Patent ID: 6831448
Filing Date: 2004-12-14
Classification: H02M

Abstract:
A DC-to-DC converter comprising:switch sections for flowing and blocking a DC input current from an input terminal, an inductor for alternately storing and releasing electromagnetic energy generated depending on the current by turning ON and turning OFF of said switches, an error amplification circuit for outputting an error voltage by comparing a DC output voltage obtained by rectifying and smoothing a voltage generating at the output terminal of said inductor with a predetermined reference voltage, and a pulse-width control circuit for controlling turn-ON and turn-OFF of said switches on the basis of said error voltage, And for controlling said DC output voltage so as to be higher or lower than the voltage of said DC input and becomes equal to a predetermined output setting voltage, a switch connected across said input terminal and said output terminal of said DC-to-DC converter, a first comparator for comparing a first voltage lower than said output setting voltage with said DC output voltage and for obtaining an output of comparison result, a second comparator for comparing a second voltage lower than said DC input voltage with said DC output voltage and for obtaining an output of comparison result, and a drive circuit for receiving the output of said first comparator and the output of said second comparator, and for turning ON said switch when said DC output voltage is lower than said first voltage and said second voltage.