Patent ID: 7714549
Filing Date: 2010-05-11
Classification: H02M

Abstract:
1. A switching regulator control circuit comprising: a first switching signal generating circuit which generates a first switching signal for driving a first switching element connected to a first output circuit; and a second switching signal generating circuit which generates a second switching signal for driving a second switching element connected to a second output circuit, wherein the first switching signal generating circuit changes a timing at which the first switching signal is turned on so that first output voltage output from the first output circuit becomes close to predetermined first reference voltage while making on-time of the first switching signal predetermined constant first on-time, and the second switching signal generating circuit changes on-time of the second switching signal so that frequency of the second switching signal becomes close to frequency of the first switching signal, and changes a timing at which the second switching signal is turned on so that second output voltage output from the second output circuit becomes close to predetermined second reference voltage, wherein the first switching signal generating circuit comprises: a first voltage comparator which compares the first output voltage with the first reference voltage; a first flip flop which is set according to an output of the first voltage comparator; and a first on-time control circuit which resets the first flip flop after lapse of the first on-time from the rising edge of an output of the first flip flop, and outputs an output of the first flip flop as the first switching signal, and the second switching signal generating circuit comprises: a second voltage comparator which compares the second output voltage with the second reference voltage; a second flip flop which is set according to an output of the second voltage comparator; and a second on-time control circuit which resets the second flip flop after lapse of the second on-time from the rising edge of an output of the second flip flop, and outputs an output of the second flip flop as the second switching signal, and the second on-time control circuit detects lapse time from the rising edge of the first switching signal to the rising edge of the second switching signal, and changes the second on-time so that the lapse time becomes close to a predetermined target value.