decision to move forward with the CC3200 very easy.

4. Where do you see your technology/solution going in the next five years?

As a fast-forward company, simplehuman is continuously working on creating new innovative connected products while still meeting the high standards our consumers have come to expect. We’re always conscious of making sure we design products with enhanced features that make sense and add value, not just for the sake of innovation. We also see our connected products in the future as being able to talk to each other in order to enhance the consumer’s overall experience.

For more information, visit:

• TI’s SimpleLink Wi-Fi solution
  • SimpleLink Wi-Fi CC3200 wireless MCU
• simplehuman wide-view sensor mirror
  • • http://www.simplehuman.com/wide-view-sensor-mirror

In the not-too-distant future – some believe as early as 2030 – a manned spacecraft will blast off from Earth. The spacecraft will be designed to travel to deep space, traveling further than any other. Its destination: the red planet, after a demanding 200-million-mile journey lasting nearly six months.

But just what will Mars be like? It will be impossible to answer that question until humans actually get there. Mars is an extreme planet; the average atmospheric temperature is 210K, while on Earth it’s 288K. That may not seem like a big difference, but converted to the Fahrenheit scale, that’s 59^oF on Earth and -81^o F on Mars.

Mars also does not have an ozone layer like Earth, and this will present a formidable challenge. No ozone layer means that astronauts will be exposed to deadly radiation from space if they are not protected. Plus, air on Mars is mostly carbon dioxide – the very compound that our bodies find toxic and work hard to eliminate each and every day. In practical terms, the rupture of personal protective equipment like a spacesuit would spell disaster for the wearer in approximately 15 seconds.

Mars also has crazy weather patterns (dust storms are common), extreme temperature differences between day and night, arid conditions, rocky terrain, deep canyons, tall volcanoes, and no apparent surface life-forms.

So how will the astronauts survive? First, transporting them safely there and back will be paramount. As depicted in the motion picture “The Martian,” the astronauts will likely set up habitats, or “habs” for short – protected ecological or environmental areas where they can live and work safely. In order to colonize Mars, they will need to grow their food, build medical clinics, construct data and communication centers, make oxygen and water, and build factories for spare parts; after all, the next delivery from Earth may be 200 Mars days away (more than 300 earth days). They will need to innovate.

But what will power this innovation? A continuous source of energy. Although sunlight on Mars is not the same as sunlight on Earth (actually, the solar irradiance on Mars is about half as much as that on Earth), high-efficiency solar panels could provide this source of energy. But solar energy alone may not be sufficient to run large habitats 24/7/669, the length of a Martian year.

Fortunately, the crazy weather on Mars is ideal for harvesting lots of energy. Wind is a significant weather pattern on Mars and can provide an abundant supply of energy. The extreme temperature gradients can also be a plentiful source of power for thermoelectric harvesting.

TI has breakthrough technology that allows today’s real-world systems to extract and manage power from a variety of sources: solar, thermoelectric, electromagnetic and vibration. From solar (ambient light)-powered sensors for monitoring factories or agricultural farms wirelessly, to body heat-powered sensors for medical and fitness-tracking sensors, you can use TI energy-harvesting solutions to create complete sensing ecosystems that are either self-powered or designed to supplement battery power. Figure 1 shows a simplified block diagram of an energy-harvesting sensor.

Figure 1: Simplified block diagram of an energy-harvesting sensor

The TI Design Energy Harvesting Ambient Light and Environment Sensor Node for Sub-1GHz Networks Reference Design is an ambient light-powered environment sensor node that you can use to create a system that monitors ambient light to precisely control a building’s lighting system, for example. It can also be used to collect remote temperature and humidity measurements in inaccessible areas of a building.

TI Designs reference design, the Energy Harvester BoosterPack (Figure 2) is especially suitable for creating an energy harvesting-based automated farm-irrigation management system – just like what “The Martian’s fictional astronaut and biologist Mark Watney could have used to conserve water for his potato farm. TI will have an example of such a system on display in its booth (#N115-N118) at the 2016 Consumer Electronics Show.

Figure 2: Energy Harvester BoosterPack Reference Design board (TIDA-00588)

Few will argue that interplanetary expeditions are simple. No one knows what failure rates will be experienced. The hope is that the exploration of Mars will meet unbelievable success. But in the meanwhile, technology has emerged on earth that has made energy harvesting a reality. Today’s connected buildings. factories, cities, farms, and many other industries can benefit from this advancement in extracting free energy from the ambient.

