| 摘要 |
PROBLEM TO BE SOLVED: To provide technology which can simply generate correction voltage which is increasingly small as the input voltage rises and increasingly large as the input voltage drops, and can output it to a control unit controlling a switching unit.SOLUTION: A step-down switching element Q1 of a step-down switching regulator 10 provided as a drive power supply for a main control circuit 4 outputs a pulse voltage S, which is input to a correction voltage output unit 100. The correction voltage output unit 100 generates a correction voltage Vc whose value corresponds to an ON period of the step-down switching element Q1 within one cycle of the input pulse voltage S, which is increasingly small as the ON period is short and increasingly large as the ON period is long. Therefore, a correction voltage Vc whose value is increasingly small as an input voltage Vi rises and increasingly large as the input voltage Vi drops can be simply generated by the correction voltage output unit 100 and can be output to the main control circuit 4 which controls the switching element Q10. |
