| 摘要 |
Disclosed are a constant current driving method and circuit enabling dimming of an LED lamp. The circuit is based on a DC-DC buck circuit consisting of a switch element (300), a diode D1, an inductor L1 and an LED lamp. The method comprises the following steps: configuring a voltage detection module (100), wherein the voltage detection module (100) receives a voltage signal of a pulsating power from rectified mains power; configuring a regulation and control circuit (200) for controlling turn-on and turn-off of the switch element (300), wherein the regulation and control circuit (200) receives a voltage signal output by the voltage detection module (100), analyzes the output voltage signal to monitor an input voltage Vi across the DC-DC buck circuit in real time, and calculates a turn-on time TH and a turn-off time TL of the switch element (300) to control a ratio of turn-on to turn-off of the switch element (300), thereby maintaining a driving current of the LED lamp to be constant. The constant current driving method and circuit are advantageous in simple circuit structure, low cost, easy dimming, safety and reliability. |
