led linear constant power drive circuit

Abstract

The invention discloses an LED linear constant power drive circuit, comprising an AC power supply, a rectifier bridge, an LED lamp string, a main control chip, a voltage regulating resistor, a voltage stabilizing capacitor, a compensation capacitor and a current regulating resistor; the input end of the rectifying bridge is connected to an AC Power supply, the output end of the rectifier bridge is connected to the LED light string and the main control chip. The peripheral circuit of the main control chip includes a voltage regulation resistor, a voltage stabilization capacitor, a compensation capacitor and a current regulation resistor. The current regulation resistor controls the output average current of the system. The LED linear constant power driving circuit of the present invention can realize constant power output in the application environment of voltage fluctuation; it has the advantages of high utilization rate of the light string, high power factor, good circuit effect and the like.

Description

technical field [0001] The invention relates to a constant output power circuit, in particular to an LED linear constant power drive circuit. Background technique [0002] LED high-voltage linear constant current technology has been more and more widely used due to its advantages of simple scheme, low cost, no high-frequency transformer and no EMC problems, and is gradually applied to LED thyristor dimming. [0003] The existing LED linear constant current circuit on the market such as figure 1 As shown, the input AC voltage source is rectified by the rectifier bridge 101 and connected to the positive end of the LED light string 104, and the negative end of the LED light string 104 is connected to the main control chip 102, and the current flowing through the LED light string 104 is controlled by the main control chip 102 and the current The adjustment resistor 103 is controlled, and the maintaining current control chip and the maintaining current regulating resistor contro...

AI Technical Summary

Problems solved by technology

The existing circuit has the problem that the output power cannot be constant. It changes with the change of the bus voltage. When the bus voltage is higher than the voltage drop of the LED light string and the starting voltage of the chip, the constant current output can be realized, but when the bus voltage is lower than the LED When the voltage drop of the light string and the start-up voltage of the chip, the light string cannot turn on and emit light. This working method will cause the actual average current value of the LED light to be inconsistent under different input voltages and different LED light groups, and constant power output cannot be achieved.

Images