CN202696967U - Light-emitting diode (LED) constant-current drive circuit - Google Patents
Light-emitting diode (LED) constant-current drive circuit Download PDFInfo
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- CN202696967U CN202696967U CN 201220301501 CN201220301501U CN202696967U CN 202696967 U CN202696967 U CN 202696967U CN 201220301501 CN201220301501 CN 201220301501 CN 201220301501 U CN201220301501 U CN 201220301501U CN 202696967 U CN202696967 U CN 202696967U
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Abstract
The utility model discloses a light-emitting diode (LED) constant-current drive circuit. The LED constant-current drive circuit consists of a power conversion circuit and a control circuit, wherein the power conversion circuit comprises a rectifier bridge, a power transformer, an inductor, two triodes which are connected in parallel with fly-wheel diodes, three capacitors and two rectifier diodes, wherein the input end of the rectifier bridge is connected with commercial power; the first triode is connected in series with the second triode and then is connected with the output voltage of the rectifier bridge; the bases of the first triode and the second triode are connected with the control circuit; the first capacitor is connected in series with the second capacitor and then is connected with the output voltage of the rectifier bridge; one end of the coil of a primary side of the power transformer is connected with the series point of the first capacitor and the second capacitor; the other end of the coil of the primary side of the power transformer is connected with the series point of the two triodes; the output voltage of the coil of a secondary side of the power transformer drives an LED light source after being rectified by all waves of the two rectifier diodes and filtered by the inductor and the third capacitor. The utility model has the advantages that the LED constant-current drive circuit is high in loading capacity, low in manufacturing cost, high in reliability, high in conversion efficiency and the like, and is an ideal high-power LED lighting lamp drive circuit.
Description
Technical field
The utility model relates to a kind of constant-current circuit for the driving LED illuminating lamp, belongs to power technique fields.
Background technology
In recent years, life-span and the light efficiency of white light LEDs improve rapidly, and led light source becomes strong competitor in the illumination market just gradually.Because LED is the semiconductor device of characteristic sensitivity, has again negative temperature characteristic, need to use the low voltage constant current source to drive, and the LED device is intimate harsh to the requirement of driving power.
At present, using more LED drive scheme is to adopt special-purpose great power LED to drive chip, but LED driving chip cost is higher, and the power capacity of its inner integrated switch pipe is limited, and load capacity is not strong, can't drive high-power LED.The regular tap power technology is ripe, and power bracket is large, but all is constant voltage output, lacks constant current control, if as the driving power of great power LED, also must add second level constant-current source thereafter, has so not only increased cost, has also reduced energy conversion efficiency.
The utility model content
The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of load capacity strong, reliable, and cost is low, the LED constant-current drive circuit that efficient is high.
The alleged problem of the utility model realizes with following technical proposals:
A kind of LED constant-current drive circuit, formed by power conversion circuit and control circuit, described power conversion circuit comprises rectifier bridge, power transformer, inductance, two triode, three electric capacity and two rectifier diodes of also following fly-wheel diode, the input termination civil power of described rectifier bridge; The first triode with connect the rectifier bridge output voltage, the base stage connection control circuit of the two after the second triode is connected in series; Also connect the rectifier bridge output voltage behind the first electric capacity and the second capacitance series; Primary coil one termination first electric capacity of described power transformer and being connected in series a little of the second electric capacity, the serial connection point of two triodes of another termination, the output voltage of secondary coil are successively through two rectifier diode full-wave rectifications, inductance and the 3rd capacitor filtering rear drive led light source.
Above-mentioned LED constant-current drive circuit, described control circuit comprises PWM chip, control transformer, two triodes and current sampling resistor, described PWM chip adopts TL494, the mid point of the primary coil of described control transformer meets Vcc, and the output voltage of two secondary coils drives respectively the emitter junction of the first triode and the second triode; The grounded emitter of the 3rd triode and the 4th triode, base stage connect respectively 8 pin and 11 pin of PWM chip, and collector electrode connects respectively the two ends of the primary coil of control transformer; Described current sampling resistor is connected in the driving loop of led light source, 2 pin of its output voltage access PWM chip.
Above-mentioned LED constant-current drive circuit also comprises two voltage sample resistance in the formation of described control circuit, connect the driving voltage of led light source after the two is connected in series, and their serial connection point connects 16 pin of PWM chip.
The utility model is the LED constant-current drive circuit that adopts the design of regular tap power supply chip, has a load capacity strong, low cost of manufacture, and high reliability, by single-stage converter driving LED light source, efficient is better than two-step scheme to this circuit with the commercial power rectification.Power output of the present utility model can reach 1000W, is a kind of desirable high-power LED illuminating lamp drive circuit.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is electrical schematic diagram of the present utility model.
Each label is among the figure: D1, rectifier bridge; D2, D3, fly-wheel diode; D4, D5, rectifier diode; C1～C3, electric capacity; T1, power transformer, T2, control transformer; L, inductance; Q1～Q4 triode; U, PWM chip; R1～R3, resistance; LEDs, led light source.
