Lighting control unit for vehicle lighting fixture

摘要

In a process where the energy accumulated in the transformer while a transistor is turned ON is emitted to an output circuit and an LED is illuminated with the emitted energy, a voltage generated across a resistor is monitored by a control circuit. When the current flowing through the transistor has reached a limit current value, the ON operation of the transistor is limited. When the output voltage of the output circuit has exceeded a first set voltage, the limit current value is lowered and the ON operation of the transistor is further limited. When the output voltage of the output circuit has exceeded a second set voltage, the ON operation of the transistor is forcibly stopped.