An LED driving circuit is provided for driving an LED module, comprising a transistor switch and a feedback controller. The transistor switch has a control terminal, a first terminal, and a second terminal. The first terminal is coupled to the LED module and the control terminal receives a control signal for controlling a current passing through the transistor switch. The feedback controller receives a reference voltage and a current detecting signal indicative of the magnitude of the current and generates the control signal accordingly. The feedback controller is connected to a driving power source with level higher than the level of the first terminal of the transistor switch. Hence, the maximum level of an adjustable range of the control signal is higher than the first terminal of the transistor switch.