| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit wherein its switching element is never latched in an interrupted condition even if the input power supply is temporarily interrupted. SOLUTION: The control power supply circuit 5 comprising a step-down chopper circuit is provided with a switching element Q2, an inductor L5, a filter capacitor C5, and a diode D5. The switching element Q2, in conjunction with a controller 51 using the filter capacitor C5 as its power source, composes an integrated circuit IC. The controller 51 contains a function to break and latch the switching element Q2 when a current flows into the switching element Q2 in the direction opposite to the one in ON status. A reverse current blocking diode Dc blocking the above reverse direction current for the switching element Q2 is connected to the drain side of the switching element Q2, preventing the latching function activated by the controller 51. |
