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

An alternating current (AC) to direct current (DC) power converter comprising:

• a rectifier operable to receive power from an AC power supply and provide a rectified voltage;
• a power factor correction (PFC) circuit coupled to receive the rectified voltage and functional to provide an output voltage and current, said PFC circuit comprising
• an adaptive multiplier feedback control circuit comprising,
• a current sensor operable to sense a current of the PFC circuit, and
• 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;
• and
• wherein the output stage comprises
• a pull-up resistor coupled between a positive input of the PFC circuit and a multiplier voltage input of a controller of the PFC circuit, and
• a 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 a ground of the PFC circuit, and a control terminal coupled to an output current sensing resistor of the PFC circuit via an input resistor of the adaptive multiplier feedback control circuit.

A light fixture comprising:

• a light source operable to provide light in response to receiving power;
• a driver circuit operable to provide power from a power source to the light source;
• the driver circuit comprises an alternating current (AC) to direct current (DC) power converter;
• the AC to DC converter comprises
• a rectifier operable to receive power from an AC power supply and provide a rectified voltage, and
• a power factor correction (PFC) circuit operable to receive the rectified voltage and provide an output voltage and current;
• the PFC circuit comprises an adaptive multiplier feedback control circuit;
• the adaptive multiplier feedback control circuit comprises
• 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;
• a DC to DC converter operable to receive the output voltage and current from the PFC circuit and provide power to the light source;
• and
• a housing configured to support the light source and the driver circuit;
• and
• wherein the output stage comprises
• a pull up resistor coupled between a positive input of the PFC circuit and a multiplier voltage input of a controller of the PFC circuit, and
• a 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 a ground of the PFC circuit, and a control terminal coupled to an 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.