Additional resources

• Check out these other TI Designs reference designs and start designing with energy harvesting today:
  • Solar Power Energy Harvester Reference Design Using a Super Cap.
  • Indoor Light Energy Harvesting Reference Design for Bluetooth® Low Energy (BLE) Beacon Subsystem.
  • Energy Harvesting LaunchPad BoosterPack for Brushed DC Motor Control Reference Design.

Surviving on Mars take brains, resources and technology, much like the technology that was discussed in today’s blog. Mark Watney masters the art of survival on Mars in The Martian. Take a firsthand look at his skills in the movie The Martian on digital HD today and Blu-ray^TM and DVD Jan. 12: http://www.foxdigitalhd.com/the-martian

Most electronics require an input supply from an AC power line. For voltage regulators, switch-mode power supplies and other downstream electronic components, a full- or half-bridge diode-rectifier device rectifies the sinusoidal AC voltage waveform and converts it to a DC voltage.

Using four diodes in a bridge-rectifier configuration is the simplest and most conventional way to rectify an AC voltage. Implementing diodes in a bridge rectifier provides a simple, cost-efficient and zero quiescent current solution for full-bridge rectifiers and automotive alternators.

But while diodes also generally have the fastest response to a negative voltage, they cause high power losses due to the positive-negative junction forward-voltage drop (Vf ~0.7V). These power losses cause thermal dissipation, requiring designers to implement thermal management, which adds cost to the system and increases solution size. Another disadvantage of diodes is a higher reverse-leakage current – as high as ~1mA.

Replacing lossy diodes with N-channel MOSFETs can lower power losses significantly by eliminating the forward-voltage drop of the diode-rectifier device. N-channel MOSFETs have small RDSON, and their associated voltage drops are minimal.

Table 1 compares the efficiency of a 5A (I_rms = 3.5A) diode rectifier with a 10mΩ MOSFET-based rectifier device.

Table 1: MOSFET vs. diode power losses comparison 

It’s clear that the power losses are incredibly smaller with MOSFETs, and designers can avoid using expansive and bulky heat sinks for thermal management. However, good things don’t come easy. N-channel MOSFETs need a gate drive to conduct from source to drain and also require fast shutdown when the AC sinusoidal becomes negative. Turning the MOSFET gate OFF during the negative cycle of sine wave is possible by combining the N-channel MOSFETs with four LM74670-Q1 smart diode-rectifier controllers. The LM74670-Q1 is designed to drive each N-channel MOSFET independently to emulate an ideal diode with no forward conduction losses. The LM74670-Q1 offers a true diode replacement with a floating topology and charge pump.

Figure 1 shows the LM74670-Q1 implemented in a full-wave bridge-rectifier design.

Figure 1: LM74670-Q1 smart-diode bridge-rectifier implementation

Operations

In this bridge rectifier approach, each diode is replaced with the LM74670-Q1 solution, which includes the integrated circuit MOSFET and a charge-pump capacitor. Each solution operates independently and responds to the AC input waveform like a diode. The LM74670-Q1 constantly senses the voltage across the MOSFET with anode and cathode pins, and based on the voltage polarity turns the MOSFET gate on and off. During the positive cycle of the AC waveform, MOSFETs M1 and M3 conduct as shown in Figure 2, whereas the gates for M2 and M4 are shut down by the corresponding LM74670-Q1.

Figure 2: Forward conduction during positive cycle of AC input

When the AC waveform becomes negative, the corresponding LM74670-Q1s for M1 and M3 react to the negative voltage within 2µs and shut down the gates for both MOSFETs. During this time the M2 and M4 MOSFETs turn on, as shown in Figure 3.

Figure 3: Forward conduction during negative cycle of AC input

The MOSFETs used in this application must have a gate to source voltage (VGS) threshold ≤ 3V and low gate capacitance. Other important electrical parameter is voltage across the MOSFET body diode which must be ~0.48V at low output currents. The Texas Instruments 60-V CSD18532KCS N-channel power MOSFET or other NexFET™ MOSFETs are most suitable for this application.

