CN211606861U - Parallel LED current-sharing control circuit - Google Patents
Parallel LED current-sharing control circuit Download PDFInfo
- Publication number
- CN211606861U CN211606861U CN201921891476.3U CN201921891476U CN211606861U CN 211606861 U CN211606861 U CN 211606861U CN 201921891476 U CN201921891476 U CN 201921891476U CN 211606861 U CN211606861 U CN 211606861U
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- led
- resistance
- operational amplifier
- control circuit
- pmos
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- 230000000295 complement effect Effects 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 description 2
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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Abstract
The utility model provides a parallelly connected LED current-sharing control circuit, includes first PMOS pipe and second PMOS pipe, and the grid of two PMOS pipes links to each other, and the source electrode all is connected with the power, and the drain electrode is connected two input of operational amplifier through the first resistance that the resistance equals and second resistance respectively, be connected with a pair of complementary adjusting tube between first LED and second LED's the positive pole, the control end of adjusting tube all is connected with an operational amplifier output, be connected with the same feedback resistance between two input of operational amplifier and the positive pole of first LED and second LED respectively, first LED and second LED's negative pole ground connection. Adopt parallelly connected LED flow equalization control circuit, can carry out the constant current and further comparatively accurate feedback control to the electric current between the parallelly connected LED of two tunnel automatically, improved different LED's current homogeneity.
Description
Technical Field
The utility model belongs to the technical field of the LED, a LED control technique is related to, concretely relates to parallelly connected LED flow equalization control circuit.
Background
The multiple LEDs emit light simultaneously, which generally adopts a parallel connection form, but the currents of the parallel LEDs are not naturally equal, and a constant current source is needed to provide an equal current source for each parallel LED, the relationship between the LED light-emitting brightness and the LED current is tight, and the light-emitting brightness is basically the same if the LED currents are the same.
SUMMERY OF THE UTILITY MODEL
For the technical defect who overcomes prior art existence, the utility model discloses a parallelly connected LED flow equalization control circuit.
A parallelly connected LED flow equalization control circuit, including first PMOS pipe and second PMOS pipe, the grid of two PMOS pipes links to each other, and the source electrode all is connected with the power, and the drain electrode is respectively through first resistance and two inputs of second resistance connection operational amplifier that the resistance equals, be connected with a pair of complementary adjustment pipe between first LED and the second LED's the positive pole, the control end of adjustment pipe all is connected with an operational amplifier output, be connected with the same feedback resistance between two inputs of operational amplifier and first LED and the second LED's the positive pole respectively, first LED and second LED's negative pole ground connection.
Preferably, the gate of the first PMOS transistor or the second PMOS transistor is connected to the source.
Specifically, the resistance values of the first resistor and the second resistor are 1-10 ohms.
Adopt parallelly connected LED flow equalization control circuit, can carry out the constant current and further comparatively accurate feedback control to the electric current between the parallelly connected LED of two tunnel automatically, improved different LED's current homogeneity.
Drawings
Fig. 1 is a schematic diagram of a specific implementation manner of the parallel LED current-sharing control circuit of the present invention, in which the reference numbers are: VCC-power supply, VB-bias voltage, P1-first PMOS tube, P2-second PMOS tube, D1-first LED tube, D2-second LED tube, R1-first resistor, R2-second resistor, RF-feedback resistor, AMP-operational amplifier and TG-complementary adjusting tube.
Detailed Description
The following describes the present invention in further detail with reference to the accompanying drawings.
Parallelly connected LED flow equalization control circuit, including first PMOS pipe and second PMOS pipe, the grid of two PMOS pipes links to each other, and the source electrode all is connected with the power, and the drain electrode is respectively through first resistance and two inputs of second resistance connection operational amplifier that the resistance equals, be connected with a pair of complementary adjustment pipe between first LED and second LED's the positive pole, the control end of adjustment pipe all is connected with an operational amplifier output, be connected with the same feedback resistance between two inputs of operational amplifier and first LED and second LED's the positive pole respectively, first LED and second LED's negative pole ground connection.
The first PMOS tube and the second PMOS tube can be connected with an external bias voltage VB, the gate source of one MOS tube can also be connected to form a self-bias state, and the complementary adjusting tube is a PMOS tube and an NMOS tube or a PNP tube and an NPN tube, wherein a pair of source and drain are respectively and correspondingly connected.
