Patent ID: 7630218

Claim:
A voltage converter for converting an input voltage signal into an output voltage signal, comprising: a primary converting module, comprising a first electronic induction device, coupled to an input port of the voltage converter; a secondary converting module, comprising: a second electronic induction device, coupled to the first electronic induction device, the second electronic induction device comprising a first end and a second end, wherein the first end of the second electronic induction device is coupled to an output port of the voltage converter; and a switch device, coupled to the second end of the second electronic induction device, for enabling the secondary converting module when switched on; and a switch controller, coupled to the switch device and the second electronic induction device, comprising: a slope detecting circuit, coupled to a detection end of the second electronic induction device, for measuring a slope of an output at the detection end of the second electronic induction device to generate a slope indication signal having different pulse amplitudes representative of different slope values; and a decision circuit, coupled to the slope detecting circuit and the switch device, for referencing the output at the detection end of the second electronic induction device, the slope indication signal, a first predetermined reference level, and a second predetermined reference level to generate a control signal for controlling an on/off status of the switch device; wherein the detection end of the second electronic induction device is selected from one of the first and second ends of the second electronic induction device.