A single-stage driver for an LED device, configured to be coupled between a power supply and the LED device, comprises: a rectifier, a DC-to-DC converter, a resistor and a controller. The rectifier is configured to be coupled to the power supply and convert an alternating voltage from the power supply into a first direct voltage. The DC-to-DC converter, which comprises at least two switches, is coupled between the rectifier and the LED device and configured to receive the first direct voltage and provide a constant current to the LED device. The resistor is configured to be coupled in series with the LED device. The controller is coupled between the resistor and the at least two switches, and configured to keep the current through the LED device stable around a predetermined current value by controlling the switches based on a voltage across the resistor, wherein all the at least two switches are turned on or off synchronously.