VOLTAGE GENERATING CIRCUIT, CONSTANT CURRENT CIRCUIT AND LIGHT EMITTING DIODE DRIVING CIRCUIT

摘要

A voltage generating circuit whose voltage value can be highly accurately adjusted, a constant current source using such voltage generating circuit and a light emitting diode driving circuit. The voltage generating circuit (100) includes a voltage generating section (50) for generating a plurality of constant voltages, a plurality of switches (SW1-SW8), a control signal generating section (30), and a decode circuit (40). The switches (SW1-SW8) select a voltage from the plurality of constant voltages (V1-V8) generated by the voltage generating section (50) and output the voltage from a voltage output terminal (102). The control signal generating section (30) generates a plurality of control signals (Vcnt1-Vcnt3) which can be switched to a high level or a low level by trimming a plurality of fuse resistors (Rf1-Rf3), and the decode circuit (40) controls the connection status of the switches (SW1-SW8) by the control signal (Vcnt). A reference voltage (Vx) outputted from a voltage output terminal (102) is applied to a current generation resistor (Ri1) through an operating amplifier (10) and a transistor (12), and a constant current (Iled) is generated.