CN203801108U - LED drive circuit - Google Patents
LED drive circuit Download PDFInfo
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- CN203801108U CN203801108U CN201420055732.6U CN201420055732U CN203801108U CN 203801108 U CN203801108 U CN 203801108U CN 201420055732 U CN201420055732 U CN 201420055732U CN 203801108 U CN203801108 U CN 203801108U
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Abstract
An LED drive circuit comprises a silicon controlled rectifier, a rectifier bridge and a fly-back circuit. The alternating-current input end is connected with the silicon controlled rectifier. The silicon controlled rectifier is connected with the input end of the rectifier bridge. The output end of the rectifier bridge is connected with the fly-back circuit. The output end of the fly-back circuit is connected in parallel with an LED. One end of a primary winding N1 of a transformer TR1 is connected with the output end of the bridge rectifier, and the other end of the primary winding N1 is connected with the drain of a second switching tube M2. The input end of an input maintenance current controller is connected with the negative electrode of the output end of the rectifier bridge. The negative electrode of the output end of the rectifier bridge is connected with the source of the second switching tube M2 through a first resistor R1. The drain of a first switching tube M1 is connected with the positive electrode of the output end of the rectifier bridge. The source of the first switching tube M1 is grounded. The LED drive circuit of the utility model has the advantages of less power consumption, quick start and high applicability.
Description
Technical field
The utility model relates to a kind of LED drive circuit.
Background technology
In prior art, for assurance controllable silicon, normally work, need to add leadage circuit, so that the electric current that maintains of controlled silicon conducting to be provided.Referring to Fig. 1, is a kind of leadage circuit conventional in prior art.This leadage circuit adds electric capacity and resistance between bus and ground.But this circuit is released and is existed always, and power consumption is very large, greatly reduces the efficiency of drive circuit.
In LED drive circuit, require to start fast, to improve client's comfort as far as possible.Referring to Fig. 2, is start-up circuit conventional in prior art.This circuit is powered to VCC by resistance in start-up course, and after startup finishes, has power consumption on this resistance always.The method not only starts slowly and even cannot start, and especially when controllable silicon dimmer angle of flow is very little, and has reduced the efficiency of driver.
Summary of the invention
In order to overcome, existing LED drive circuit power consumption is large, toggle speed is slow, the poor deficiency of applicability, and the utility model provides less, the quick startup of a kind of power consumption, the good LED drive circuit of applicability.
The utility model solves the technical scheme that its technical problem adopts:
A kind of LED drive circuit, comprise controllable silicon, rectifier bridge and circuit of reversed excitation, ac input end is connected with controllable silicon, the input termination of controllable silicon and rectifier bridge, the output of described rectifier bridge is connected with described circuit of reversed excitation, the output of described circuit of reversed excitation is in parallel with LED, described circuit of reversed excitation comprises transformer TR1, described transformer TR1 comprises former limit winding N1 and secondary winding N2, one end of former limit winding N1 is connected with the output of described rectifier bridge, the other end of former limit winding N1 is connected with the drain electrode of second switch pipe M2, described LED drive circuit also comprises that input maintains current controller, the negative pole that described input maintains the input of current controller and the output of described rectifier bridge is connected, the negative pole of the output of described rectifier bridge is connected with the source electrode of second switch pipe M2 by the first resistance R 1, the output that described input maintains current controller is connected with the grid of the first switching tube M1, the positive pole of described the first drain electrode of switching tube M1 and the output of described rectifier bridge is connected, the source ground of the first switching tube M1.
Further, described LED drive circuit also comprises charging circuit, switch and on-off controller, the input of described charging circuit is connected with the source electrode of the first switching tube M1, described on-off controller is connected with one end of described switch, the other end of described switch is connected with the input of described charging circuit, the 3rd end ground connection of described switch.
The grid of described the first switching tube M1 is connected with the 3rd resistance R 3, and described the 3rd resistance R 3 is connected with the positive pole of the output of described rectifier bridge.
Further, described transformer TR1 also comprises tertiary winding N3, one end ground connection of tertiary winding N3; The output of described charging circuit is connected with the other end of described tertiary winding N3.
