CN202488808U - Novel LED constant-current driving circuit - Google Patents
Novel LED constant-current driving circuit Download PDFInfo
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- CN202488808U CN202488808U CN2011205716522U CN201120571652U CN202488808U CN 202488808 U CN202488808 U CN 202488808U CN 2011205716522 U CN2011205716522 U CN 2011205716522U CN 201120571652 U CN201120571652 U CN 201120571652U CN 202488808 U CN202488808 U CN 202488808U
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Abstract
The utility model provides a novel LED constant-current driving circuit, comprising a constant-voltage constant current source, n LED strings and a triode constant current circuit. Power input terminals of the n LED strings are connected with the constant-voltage constant current source, and power output terminals of the n LED strings are connected with a power input terminal of the triode constant current circuit. An output terminal of the triode constant current circuit is connected with the constant-voltage constant current source. The novel LED constant-current driving circuit also comprises a first resistor and a second resistor, which are connected in parallel between the output terminal of the triode constant current circuit and the ground. N is a positive integer grater than zero. In this way, the circuit power and the cost are reduced.
Description
Technical field
The utility model relates to the circuit engineering field, is specifically related to a kind of new LED constant-current drive circuit.
Background technology
The voltage that present widely used liquid crystal display television LED backlight constant-current circuit is exported power supply by booster circuit is elevated to the LED required voltage, and the constant current IC through special use carries out independent constant-current driving to every paths of LEDs again.As shown in Figure 1; Its circuit basic principle: will import power source voltage by booster circuit and be raised on the LED lamp string required voltage; In order to satisfy the voltage of LED lamp, all can be elevated on the LED lamp string maximum voltage, through special constant current IC every paths of LEDs is carried out constant current again.The input voltage of LED lamp string own is higher; When LED lamp individual difference is big, all be when LED modulating voltage (the voltage specification central value of each LED lamp is that the 3.0V maximum is 3.5V for the 3.25V minimum) minimum value like the LED lamp, at this moment constant current IC is in order to reach the purpose of constant current; The pressure drop of constant current IC internal transistor will increase a lot; The transistor voltage electric current multiplies each other, and transistorized power loss strengthens, and cost is high.
The utility model content
The purpose of the utility model provides a kind of new LED lamp constant-current drive circuit, can reduce circuit power, reduces cost.
For achieving the above object, the scheme of employing is:
A kind of new LED lamp constant-current drive circuit; Comprise constant voltage/current isolator, n paths of LEDs string and triode constant-current circuit; Said constant voltage/current isolator connects said n paths of LEDs crosstalk source input, and said n paths of LEDs crosstalk source output terminal connects the power input of said triode constant-current circuit, and the output of said triode constant-current circuit is connected with said constant voltage/current isolator; Wherein, Also comprise: first resistance and second resistance, said first resistance and said second resistance are connected in parallel between the output and ground of said triode constant-current circuit, and wherein n is the positive integer greater than 0.
The utility model can be realized constant-current driving, and can control the electric current of each paths of LEDs accurately, reduces transistorized energy consumption, practices thrift cost.
Preferably, in order further to improve the accuracy of constant current control, this new LED lamp constant-current drive circuit also comprises the 3rd resistance and benchmark source of stable pressure, and said the 3rd resistance is connected between said triode constant-current circuit and the said benchmark source of stable pressure.
Wherein said triode constant-current circuit comprises: n first triode and n the 4th resistance; The collector electrode of n first triode connects different LED strings respectively; The base stage of n first triode connects said benchmark source of stable pressure through said the 3rd resistance, and the emitter of n first triode connects said constant current constant voltage source through one the 4th resistance respectively.
