CN205249534U - LED load constant current source drive circuit - Google Patents
LED load constant current source drive circuit Download PDFInfo
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- CN205249534U CN205249534U CN201521060907.3U CN201521060907U CN205249534U CN 205249534 U CN205249534 U CN 205249534U CN 201521060907 U CN201521060907 U CN 201521060907U CN 205249534 U CN205249534 U CN 205249534U
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- triode
- current source
- constant current
- control
- drive circuit
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- 239000011159 matrix material Substances 0.000 claims description 2
- 238000012544 monitoring process Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 3
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Abstract
The utility model discloses a LED load constant current source drive circuit adopts discrete device such as current sample resistance, control triode, drive triode to build, through the collection to the electric current and utilize the switching effect of triode, makes the electric current that flows through the return circuit finally reach dynamic balance, realizes carrying on constant current drive's scheme to the LED load, compare with the constant current source chip, can effectual monitoring cost, improve the reliability simultaneously.
Description
Technical field
The utility model relates to the actuation techniques field of automobile LED load, is specifically related to a kind of LED load constantStream source driving circuit.
Background technology
Along with the application popularization rate of LED technology in vehicle-mounted lighting apparatus increases gradually, the driving of LED becomes moreCome more important, due to vehicle power environment more complicated, and require under different voltage conditions, LED's is brightIt is consistent that degree is also wanted, and this just improves gradually to the requirement of constant-current source driving LED.
Existing constant current source driving circuit uses constant-current source chip to be connected between LED load and power supply to ensureIn the time that supply voltage changes, the electric current that flows through LED load is consistent, ensures under different voltage LEDThe brightness of load is consistent, but the price of constant-current source chip is higher, makes the cost of drive circuit generally higher.
But in the time of the car load layoutprocedure of low side vehicle, consider cost performance factor, conventionally can not adopt costHigher constant-current source chip, therefore at present in low side car field, the constant-current source of being badly in need of a kind of high performance-price ratio drivesThe technical scheme of LED load.
Summary of the invention
The application solves the higher problem of existing constant current source driving circuit cost, and a kind of LED perseverance is providedStream source driving circuit, meeting under the prerequisite of constant-current source driving, effectively reduces cost, has improved and has driven electricityThe cost performance on road.
The application's technical scheme is as follows:
LED load constant current source drive circuit, described circuit comprises current sampling resistor, controls triode, drivingTriode;
The control end of described control triode is connected with the signal input part of described driving triode, described controlThe signal input part of triode processed is connected with external power supply, the signal output part of described control triode and instituteState and drive the control end of triode to be connected, the signal output part of described driving triode is connected with load;
Described current sampling resistor be serially connected in the signal input part of described driving triode and described external power supply itBetween, and described current sampling resistor is attempted by the control list of described control triode and the two ends of signal input part.
Particularly, described control triode and described driving triode are positive-negative-positive triode.
Preferably, described circuit also comprises pull down resistor;
The first end of described pull down resistor connect respectively described control triode signal input part and described in driveThe control end of moving triode, the second end ground connection of described pull down resistor.
Particularly, described load is LED light emitting diode or LED light emitting diode matrix.
The application's operation principle is: under original state, control triode in off state, drive three utmost pointsPipe is in open mode. When the electric current that external power supply provides passes through after current sampling resistor, at current sample electricityResistance two ends can produce voltage, after electric current is higher than the current value of setting, and the voltage meeting at current sampling resistor two endsMake to control triode in open mode, now drive triode to turn-off, electric current declines, when electric current is lower than establishingAfter fixed current value, the voltage at current sampling resistor two ends can make to control triode in off state, nowDrive triode to recover to open, Current rise. Final two states above can reach dynamic equilibrium, make electricityStream is stabilized in setting value. Because triode switch speed is very fast, the time that reaches balance is negligible,Thereby realizing constant current drives.
Compared with prior art, the utility model only needs simple circuit elements device just can play constant current drivingEffect, and do not affect performance, cheaply more a lot of than constant-current source chip, can effectively control cost, simultaneouslyImprove reliability.
Brief description of the drawings
Fig. 1 is the structural representation of LED load constant current source drive circuit of the present utility model;
Drawing reference numeral explanation:
Q1-controls triode; Q2-drives triode; R1-current sampling resistor; R2-pull down resistor;
VB_PR-external power supply;
Below in conjunction with the drawings and specific embodiments, the utility model is described in more detail, this practicality is newThe protection domain of type is not limited to following detailed description of the invention.
