Disclosed are LED driver circuits, and methods of driving LED loads. In one embodiment, an LED driver can include: (i) an SCR coupled to an AC power supply, and configured to generate a DC voltage through a first rectifier circuit; (ii) a first stage conversion circuit having an isolated topology with power factor correction, where the first stage conversion circuit is configured to convert the DC voltage to a first output voltage; (iii) where the first stage conversion circuit includes a transformer having a primary side coupled to the DC voltage, and a secondary side coupled to the first output voltage through a second rectifier circuit; and (iv) a second stage conversion circuit having a non-isolated topology, where the second stage conversion circuit is configured to convert the first output voltage to an output current configured to drive an LED load based on a conducting angle of the SCR.