pwm ripple processing and constant current control circuit

Abstract

The present invention provides a PWM ripple processing and constant current control circuit. The key points are: it includes a constant current control circuit and a ripple control circuit. The ground terminal, the second pin of the inverting input terminal is connected to the resistor R5, the other end of the resistor R5 is connected to the connection point between the voltage regulator tube VR1 and the resistor R1, the other end of the resistor R1 is connected to the positive terminal V+ of the DC voltage, and the voltage regulator tube The other end of VR1 is connected to the source of the VMOS tube; the third pin of the non-inverting input end of the operational amplifier is connected to the capacitor C3, and the other end of the capacitor C3 is connected to the sliding arm of the potentiometer RP2 to complete the sampling of the ripple; the integrated circuit The 6th pin of the output terminal of IC1 is connected to the resistor R6, the other end of the resistor R6 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the 5th pin of the PWM control chip of the constant current control circuit, and the pattern is completed through the PWM control chip. Wave PWM control. The positive effect of the invention is that: the driving problem of the LED is solved, and the service life of the LED lamp bead is greatly prolonged.

Description

technical field [0001] The invention relates to a pulse width modulation (PWM) ripple processing and constant current control circuit, in particular to a switching power supply circuit applied to LED constant current drive and other non-electrolytic capacitors with high requirements on the ripple coefficient. Background technique [0002] The current LED drive power supply circuit includes a constant current control circuit, which includes a PWM control chip. Because the circuit has no electrolytic capacitors, it is difficult for its ripple index to meet the requirements of LED drive, which affects the service life of LED lamps. The pearl light of the lamp decays seriously and will fail soon. Compared with the service life of LED lamp beads, the use of LED lamp beads is restricted. Better LED lamps basically fail after about 10,000 hours and cannot continue to work. Specifically, the current LED lamps generally have a service life of one year, and few can reach 3 years, whi...

AI Technical Summary

Problems solved by technology

Better LED lamps basically fail after about 10,000 hours and cannot continue to work. Specifically, the current LED lamps generally have a service life of one year, and few can reach 3 years, which is far from the continuous service life of 50,000 hours.

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