Further again, after being connected with the second resistance R 2, the drain electrode of described the first switching tube M1 is connected with the positive pole of the output of described rectifier bridge.
Further again, it is operational amplifier that described input maintains current controller, and the output of described operational amplifier is the output that described input maintains current controller, and the electrode input end of described operational amplifier is the input that described input maintains current controller.
Described charging circuit is diode D
bLEEDER, described switch is switching tube M
bLEEDER, described on-off controller is comparator, the source electrode of the first switching tube M1 and described diode D
bLEEDERpositive terminal connect, described diode D
bLEEDERnegative pole end be connected with the other end of described tertiary winding N3, the other end of described tertiary winding N3 connects and is connected with the electrode input end of comparator, the output of described comparator and switching tube M
bLEEDERgrid connects, described switching tube M
bLEEDERsource ground, described switching tube M
bLEEDERdrain electrode with described diode D
bLEEDERpositive pole connect.
Described input maintains current controller, charging circuit, switch and on-off controller and is integrated on a driving chip.
Use LED drive circuit of the present utility model, by detecting the voltage in the first resistance R 1, maintain current controller and carry out regulation output side voltage, thereby control maintains the input side voltage of current controller and is at least VLRTN, make input side electric current in dimmer conduction, be at least VLRTN/R1, provide dimmer to maintain electric current.
The beneficial effects of the utility model are mainly manifested in: less, the quick startup of power consumption, applicability are good.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the existing LED drive circuit with leadage circuit.
Fig. 2 is the schematic diagram of the existing LED drive circuit with start-up circuit.
Fig. 3 is the schematic diagram of LED drive circuit of the present utility model.
Fig. 4 is the schematic diagram of another kind of LED drive circuit.
Embodiment
Below in conjunction with accompanying drawing, the utility model is further described.
With reference to Fig. 3 and Fig. 4, a kind of LED drive circuit, comprise controllable silicon, rectifier bridge and circuit of reversed excitation, ac input end is connected with controllable silicon, the input termination of controllable silicon and rectifier bridge, the output of described rectifier bridge is connected with described circuit of reversed excitation, the output of described circuit of reversed excitation is in parallel with LED, described circuit of reversed excitation comprises transformer TR1, described transformer TR1 comprises former limit winding N1 and secondary winding N2, one end of former limit winding N1 is connected with the output of described rectifier bridge, and the other end of former limit winding N1 is connected with the drain electrode of second switch pipe M2; Described LED drive circuit also comprises that input maintains current controller, the negative pole that described input maintains the input of current controller and the output of described rectifier bridge is connected, and the negative pole of the output of described rectifier bridge is connected the output that described input maintains current controller and is connected with the grid of the first switching tube M1 with the source electrode of second switch pipe M2 by the first resistance R 1; The positive pole of described the first drain electrode of switching tube M1 and the output of described rectifier bridge is connected, the source ground of the first switching tube M1.
Further, described LED drive circuit also comprises charging circuit, switch and on-off controller, the input of described charging circuit is connected with the source electrode of the first switching tube M1, described on-off controller is connected with one end of described switch, the other end of described switch is connected with the input of described charging circuit, the 3rd end ground connection of described switch.
The grid of described the first switching tube M1 is connected with the 3rd resistance R 3, and described the 3rd resistance R 3 is connected with the positive pole of the output of described rectifier bridge.
Further, described transformer TR1 also comprises tertiary winding N3, one end ground connection of tertiary winding N3; The output of described charging circuit is connected with the other end of described tertiary winding N3.
Further again, after being connected with the second resistance R 2, the drain electrode of described the first switching tube M1 is connected with the positive pole of the output of described rectifier bridge.
Further again, it is operational amplifier that described input maintains current controller, and the output of described operational amplifier is the output that described input maintains current controller, and the electrode input end of described operational amplifier is the input that described input maintains current controller.
