In this day and age, you can tailor everything to your specific personality and style. Your phone can have bling, your tablet can have a picture of your family on the cover, your headphones can be polka dotted patterns and your car can have bright LED lights that make your vehicle stand out from the crowd.
LEDs are increasingly being adopted in new vehicle exterior light designs. The main driver LEDs are being accepted so quickly as front and rear light systems is their compact size and their ability to enhance attractive and innovative vehicle lighting design styling. The old design are all based on bulbs (Halogen or HID, High Density Discharge), which can only be made as round size and limit the shape design of exterior lighting of the cars. LEDs are compact and can be built as different kinds of shape with LED matrix or LED string
Other reasons for the quick adoption of LEDs for automotive front and rear lighting are vast:
- Styling – With the LEDs compact size, vehicles can be more aerodynamic and the visual appeal to consumers raises sales in LED modules.
- Light quality -- The color temperature of light emitted by LED is much closer to that of sunlight than those of other light sources, such as halogen or HID.
- Efficiency – Efficiency has been exploited by some auto makers who say that LEDs limit the ancillary drain on the battery pack of electrified powertrains.
- Integrating Functionality -- Multiple functions can potentially happen on the same LED string or even on the same LED light. Examples include cornering lights and DRLs (Daytime Running Lights) running on one string. This, in turn, can lower the costs of designing with LEDs over other light sources by not having separate lights.
- Long life -- LEDs are claimed to be more robust and last the lifetime of the vehicle. LED headlights can last 10,000 (or even 20,000) hours of normal usage, compared to 500-1,000 hours for halogen and 1,000-3,000 hours for HID.
- Rapid response -- When traveling through tunnels or reacting to different weather conditions, exterior lights must be able to respond rapidly to many different light conditions. LEDs can be switched on within 0.1 seconds, unlike HIDs at 1-1.5 seconds.
When Car OEMs are happy with the benefits of LED exterior lighting, the challenges then fall lighting module vendors – how to achieve differentiated designs while also fully meeting the regulations required in different countries. Moreover, there are challenges with meeting other requirements: high power with low EMI, self-diagnostic, thermal management, independent analog and PWM dimming etc. – all those requirements together are leading to the “Mission Impossible” that drives and controls attractive LEDs.
TI has just released two new AEC-Q100 qualified LED Drivers – TPS92630-Q1 and TPS92602-Q1. Both parts are designed for automotive exterior LED lighting applications while providing more robust, more intelligent and more flexible solutions to meet the market trends.
TPS92630-Q1 is a 3-channel device, with a maximum of 150mA per channel. It’s a constant current, linear LED driver that is designed to be a cost effective, low EMI solution for rear lamp applications. It also has fully integrated diagnostics and control. The TPS92630-Q1 uses a high side current source to implement LED strings with a common cathode connection, saving wiring cost and improving reliability. Each channel’s peak current is globally set with the Ref pin, and each individual string’s brightness & ON/OFF can be adjusted through PWM. The TPS92630-Q1 also implements thermal management and diagnostics for open, short and single LED short detection. The flexible fault pin can achieve bus connection that supports multiple parts working together - without an additional MCU.
The TPS92602-Q1 is a 2 channel, constant current, single stage switching LED driver, designed for automotive front lighting. It supports all common topologies, such as buck, boost, buck-boost, SEPIC, flyback and others. Similar to our rear lighting device, the TPS92602-Q1 also has high side control and high side current sense for demanding designs in Automotive. This device’s flexible design allows it to support both analog and PWM dimming. Having both constant current and constant voltage loops, it can protect the entire system in constant voltage mode when an LED open happens, and also recover back to constant current mode when the open is removed. Finally, the TPS92602-Q1 has full diagnostic capabilities with a dedicated DIAG pin to read back fault information through the ADC. Both channels have separate controls, diagnostics, loop compensation and switches with 180 degree out-of-phase reducing EMI. There is also a pin-to-pin single channel version, TPS92601-Q1, making this family of devices ideal to create one platform for full LED front light systems.
Do you think these two parts can help you achieve the design you want for automotive exterior lighting? There’s also a TPS92630-Q1 and TPS92602-Q1 demo video, which is also helpful to get a better understanding of the benefits these two parts can bring to your designs. If you still have questions, please ask questions in the forum or leave a comment here!