REGULAR CURRENT DRIVING DEVICE

摘要

PURPOSE: A constant current driving apparatus is provided to improve the stability of power supply towards a LED lamp by controlling a power supplied to a LED lamp with a constant voltage and a constant current way. CONSTITUTION: A voltage sensing control part(3) outputs a first control signal by comparing the output voltage of AC/DC converter(1) with a reference voltage. A current sensing resistor(R1) supplies a voltage which is proportional to the power current of an AC/DC converter to a current sensing control part(4). The current sensing control part outputs a second controlling signal by comparing the current sensing voltage with a reference voltage. A compensation part(5) supplies a compensation value to a photocoupler(PT1) according to the first control signal and the second control signal. The photocoupler supplies the compensation value through an error amplifier(OP3) of the control terminal to a controller(6).