Described charging circuit is diode D
bLEEDER, described switch is switching tube M
bLEEDER, described on-off controller is comparator, the source electrode of the first switching tube M1 and described diode D
bLEEDERpositive terminal connect, described diode D
bLEEDERnegative pole end be connected with the other end of described tertiary winding N3, the other end of described tertiary winding N3 is connected with the electrode input end of comparator, the output of described comparator and switching tube M
bLEEDERgrid connects, described switching tube M
bLEEDERsource ground, described switching tube M
bLEEDERdrain electrode with described diode D
bLEEDERpositive pole connect.
Described input maintains current controller, charging circuit, switch and on-off controller and is integrated on a driving chip.
A kind of control method of LED drive circuit, by detecting the voltage in the first resistance R 1, maintain current controller and carry out regulation output side voltage, thereby control maintains the input side voltage of current controller and is at least VLRTN, make input side electric current in dimmer conduction, be at least VLRTN/R1, provide dimmer to maintain electric current.
With reference to Fig. 3, exchange input side serial connection controllable silicon light adjusting circuit, the rectifier bridge through being comprised of D1 D2 D3 D4, is converted to direct voltage by alternating voltage, and this dc point is called VREC.Circuit in dotted line frame is FLYBACK (flyback) circuit.Circuit of reversed excitation is the common circuit in AC-DC circuit conversion.By C2 TR1 M2 R4 D5 C4, form main power circuit; D6 C3 has formed the circuit to chip power supply.The output of circuit of reversed excitation is received in LED load.
The GATE2 pin of chip is received VREC by resistance R 3; The BLEEDER pin of chip is connected by M1 and R2, receives VREC; Input current sampling resistor R1 is connected between the ground of circuit of reversed excitation and the negative terminal of rectifier bridge output, and LRTN receives the point of the negative voltage of R1.
When just powering on, GATE2 voltage is drawn high by resistance R 3.The GATE voltage of MOS M1 is high, so M1 conducting, and VREC charges to BLEEDER by current-limiting resistance R2 and M1, and the switch that chip internal is connected between BLEEDER and GND disconnects.By the charging circuit of chip internal, feeder ear VCC's BLEEDER to chip charges again.Chip is by LRTN pin, and size that can Gather and input electric current therefore when starting, can gather by R2 M1 to BLEEDER size of current, thereby control to BLEEDER charging current.During startup, give the charging current of VCC more much larger than traditional VCC charging current, greatly accelerated toggle speed.
When chip VCC voltage is enough high and power enough time, the switch conduction between BLEEDER and GND, pulls down to ground by BLEEDER, so BLEEDER stops charging to VCC.VCC is powered by the auxiliary power supply circuit N3 D6 C3 of circuit of reversed excitation.After circuit start is complete, the conducting of on-off controller control switch, BLEEDER ground connection.By detecting the voltage on R1, be LRTN voltage, maintain current controller and regulate GATE2 voltage, thereby control LRTN voltage and be at least VLRTN, make input side electric current in dimmer conduction, be at least VLRTN/R1, provide dimmer to maintain electric current, prevent from causing due to the shutoff of dimmer the flicker of LED load.
This circuit of reversed excitation can replace with the circuit such as reduction voltage circuit (BUCK CONVERTER), step-up/step-down circuit (BUCKBOOST CONVERTER).Also can realize similar function.
Refer to Fig. 4, be connected on the switch NMOS between BLEEDER and ground, be called MBLEEDER.When VCC voltage is during higher than cut-in voltage VCC_TH, comparator output is high, by MBLEEDER conducting, BLEEDER is received to GND.BLEEDER to the VCC power supply circuits diode DBLEEDER that can connect between BLEEDER and VCC.The anode of DBLEEDER is received BLEEDER, and the negative electrode of DBLEEDER is received VCC.Input maintains current controller and can realize with the following methods, LRTN and reference voltage VLRTN are received respectively to negative terminal and the anode of operational amplifier, operational amplifier, by controlling GATE2 voltage, make LRTN voltage be not less than VLRTN voltage, thereby control inputs electric current is at least VLRTN/R1.
