Patent ID: 8638389
Filing Date: 2014-01-28
Classification: H02M,H04N

Abstract:
1. A power supply circuit comprising: a comparison unit that compares a reference voltage and an input voltage and outputs a voltage difference signal; an output voltage generating unit that generates an output voltage based on the voltage difference signal; an input voltage generating unit that generates the input voltage based on the output voltage; a current output unit that outputs a reference current; a resistor that generates the reference voltage in accordance with the reference current; and a capacitor that is connected to the resistor in parallel and is charged by the reference current, wherein the current output unit allows the reference current at the time of startup to be lower than the reference current during an operation; wherein the comparison unit includes a main comparator having one pair of first input terminals, a node to which the current output unit, the resistor, and the capacitor are connected is connected to one of the first input terminals out of the one pair of the first input terminals of the main comparator, the reference voltage is input to the one of the input terminals, the input voltage is input to the other of the first input terminals, and the main comparator outputs a voltage difference signal that changes in accordance with a level of the input voltage relative to the reference voltage, the current output unit includes the first switching device controls the reference voltage by, in accordance with the voltage difference signal, being in an On-state in a case where the input voltage is lower than the reference voltage and being in an Off-state in a case where the input voltage is higher than the reference voltage.