Capacitance amplifying circuit applied to a controller of a power convertor and operation method thereof

摘要

A capacitance amplifying circuit applied to a controller of a power convertor includes a comparison unit and a capacitance amplifying module. The comparison unit receives a feedback voltage corresponding to a load coupled to the power convertor, a dimming signal, and a reference voltage, and outputs a compensation current. The capacitance amplifying module generates an equivalent capacitor. A capacitance of the equivalent capacitor is K times to a capacitance of a reference capacitor of the capacitance amplifying module, and K is a real number greater than 1. The compensation current and the equivalent capacitor are used for determining a compensation voltage, and when the dimming signal is disabled, a closed loop within the capacitance amplifying module is changed to an open loop to keep the compensation voltage at a fixed value.

主权项

1. A capacitance amplifying circuit applied to a controller of a power convertor, the capacitance amplifying circuit comprising:
a comparison unit for receiving a feedback voltage corresponding to a load coupled to the power convertor, a dimming signal, and a reference voltage, and outputting a compensation current according to the feedback voltage and the reference voltage, wherein when the dimming signal is disabled, the comparison unit is turned off; and a capacitance amplifying module coupled to the comparison unit for generating an equivalent capacitor, wherein a capacitance of the equivalent capacitor is K times to a capacitance of a reference capacitor of the capacitance amplifying module, and K is a real number greater than 1; wherein the compensation current and the equivalent capacitor are used for determining a compensation voltage, and when the dimming signal is disabled, a closed loop coupled to the comparison unit within the capacitance amplifying module is changed to an open loop to keep the compensation voltage at a fixed value.