Figure 4 shows an oscilloscope plot for the LM74670-Q1-based smart-bridge rectifier with four CSD18532KCS MOSFETs. The rectifier is operated with a 12V 60Hz AC input to produce a rectified output for this example.  The VGS for MOSFET M1 shows how the LM74670-Q1 controls the forward conduction through the MOSFET and blocks the reverse voltage by shutting down the gate.

Figure 4: LM74670-Q1 smart-bridge rectified output

Figure 5 compares the thermal performance of the LM74670-Q1 smart-bridge rectifier configured with four CSD18532KCSN-channel MOSFETs (left) and a conventional low-forward-drop diode (Vf = 0.5V) rectifier (right). Both designs are operated at high current (10A) without thermal management and air flow. The temperature of each diode in a diode rectifier reaches ~71°C, whereas CSD18532KCS MOSFETs in the LM74670-Q1 rectifier are at ~31°C at the same operating conditions. 

Figure 5: Thermal performance comparison with a conventional diode rectifier

In summary, the LM74670-Q1-based smart-diode full-bridge rectifier design has these features and benefits:

• Improves system efficiency by ~10x.
• The MOSFETs do not require any thermal management for higher-current applications.
• The design reduces system cost and space on the printed circuit board.
• Supports higher frequencies up to 400Hz and an AC voltage level up to 45V,which makes it a suitable replacement in automotive alternator applications.

Additional Resources:

• Download  the “Novel, High Efficiency Full-Bridge Rectifier Reference Design.”  This TI Design features the LM74670-Q1 smart diode controller in a full bridge rectifier configuration and replaces the diodes with four N-channel MOSFETs.
• Consider TI’s LM74670-Q1 smart diode and CSD18532KCS N-channel power MOSFET for your next design.

Guest blog post by Gautam Banerjee, product manager of dweet.io

We were thrilled when the SimpleLink™ SensorTag team at Texas Instruments told us they wanted to add dweet.io support to their smartphone app. The SensorTag is one of the most robust, developer friendly Internet of Things (IoT) prototyping kits we’ve come across. And with dweet.io, prototyping with the SensorTag just became even easier.

What is dweet.io?

In a nutshell, dweet.io is like Twitter for machines. It’s a platform that enables “things” on the Internet of Things to publish their data to the cloud. In turn, other “things” or apps may subscribe to that data. As a developer, dweet is a common, RESTful api layer for all your connected hardware. You can then build, prototype and deploy your IoT apps in any platform. Essentially, you can focus more on solutions and user experience, and less on the IoT infrastructure. 

A quick tutorial

Let’s walk through getting your SensorTag data on dweet.io. The first thing need is the latest version of the SensorTag app. The app uses Bluetooth® Smart to connect your phone to your SensorTag kit and acts as an Internet gateway to send your data to the cloud (dweet). Make sure your SensorTag is on.

Launch the app.

Make sure Bluetooth is enabled on your phone. On the first screen you should see your SensorTag in the list of Bluetooth devices.

The SensorTag apps searches for Bluetooth Smart devices

Select your SensorTag and choose “Sensor View” from the pop up. This will give you a real-time view of your SensorTag sensor outputs. We want to send this data to the cloud. The default app cloud configuration is for IBM Bluemix, so we’ll have to edit that to dweet. Click on the cloud view cell to enter the configuration. Then click edit. Select dweet.io from the list of built-in cloud services.

Next, you’ll see that you’ve been given a thingname for dweet. A thingname on dweet is like a username on Twitter. It is just a way to uniquely identify your machine or device. Since we’re using dweet’s free service, all your data is publicly viewable. If you want to secure it, you can buy a lock. Also, your thingname is not protected — that is, anyone can write to it unless you lock it. So I recommend you change the default thingname you were assigned to something unique to you (I just used mysensortag). 

Now click save and go back to the sensor-view page. Make sure the push-to-cloud switch is on and you’re all set. You can see what it is dweeting in real time if you go to http://dweet.io/follow/your-thingname in any browser. Be sure to replace your-thingname with the name you set in the app. 

You can toggle between raw values and a visual view. As you can see, the dweet app is ‘dweeting’ SensorTag data like your accelerometer, speed, altitude, temperature, and orientation. In other words, the app is publishing your SensorTag’s data to dweet.io. Any other party may subscribe or follow your Thing’s datastream via dweet.io’s api (or simply typing the follow URL above if they know your thingname).

But wait, there’s more!

