PWM ripple wave treatment and constant-current control circuit

Abstract

The invention provides a PWM ripple wave treatment and constant-current control circuit. The PWM ripple wave treatment and constant-current control circuit is characterized in that the circuit comprises a constant-current control circuit and a ripple wave control circuit; according to the ripple wave control circuit, a seventh pin of an operational amplifier is a power supply end, a fourth pin of the operational amplifier is a grounding end, a second pin of the inverted input end of the operational amplifier is connected with a resistor R5, the other end of the resistor R5 is connected to the point of junction of a voltage-regulator tube VR1 and a resistor R1, the other end of the resistor R1 is connected with the positive electrode end V+ of a direct-current voltage, and the other end of the voltage-regulator tube VR1 is connected to the source electrode of a VMOS transistor; a third pin of the non-inverting input end of the operational amplifier is connected with a capacitor C3, and the other end of the capacitor C3 is connected to a sliding arm of a potentiometer RP2, so that ripple waves are sampled; a sixth pin of the output end of an integrated circuit IC1 is connected with a resistor R6, the other end of the resistor R6 is connected to the base electrode of an audion Q1, the collector electrode of the audion Q1 is connected with a fifth pin of a PWM control chip of the constant-current control circuit, and PWM control over the ripple waves can be completed through the PWM control chip. The PWM ripple wave treatment and constant-current control circuit has the advantages that the driving problem of LEDs is solved, and the service life of LED lamp beads 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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