Adaptive Output Discharge DC-DC for glare free LED front-light

This work presents a new control system implemented with a single DC-DC controller to power a fully dynamic adaptive lighting application. Daytime running light, low beam, high beam and full adaptive LED Matrix are typical functions requiring a dedicated LED driver solution to fulfill car maker requirements for front light applications. Single stage drivers experience a sharp overshoot in LED current when transitioning from driving a higher number to a lower number of LEDs. To ensure the LED reliability the current overshoot must be lower the maximum LED current rating. In case the current overshoot exceeds the maximum rating, the LED could face a permanent damage. A complete system will be presented to limit LED current overshoots peak and duration when the switchover of different functions or between different number of series LEDs string is applied. A prototype with an integrated test-chip was built. Measurement results and comparison with state-of-the-art solution available in the market are shown.