To help your development journey, Bug Labs also provides an open-sourced visualization web app called freeboard™. Freeboards are easily configurable dashboards that allow you to display a combination of thing and web accessible data in real time. Dashboards help you make better design decisions, observe and understand the things behavior, spot trends or identify issues quickly. Many of our customers use freeboard as their main end user application, such as vehicle fleet management (location, speed, heading), public swimming pool temperature and providing air quality information.

Getting started with freeboard

Freeboard is free to use unless you want to keep your dashboards private. Once you signup, click on “Create New” and give your first freeboard a name. A freeboard is comprised of three of things:

1. Widgets, which are different types of visualizations you may have
2. Panes, which are display panels that hold one or more widgets (eg speed & heading)
3. Datasources, which are data streams that feed into your dashboard to be visualized. Datasources can be physical things dweeting, or any Internet accessible API with JSON payloads. Freeboard supports several datasources by default, or you can add your own.

Step 1: Add a datasource

Once you’ve created a new dashboard, you will see a blank canvas and a configuration panel on top. Before we add panels to your dashboard, we must add at least one datasource. Click on “add” under datasources and select dweet.io as the type.

Select dweet.io as your datasource type

Now give this dweet datasource a name, like SensorTag. For thingname, you must use the name that the app is using for your SensorTag. In my case, it was mysensortag. Since we’re using the free tier of dweet, there is no value for key, so you can leave it blank.

Once you hit save, you’ll see the name of your datasource on the top panel. You’ll know that your datasource is alive if you see the time it was last updated. 

Our SensorTag is connected!

 Step 2: Adding Panels and Widgets

Now that you have at least one datasource, you can start adding panels and widgets. A panel is a container that you can drag around your dashboard for your preferred placement. Panels can hold one or more widgets, usually in logical groupings.

Click add pane to get started. You’ll see that a pane has an action bar on top. To add widgets to pane, click on the “+” and select your type. Our first widget will be a temperature gauge. 

Configuring your widget involves selecting the datasource (in our case, there’s only one), and then selecting which key-values in that datasource you want.

First, add your datasource to the first input field by clicking on “+ datasource”. Next, you can traverse the key-value pairs in your datasource via a dropdown. Select ambient temperature. Set your units to C. I put my max range to 50. 

And that’s it! You have your first widget.

Try repeating these steps for different types of widgets and datasource values. I did a text widget with a sparkline for the light sensor. I ended up with this simple dashboard in about 2 minutes. 

A simple freeboard for my SensorTag!

We are excited our tools are available for TI’s SimpleLink SensorTag. We believe dweet.io and freeboard can accelerate your product development because they’re so easy to use. If you have questions for TI or us, just tweet us at @dweet.io or @TXInstruments.  Happy prototyping!

Buy the SimpleLink SensorTag today!

“Wrestling a bull is easy. Try wrestling an electron.”

Wrestling electrons, as TIer Stephanie Butler puts it, is exactly what she’s been doing at our company for the last 31 years. Now a technology innovation architect in our high voltage power solutions business, Stephanie started as a co-op student at our wafer fabrication plant in Sherman, Texas.

At the time, female engineers in the semiconductor industry were few and far between. She holds a very distinct memory from that time:

A long department meeting had just ended, and everyone rushed to the bathroom. Stephanie walked toward the women’s restroom unimpeded, passing a long line of men “tap dancing” as they waited outside the completely full men’s restroom.

When she came out of the ladies’ room, she told her colleagues, “‘Hey guys, use the women’s restroom, I’m the only one here,’” she remembers. “And they all went running.”

Thirty-one years later, the engineering landscape has significantly evolved to include more women and people from all different backgrounds and ethnicities. Stephanie credits the world we live in today – equipped with semi-autonomous vehicles and energy efficient factories – to the diversity of thought that comes from having those unique voices finding creative solutions together.

Which brings us back to “wrestling electrons.”

“There are times when I face a bit of a mind block, and I don’t know how to make that electron do what I want,” she said. “Then there is someone with their mind on another planet, and they can do it. That person may not have been in the room three decades ago.”

While Stephanie believes having those people in a room together spurs innovation, her longtime friend and senior vice president of our analog business, Steve Anderson, believes Stephanie’s ability to connect people is what really enables her success. He’s encountered few people like Stephanie who can break down barriers and pull together a wide range of engineers to step into the ring with her and tackle a problem.

