The present invention relates to a high efficiency LED driver, and driving methods thereof. In one embodiment, a high efficiency LED driving method can include: (i) receiving an AC input voltage to obtain an absolute value thereof; (ii) receiving a DC bus voltage, and driving the LED device through a power switch; (iii) generating a first reference voltage according to a driving current and an expected driving current; (iv) comparing the absolute value against a sum of a driving voltage and the first reference voltage; (v) when the absolute value is greater than the sum of the driving voltage and the first reference voltage, turning off the power switch; and (vi) when the absolute value is greater than the driving voltage but less than the sum of the driving voltage and the first reference voltage, turning on the power switch to generate an output current.