Abstract: The present invention relates to a power supply circuit for driving at least one light emitting diode (LED). The power supply circuit comprises: an input unit, an active power factor corrector, a converter, an output unit and a feedback unit. The input unit is utilized to receive power signal from a power source, and the output unit is utilized to receive power transferred from the converter for driving at least one LED. The feedback unit couples to a node between the converter and the output unit, and delivers the power signal, from the converter to the output unit, back to the active power factor corrector. The active power factor corrector monitors the power signal based on the power signal from the feedback unit for stabilizing the outputting power from the output unit and thereby driving the LED.