CN202172519U

CN202172519U - Discharge circuit for solving problem of surplus brightness after switching off of LED lamp

Info

Publication number: CN202172519U
Application number: CN2011202902399U
Authority: CN
Inventors: 唐晓龙
Original assignee: Sichuan Jiuzhou Optoelectronics Technology Co Ltd
Current assignee: Sichuan Jiuzhou Electronic Technology Co Ltd; Sichuan Jiuzhou Optoelectronics Technology Co Ltd
Priority date: 2011-08-11
Filing date: 2011-08-11
Publication date: 2012-03-21
Anticipated expiration: 2021-08-11

Abstract

The utility model discloses a discharge circuit for solving the problem of surplus brightness after switching off of an LED lamp, belonging to a matching circuit of the LED lamp. The discharge circuit comprises LED luminescent devices serially connected between an input end VCC and a power supply, wherein the LED luminescent devices comprise a sampling LED, two ends of the sampling LED are respectively parallelly connected with a triode Q1 and a resistor R1, the triode Q1 and the resistor R1 are serially connected with at least three diodes, one end of the triode Q1 is connected with a triode Q2 via a resistor R2, and the triode Q2 is parallelly connected with two ends of the serially connected LED luminescent devices via a resistor R3. The discharge circuit is simple in structure, and can be applied to a power supply and an input end of any LED lamp to solve the problem of remaining brightness after power off, and has a wide application scope.

Description

Solve the LED light fixture and close the discharge circuit of the surplus bright problem in back

Technical field

The utility model relates to the support circuit in the LED light fixture, and a kind of LED of solution light fixture of saying so is more specifically closed the discharge circuit of the surplus bright problem in back.

Background technology

At the LED lighting field, common topological structure is the electrode interface that Switching Power Supply directly inserts the LED light fixture, causes it luminous after the energising; When switch breaks off, because also can there be lighting of part trace in its circuit output end, and then it is surplus bright that the LED light fixture can be taken place within a certain period of time; Its light can't complete obiteration, and its reason is that Switching Power Supply output operated by rotary motion has big filter capacitor, after the outage; Its inside also stores part and lights, and still can keep continuous discharge a period of time, and this problem can not influence its use in general illumination place; But in some special places, use like the LED lighting in the optical detection chamber, the existence of Yu Liang can influence the testing result of instrument; Therefore to the surplus bright problem after the outage of LED light fixture, be necessary its input circuit is improved.

The utility model content

The purpose of the utility model is to solve above-mentioned deficiency, provides a kind of LED of solution light fixture to close the discharge circuit of the surplus bright problem in back.

For solving above-mentioned technical problem, the utility model adopts following technical scheme:

A kind of LED of solution light fixture that the utility model provided is closed the discharge circuit of the surplus bright problem in back, comprises the LED luminescent device that is series between input VCC and the power supply, also comprises a sampling LED in the described LED luminescent device; Sampling LED two ends are parallel with triode Q1 and resistance R 1; Triode Q1 and resistance R 1 also are in series with at least three diodes; The end of triode Q1 also inserts triode Q2 through resistance R 2, and triode Q2 is parallel to the two ends of all LED luminescent devices of mutual series connection through resistance R 3; The two ends of all LED luminescent devices of described mutual series connection also are parallel with pliotron Q3, and pliotron Q3 also inserts between triode Q2 and the resistance R 3.

Further technical scheme is: described pliotron Q3 and triode Q2 are parallel to the two ends of mutual all LED luminescent devices of connecting through the same line road.

Technical scheme further is: described sampling LED is arranged in all LED luminescent devices that are series between VCC input and the power supply luminescent device near the power supply place.

Further technical scheme is again: the resistance of described R1, R2, R3 all is 1000 ohm.

Compared with prior art; The beneficial effect of the utility model is: through in the circuit parallelly connected pliotron Q3 device; Can carry out conducting and bleed off the electric weight in the big filter capacitor on the output VCC rapidly in the input outage of LED light fixture; After not having stored current in the middle of the big filter capacitor, the LED light fixture naturally also can its outage after not take place again surplus bright, and a kind of LED of solution light fixture that the utility model provided close the back surplus bright problem discharge circuit simple in structure; Also can act between power supply and the input of any LED light fixture and solve the surplus bright problem of outage, range of application is wide.

Description of drawings

Fig. 1 is the circuit structure diagram of the utility model.

Embodiment

Below in conjunction with accompanying drawing the utility model is done further to set forth.

