LIGHT EMITTING DIODE DRIVE CIRCUIT

摘要

A reference current unit (33) includes: a calculation amplifier (30) which controls a reference current so that a voltage generated by the reference current flowing in a resistor is identical to a constant reference voltage; and a first current mirror circuit which generates a first current based on the reference current. A current output unit of each channel includes: a second current mirror circuit which is configured together with a part of the reference current unit and generates a second current based on the first current; and a third current mirror circuit to which the second current is supplied and which generates a current proportional to the second current in response to one of the system switches which has turned ON. Each of the first, the second, and the third current mirror circuit is a 2-stage current mirror circuit formed by cascade connection.