Patent ID: 9231483
Filing Date: 2016-01-05
CPC Classification: H02M,Y02B

Claim Text:
1. A control circuit for a DC/DC converter comprising a switching transistor and a detection resistor arranged on a path of the switching transistor, the control circuit comprising: an error comparator configured to compare a feedback voltage that corresponds to an output voltage of the DC/DC converter with a detection voltage across the detection resistor, and to generate an OFF signal which is asserted according to a comparison result; a first oscillator configured to generate a first cyclic signal which is asserted with each of a predetermined first period; a logic unit configured to generate a pulse modulation signal having a level that is switched according to the OFF signal and the first cyclic signal; a second oscillator configured to generate a second cyclic signal which is asserted with each of a second period that is longer than the first period; a light load detection circuit configured to generate a light load detection signal which is asserted when the feedback voltage becomes lower than a predetermined first threshold voltage; and a driving circuit configured to drive the switching transistor according to the pulse modulation signal, and to suspend the driving of the switching transistor during a period until the second cyclic signal is next asserted after the light load detection signal is asserted.