Driving circuit for light emitting elements

摘要

Multiple LED terminals are provided to multiple LEDs, respectively. Each of these LED terminals is connected to the anode of the corresponding LED. A booster circuit boosts an input voltage. Multiple constant current sources are provided to the multiple LEDs, respectively. One terminal of each of the constant current sources is connected to the corresponding one of the LEDs via the corresponding one of the LED terminals. Multiple switches are provided to the multiple constant current sources, respectively, each of which selectively outputs a voltage selected from the input voltage and the output voltage of the booster circuit to the corresponding constant current source. A control circuit monitors each of the voltages at the multiple LED terminals, and controls the connection state of each of the switches based upon the corresponding voltage.