Steve remembers one particularly challenging power module project that involved TIers from a variety of teams across our company. There were significant challenges to make the module extremely small and efficient. Her ability to gather the experts from across the company and push them to success resulted in a differentiated, breakthrough innovation.

“She held the drive and ability to ‘herd the cats’ to make this thing happen,” Steve said. “But she also possesses the technical chops to understand the technology, break down silos and get answers. You can’t fool her.”

Some of her closest friends explain it in a different way.

“She is a pouncer,” said Cecelia Smith, vice president and general manager of the Mixed-Signal Automotive organization.

Like Steve has seen, Cecelia time and again watched as Stephanie tackled a problem by finding the right circle of knowledge to help her discover a solution and then brought out the best in them.

“She has the capability to reach throughout the whole company. She starts with her agenda, but it quickly turns into, ‘How can I help you?’ ‘Let me go find out more about this.’ And that is what it takes for our company to be better.”

Stephanie’s deep technical knowledge and ability to collaborate with others – who may have different ways of wrestling electrons – has resulted in a long and successful career at TI. It’s also why she was named one of the honorees for Dallas Business Journal’s 2015 North Texas Women in Technology Awards. But Cecelia points to one other important attribute that makes Stephanie so deserving– her willingness to take time out of her busy schedule to help other women in engineering succeed.

Both Cecelia and Stephanie are passionate about supporting other women in technology and ensuring that the next generation focuses on STEM (science, technology, engineering and math) studies. Stephanie attends countless STEM events and mentors and encourages colleagues to help them become the “pouncers” needed to deal with complex technological problems.

“She acts as a mirror, helping women in our company see their blind spots so they can become more self aware, while also deepening and strengthening their own personal and career development,” Cecelia said.

In the end, Stephanie is grateful for the evolving landscape of engineers in the semiconductor industry and looks forward to learning from others who have all different sorts of ways to wrestle electrons.

Q: What is the most impactful piece of feedback you got at TI?

A:  Influence management is critical to become a successful technical leader and contributor. In college, you are falsely led to believe that being the smartest and most skilled will result in your ideas being accepted, funded and implemented. I was rather shocked to discover otherwise.

Q: Looking back, what opportunities have helped you grow and develop the most at TI?

A:   From day one, TI has proven to be an environment where I can propose new ideas and be given the opportunity to make them happen. For example, I proposed turning a summer offer into a co-op assignment with my first boss, and became their first co-op student in Sherman. Over half of my jobs have been as the result of proposing a new technical approach or a change in our business process. With time, I have developed the reputation for being able to grasp a fuzzy conceptual idea and transform it into a well-run project to make it happen.

Q: What was the most difficult stretch assignment you’ve received at TI, and how did it help you in your career?

A: The first big stretch assignment was the most difficult. The uncertainty of knowing if I could ramp quickly enough or if people would support me was almost paralyzing. Ultimately, I learned how supportive people are of someone striving to help the team be successful, and with my tenacious drive, I enjoyed a successful assignment. Each stretch assignment builds confidence and improves rapid learning skills, which makes the next stretch assignment easier.

Q: What career advice would you give your 22-year-old self?

A: The same advice and wisdom I share with new employees and those I mentor and coach:

• Everybody needs to be a fantastic manager, because you will always be your own manager and you deserve to have the best (and your teammates will appreciate you for it).
• You own communication regardless of who is giving and who is receiving. Behave like you own it and make all communications successful.
• Influence management is critical to become a successful technical leader and contributor.  

In T.K. Chin’s blog post, “Differential pairs: what you really need to know,” he talked about the requirements for a differential pair. In the real world, differential pairs are implemented with either copper traces in a printed circuit board (PCB) or copper wires in a cable assembly. Long PCB traces or cables exhibit high transmission loss that degrades signal quality. In this post, I will explain how insertion loss of a differential pair impacts signal quality, and how an equalizer corrects this impairment.

What is insertion loss?

Transmission loss consists of two parts: skin loss at low frequency and dielectric loss at high frequency. Skin loss depends on the cross-sectional area of an interconnect; for example, the width and metal thickness of a PCB trace, or a cable’s wire diameter. At frequencies below a few hundred megahertz, skin loss is dominant and proportional to the square root of the frequency. At higher frequencies, dielectric loss becomes the dominant transmission loss. The amount of dielectric loss depends on the material property of the dielectric and is directly proportional to the frequency.

