| 摘要 |
Provided is a power factor improving circuit whereby the problem of reverse voltage can be solved. A master transistor (S1) and a slave transistor (S2) both are insulated-gate bipolar transistors. A slave diode (D21) is anti-parallel connected to the slave transistor (S2). The master transistor (S1) is rendered conductive when the current flowing through a main reactor (L1) becomes null, and the master transistor (S1) is rendered nonconductive after a lapse of a first time period. The slave transistor (S2) is rendered conductive on conditions including one condition that a time period, which is shorter than a time period from the time the master transistor (S1) is rendered conductive to the time the master transistor (S1) is rendered conductive next, has elapsed, and the slave transistor (S2) is rendered nonconductive after a lapse of a second time period that is shorter than the first time period. |