Preferably, this new LED lamp constant-current drive circuit also comprises the LED short-circuit protection circuit, and the input of said LED short-circuit protection circuit is connected with the output of said n paths of LEDs, and the output of said LED short-circuit protection circuit is connected with said constant voltage/current isolator.Wherein, said LED short-circuit protection circuit comprises second triode, the 5th resistance, the 6th resistance, the 7th resistance and several diodes; Each anode of said diode connects the collector electrode of different said first triodes; The negative electrode of each diode connects the base stage of said second triode through said the 5th resistance, and is connected to said the 6th resistance between the base stage of said second triode and the emitter; The collector electrode of said second triode connects said constant voltage/current isolator through said the 7th resistance.
Wherein, the parameter specification of said first triode is identical; The parameter specification of said the 4th resistance is identical.
Description of drawings
Fig. 1 is a sketch map of traditional LED constant-current drive circuit;
Fig. 2 is a structural representation of the utility model;
Fig. 3 is the schematic block circuit diagram of the utility model;
Fig. 4 is another structural representation of the utility model.
Embodiment
For ease of understanding, will combine accompanying drawing to set forth below.
As a kind of embodiment; See also Fig. 2; A kind of new LED lamp constant-current drive circuit comprises constant voltage/current isolator T1, n paths of LEDs string (L1......Ln), triode constant-current circuit T2, the 3rd resistance T4, benchmark source of stable pressure T5, the first resistance T6 and the second resistance T7;
Wherein the 3rd resistance T4 is connected between triode constant-current circuit T2 and the benchmark source of stable pressure T5; Triode constant-current circuit T2 comprises: n the first triode T21 and n the 4th resistance T22; The collector electrode of n the first triode T21 connects different LED strings respectively; The base stage of n the first triode T21 connects benchmark source of stable pressure T5 through the 3rd resistance, and benchmark source of stable pressure T5 is that the base stage of the first triode T21 provides high accuracy constant voltage; The emitter of n the first triode T21 connects constant current constant voltage source T1 through one the 4th resistance T22 respectively; Wherein, the parameter specification of the first triode T21 is identical; The parameter specification of the 4th resistance T22 is identical;
Constant voltage/current isolator T1 connects n paths of LEDs crosstalk source input, and n paths of LEDs crosstalk source output terminal connects the power input of triode constant-current circuit T2, and the output of triode constant-current circuit T2 is connected with constant voltage/current isolator T1; The first resistance T6 and the second resistance T7 are connected in parallel between the output and ground of triode constant-current circuit T2, and wherein n is the positive integer greater than 0; Total current signal controlling output voltage electric current through the first resistance T6 and each paths of LEDs of second resistance T7 collection.
The utility model can be realized constant-current driving, and can control the electric current of each paths of LEDs accurately, reduces transistorized energy consumption, practices thrift cost.
The operation principle of the utility model, as shown in Figure 3, the utility model carries out the PWM conversion according to the sample rate current signal again through LED multi-path total current signal is sampled, and realizes constant pressure and flow output.Each paths of LEDs is realized automatic constant current through the triode constant-current circuit.
Operation principle is specially: constant voltage/current isolator T1 gathers the total current signal of each LED string through the first resistance T6 and the second resistance T7; When output current during greater than set point; Constant voltage/current isolator T1 regulates through PWM (Pulse Width Modulation, pulse width modulation) and reduces output voltage and electric current; When output current during less than set point, constant voltage/current isolator T1 regulates through PWM and promotes output voltage and electric current, thereby realizes the constant-current driving function of LED, and remains triode and be in low power consumpting state.Each paths of LEDs is to realize constant current through triode constant-current circuit T2.
The base stage of n the first triode T21 is through the 3rd resistance T4 high-precision constant voltage to be provided by benchmark source of stable pressure T5; Voltage accuracy is very high; Can guarantee the constant current accuracy of the first triode T21; Let n the first triode T21 base potential all be at same voltage, same current potential, the model of each first triode T21 and characterisitic parameter are all identical; N the 4th resistance T22 resistance, specification are the same; Characteristic according to the first triode T21; The amplification of each first triode T21, saturation condition striking resemblances; The electric current that then flows through collector electrode is the same, again because constant voltage/current isolator to be input to the power supply total current of every string LED constant, so the every string LED electric current that flows through in the backlight is equal constant current.
