Concurrent Current and Voltage Regulated Buck–Boost Converter for Automotive LED Matrix Headlights

Abstract

Automotive light-emitting diode (LED) matrix headlights require both high-power efficiency and stable control of individual LEDs. The proposed power converter uses a buck–boost converter and a concurrent current and voltage regulation circuit to increase the overall efficiency. Additionally, the proposed system requires only one small inductor instead of two large inductors in other designs. The reference voltage for the buck–boost converter was generated according to the number of turned-on LEDs. Subsequently, for the optimum current regulation of the LED matrix headlight, the output voltage of the buck–boost converter follows the reference voltage. The main control circuit was fabricated on a chip using a 0.18-μm BCD process for functional testing. The proposed system has an operating input voltage range of 7–60 V and an output voltage range of 1.05–60 V, depending on the number of LEDs. The proposed power system successfully demonstrated the individual control of LEDs for matrix headlights. Moreover, a dimming test was conducted to confirm that the brightness of the LEDs could be individually controlled.