High efficiency constant current LED drive circuit and drive method

Abstract

The invention discloses a high efficiency constant current LED drive circuit and a drive method. The drive circuit comprises a resistor R1 and a stabilizer tube Z1 which are connected in series, a first capacitor C1 connected in parallel with the stabilizer tube Z1, and a freewheeling diode D1 and an inductor L which are connected in series at the two ends of a load LED. The drive circuit also comprises a power switch MOS transistor which has a grid connected with the cathode of the stabilizer tube Z1, a drain electrode connected between the inductor L and the freewheeling diode D1 and a source electrode connected with the anode of a current feed diode D2 of which the cathode is connected with the cathode of the stabilizer tube Z1, and a source electrode drive control circuit which is connected between the source electrode of the power switch MOS transistor and a sampling resistor RCS so as to adaptively control the power switch MOS transistor from the source electrode. The drive circuit consumes lower current and reduces the voltage on a power supply circuit, thereby reducing the power consumption, improving the efficiency, simultaneously generating a self-adapting turnoff time which is inversely proportional to an output voltage, and realizing the constant current output.

Description

technical field [0001] The invention relates to an LED driving circuit and a driving method, in particular to a high-efficiency constant current LED driving circuit and a driving method. Background technique [0002] figure 1 is a schematic diagram of a traditional LED drive circuit. like figure 1 As shown, the resistor R1 and the voltage regulator tube Z1 are connected in series between the power supply VIN and the ground, the positive pole of the voltage regulator tube Z1 is connected to the ground, the negative pole of the voltage regulator tube Z1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to The power supply VIN; the capacitor C1 is connected in parallel to both ends of the Zener tube Z1; the negative pole of the freewheeling diode D1 is connected to the positive pole of the load LED and the power supply VIN, and the positive pole of the freewheeling diode D1 is connected to the first end of the inductor L, and the in...

AI Technical Summary

Problems solved by technology

[0004] In the above-mentioned traditional drive circuit, there are two disadvantages as follows: First, the power supply VIN supplies power to the drive circuit through the resistor R1, the capacitor C1, and the voltage regulator tube Z1

[0007] It can be seen that the traditional LED drive efficiency is low, and the output current is greatly affected by the output voltage

Images