CN202026504U - Driving circuit of light emitting diode (LED) constant current source - Google Patents
Driving circuit of light emitting diode (LED) constant current source Download PDFInfo
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- CN202026504U CN202026504U CN2011200757738U CN201120075773U CN202026504U CN 202026504 U CN202026504 U CN 202026504U CN 2011200757738 U CN2011200757738 U CN 2011200757738U CN 201120075773 U CN201120075773 U CN 201120075773U CN 202026504 U CN202026504 U CN 202026504U
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Abstract
The utility model relates to a driving circuit of a light emitting diode (LED) constant current source, which comprises a tantalum capacitor, a high-accuracy resistor RS, a diode D1, a first voltage comparator, a second voltage comparator, a gate circuit, a metal oxide semiconductor (MOS) tube, an inductor L1, a voltage stabilizing block, a bandgap reference block and resistors R1 and R2, wherein the positive pole of a C1, the negative pole of the D1, the negative pole of the first voltage comparator and one side of the RS are connected with a power supply, the other side of the RS is connected with the positive pole of the first voltage comparator and is also the positive pole of an output end, the output of the first voltage comparator is connected with a pin 1 of the gate circuit, the output of the gate circuit is connected with the grid electrode of the MOS tube, the source electrode of the MOS tube is grounded, the drain electrode of the MOS tube is connected with the positive pole of the D1 and one end of the L1, the other end of the L1 is the negative pole of the output end, a pin 2 of the bandgap reference block and the input of the voltage stabilizing block are connected with the power supply, the output of the voltage stabilizing block is connected with a pin 1 of the bandgap reference block and a pin 3 of the gate circuit, the output of the bandgap reference block is connected with the positive pole of the second voltage comparator and is connected with the negative pole of the second voltage comparator by the resistors R1 and R2 in a pressure dividing way, and the output of the second voltage comparator is connected with a pin 2 of the gate circuit. The driving circuit of the LED constant current source has the advantages of high accuracy and strong reliability.
Description
[technical field]
The utility model belongs to power circuit control field, relates to the LED Driving technique, particularly a kind of LED constant current source driving circuit.
[background technology]
LED (LightEmittingDiode, light-emitting diode) illumination has obtained global concern as a kind of brand-new lighting technology, is described as the revolution for the third time on the human illumination history.Compare with relative traditional halogen low-voltage lighting, adopt high-brightness LED to have a lot of benefits as interior decoration lamp, Landscape Lighting, vehicle-mounted illumination.High-brightness LED can provide bigger brightness with littler power consumption, the characteristics that have energy-saving and environmental protection, antidetonation, long service life and connect fast.
Because environment supply voltage difference in different application, and the difference of LED forward voltage in order to ensure performance of LED the best and permanent working life, just need an effective constant-current drive circuit.And the control of the constant voltage of traditional AC/DC or DC/DC can not be played the effect of constant current, therefore, adopts a current sense resistor to feed back the LED electric current usually and realizes its constant current control.
[utility model content]
The purpose of this utility model provides a kind of LED constant current source driving circuit, and it is low to drive precision at general LED, the shortcoming of poor reliability; utilize precision sampling resistor and overheat protector technology; cooperate corresponding circuit, formation has temperature protection, the high accuracy LED constant-current controller of LED open-circuit-protection.
To achieve these goals, the technical scheme that the utility model adopted is as follows: a kind of LED constant current source driving circuit, it is characterized in that: comprise tantalum electric capacity, precision resister RS, diode D1, first voltage comparator, gate circuit, metal-oxide-semiconductor, and inductance L 1, the positive pole of capacitor C 1 wherein, the negative pole of diode D1, the side of the negative pole of first voltage comparator and precision resister RS links to each other with power supply, the opposite side of precision resister RS links to each other with the positive pole of first voltage comparator, and be the positive pole of this drive circuit output, the pin 1 of the output AND circuit of first voltage comparator links to each other, the output of gate circuit links to each other with the grid of metal-oxide-semiconductor, the source ground of metal-oxide-semiconductor, the positive pole of drain electrode and diode D1, one end of inductance L 1 links to each other, and the other end of inductance L 1 is the negative pole of this drive circuit output;
Described temperature protection circuit comprises regulator block, band-gap reference piece, the second voltage comparator resistance R 1, R2, described gate circuit; described metal-oxide-semiconductor; the pin 2 of band-gap reference piece, the input of regulator block link to each other with power supply; the output of regulator block links to each other with the pin 1 of band-gap reference piece, the pin 3 of gate circuit; the output of band-gap reference piece links to each other with the positive pole of second voltage comparator; resistance R 1, R2 are connected between power supply and the ground; node between resistance R 1, the R2 connects the negative pole of second voltage comparator, and the pin 2 of the output AND circuit of second voltage comparator links to each other.
