| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: conventional PWM controllers cannot control the duty ratio at a high resolution while controlling the period of pulse width modulation signals to be constant. SOLUTION: A PWM controller has: a first counter 40 which counts a reference clock signal REFC and outputs a first count value CNT1; a front edge control signal generator 41 which outputs a front edge control signal FCNTL based on the first count value CNT1; an adjustment clock generator 30b which generates an adjustment clock signal ADJC; a second counter controller 20 which instructs output start of the adjustment clock signal ADJC based on the first count value CNT1; a second counter 50 which outputs a second count value CNT2; a rear edge control signal generator 51 which outputs a rear edge control signal ECNTL based on the second count value CNT2; and a PWM pulse generator 60 which synthesizes the front edge control signal FCNTL and the rear edge control signal ECNTL to generate a pulse width modulation signal. COPYRIGHT: (C)2010,JPO&INPIT
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