| 摘要 |
PROBLEM TO BE SOLVED: To sufficiently raise the carrier frequency of a PWM signal, by multiplying the PWM signal obtained through pulse width calculation to a complex pulse for each period, and then outputting it to each switching element. SOLUTION: DSP 8 performs the pulse width calculation of PWM signal due to the feedback control and momentary value control of an output current of a power supply, but it also outputs the data obtained by dividing the data of pulse width into 1/N as the final result of calculation. Therefore, when the pulse output number data N is set to 4 (N=4), the frequency data Δt/4 is latched to a latch circuit 17 of the frequency control circuit 13, while the pulse output number data N=4 is latched to a latch circuit 31 of the operation intermitting means 30. Since the pulse width data ΔW/4 is outputted to the pulse width control circuit 12 for every constant period Δt, the carrier frequency in the constant period Δt of the PWM signal becomes four times. As a result, each switching element can be controlled with a higher frequency obtained by multiplying the carrier frequency of PWM signal by N times. |
