PWM signal generating circuit for DC-DC converter using dimming signal and LED driver circuit using the same in digital PWM method having fixed phase mode

摘要

A PWM signal generating circuit and method, and an LED driver circuit using same, is disclosed. The PWM signal generating circuit generates a PWM signal for a DC-DC converter using a dimming signal, and includes an oscillator which generates a first clock signal having a predetermined frequency, a synchronizing unit which synchronizes the dimming signal to the first clock signal, and a PWM signal generating unit which generates the PWM signal in response to the first clock signal having a falling edge while the synchronized dimming signal is on.

主权项

1. A pulse-width modulation (PWM) signal generating circuit configured to generate a PWM signal for a direct current to direct current (DC-DC) converter based on a dimming signal, the PWM signal generating circuit comprising:
an oscillator configured to generate a first clock signal having a predetermined frequency; a synchronizing unit configured to generate a synchronized dimming signal by synchronizing the dimming signal to the first clock signal; and a PWM signal generating unit configured to generate the PWM signal having a rising edge in response to the first clock signal having a falling edge while the synchronized dimming signal is on.