The utility model has the following adjustment principle that the bias voltage makes the grid source voltage VGS of two PMOS tubes equal, the output current of the two PMOS tubes has difference due to the performance difference of the first PMOS tube and the second PMOS tube, for example, the output current of the first PMOS tube is larger, the working characteristics of the PMOS tubes in the saturation region are known, when the output current is larger, the general drain source voltage VDS is also larger, the voltage drop on the first resistor is also larger, finally, the voltage of the positive pole of the first LED tube D1 connected in series with the first PMOS tube is smaller, after the operational amplifier detects the difference between the positive pole of D1 and the positive pole of D2, if the positive pole of the first LED tube D1 is connected with the positive input end of the operational amplifier, the low level is output, the N tube of the complementary adjusting tube is closed, the P tube is adjusted together with the feedback resistor as the adjusting tube, the voltage of the first LED tube D1 is increased through the negative feedback of the operational amplifier, thereby the drain voltage of the first PMOS tube is increased, the source-drain voltage difference of the first PMOS tube is reduced, so that the output current of the first PMOS tube tends to be reduced.
On the contrary, if the output current of the first PMOS transistor is small, it can be known from the operating characteristics of the PMOS transistor in the saturation region that when the output current is large, the general drain-source voltage VDS is also small, the voltage drop through the first resistor is also small, and finally the voltage of the positive electrode of the first LED transistor D1 connected in series with the first PMOS transistor is large, after the operational amplifier detects the difference between the positive electrode of D1 and the positive electrode of D2, it is still assumed that the positive electrode of the first LED transistor D1 is connected to the positive input end of the operational amplifier, a high level is output, the P transistor of the complementary adjusting transistor is turned off, the N transistor is used as an adjusting transistor for adjustment, and the voltage of the positive electrode of the first LED transistor D1 is reduced through the negative feedback of the operational amplifier, so that the drain voltage of the first PMOS transistor is reduced, and the; the output current of the first PMOS tube tends to increase; and finally, the two ends of the operational amplifier are balanced, and the output currents of the two LED tubes tend to be equal. The resistance value range of the first resistor and the second resistor is 3-5V of power supply voltage, and the value range of the resistance value of the first resistor and the second resistor is generally below 10 ohms when the LED conducts current in milliampere level.
Adopt parallelly connected LED flow equalization control circuit, can carry out the constant current and further comparatively accurate feedback control to the electric current between the parallelly connected LED of two tunnel automatically, improved different LED's current homogeneity.
In the foregoing, the preferred embodiments of the present invention, if not obviously contradictory or based on a certain preferred embodiment, can be combined and used by any superposition, the specific parameters in the embodiments and examples are only for clearly expressing the utility model verification process of the utility model, and are not used for limiting the patent protection scope of the present invention, the patent protection scope of the present invention is still based on the claims, and all the equivalent structural changes made by the contents of the specification and the drawings of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. The utility model provides a parallelly connected LED current-sharing control circuit, its characterized in that includes first PMOS pipe and second PMOS pipe, and the grid of two PMOS pipes links to each other, and the source electrode all is connected with the power, and the drain electrode is connected two input of operational amplifier through first resistance and the second resistance that the resistance equals respectively, is connected with a pair of complementary adjusting tube between first LED and the second LED's the positive pole, the control end of adjusting tube all is connected with an operational amplifier output, be connected with the same feedback resistance respectively between two input of operational amplifier and the first LED of first LED and the second LED's the positive pole, first LED and second LED's negative pole ground connection.
2. The parallel LED current-sharing control circuit of claim 1, wherein the gate of the first PMOS transistor or the second PMOS transistor is connected with the source.
3. The parallel LED current-sharing control circuit of claim 1, wherein the first resistor and the second resistor have a resistance value of 1-10 ohms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921891476.3U CN211606861U (en) | 2019-11-05 | 2019-11-05 | Parallel LED current-sharing control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921891476.3U CN211606861U (en) | 2019-11-05 | 2019-11-05 | Parallel LED current-sharing control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211606861U true CN211606861U (en) | 2020-09-29 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921891476.3U Expired - Fee Related CN211606861U (en) | 2019-11-05 | 2019-11-05 | Parallel LED current-sharing control circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211606861U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11917737B2 (en) | 2021-08-02 | 2024-02-27 | Bio-Rad Laboratories, Inc. | Circuit for sharing current between parallel LEDs or parallel strings of LEDs |
-
2019
- 2019-11-05 CN CN201921891476.3U patent/CN211606861U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11917737B2 (en) | 2021-08-02 | 2024-02-27 | Bio-Rad Laboratories, Inc. | Circuit for sharing current between parallel LEDs or parallel strings of LEDs |
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200929 |