CN203327319U

CN203327319U - BUCK circuit-based high-power LED constant-current driving device

Info

Publication number: CN203327319U
Application number: CN201320370773XU
Authority: CN
Inventors: 戴伟; 陈芳; 牟长洲; 李科
Original assignee: XINJIANG HOPE ELECTRONIC CO Ltd
Current assignee: XINJIANG HOPE ELECTRONIC CO Ltd
Priority date: 2013-06-26
Filing date: 2013-06-26
Publication date: 2013-12-04
Anticipated expiration: 2023-06-26

Abstract

Disclosed in the utility model is a BUCK circuit-based high-power LED constant-current driving device. The LED constant-current driving device comprises a switch tube control module, a BUCK main circuit, a voltage-controlled current source module and a reference capacity module, wherein the switch tube control module, the BUCK main circuit, the voltage-controlled current source module and the reference capacity module are successively connected to the ground. A common terminal of the voltage-controlled current source module and the reference capacity module is connected with an input terminal of the switch tube control module; the control terminal of the reference capacity module is connected with a drive output terminal of the switch tube control module; and a grounding terminal of the reference capacity module is grounded. According to the BUCK circuit-based high-power LED constant-current driving device, defects of high cost, low steady current precision, low reliability and small application range and the like in the prior art can be overcome, thereby realizing advantages of low cost, high steady current precision, high reliability, and large application range.

Description

A kind of large power LCD constant current driving device based on the BUCK circuit

Technical field

The utility model relates to the LED drive circuit technical field, particularly, relates to a kind of large power LCD constant current driving device based on BUCK circuit (the BUCK circuit is a kind of buck chopper device).

Background technology

Along with the rapid raising of LED efficiency, the continuous decline of cost, thrown light on by backlight and the automobile instrument of mobile phone in LED market, and not high special lighting and the Landscape Lighting field of brightness requirement expanded to common white optical illumination field.High-power (>=1W) LED lighting source and traditional incandescent lamp, the fluorescent lighting light source is compared, and has energy-conservation, photochromic purely, and the light quality is good, the life-span is long, reliable, durable, applying flexible, response are fast, environmental protection, control advantage flexibly.

For making many large power white light LEDs there is brightness and the colourity of coupling, should select constant current (LED Mean Forward Current) type of drive to drive reliably them, and the existing great power LED driving transducer that adopts peak current to control can only be controlled the peak current on LED, with the average current of brightness requirement, there is certain error.And the constant current control mode of traditional B UCK current transformer, all need Bootstrapping drive circuit or high-frequency drive transformer to carry out the driving switch pipe, and cost is higher; For floating the current transformer topology of exporting, although can simplify the driving of switching tube, but the isolating amplifier circuits such as needs increase optocoupler will be exported DC current signal and amplify, and need very high common-mode rejection ratio, and these all can increase cost and the complexity of circuit.And while being applied in the larger situation of the lighting environment temperature inversion scopes such as street lamp, the transfer ratio of the devices such as optocoupler can alter a great deal along with parameters such as temperature, has reduced precision of steady current, has also reduced reliability, has affected the scope of application.

In realizing process of the present utility model, the inventor finds in prior art at least to exist the defect such as cost is high, precision of steady current is low, reliability is low and the scope of application is little.

The utility model content

The purpose of this utility model is, for the problems referred to above, proposes a kind of large power LCD constant current driving device based on the BUCK circuit, with the advantage that realizes that cost is low, precision of steady current is high, reliability is high and the scope of application is large.

For achieving the above object, the technical solution adopted in the utility model is: a kind of large power LCD constant current driving device based on the BUCK circuit comprises the switch controlled module, BUCK main circuit, voltage controlled current source module and the reference capacitance module that are connected to successively ground; The common port of described voltage controlled current source module and reference capacitance module, be connected with the input of switch controlled module; The control end of described reference capacitance module, be connected with the drive end of switch controlled module; The earth terminal ground connection of reference capacitance module.

Further, described switch controlled module, comprise current mode controller and the driver of the control end that is connected to successively described reference capacitance module, and the oscillator and the comparator that are connected to respectively described current mode controller; Described oscillator, away from an end of current mode controller, is connected to the common port of voltage controlled current source module and reference capacitance module; The in-phase input end of described comparator is reference current Iref input, and the inverting input of comparator is connected with the BUCK principal current.

Further, the model of described current mode controller comprises UC3843.

