A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boost converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.

The present disclosure relates to an AC-DC converter comprising: an AC side input port; a first DC connection and a second DC connection defining a DC side output port connectable to a load; an AC-DC rectifier having an AC rectifier side connected to the AC side input port and a DC rectifier side comprising a first DC rectifier connection and a second DC rectifier connection, wherein the first DC rectifier connection is connected to the first DC connection; a DC-AC converter having a first DC input and a second DC input, wherein the first DC input is connected to the second DC connection, and a first AC output and a second AC output, wherein the first AC output and the second AC output are connected to the AC side input port, or an AC-AC converter having a first AC input and a second AC input, wherein the first AC input is connected to the second DC connection, and a first AC output and a second AC output, wherein the first AC output and the second AC output are connected to the AC side input port. The disclosure further relates to a method of supplying power to a load by an AC-DC converter.

A Power Factor Correction (PFC) circuit that includes an unusually low value output bus capacitor is disclosed. In an embodiment, the PFC circuit includes a rectifier bridge circuit, a PFC power stage, a PFC control segment, and the small value, high-voltage capacitor. In some embodiments, the PFC control segment includes a PFC controller and a digital signal processor (DSP), and the DSP is configured to convert an high AC ripple feedback signal received from the high-voltage feedback divider to a digital high ripple feedback digital signal, transform the digital high ripple feedback digital signal to a suitable low-ripple feedback signal, convert the digital low-ripple feedback signal to an AC low-ripple feedback signal, and input the analog low-ripple feedback signal to the PFC control segment enabling the PFC circuit to operate correctly and reliably even though use of the low value output bus capacitor results in the presence of a very high AC ripple on the output voltage.