| 摘要 |
<p>A problem of the present invention is to prevent an overcurrent at the time of starting a switching operation in a power supply circuit using a boost chopper circuit (3). In order to solve the above-described problem, the present invention is characterized in that in the power supply circuit using a boost chopper circuit, a switching operation is started in a vicinity of a peak value of an input current once per a half cycle of a power supply cycle. As one of specific arrangement, a ripple component of a DC voltage is detected, and the switching operation is started at a timing when the ripple component of the DC voltage becomes "positive". As another specific arrangement, an input current instantaneous value is compared with a value proportional to the magnitude of the input current (e.g., the effective value or the like), and a switching operation is started in a period during which the input current instantaneous value exceeds the value proportional to the magnitude of the input current.
</p> |
