Patent ID: 9331583
Filing Date: 2016-05-03
CPC Classification: H02M,Y02B

Claim Text:
1. A control circuit for controlling a switch mode power supply, the switch mode power supply having an output terminal configured to provide an output voltage and having a first switch with a control terminal, wherein the control circuit comprising: a mode management unit, having an input terminal and an output terminal, wherein the output terminal of the mode management unit is configured to provide a mode control signal; a skip cycle mode control unit, having an input terminal and an output terminal, wherein the input terminal of the skip cycle mode control unit is configured to receive a feedback signal representing the output voltage, wherein the output terminal of the skip cycle mode control unit is configured to provide a first pulse signal having a first frequency and a second frequency, wherein the first frequency and the second frequency are predetermined; a normal mode control unit, having an output terminal configured to provide a second pulse signal; and a drive signal management unit, having a first input terminal, a second input terminal, a third input terminal and an output terminal, wherein the first input terminal of the drive signal management unit is coupled to the output terminal of the mode management unit, the second input terminal of the drive signal management unit is coupled to the output terminal of the skip cycle mode control unit, the third input terminal of the drive signal management unit is coupled to the output terminal of the normal mode control unit, and the output terminal of the drive signal management unit is configured to provide a switching control signal to the control terminal of the first switch based on the first pulse signal, the second pulse signal and the mode control signal; wherein the input terminal of the mode management unit is configured to receive the switching control signal, and the output terminal of the mode management unit is configured to provide the mode control signal via comparing a frequency of the switching control signal with a frequency threshold.