Insertion loss is a common term used to describe the transmission loss of an interconnect. It is a ratio of the voltages at the load with and  without the interconnect. A network analyzer measures insertion loss in amplitude and phase. Figure 1 shows the typical insertion loss of two PCB traces on FR4 substrate: one being 5 inches long (blue) and the other 10 inches (red), but both having equal width of 5 mil. As you can see from Figure 1, the loss characteristic behaves as a low-pass filter, with higher signal attenuation as the frequency increases. The loss increases linearly with the length of the PCB trace.

Figure 1: Insertion loss of FR4 PCB traces

Why insertion loss hurts signal quality

Data traffic consists of logic 1s and 0s of various durations in a serial bit-stream. In Figure 2, you can see that the transmitter waveform consists of data bits of longer duration (lower-frequency pulses) and shorter duration (higher-frequency pulses). Their amplitudes are approximately equal and the transition paths are almost identical, resulting in a clean and wide-open data eye.

When the signal propagates through the PCB trace, the low-pass-filter effect slows down the pulses’ transition times – there is not enough time for the short-duration pulses to reach their full amplitudes. The high-frequency pulses are also attenuated more than the low-frequency pulses: their amplitudes are quite different when they reach the destination. With different amplitudes from longer and shorter pulses, the transition paths vary and result in timing jitter. This timing jitter is data-dependent and is commonly called inter-symbol interference (ISI). Figure 2 illustrates the receiver waveform and the corresponding eye diagram with significant added jitter caused by the insertion loss of the differential pair.

Figure 2: Signal integrity degradation caused by insertion loss

How a TI equalizer solves this impairment

The fundamental problem of signal degradation is caused by unequal pulse amplitudes resulting from a low-pass filter. The solution to this problem is to correct the signal attenuation, with the goal to achieve an equal pulse amplitude. An equalizer is a high-pass filter designed with a transfer function equal to the reciprocal of the interconnect’s low-pass filter. There are many common implementations of equalizers. You could use a continuous-time linear equalizer (CTLE) implemented with a high-gain active filter that provides more gain at high frequency and less gain at low frequency. Or you could use a high-pass filter implemented with attenuation at lower frequencies, commonly used as a transmitter equalizer in many de-emphasis driver designs. There are also many digital implementations with finite impulse response filters (FIRs) or decision feedback equalizers (DFEs) commonly used in retimers.

Figure 3 illustrates the TI DS125BR800A with a CTLE to correct the ISI caused by the interconnect. By choosing the proper amount of equalization comparable to the insertion loss characteristic of the interconnect, the repeater cleans up the ISI and delivers a clean data eye at the receive destination.

Figure 3: A CTLE repeater corrects ISI

Texas Instruments’ broad portfolio of signal-conditioning devices can enable you to compensate for differential pair impairments and address the needs of many common communication protocols.

Additional resources

• To learn more about Peripheral Component Interconnect Express (PCIe) repeaters, check out the PCIe redrivers/repeaters product selection tool.
• To learn more about multiprotocol repeaters, check out the redrivers/repeaters product selection tool.
• See an overview of TI retimers with advanced adaptive CTLE and DFE equalization.
• See an overview of broadcast video equalizers and reclockers for SMPTE applications.
• Read more about the WEBENCH® Interface Designer tool, an easy way to run simulations with TI signal-conditioning integrated circuits (ICs) to solve differential pair impairments.

With electricity providers striving to reduce energy loss, energy theft prevention is a major concern.  Specifically, utility companies seek to prevent energy meter tampering that may lead to obtaining electricity that is not properly billed by the meter to the customer.  To prevent energy theft due to the unauthorized modification of energy meters, many markets require that meters include anti-tamper mechanisms to not only detect different meter tampering methods but also to prevent or mitigate their effects.

There are multiple techniques for tamper detection and prevention.  First, for tamper prevention the first line of defense should always be the meter case.  The meter case should be sealed so that easy access to the meter is not allowed and there are no spaces that may allow entering objects to bypass the sensed current.  As an additional precaution, a button can be added within the case so that a trigger is generated whenever a case is opened.  For some processors such as the ultra-low power MSP430F67791A microcontroller (MCU), there are specific capture pins on the chip that can be used to log the time of the trigger even when the main power to the DVCC is not available.   An example of this functionality can be found in the TIDM-AUX-MODULE design.

