Abstract: A control method includes the steps of: setting first control periods of a switching transistor group, the first control periods including operating periods in the first driving mode and operating periods in the second driving mode; setting an output voltage and a K value in a directly proportional relationship, wherein the K value is the ratio of the number of the operating periods in the second driving mode to the number of the operating periods in the first driving mode; receiving the output voltage, and determining a K value corresponding to the existing output voltage according to the set relationship between the output voltage and the K value; and outputting a driving signal group of the switching transistor group according to the number of the operating periods in the first driving mode and the number of the operating periods in the second driving mode.

Abstract: A control method includes the steps of: setting first control periods of a switching transistor group, the first control periods including operating periods in the first driving mode and operating periods in the second driving mode; setting an output voltage and a K value in a directly proportional relationship, wherein the K value is the ratio of the number of the operating periods in the second driving mode to the number of the operating periods in the first driving mode; receiving the output voltage, and determining a K value corresponding to the existing output voltage according to the set relationship between the output voltage and the K value; and outputting a driving signal group of the switching transistor group according to the number of the operating periods in the first driving mode and the number of the operating periods in the second driving mode.

Abstract: Disclosed is a light load control circuit and the method accordingly where the synchronous rectification is latched off when the light load condition is detected for several successive cycles.

Abstract: The present invention discloses a light load control circuit and the method accordingly where the synchronous rectification is latched off selectively according to the gate voltage of the synchronous rectifier.

Abstract: The present invention discloses a smart driving method for a secondary synchronous rectifier of an isolated converter and its apparatus thereof. The apparatus comprises: a main circuit having a secondary synchronous rectifier Q1; a differentiation filter circuit, filtering the drain-source voltage Vds of the secondary synchronous rectifier, comprising a capacitor and at least one resistor connected in series and outputting a filtered voltage Vf from either between said capacitor and said at least one resistor or between said at least one resistor; a smart driver, receiving Vf and Vds and putting out a driving signal to the gate of the secondary synchronous rectifier. The control approach is fulfilled by comparing Vds to a reference voltage Vthr2 and comparing the absolute value of Vf to another reference voltage Vthr3. When Vds<Vthr2 and |Vf|>Vthr3, Q1 is turned on. When Vds>Vthr1, Q1 is turned off, where Vthr1 is a predetermined reference voltage.

Abstract: Disclosed is a light load control circuit and the method accordingly where the synchronous rectification is latched off when the light load condition is detected for several successive cycles.

Abstract: The present invention discloses a light load control circuit and the method accordingly where the synchronous rectification is latched off selectively according to the gate voltage of the synchronous rectifier.

Abstract: The present invention discloses a smart driving method for a secondary synchronous rectifier of an isolated converter and its apparatus thereof. The apparatus comprises: a main circuit having a secondary synchronous rectifier Q1; a differentiation filter circuit, filtering the drain-source voltage Vds of the secondary synchronous rectifier, comprising a capacitor and at least one resistor connected in series and outputting a filtered voltage Vf from either between said capacitor and said at least one resistor or between said at least one resistor; a smart driver, receiving Vf and Vds and putting out a driving signal to the gate of the secondary synchronous rectifier. The control approach is fulfilled by comparing Vds to a reference voltage Vthr2 and comparing the absolute value of Vf to another reference voltage Vthr3. When Vds<Vthr2 and |Vf|>Vthr3, Q1 is turned on. When Vds>Vthr1, Q1 is turned off, where Vthr1 is a predetermined reference voltage.