A Four-Phase Gain Control Method to Reduce the Ignited Current Spike of the Laser Diode Using in a Laser Headlight Power Supply Unit

K.-J. Pai (National Taiwan Normal Univ., Taiwan)

A laser headlight power supply unit (LHPSU) was implemented and developed to drive laser diodes. The LHPSU possessed with the buck-boost converter (BBC), the BBC controller, and the current error amplifier (CEA). When the dynamic resistance of the laser diode was increased under the high ambient air temperature, the BBC operated in the buck mode, and the CEA employed the proportional-integral control, the driving current of the laser diode exhibited an ignition current spike, which can damage the laser diode configuration, resulting in optical output power decay. Therefore, a four-phase gain control method was proposed to reduce the ignited current spike of the laser diode.