Non-overshoot LED linear constant current drive circuit

Abstract

The invention discloses a non-overshoot LED linear constant current drive circuit. The circuit comprises an input rectifier bridge, an input voltage detection network, a power supply network, an LED constant current drive circuit core control unit whose input end is respectively connected with the input voltage detection network and the power supply network, an LED control switch whose input end is respectively connected with the output end of the LED constant current drive circuit core control unit. One end of the input voltage detection network is connected with the input rectifier bridge, and the other end is grounded. The power supply network is formed by connecting a resistor and a capacitor in series, wherein one end of the power supply network is connected with the input rectifier bridge, and the other end is grounded. The output end of the LED control switch is connected with an LED lamp string. According to the invention, various disadvantages of a common LED linear drive circuit can be eliminated; the LED use efficiency can be effectively improved; and the non-overshoot LED linear constant current drive circuit has the advantages of low cost, high power factor, high engineering applicability and the like.

Description

technical field [0001] The invention relates to a non-overshoot LED linear constant current drive circuit, which can adjust the brightness of the LED by changing the phase-cut angle of the input thyristor regulator. Background technique [0002] figure 1 It is an ordinary high voltage LED linear constant current drive circuit. In the figure, rectifier diodes 101, 102, 103, 104 form an AC input rectifier bridge. LED1, LED2, and LED3 are LED light strings, which are composed of multiple LEDs. The LED light strings LED1, LED2, and LED3 are connected in series, and the anode of LED1 is connected to the output of the rectifier bridge. Resistor 111 is a high-precision LED current detection resistor, REFcs is an internal reference voltage, operational amplifier 120, power MOS tube 121 and current detection resistor together form an LED linear constant current drive network. [0003] Since the LED1 light string is composed of many single LEDs in series, the forward voltage is ve...

AI Technical Summary

Problems solved by technology

If the number of LED lamps is reduced, although the utilization rate can be increased, the power consumption of the line circuit will be greatly increased, thereby reducing the overall working efficiency of the entire LED drive scheme

If you increase the current when the LED light is on, although the brightness of the LED can be improved, you need to use a higher power LED, which increases the cost of the system, and the power consumption of the system will also increase greatly.

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