| 摘要 |
PROBLEM TO BE SOLVED: To provide a power unit which is equipped with a margin check voltage setting circuit that is easily miniaturized and integrated. SOLUTION: This power unit has a margin check voltage setting circuit which sets desired margin check voltage by inputting reference voltage, an error amplifier which receives the input of the margin check voltage and the output voltage of itself and outputs the difference between both as an error signal, a pulse width modulating oscillator which modulates the pulse width of the output of the above error amplifier, a driving circuit which generates a drive signal by the pulse signal from the pulse width modulating oscillator, and a pair of power semiconductor switching elements which step down the input voltage, based on the drive signal from the driving circuit, and generate output voltage. The output end of the margin check voltage setting circuit is provided with an overvoltage detecting circuit which sets comparative voltage for overvoltage detection and a power good circuit which sets comparative voltage for determining power good. COPYRIGHT: (C)2007,JPO&INPIT |
