Control circuit and method for programming an output voltage of a power converter
AssigneeRichtek Technology Corporation
InventorIsaac Y. Chen
Life of this patent
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Abstract
A power converter determines a feedback signal according to a voltage signal related to an output voltage of the power converter and a reference voltage, thereby regulating the output voltage. A control circuit and method for programming the output voltage of the power converter utilize an offset current generator to inject a current or sink a current for changing the voltage signal or the reference signal, thereby adjusting the output voltage. As a result, it gets rid of complicated circuitry but provides more steps adjustment, which reduces related costs.
Claims5
A control circuit for programming an output voltage of a power converter including an auxiliary coil in a primary side of a transformer configured to operably detect the output voltage to generate a first voltage signal and a voltage divider coupled to the auxiliary coil configured to operably divide the first voltage signal to generate a second voltage signal, the control circuit comprising:
- an offset resistor having a first terminal coupled to the voltage divider configured to operably receive the second voltage signal, and a second terminal configured to operably provide a third voltage signal;
- and
- an offset current generator coupled to the second terminal of the offset resistor and configured to operably inject a first current to the offset resistor or sink a second current from the offset resistor so as to offset the second voltage signal to generate the third voltage signal to regulate the output voltage;
- wherein, the offset current generator adjusts the first current or the second current so as to adjust the third voltage signal, thereby adjusting the output voltage.
A control method for programming an output voltage of a power converter including an auxiliary coil in primary side of a transformer configured to operably detect the output voltage to generate a first voltage signal, the control method comprising the steps of:
- dividing the first voltage signal to generate a second voltage signal to a first terminal of an offset resistor;
- injecting a first current to a second terminal of the offset resistor or sinking a second current from the second terminal of the offset resistor, thereby offsetting the second voltage signal to generate a third reference voltage so as to regulate the output voltage;
- and
- adjusting the first current or the second current so as to regulate the third voltage signal and adjust the output voltage.
Dependencies are inferred from the claim text.