| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve power saving at the time of no-load in which a load is in a standby state by using a latch stop function for overvoltage protection to the load and enhance silence by preventing a squeak of a switching transformer. <P>SOLUTION: At the time of no-load in which a load 1 is in a standby state, a terminal voltage applied to a power supply terminal P420c of a control IC 420 is increased by comparing it with a threshold voltage necessary for overvoltage protection to the load to latch and stop switching operation of a transistor 41, by control from a main control part 2 controlling the load to a voltage boosting circuit 43. The terminal voltage applied to the power supply terminal of the control IC 420 is dropped by comparing it with a minimum operation voltage at which the control IC 420 operates to cancel the latch stop and resume the switching operation of the transistor 41, by control from the main control part controlling the load to a latch cancellation circuit 44. <P>COPYRIGHT: (C)2013,JPO&INPIT |