Further, described BUCK main circuit comprises direct-current input power supplying Vin, the first capacitor C 1, the second capacitor C 2, inductance L, diode D1, the first switching tube Q1, LED and for detection of the resistance R of peak current, wherein:

The positive pole of described direct-current input power supplying Vin, through the first capacitor C 1 ground connection, with the negative electrode of diode D1, be connected, successively through the second capacitor C 2 with after inductance L, with the drain electrode of the first switching tube Q1, be connected, with the anodic bonding of LED, with the input of voltage controlled current source module, be connected;

The negative electrode of described LED, be connected to the common port of the second capacitor C 2 and inductance L; The grid of described the first switching tube Q1 is connected with the drive end of driver, and the source electrode of the first switching tube Q1 is connected with the inverting input of comparator, and the source electrode of the first switching tube Q1 is connected and ground connection with the negative pole of direct-current input power supplying Vin after resistance R.

Further, described direct-current input power supplying Vin, comprise storage battery or solar cell or ups power.

Further, described the first switching tube Q1, comprise metal-oxide-semiconductor or triode.

Further, described base station capacitance module, comprise parallel second switch pipe and the electric capacity arranged; The grid of described second switch pipe is connected with the drive end of driver; The source electrode of second switch pipe and drain electrode, be connected respectively the source ground of second switch pipe with the two ends of electric capacity.

Further, described second switch pipe, comprise metal-oxide-semiconductor or triode.

The large power LCD constant current driving device based on the BUCK circuit of each embodiment of the utility model, owing to comprising switch controlled module, BUCK main circuit, voltage controlled current source module and the reference capacitance module that is connected to successively ground; The common port of voltage controlled current source module and reference capacitance module, be connected with the input of switch controlled module; The control end of reference capacitance module, be connected with the drive end of switch controlled module; The earth terminal ground connection of reference capacitance module; Can realize that output current Io is constant current value; Thereby can overcome the defect that in prior art, cost is high, precision of steady current is low, reliability is low and the scope of application is little, with the advantage that realizes that cost is low, precision of steady current is high, reliability is high and the scope of application is large.

Other features and advantages of the utility model will be set forth in the following description, and, partly from specification, become apparent, or understand by implementing the utility model.

Below by drawings and Examples, the technical solution of the utility model is described in further detail.

The accompanying drawing explanation

Accompanying drawing is used to provide further understanding of the present utility model, and forms the part of specification, with embodiment mono-of the present utility model, is used from explanation the utility model, does not form restriction of the present utility model.In the accompanying drawings:

The operation principle schematic diagram that Fig. 1 is the large power LCD constant current driving device based on the BUCK circuit.

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment of the present utility model is described, should be appreciated that preferred embodiment described herein is only for description and interpretation the utility model, and be not used in restriction the utility model.

According to the utility model embodiment, as shown in Figure 1, provide a kind of large power LCD constant current driving device based on the BUCK circuit.

Referring to Fig. 1, the large power LCD constant current driving device based on the BUCK circuit of the present embodiment, comprise the switch controlled module, BUCK main circuit, voltage controlled current source module and the reference capacitance module that are connected to successively ground; The common port of voltage controlled current source module and reference capacitance module, be connected with the input of switch controlled module; The control end of reference capacitance module, be connected with the drive end of switch controlled module; The earth terminal ground connection of reference capacitance module.

Wherein, above-mentioned switch controlled module, comprise current mode controller and the driver of the control end that is connected to successively the reference capacitance module, and the oscillator and the comparator that are connected to respectively current mode controller; Oscillator, away from an end of current mode controller, is connected to the common port of voltage controlled current source module and reference capacitance module; The in-phase input end of comparator is reference current Iref input, and the inverting input of comparator is connected with the BUCK principal current.The model of this current mode controller comprises UC3843.

Above-mentioned BUCK main circuit, comprise direct-current input power supplying Vin, the first capacitor C 1, the second capacitor C 2, inductance L, diode D1, the first switching tube Q1, LED and for detection of the resistance R of peak current, wherein: the positive pole of direct-current input power supplying Vin, through the first capacitor C 1 ground connection, with the negative electrode of diode D1, be connected, successively through the second capacitor C 2 with after inductance L, with the drain electrode of the first switching tube Q1, be connected, with the anodic bonding of LED, with the input of voltage controlled current source module, be connected; The negative electrode of LED, be connected to the common port of the second capacitor C 2 and inductance L; The grid of the first switching tube Q1 is connected with the drive end of driver, and the source electrode of the first switching tube Q1 is connected with the inverting input of comparator, and the source electrode of the first switching tube Q1 is connected and ground connection with the negative pole of direct-current input power supplying Vin after resistance R.This direct-current input power supplying Vin, comprise storage battery or solar cell or ups power.The first switching tube Q1, comprise metal-oxide-semiconductor or triode.