Claims (8)
1. a LED drive circuit, comprise controllable silicon, rectifier bridge and circuit of reversed excitation, ac input end is connected with controllable silicon, the input termination of controllable silicon and rectifier bridge, the output of described rectifier bridge is connected with described circuit of reversed excitation, the output of described circuit of reversed excitation is in parallel with LED, described circuit of reversed excitation comprises transformer TR1, described transformer TR1 comprises former limit winding N1 and secondary winding N2, one end of former limit winding N1 is connected with the output of described rectifier bridge, and the other end of former limit winding N1 is connected with the drain electrode of second switch pipe M2; It is characterized in that: described LED drive circuit also comprises that input maintains current controller, the negative pole that described input maintains the input of current controller and the output of described rectifier bridge is connected, and the negative pole of the output of described rectifier bridge is connected with the source electrode of second switch pipe M2 by the first resistance R 1; The output that described input maintains current controller is connected with the grid of the first switching tube M1; The positive pole of described the first drain electrode of switching tube M1 and the output of described rectifier bridge is connected, the source ground of the first switching tube M1.
2. a kind of LED drive circuit as claimed in claim 1, it is characterized in that: described LED drive circuit also comprises charging circuit, switch and on-off controller, the input of described charging circuit is connected with the source electrode of the first switching tube M1, described on-off controller is connected with one end of described switch, the other end of described switch is connected with the input of described charging circuit, the 3rd end ground connection of described switch.
3. a kind of LED drive circuit as claimed in claim 1 or 2, is characterized in that: the grid of described the first switching tube M1 is connected with the 3rd resistance R 3, and described the 3rd resistance R 3 is connected with the positive pole of the output of described rectifier bridge.
4. a kind of LED drive circuit as claimed in claim 2, is characterized in that: described transformer TR1 also comprises the tertiary winding N3 one end ground connection of tertiary winding N3; The output of described charging circuit is connected with the other end of described tertiary winding N3.
5. a kind of LED drive circuit as claimed in claim 1 or 2, it is characterized in that: it is operational amplifier that described input maintains current controller, the output of described operational amplifier is the output that described input maintains current controller, and the electrode input end of described operational amplifier is the input that described input maintains current controller.
6. a kind of LED drive circuit as claimed in claim 1 or 2, is characterized in that: after the drain electrode of described the first switching tube M1 is connected with the second resistance R 2, be connected with the positive pole of the output of described rectifier bridge.
7. a kind of LED drive circuit as claimed in claim 4, is characterized in that: described charging circuit is diode D
bLEEDER, described switch is switching tube M
bLEEDER, described on-off controller is comparator, the source electrode of the first switching tube M1 and described diode D
bLEEDERpositive terminal connect, described diode D
bLEEDERnegative pole end be connected with the other end of described tertiary winding N3, the other end of described tertiary winding N3 connects and is connected with the electrode input end of comparator, the output of described comparator and switching tube M
bLEEDERgrid connects, described switching tube M
bLEEDERsource ground, described switching tube M
bLEEDERdrain electrode with described diode D
bLEEDERpositive pole connect.
8. a kind of LED drive circuit as claimed in claim 2, is characterized in that: described input maintains current controller, charging circuit, switch and on-off controller and is integrated on a driving chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420055732.6U CN203801108U (en) | 2014-01-28 | 2014-01-28 | LED drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420055732.6U CN203801108U (en) | 2014-01-28 | 2014-01-28 | LED drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203801108U true CN203801108U (en) | 2014-08-27 |
Family
ID=51383291
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420055732.6U Withdrawn - After Issue CN203801108U (en) | 2014-01-28 | 2014-01-28 | LED drive circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203801108U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103826362A (en) * | 2014-01-28 | 2014-05-28 | 杰华特微电子（杭州）有限公司 | LED drive circuit and control method thereof |
-
2014
- 2014-01-28 CN CN201420055732.6U patent/CN203801108U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103826362A (en) * | 2014-01-28 | 2014-05-28 | 杰华特微电子（杭州）有限公司 | LED drive circuit and control method thereof |
| CN103826362B (en) * | 2014-01-28 | 2016-03-16 | 杰华特微电子（杭州）有限公司 | A kind of LED drive circuit and control method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20140827 Effective date of abandoning: 20160316 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |