| 摘要 |
<P>PROBLEM TO BE SOLVED: To maintain a critical operation of a sub-circuit, even when an output voltage rises for some reason by attaining a control system, using a simple configuration. <P>SOLUTION: In a power supply consists of two critical boosting chopping converters for respectively boosting and chopping the outputs of the rectifying circuit and an output voltage detection circuit and in which a control circuit of the first critical boost chopping converter generates an on-timing of a switching element of the first critical boost chopping, converter from a voltage of a control winding of the converter and a control circuit of the second critical boost chopping converter generates an on-timing of a switching element of the second critical boost chopping converter, with such a timing that the switching element of the first critical boost chopping converter is off. The control circuit of the first critical boost chopping converter, when detecting an overvoltage with a signal from an output voltage detection circuit, sets the operation of the second critical boost chopping converter discontinuous for a predetermined time. <P>COPYRIGHT: (C)2011,JPO&INPIT |