In order to guarantee the safety of LED; The foregoing description has been done further improvement; Please refer to Fig. 4; This new LED lamp constant-current drive circuit also comprises LED short-circuit protection circuit T8, and the input of LED short-circuit protection circuit T8 is connected with the output of n paths of LEDs, and the output of LED short-circuit protection circuit T8 is connected with constant voltage/current isolator T1.Wherein, LED short-circuit protection circuit T8 comprises several diodes T81, the 5th resistance T82, the 6th resistance T83, the second triode T84 and the 7th resistance T85; Each anode of diode T81 connects the collector electrode of the first different triode T21, and the negative electrode of each diode T81 connects the base stage of the second triode T84 through the 5th resistance T82, and is connected to the 6th resistance T83 between the base stage of the second triode T84 and the emitter; The collector electrode of the second triode T84 connects constant voltage/current isolator through the 7th resistance T85.
The operation principle of LED short-circuit protection circuit T8 is: as LED string or the short circuit of partial L ED string, the collector potential of the second triode T84 is elevated, and detects through diode T81; The 5th resistance T82 and the 6th resistance T83 dividing potential drop; Output to the base stage of the second triode T84, then the collector potential of the second triode T84 is undercuted, and will press the constant-current source related potential to drag down through the 7th resistance T85 again; Constant voltage/current isolator T1 just closes output after detecting this voltage signal, thereby realizes short-circuit protection.
Above the utility model execution mode does not constitute the qualification to the utility model protection range.The modification of being done within any spirit and principle at the utility model, be equal to replacement and improvement etc., all should be included within the claim protection range of the utility model.
Claims (6)
1. new LED constant-current drive circuit; Comprise constant voltage/current isolator, n paths of LEDs string and triode constant-current circuit; Said constant voltage/current isolator connects said n paths of LEDs crosstalk source input; Said n paths of LEDs crosstalk source output terminal connects the power input of said triode constant-current circuit, and the output of said triode constant-current circuit is connected with said constant voltage/current isolator, it is characterized in that:
Said new LED constant-current drive circuit also comprises first resistance and second resistance, and said first resistance and said second resistance are connected in parallel between the output and ground of said triode constant-current circuit, and wherein n is the positive integer greater than 0.
2. new LED constant-current drive circuit according to claim 1 is characterized in that:
Said new LED constant-current drive circuit also comprises the 3rd resistance and benchmark source of stable pressure, and said the 3rd resistance is connected between said triode constant-current circuit and the said benchmark source of stable pressure.
3. new LED constant-current drive circuit according to claim 2 is characterized in that:
Said triode constant-current circuit comprises: n first triode and n the 4th resistance; The collector electrode of n first triode connects the LED string of not going the same way respectively; The base stage of n first triode connects said benchmark source of stable pressure through said the 3rd resistance, and the emitter of n first triode connects said constant current constant voltage source through one the 4th resistance respectively.
4. new LED constant-current drive circuit according to claim 1 is characterized in that:
Said new LED constant-current drive circuit also comprises the LED short-circuit protection circuit, and the input of said LED short-circuit protection circuit is connected with the output of said n paths of LEDs string, and the output of said LED short-circuit protection circuit is connected with said constant voltage/current isolator.
5. new LED constant-current drive circuit according to claim 4 is characterized in that:
Said LED short-circuit protection circuit comprises second triode, the 5th resistance, the 6th resistance, the 7th resistance and several diodes; Each anode of said diode connects the collector electrode of different said first triodes; The negative electrode of each diode connects the base stage of said second triode through said the 5th resistance, and is connected to said the 6th resistance between the base stage of said second triode and the emitter; The collector electrode of said second triode connects said constant voltage/current isolator through said the 7th resistance.
