OSCILLATORY CIRCUIT FOR DIGITAL DIMMING CIRCUIT OF INVERTER

摘要

PURPOSE: An oscillatory circuit for a digital dimming circuit of an inverter is provided to produce a complete trigonometric wave and to adjust the brightness of the backlight by using the exact brightness ratio of an LCD responding to the dimming signal. CONSTITUTION: The oscillatory circuit for a digital dimming circuit of an inverter comprises a trigonometric wave generator(21) for generating a prescribed trigonometric wave, a dimming signal input unit(22) for receiving the external dimming signal, a comparator(23) to compare the trigonometric wave with dimming signal generated from the dimming signal input unit, and an oscillatory circuit(24) for producing the duty adjusted oscillation signal according to the output signal generated from the comparator. The trigonometric wave generator has a transistor to generate a driving voltage(Vcc) by turning on/off operations according to the output signal generated from the comparator. The non-inversion terminal of the comparator receives a divided driving voltage by resistors, and the inversion terminal receives a feedback signal. A capacitor is connected to the output port of the transistor to charge during the turn on duration of the transistor and to discharge during the turn off duration.