Patent ID: 8106634
Filing Date: 2012-01-31
Classification: H02M,Y02B

Abstract:
1. A switching power supply comprising: a switching element which is connected to a power supply voltage and performs ON and OFF operation; a control circuit for performing ON and OFF control of the switching element; a coil by which the amount of current value which flows through the switching element is controlled; a capacitor which is connected to the coil and performs a rectifying operation with the coil; an oscillator for outputting an oscillator signal for controlling the switching element into ON for every constant period to the control circuit; a first comparator for comparing a current detection voltage which transforms a detection current which flows through the coil into a voltage, and the feedback voltage according to a difference of a voltage according to an output voltage outputted from a connection node between the capacitor and the coil with a reference voltage; and a second comparator for comparing a threshold voltage set as a voltage value which is higher than the current detection voltage and is lower than the power supply voltage, with the feedback voltage.