Afterglow eliminating circuit

Abstract

The embodiment of the invention discloses an afterglow eliminating circuit which is applied to the field of electronics. The afterglow eliminating circuit comprises input ends, an eliminating triode, an eliminating resistor and a trigger circuit, wherein the inputs ends are used for being connected with an output end of a driving power supply and comprise a positive pole input end and a negative pole input end; a collector and an emitter of the eliminating triode and the eliminating resistor are connected in series between the input ends; and the trigger circuit is connected with a base of the eliminating triode and is used for closing the eliminating triode when voltage at the input ends is reduced to trigger voltage. The afterglow eliminating circuit disclosed by the embodiment of the invention can rapidly eliminate afterglow.

Description

technical field [0001] The invention relates to the field of electronics, in particular to an afterglow elimination circuit. Background technique [0002] LED lighting has the advantages of energy saving, long life, and high display index, and is widely used in commercial, public welfare, and family fields. Among them, low-power LED lighting systems are widely used, such as spotlights, bulb lamps, T5 / T8 lamps, etc. The low-power LED lighting system includes a driving power supply and LED lights. [0003] At present, in low-power LED lighting systems, low cost and high performance are generally required. Therefore, the driving power supply in this type of lighting system mostly adopts a single-stage structure to reduce costs, please refer to figure 1 Shown is a schematic diagram of the structure of the driving power supply. The driving power supply includes a rectification and filtering unit 101, a power conversion unit 102, and output terminals X1 and X2. The power conver...

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Problems solved by technology

[0004] In the prior art, since there is a large-value filter capacitor between the output terminals, when the power is turned off, there is still a large amount of energy stored in the filter capacitor, and the LED is slowly discharged. Please refer to figure 2 It is a schematic diagram of the output voltage during the shutdown process of the driving power in the prior art, that is, the voltage across the LED, where Un is the normal voltage during normal operation, and Uth is the LED turn-on voltage, that is, as long as the voltage across the LED is greater than Uth, the LED will generate Visible light, when the power supply is turned off at t0, the output voltage Uo rapidly decreases from Un to U1 during the period from t0 to t1, and then the output voltage Uo drops slowly, causing the LED to maintain a weak current flow and emit a faint light visible to the naked eye, namely Afterglow, until Uo decreases to Uth at time t2, the inventors have found through research that the afterglow can last for tens of seconds during the period from t1 to t2. For users who need specific effects, this effect is very large

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