Advantage of the present utility model is: when output driving current during at 600～700mA, constant current accuracy can be better than ± and 5%; Working temperature surpasses 160 ℃, and circuit enters the overtemperature protection state automatically, is lower than 140 ℃, reworks; The LED open-circuit-protection; Efficient is up to 95%; Wide input voltage range: 8V～32V very, maximum output current 1.2A; Can drive tens of watts LED.
[description of drawings]
Below in conjunction with the drawings and specific embodiments this module is described in further detail;
Fig. 1 is the utility model LED constant current source driving circuit schematic diagram
[embodiment]
See also shown in Figure 1ly, the utility model is divided into constant-current circuit and temperature protection circuit two parts.
Constant-current circuit comprises tantalum capacitor C 1 (10uF～100uF), precision resister RS (0.14～0.16 Ω), Schottky diode D1 (V
RRM, V
RSM〉=50V), voltage comparator CS, gate circuit J, metal-oxide-semiconductor T1, and inductance L 1.Wherein the side of the negative pole of the negative pole of the positive pole of capacitor C 1, diode D1, voltage comparator CS and precision resister RS links to each other with power supply.The opposite side of precision resister RS links to each other with the positive pole of voltage comparator CS, and is the positive pole of this drive circuit output.The pin 1 of the output AND circuit J of voltage comparator CS links to each other, the output of gate circuit J links to each other with the grid of metal-oxide-semiconductor T1, the source ground of metal-oxide-semiconductor T1, drain electrode links to each other with the positive pole of diode D1, an end of inductance L 1, and the other end of inductance L 1 is the negative pole of this drive circuit output.
The said temperature protective circuit comprises regulator block U1, band-gap reference piece (BANDGAP REF), voltage comparator UVLO, resistance R 1, R2, gate circuit J, metal-oxide-semiconductor T1.The pin 2 of band-gap reference piece, the input of regulator block link to each other with power supply.The output of regulator block links to each other with the pin 1 of band-gap reference piece, the pin 3 of gate circuit J.The output of band-gap reference piece links to each other with the positive pole of voltage comparator UVLO.Resistance R 1, R2 are connected between power supply and the ground, and the node between resistance R 1, the R2 connects the negative pole of voltage comparator UVLO, and the pin 2 of the output AND circuit J of voltage comparator UVLO links to each other.
The operation principle of the utility model circuit is: the one tunnel is constant-current circuit, and one the tunnel is overheating protection circuit.In constant-current circuit, when power supply VCC powered on, the initial current of inductance L 1 and precision resister RS was zero, and the output current of LED also is zero.At this time, voltage comparator CS is output as height, the internal power switch conduction, and the drain electrode output potential of metal-oxide-semiconductor T1 is low.Electric current flows to ground by inductance L 1, precision resister RS, LED and internal power switch from VCC.The slope that electric current rises is by VCC, inductance L 1 and LED pressure drop decision.On precision resister RS, produce a pressure reduction VCSN, when (VIN-VCSN)＞115mV, the output step-down of voltage comparator CS, the internal power switch turn-offs, electric current flows through inductance L 1, precision resister RS, LED and Schottky diode D1 with another slope, when (VIN-VCSN)＜85mV, power switch reopens, and is formed in the average current on the LED like this.The high-side current sampling structure makes external component quantity seldom, adopts the precision resister resistance R S of 1% precision, the LED output current is controlled at ± 5% precision, realize constant current.