6. according to each described new LED constant-current drive circuit of claim 1 to 5, it is characterized in that: the parameter specification of said first triode is identical; The parameter specification of said the 4th resistance is identical.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205716522U CN202488808U (en) | 2011-12-29 | 2011-12-29 | Novel LED constant-current driving circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205716522U CN202488808U (en) | 2011-12-29 | 2011-12-29 | Novel LED constant-current driving circuit |
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| CN202488808U true CN202488808U (en) | 2012-10-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011205716522U Expired - Lifetime CN202488808U (en) | 2011-12-29 | 2011-12-29 | Novel LED constant-current driving circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103401209A (en) * | 2013-08-02 | 2013-11-20 | 广州视源电子科技股份有限公司 | LED backlight short-circuit protection circuit |
| CN103561514A (en) * | 2013-10-30 | 2014-02-05 | 广东省人民医院 | Thoracic cavity minimally-invasive surgery lamp block, single-lamp device, double-lamp device and using methods of three parts |
| CN104219843A (en) * | 2014-08-29 | 2014-12-17 | 深圳市奋勇光电有限公司 | Multi-output circuit with superposed constant-current control architecture |
| CN111883068A (en) * | 2020-06-18 | 2020-11-03 | 惠州市德赛西威汽车电子股份有限公司 | LCD screen constant current drive circuit that is shaded |
| CN114340086A (en) * | 2022-01-14 | 2022-04-12 | 英飞特电子（杭州）股份有限公司 | Lighting system, target voltage value determination method, system and related assembly |
-
2011
- 2011-12-29 CN CN2011205716522U patent/CN202488808U/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103401209A (en) * | 2013-08-02 | 2013-11-20 | 广州视源电子科技股份有限公司 | LED backlight short-circuit protection circuit |
| CN103401209B (en) * | 2013-08-02 | 2016-04-27 | 广州视源电子科技股份有限公司 | LED backlight short-circuit protection circuit |
| CN103561514A (en) * | 2013-10-30 | 2014-02-05 | 广东省人民医院 | Thoracic cavity minimally-invasive surgery lamp block, single-lamp device, double-lamp device and using methods of three parts |
| CN103561514B (en) * | 2013-10-30 | 2015-08-12 | 广东省人民医院 | The using method of thoracic cavity Minimally Invasive Surgery lamp block, single lamp device and two lamp device and three |
| CN104219843A (en) * | 2014-08-29 | 2014-12-17 | 深圳市奋勇光电有限公司 | Multi-output circuit with superposed constant-current control architecture |
| CN104219843B (en) * | 2014-08-29 | 2016-11-16 | 深圳市奋勇光电有限公司 | The multiplex output circuit of superposition current constant control framework |
| CN111883068A (en) * | 2020-06-18 | 2020-11-03 | 惠州市德赛西威汽车电子股份有限公司 | LCD screen constant current drive circuit that is shaded |
| CN114340086A (en) * | 2022-01-14 | 2022-04-12 | 英飞特电子（杭州）股份有限公司 | Lighting system, target voltage value determination method, system and related assembly |
| CN114340086B (en) * | 2022-01-14 | 2024-04-09 | 英飞特电子（杭州）股份有限公司 | Lighting system, target voltage value determining method and system and related components |
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| GR01 | Patent grant | ||
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| CP01 | Change in the name or title of a patent holder |
Address after: 510663 Guangdong city of Guangzhou province Guangzhou high tech Industrial Development Zone Science Road No. 192 building 4 Xue Cheng Ke Zhu Patentee after: Guangzhou Shiyuan Electronic Technology Company Limited Address before: 510663 Guangdong city of Guangzhou province Guangzhou high tech Industrial Development Zone Science Road No. 192 building 4 Xue Cheng Ke Zhu Patentee before: Guangzhou Shiyuan Electronic Technology Co.,Ltd. |
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| CX01 | Expiry of patent term |
Granted publication date: 20121010 |
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| CX01 | Expiry of patent term |