| 摘要 |
The present invention relates to improving efficiency in a driver circuit for an LED lamp which uses a constant current circuit in the load. The LED driver circuit having an efficiency improving function which is connected to an AC power source includes: a rectifying circuit rectifying the AC power source; a control circuit connected to the output of the rectifying circuit; an LED load and a constant current circuit connected in series to the output of the control circuit; a capacitor connected in parallel to the LED load and the constant current circuit smoothing the output of the constant current circuit; a detection circuit for detecting whether the rectified voltage exceeds a pre set specific voltage value which is equal to or greater than the sum of the voltage of the LED when the LED load is turned on and the voltage of the constant current circuit at a point in time when the LED load is first turned on wherein the control circuit controls the output of the rectifying circuit to pass without any change when the rectified voltage does not exceed the specific voltage value and controls a first operation for blocking the output of the rectifying circuit and a second operation for passing the output of the rectifying circuit without any change to be repeated when the rectified voltage exceeds the specific voltage value. |
