Referring now to FIG. 1, shown is a schematic block diagram of an example LED drive circuit. Referring also to FIG. 2, shown is a waveform diagram of example operation of the LED drive circuit of FIG. 1. In this example, LED drive circuit A can include silicon-controlled rectifier dimmer TRIAC, bleeder circuit 1′, controller 2′, constant current control circuit 3′, and rectification circuit 4′. LED drive circuit A may also include diode D1 connected to a direct current bus, and filter capacitor C1 connected in parallel with an LED load. Silicon-controlled rectifier dimmer TRIAC can connect between rectification circuit 4′ and an alternating current input terminal to chop an alternating current input voltage. Rectification circuit 4′ can convert the alternating current input voltage into a direct current bus voltage VBUS at a terminal of the direct current bus. Constant current control circuit 3′ may be substantially connected in series with the LED load. Constant current control circuit 3′ can control transistor Q1 to operate in a linear region such that a current flowing through the LED load is constant and controllable.