Stability control of a power factor correction circuit using adaptive mulitplier voltage feedback

摘要

A power factor correction (PFC) circuit includes an adaptive multiplier feedback control circuit to enhance stability of the PFC circuit for high input voltage and low input power (i.e., low input current) conditions. The adaptive multiplier feedback control circuit controls a voltage provided to a multiplier voltage input of a controller of the PFC circuit. The controller determines control loop gain as a function of the voltage at the multiplier voltage input terminal of the controller. The adaptive multiplier feedback control circuit increases the voltage at the multiplier voltage input of the controller is the input current to the PFC circuit increases. The PFC circuit may be used in an AC to DC converter of the driver circuit of a light fixture operable to provide power to a light source of the light fixture.

主权项

1. An adaptive multiplier feedback control circuit for a power factor correction (PFC) circuit, said adaptive multiplier feedback control circuit comprising:
a current sensor operable to sense a current of the PFC circuit; an output stage operable to provide a multiplier voltage to the PFC circuit, wherein the provided multiplier voltage is directly related to the current of the PFC circuit; the PFC circuit includes a ground, a positive input, output current sensing resistor, and a controller having a multiplier voltage input; and the output stage comprises
a pull-up resistor coupled between the positive input of the PFC circuit and the multiplier voltage input of the controller of the PFC circuit, anda p-type transistor having a first terminal coupled to the multiplier voltage input of the controller of the PFC circuit, a second terminal coupled to the ground of the PFC circuit, and a control terminal coupled to the output current sensing resistor of the PFC circuit, wherein the control terminal is coupled to the output current sensing resistor of the PFC circuit via an input resistor of the adaptive multiplier feedback control circuit.