POWER CONTROLLABLE ELECTRONIC BALLAST OF MIXED GATE DRIVING TYPE, CAPABLE OF TURNING ON A POWER SWITCH BY USING RESONANT CURRENT AND TURNING OFF THE POWER SWITCH THROUGH A GATE DRIVING CIRCUIT, AND METHOD FOR CONTROLLING THE SAME

摘要

PURPOSE: A power controllable electronic ballast and a method for controlling the same are provided to turn on a power switch by using a resonant current and turn off the power switch by using a gate driving circuit. CONSTITUTION: An electronic ballast comprises a voltage source for supplying power; a self-excited half bridge converter(3); a lamp unit(5) including a lamp and a resonant circuit; and a control circuit(1) for generating a signal for shorting a fourth winding(34) of the self-excited half bridge converter so as to turn off a power switch(M1). The self-excited half bridge converter senses the current flowing along the lamp unit through a first winding(31) of a transformer(T1), and inputs the current induced through a second winding(32) and a third winding(33) of the transformer to a gate driver so as to turn on the power switch and output a first current in a predetermined direction. The self-excited half bridge converter turns off the power switch in accordance with the signal output from the control circuit so as to thereby output a second current in the direction opposite from the direction of the first current through an inverse parallel diode of the power switch.