| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress the occurrence of a switching noise due to reverse currents when a switching element turns on.SOLUTION: A power supply circuit 2 as a step-down switching power source includes; a transistor 4, a smoothing circuit 5, a voltage control circuit 6; a drive circuit 7 and a suppressing operation control circuit 9. The transistor 4 is configured to switch a DC power to be supplied from a battery 9. The smoothing circuit 5 is configured to smooth and output the voltage switched by the transistor 4. The voltage control circuit 6 is configured to generate a control signal for controlling the driving of the transistor 4 on the basis of the output of the smoothing circuit 5. The drive circuit 7 is configured to drive the transistor 4 on the basis of the control signal. The suppressing operation control circuit 8 is configured to execute a suppressing operation of suppressing the turn-on speed of the transistor 4 during a period since the turn-on period of the transistor 4 starts until a predetermined time elapses, and to stop the suppressing operation in the following period.</p> |