To deal with meter tamperer specifically bypassing current on the live channels, one anti-tamper technique is to measure the current on the neutral channel. For three-phase meters the neutral current should ideally be zero if loads are balanced for all phases.  If there is a large current on the neutral channel this can indicate tampering. For single-phase meters, under ideal conditions, the live current should be equal to the neutral current.  If there is a significant mismatch between the measured live and neutral currents, this also may indicate that a tamper event has occurred.   In the drawing below, the method of measuring both neutral and live currents is shown.

Figure 1: Single phase meter diagram

In the drawing, the red arrow connected to the first terminal on the left corresponds to Live_In, the black arrow connected to the second terminal on the left corresponds to Neutral_In, the red arrow connected to the third terminal on the left corresponds to Live_Out, the black arrow connected to the fourth terminal corresponds to Neutral_Out, and the set of green arrows represent someone trying to bypass current at the terminals pointed to by the green arrows.  In this configuration, the energy consumption is calculated using the voltage between Live_In and Neutral _In and the current sensed across a shunt connected between Live_In and Live_Out.  A similar calculation is also done using the same voltage between Live_In and Netural_In as well as the current produced at the secondary of a current transformer that has its primary connected between Neutral_In and Neutral_Out.  By measuring both line and neutral currents, this can help detect someone trying to tamper a meter by bypassing current. Additionally, by calculating average active power as a signed number, tampering with a meter to count in reverse can be detected by checking if the signed average active power is negative (assuming net metering is not supported).

There are multiple options to combat magnetic tampering.  First, any items that are vulnerable to magnetic tampering should be orientated such that it is difficult to place a magnet near these susceptible items.  Susceptible components should also be magnetically screened to help lessen the effects of this type of tampering.  If it is difficult or not cost-effective to provide magnetic screening, another option is to use a hall-effect sensor such as the DRV5033 to detect the magnetic field and take special action, as is done in the TIDA-00839 design.

Because transformer-based power supplies are susceptible to magnetic tampering, RC power supplies such as the PMP6960 are often used instead of transformer-based power supplies.  Alternatively, transformer-based power supplies can use more magnetically immune air-core transformers.

Due to the effects of magnetic tampering on current transformers (CTs), shunts resistors may be used as current sensors instead of current transformers.  For single-phase meters that measure both neutral and live current for anti-tamper purposes, many times one current channel would be measured with a CT and the other channel would be measured with a shunt to help deal with magnetic tampering of the CT.  For poly-phase meters, shunts can also be used as current sensors, as is done in the TIDA-00601 design.  In order to allow shunts to be used in poly-phase systems, an isolated sigma delta modulator such as the AMC1304M05 is used to compensate for shunts not having inherent isolation.

Lastly, another anti-tamper technique consideration is to make a meter robust against electrostatic discharge (ESD) and electromagnetic immunity (EMI) attacks.  There are many design considerations needed to harden a meter against these attacks.  The TIDM-3PHMTR-TAMP-ESD, TIDM-3PH-ENERGY5-ESD, and TIDM-1PHMTR-ESD designs provide more details about these design considerations.

With some of the common anti-tamper methods discussed, you now have knowledge on how to defend against common meter tampering techniques.  In order to make your job easier, here are some designs and devices from TI that simplify the tamper detection and prevention process:

• TI Design reference designs:
  • Magnetic Tamper detection using low-power hall effect sensors reference design (TIDA-00839)
  • Multi-phase energy measurement with isolated shunt sensors reference design (TIDA-00601)
  • Three-phase metrology with enhanced ESD protection and tamper detection reference design (TIDM-3PHMTR-TAMP-ESD)
  • Class 0.5 three-phase energy measurement system with enhanced ESD protection reference design (TIDM-3PH-ENERGY5-ESD)
  • One-phase metrology with enhanced ESD protection reference design (TIDM-1PHMTR-ESD)
  • Battery management and auxiliary power supply options for e-meters (TIDM-AUX-MODULE)
  • Relevant TI products:
    • DRV5033 2.5 to 38 V digital omnipolar-switch hall effect sensor
    • Reinforced isolated modulator with LDO regulator, ±50mV Input, and CMOS interface AMC1304M05
    • Ultra-low power MSP430F67791A mixed signal microcontroller