In overheating protection circuit, the band-gap reference piece can accurately characterize variation of temperature.By the ratio of resistance R 1 with R2, the turnover voltage of setting voltage comparator UVLO.When circuit temperature surpasses 160 ℃, built-in potential is higher than pin 2 current potentials of band-gap reference piece, and output is higher than inverse values, and then driving gate circuit J, makes circuit enter the TSD guard mode, and stops electric current output.When circuit temperature is lower than 140 ℃, built-in potential is lower than pin 1 current potential of band-gap reference piece, and output 1.23V is lower than inverse values, and then cancellation is to the influence of gate circuit J, and circuit returns to operating state again.Wherein the current potential of the pin 1,2 of band-gap reference piece is realized overheat protector thus by output, the input decision of regulator block U1.
Claims (1)
1. a LED constant current source driving circuit is characterized in that: comprise constant-current circuit and temperature protection circuit;
Described constant-current circuit comprises tantalum electric capacity, precision resister RS, diode D1, first voltage comparator, gate circuit, metal-oxide-semiconductor, and inductance L 1, the positive pole of capacitor C 1 wherein, the negative pole of diode D1, the side of the negative pole of first voltage comparator and precision resister RS links to each other with power supply, the opposite side of precision resister RS links to each other with the positive pole of first voltage comparator, and be the positive pole of this drive circuit output, the pin 1 of the output AND circuit of first voltage comparator links to each other, the output of gate circuit links to each other with the grid of metal-oxide-semiconductor, the source ground of metal-oxide-semiconductor, the positive pole of drain electrode and diode D1, one end of inductance L 1 links to each other, and the other end of inductance L 1 is the negative pole of this drive circuit output;
Described temperature protection circuit comprises regulator block, band-gap reference piece, second voltage comparator, resistance R 1, R2, described gate circuit; described metal-oxide-semiconductor; the pin 2 of band-gap reference piece, the input of regulator block link to each other with power supply; the output of regulator block links to each other with the pin 1 of band-gap reference piece, the pin 3 of gate circuit; the output of band-gap reference piece links to each other with the positive pole of second voltage comparator; resistance R 1, R2 are connected between power supply and the ground; node between resistance R 1, the R2 connects the negative pole of second voltage comparator, and the pin 2 of the output AND circuit of second voltage comparator links to each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200757738U CN202026504U (en) | 2011-03-22 | 2011-03-22 | Driving circuit of light emitting diode (LED) constant current source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200757738U CN202026504U (en) | 2011-03-22 | 2011-03-22 | Driving circuit of light emitting diode (LED) constant current source |
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| Publication Number | Publication Date |
|---|---|
| CN202026504U true CN202026504U (en) | 2011-11-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011200757738U Expired - Fee Related CN202026504U (en) | 2011-03-22 | 2011-03-22 | Driving circuit of light emitting diode (LED) constant current source |
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| CN (1) | CN202026504U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102595727A (en) * | 2012-02-15 | 2012-07-18 | 深圳市金积嘉电子工业有限公司 | Control system of vehicle-mounted LED (Light Emitting Diode) daytime running light |
| CN103338563A (en) * | 2013-07-10 | 2013-10-02 | 电子科技大学 | Alternating current LED driving circuit free from influence of power grid fluctuation |
| CN111107695A (en) * | 2019-11-27 | 2020-05-05 | 武汉常恒科技有限公司 | Intelligent LED lamp dimming system |
-
2011
- 2011-03-22 CN CN2011200757738U patent/CN202026504U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102595727A (en) * | 2012-02-15 | 2012-07-18 | 深圳市金积嘉电子工业有限公司 | Control system of vehicle-mounted LED (Light Emitting Diode) daytime running light |
| CN103338563A (en) * | 2013-07-10 | 2013-10-02 | 电子科技大学 | Alternating current LED driving circuit free from influence of power grid fluctuation |
| CN103338563B (en) * | 2013-07-10 | 2015-04-22 | 电子科技大学 | Alternating current LED driving circuit free from influence of power grid fluctuation |
| CN111107695A (en) * | 2019-11-27 | 2020-05-05 | 武汉常恒科技有限公司 | Intelligent LED lamp dimming system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20111102 Termination date: 20160322 |