Above-mentioned base station capacitance module, comprise parallel second switch pipe and the electric capacity arranged; The grid of second switch pipe is connected with the drive end of driver; The source electrode of second switch pipe and drain electrode, be connected respectively the source ground of second switch pipe with the two ends of electric capacity.The second switch pipe, comprise metal-oxide-semiconductor or triode.

The large power LCD constant current driving device based on the BUCK circuit of above-described embodiment, during work, the BUCK main circuit, the output current Ic with output voltage V o control voltage controlled current source module, give a capacitor charging in the reference capacitance module; Use capacitor charging time, the turn-off time To of control switch pipe, can realize that To*Vo is constant like this.The switch controlled module, by the oscillator signal of processing oscillator and the sensed current signal of peak current detection resistance R, control the break-make of the first switching tube Q1.When in the reference capacitance module, the voltage of reference capacitance reaches set point, trigger generator, the signal controlling first switching tube Q1 of oscillator is open-minded; When the voltage that the peak current detection resistance R detected reaches set point, trigger comparator, the signal controlling first switching tube Q1 of comparator turn-offs.After the output voltage V c of capacitor C 1, peak current detection resistance R, inductance L, voltage controlled current source module determines, the error △ Io of output circuit is definite value; Adding and controlling given electric current I g by peak current is set-point, has realized that output current Io is constant current value, that is to say, output current Io is not subject to the impact of output voltage V o.

In sum, the large power LCD constant current driving device based on the BUCK circuit of the utility model the various embodiments described above, compare with the peak current control circuit, can accurately control the Mean Forward Current on great power LED; Control circuit is simple in structure, cost is low, efficiency is high; Without output sampling resistor and the sampling of isolation current signal, be particularly suitable for high pressure applications.

Finally it should be noted that: the foregoing is only preferred embodiment of the present utility model, be not limited to the utility model, although with reference to previous embodiment, the utility model is had been described in detail, for a person skilled in the art, its technical scheme that still can put down in writing aforementioned each embodiment is modified, or part technical characterictic wherein is equal to replacement.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection range of the present utility model.

Claims

1. the large power LCD constant current driving device based on the BUCK circuit, is characterized in that, comprises the switch controlled module, BUCK main circuit, voltage controlled current source module and the reference capacitance module that are connected to successively ground; The common port of described voltage controlled current source module and reference capacitance module, be connected with the input of switch controlled module; The control end of described reference capacitance module, be connected with the drive end of switch controlled module; The earth terminal ground connection of reference capacitance module.

2. the large power LCD constant current driving device based on the BUCK circuit according to claim 1, it is characterized in that, described switch controlled module, comprise current mode controller and the driver of the control end that is connected to successively described reference capacitance module, and the oscillator and the comparator that are connected to respectively described current mode controller; Described oscillator, away from an end of current mode controller, is connected to the common port of voltage controlled current source module and reference capacitance module; The in-phase input end of described comparator is reference current Iref input, and the inverting input of comparator is connected with the BUCK main circuit.

3. the large power LCD constant current driving device based on the BUCK circuit according to claim 2, is characterized in that, the model of described current mode controller comprises UC3843.

4. according to the described large power LCD constant current driving device based on the BUCK circuit of claim 2 or 3, it is characterized in that, described BUCK main circuit, comprise direct-current input power supplying Vin, the first capacitor C 1, the second capacitor C 2, inductance L, diode D1, the first switching tube Q1, LED and for detection of the resistance R of peak current, wherein:

5. the large power LCD constant current driving device based on the BUCK circuit according to claim 4, is characterized in that, described direct-current input power supplying Vin, comprise storage battery or solar cell or ups power.

6. the large power LCD constant current driving device based on the BUCK circuit according to claim 4, is characterized in that, described the first switching tube Q1, comprise metal-oxide-semiconductor or triode.

7. the large power LCD constant current driving device based on the BUCK circuit according to claim 4, is characterized in that, described reference capacitance module comprises parallel second switch pipe and the electric capacity arranged; The grid of described second switch pipe is connected with the drive end of driver; The source electrode of second switch pipe and drain electrode, be connected respectively the source ground of second switch pipe with the two ends of electric capacity.

8. the large power LCD constant current driving device based on the BUCK circuit according to claim 7, is characterized in that, described second switch pipe, comprise metal-oxide-semiconductor or triode.