An Adaptive Output Current Ripple Removal Circuit and Ripple Removal Method

Abstract

The present invention provides an adaptive output current removing ripple circuit and its removing method, comprising: detecting the negative terminal voltage of the LED load, when it is lower than the set voltage, the first constant current source is turned off, the second constant current source is turned on, The second constant current source discharges the compensation capacitor, the compensation voltage decreases, the output current decreases, and the negative terminal voltage of the LED load increases; when the negative terminal voltage of the LED load is greater than the set voltage, the first constant current source is turned on, and the second constant current source is turned on. The second constant current source is turned off, the first constant current source charges the compensation capacitor, the compensation voltage increases, the output current increases, and the negative terminal voltage of the LED load decreases. The present invention only detects the lowest value of the output ripple voltage, and is suitable for thyristor dimming and linear output ripple removal applications; the overheat protection of the present invention does not affect the work of the previous system, does not appear to flicker to affect the experience, and can be controlled separately MOSFET heat loss.

Description

technical field [0001] The invention relates to the field of circuit design, in particular to an adaptive output current elimination ripple circuit and a ripple elimination method thereof. Background technique [0002] Usually in the application of high power factor (PF, Power Factor), due to the limitation of the output capacitor, the output current has the AC component of the power frequency, which may cause flicker in some occasions, and it is necessary to add a ripple circuit to filter the power frequency Element. [0003] Such as figure 1 Shown is a traditional MOSFET ripple removal circuit, including resistor R1 and capacitor C1 connected in series and parallel to the output terminal, the positive-phase output terminal Vo+ is connected to the positive terminal LED+ of the LED through the transistor Q1, and the inverting output terminal Vo- is connected to the negative terminal of the LED LED-; the positive pole of diode D1 is connected to the positive phase output te...

AI Technical Summary

Problems solved by technology

[0007] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide an adaptive output current ripple removal circuit and a ripple removal method thereof, which are used to solve the low efficiency of the ripple removal scheme in the prior art and the current application range. Small, does not support thyristor dimming applications, does not support linear output ripple applications, etc.

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