Embodiment
Referring to Fig. 1, civil power is through rectifier bridge D1 rectification, capacitor C 1, C2 filtering, from the power supply of the dividing potential drop place of two electric capacity, half-bridge switch circuit conversion through power transformer T1 sustained diode 2, D3 switch triode Q1, Q2 composition, secondary through rectifier diode D4, D5 full-wave rectification at power transformer T1, inductance L and capacitor C 3 are filtered into that to supply with led light source behind the smooth direct current electricity luminous.
The electric current of led light source LEDs of flowing through enters the 2nd pin of PWM chip U after current sampling resistor R1 sampling, after the inner comparison operation of PWM chip U, regulate PWM chip the 8th, 11 pin and recommend the duty ratio of the pulse signal of output, pulse signal drives control transformer T2 through triode Q3, Q4 respectively, pulse signal makes constant output current through the duty ratio that control transformer T2 is isolated in secondary drive switch triode Q1, Q2 conducting.When led light source generation open circuit etc. makes the situation of power supply zero load, for not making output voltage too high, output voltage enters the 16th pin of PWM chip U after resistance R 2, the sampling of R3 dividing potential drop, after the inner comparison operation of PWM chip U, regulate PWM chip U the 8th, 11 pin and recommend the duty ratio of the pulse signal of output, pulse signal drives control transformer T2 through triode Q3, Q4 respectively, is isolated in the duty ratio of secondary drive switching tube Q1, Q2 conducting through T2, with the output voltage control of power supply in set point.
The characteristics of the utility model circuit
The commercial power rectification is by single-stage converter output driving LED light source, and efficient is better than two-step scheme.The half-bridge switch power source design power is in 1000W, adopt cheap both-end PWM chip TL494, this chip is by Texas Instruments's design and release at the beginning of the 1980's, obtain at once accepting extensively of market after the release, for many years especially extensive use on the ATX of PC half-bridge power supply, it is very outstanding that the framework of TL494 is proved, and reliability is high.TL494 has become a kind of industrial standard chip, by the compatible chip of a lot integrated circuit manufacturers produce, chooses cheap.
Claims (3)
1. LED constant-current drive circuit, it is characterized in that, it is comprised of power conversion circuit and control circuit, described power conversion circuit comprises rectifier bridge (D1), power transformer (T1), inductance (L), two triode, three electric capacity and two rectifier diodes of also following fly-wheel diode, the input termination civil power of described rectifier bridge (D1); The first triode (Q1) with connect rectifier bridge (D1) output voltage, the base stage connection control circuit of the two after the second triode Q2 is connected in series; The first electric capacity (C1) with also connect rectifier bridge (D1) output voltage after the second electric capacity (C2) is connected in series; Primary coil one termination, first electric capacity (C1) of described power transformer (T1) and being connected in series a little of the second electric capacity (C2), the serial connection point of two triodes of another termination, the output voltage of secondary coil are successively through two rectifier diode full-wave rectifications, inductance (L) and the 3rd electric capacity (C3) filtering rear drive led light source (LEDs).
2. described LED constant-current drive circuit according to claim 1, it is characterized in that, described control circuit comprises PWM chip (U), control transformer (T2), two triodes and current sampling resistor (R1), described PWM chip (U) adopts TL494, the mid point of the primary coil of described control transformer (T2) meets Vcc, and the output voltage of two secondary coils drives respectively the emitter junction of the first triode (Q1) and the second triode (Q2); The grounded emitter of the 3rd triode (Q3) and the 4th triode (Q4), base stage connect respectively 8 pin and 11 pin of PWM chip (U), and collector electrode connects respectively the two ends of the primary coil of control transformer (T2); Described current sampling resistor (R1) is connected in the driving loop of led light source (LEDs), 2 pin of its output voltage access PWM chip (U).
3. described LED constant-current drive circuit according to claim 2 is characterized in that, described control circuit also comprises two voltage sample resistance, connects the driving voltage of led light source (LEDs) after the two is connected in series, and their serial connection point connects 16 pin of PWM chip (U).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220301501 CN202696967U (en) | 2012-06-26 | 2012-06-26 | Light-emitting diode (LED) constant-current drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220301501 CN202696967U (en) | 2012-06-26 | 2012-06-26 | Light-emitting diode (LED) constant-current drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202696967U true CN202696967U (en) | 2013-01-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220301501 Expired - Fee Related CN202696967U (en) | 2012-06-26 | 2012-06-26 | Light-emitting diode (LED) constant-current drive circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202696967U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108521694A (en) * | 2018-03-29 | 2018-09-11 | 电子科技大学 | A kind of LED half-bridge circuits of band feedback frequency-conversion constant-current driving |
-
2012
- 2012-06-26 CN CN 201220301501 patent/CN202696967U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108521694A (en) * | 2018-03-29 | 2018-09-11 | 电子科技大学 | A kind of LED half-bridge circuits of band feedback frequency-conversion constant-current driving |
| CN108521694B (en) * | 2018-03-29 | 2023-09-22 | 电子科技大学 | LED half-bridge circuit with feedback variable-frequency constant-current drive |
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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 |
Granted publication date: 20130123 Termination date: 20140626 |
|
| EXPY | Termination of patent right or utility model |