| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent narrowing of an operation range by performing suitable mask processing for a current detection signal to stably output a highly precise voltage equal to a target voltage.SOLUTION: When a PWM signal output by a PWM signal generation circuit 6 changes into a H level, a mask processing circuit 7 turns on a switch circuit 24 to fix a current detection signal output by a current detection circuit 3 at a mask level set lower than an error signal. Thereafter, mask processing circuit 7 turns off the switch circuit 24 after a mask time has elapsed to release the current detection signal from the mask level. The mask processing circuit 7 detects a valley where the current detection signal transits from decrease to increase to optimize it by setting a time from the start of one cycle of PWM to the valley as a mask time.</p> |