As shown in Figure 1; A kind of LED of solution light fixture that the utility model provided is closed the discharge circuit of the surplus bright problem in back; Comprise the LED luminescent device that is series between input VCC and the power supply; Also comprise a sampling LED in the described LED luminescent device, this sampling LED can be set to any LED luminescent device between input VCC and the power supply in principle, but for guaranteeing the accuracy of its circuit sampling; Preferably it is arranged in all LED luminescent devices that are series between VCC input and the power supply one near the power supply place, i.e. penult LED luminescent device among Fig. 1; Sampling LED two ends are parallel with triode Q1 and resistance R 1; And triode Q1 and resistance R 1 also are in series with three diodes and are the base stage step-down of triode Q1; The end of triode Q1 also inserts triode Q2 through resistance R 2, and triode Q2 is parallel to the two ends of all LED luminescent devices of mutual series connection through resistance R 3; The two ends of all LED luminescent devices of described mutual series connection also are parallel with pliotron Q3, and the technical scheme that is more preferably is described pliotron Q3 and triode Q2 are parallel to mutual all LED luminescent devices of connecting through the same line road two ends; Described pliotron Q3 also inserts between triode Q2 and the resistance R 3; Wherein R1, R2 and R3 adopt big value resistance, and what all adopt in this execution mode is that resistance is 1000 ohm a resistance.

Being example with the LED luminescent device of rated power below describes the principle of the utility model: when LED luminescent device energising operate as normal, because sampling LED is in the LED luminescent device, its voltage is 3.3V; Because this moment, triode Q1 base voltage was lower than emitter voltage, its reason be three diode drops being provided with in the circuit to make the voltage of triode Q1 be 2.1V, the voltage at sampling LED two ends is 3.3V; So its base voltage is lower than emitter voltage, the pressure reduction between base stage and the emitter-base bandgap grading causes triode Q1 conducting, because triode Q1 connects triode Q2; Triode Q2 base voltage is higher than emitter voltage thereupon, and its reason is the two ends that triode Q2 is parallel to all LED luminescent devices, and the voltage of its base stage is 3.3V; Emitter voltage is 2.1V; Pressure reduction causes also conducting of triode Q2, because triode Q1 and all conductings of Q2, therefore this moment, pliotron Q3 base voltage was 0; Can't realize the pressure reduction conducting, input VCC can not discharged by power triode Q3.After the outage of LED luminescent device, sampling LED voltage descends, when probably dropping to 2V; Pressure reduction between triode Q1 base stage and the emitter-base bandgap grading is not enough at this moment, and its reason is that triode conducting pressure reduction is 0.7V, and this moment, the LED voltage was merely 2V; Be not enough to act on three diodes and realize its step-downs and turn-on transistor Q1, therefore do not produce base current, so triode Q1 can not conducting; And then triode Q2 can not conducting, and its reason is that triode Q1 does not have conducting, and triode Q1 collector electrode this moment is unsettled; Can't bias voltage be provided for the base stage of triode Q2, and pliotron Q3 base voltage is higher than emitter voltage at this moment, its reason is that triode Q2 does not have conducting at this moment; The voltage of triode Q2 collector electrode equals the voltage on the resistance R 3, so pliotron Q3 obtains conducting, the power output end electric weight is consumed by pliotron Q3 rapidly after the conducting; Make the big filter capacitor of input VCC no longer include remaining capacity, the LED light fixture no longer takes place surplus bright after outage.

Claims

1. one kind solves the discharge circuit that the LED light fixture is closed the surplus bright problem in back, comprises the LED luminescent device that is series between input VCC and the power supply, it is characterized in that: also comprise sampling LED in the described LED luminescent device; Sampling LED two ends are parallel with triode Q1 and resistance R 1; Triode Q1 and resistance R 1 are in series with at least three diodes; The end of triode Q1 also inserts triode Q2 through resistance R 2, and triode Q2 is parallel to the two ends of all LED luminescent devices of mutual series connection through resistance R 3; The two ends of all LED luminescent devices of described mutual series connection also are parallel with pliotron Q3, and pliotron Q3 also inserts between triode Q2 and the resistance R 3.

2. solution according to claim 1 LED light fixture is closed the discharge circuit of the surplus bright problem in back, it is characterized in that: described pliotron Q3 and triode Q2 are parallel to the two ends of mutual all LED luminescent devices of connecting through the same line road.

3. solution according to claim 1 LED light fixture is closed the discharge circuit of the surplus bright problem in back, it is characterized in that: described sampling LED is arranged in all LED luminescent devices that are series between VCC input and the power supply luminescent device near the power supply place.

4. solution LED light fixture according to claim 1 is closed the discharge circuit of the surplus bright problem in back, and it is characterized in that: the resistance of described R1, R2, R3 all is 1000 ohm.