Detailed description of the invention
As shown in Figure 1, LED load constant current source drive circuit, comprises current sampling resistor R1, controls three utmost pointsPipe Q1, driving triode Q2;
Described control triode Q1 and described driving triode Q2 are positive-negative-positive triode, described control threeThe base stage of utmost point pipe Q1 is connected with the emitter stage of described driving triode Q2, and described control triode Q1 sends outEmitter-base bandgap grading is connected with external power supply VB_PR, the colelctor electrode of described control triode Q1 and described driving triodeThe base stage of Q2 is connected, and the colelctor electrode of described driving triode Q2 is connected with the first end of load, described negativeThe second end ground connection of carrying, described load is LED light emitting diode.
Described current sampling resistor R1 is serially connected in emitter stage and the described external power supply of described driving triode Q2Between VB_PR, and described current sampling resistor R1 is attempted by base stage and the emitter stage of described control triode Q1Two ends.
External power supply is as the input of current sampling resistor R1 and control triode Q1 emitter stage, current sampleThe other end of resistance R 1 is as the input that drives triode Q2 emitter stage, simultaneously also as controlling triode Q1The control signal input of base stage, controls the colelctor electrode of triode Q1 as the control that drives triode Q2 base stageSignal input, drives the colelctor electrode of triode Q2 as the input of load LED.
Preferably, described circuit also comprises pull down resistor R2, and the first end of described pull down resistor R2 connects respectivelyThe base stage of the drain electrode of described control triode Q1 and described driving triode Q2, described pull down resistor R2'sThe second end ground connection.
Technique scheme is a kind of embodiment of the present utility model, for those skilled in the art, the utility model discloses on the basis of application process and principle, be easy to make various types ofImprove or distortion, and be not limited only to the described structure of the above-mentioned detailed description of the invention of the utility model, because of before thisThe mode that face is described is preferably, and does not have restrictive meaning.
Claims (4)
1.LED load constant current source drive circuit, is characterized in that:
Described circuit comprises current sampling resistor, controls triode, drives triode;
The control end of described control triode is connected with the signal input part of described driving triode, described controlThe signal input part of triode processed is connected with external power supply, the signal output part of described control triode and instituteState and drive the control end of triode to be connected, the signal output part of described driving triode is connected with load;
Described current sampling resistor be serially connected in the signal input part of described driving triode and described external power supply itBetween, and described current sampling resistor is attempted by the control list of described control triode and the two ends of signal input part.
2. LED load constant current source drive circuit according to claim 1, is characterized in that:
Described control triode and described driving triode are positive-negative-positive triode.
3. LED load constant current source drive circuit according to claim 2, is characterized in that:
Described circuit also comprises pull down resistor;
The first end of described pull down resistor connect respectively described control triode signal input part and described in driveThe control end of moving triode, the second end ground connection of described pull down resistor.
4. LED load constant current source drive circuit according to claim 1, is characterized in that:
Described load is LED light emitting diode or LED light emitting diode matrix.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521060907.3U CN205249534U (en) | 2015-12-17 | 2015-12-17 | LED load constant current source drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521060907.3U CN205249534U (en) | 2015-12-17 | 2015-12-17 | LED load constant current source drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205249534U true CN205249534U (en) | 2016-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521060907.3U Active CN205249534U (en) | 2015-12-17 | 2015-12-17 | LED load constant current source drive circuit |
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| Country | Link |
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| CN (1) | CN205249534U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107528307A (en) * | 2016-06-22 | 2017-12-29 | 赛尔富电子有限公司 | A kind of protection circuit for LED power load short circuits |
-
2015
- 2015-12-17 CN CN201521060907.3U patent/CN205249534U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107528307A (en) * | 2016-06-22 | 2017-12-29 | 赛尔富电子有限公司 | A kind of protection circuit for LED power load short circuits |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 4 / F, building 1, No.14 Jiuxianqiao Road, Chaoyang District, Beijing 100020 Patentee after: Beijing Jingwei Hirain Technologies Co.,Inc. Address before: 8 / F, block B, No. 11, Anxiang Beili, Chaoyang District, Beijing 100101 Patentee before: Beijing Jingwei HiRain Technologies Co.,Ltd. |