Patent ID: 9083245
Filing Date: 2015-07-14
Classification: H02M,H05B,Y02B

Abstract:
1. A switching power supply, comprising: a switching circuit having a main switch and a tank element, wherein the switching circuit converts an input voltage into an output voltage through the ON and OFF switching of the main switch; a current sensing circuit coupled to the switching circuit, wherein the current sensing circuit senses the input current of the switching circuit and generates a current sensing signal representative of the input current; a preprocessing circuit coupled to the switching circuit to receive the input voltage and the output voltage, wherein based on the input voltage and output voltage, the preprocessing circuit generates a first multiplication input signal; a first multiplier coupled to the preprocessing circuit to receive the first multiplication input signal, wherein the first multiplier multiplies the first multiplication input signal by a second multiplication input signal and generates a first product signal, wherein the second multiplication input signal is a compensation signal related to the output voltage, the output current or the output power of the switching circuit; a first comparing circuit coupled to the current sensing circuit and the first multiplier to receive the current sensing signal and the first product signal, wherein the first comparing circuit compares the current sensing signal with the first product signal and generates a first comparison signal; and a logic circuit coupled to the first comparing circuit to receive the first comparison signal, wherein the logic circuit turns off the main switch when the current sensing signal is larger than the first product signal.