CN202918545U - Average linear LED (Light Emitting Diode) drive circuit - Google Patents
Average linear LED (Light Emitting Diode) drive circuit Download PDFInfo
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- CN202918545U CN202918545U CN2012205341672U CN201220534167U CN202918545U CN 202918545 U CN202918545 U CN 202918545U CN 2012205341672 U CN2012205341672 U CN 2012205341672U CN 201220534167 U CN201220534167 U CN 201220534167U CN 202918545 U CN202918545 U CN 202918545U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model discloses an average linear LED (Light Emitting Diode) drive circuit, comprising a rectifier bridge, an LED load, a compensation network and a voltage feedback network, wherein the rectifier bridge is connected with an input alternating voltage; and the LED load is connected with a filter capacitor in parallel and then connected to a power switch. When the output direct voltage of the rectifier bridge is higher than the voltage of the filter capacitor, the drain voltage of the power switch rises, the current in the power switch is reduced or switched off through the feedback network, and the current average value in the power switch is enabled to be equal to the current of the LED load through the compensation network. According to the average linear LED drive circuit provided by the utility model, the current of the drive circuit can be intelligently controlled, so that the power consumption of a system is reduced, and the efficiency is improved. The drive circuit is capable of keeping higher conversion efficiency under the condition of higher input voltage in particular.
Description
Technical field
The utility model relates to a kind of led drive circuit, relates in particular to a kind of average linear led drive circuit of high-efficiency constant-current.
Background technology
Led light source has advantages of energy-conserving and environment-protective, greatly reduces yet the technological difficulties that led light source is used are the unstable LED of the causing life-span of control circuit.The failure of removal of at present LED lighting appearance largely is because the unreasonable structure of led drive circuit causes.Employed linear led drive circuit as shown in Figure 1 in the prior art, alternating current by capacitor C1 filtering, produces a direct current power supply through rectifier bridge 1 rectification, and DC power supply connects the LED load, the negative terminal of LED load connects an electric current and sinks 2, and this electric current heavy 2 makes the electric current of LED load keep constant.This led drive circuit major defect is that in the situation that input voltage is higher, electric current heavy 2 produces larger pressure drop, makes the Efficiency Decreasing of drive circuit, and produces larger heat at electric current heavy 2, easily causes thrashing.
The utility model content
In order to overcome the defective that exists in the prior art, the utility model provides a kind of average linear led drive circuit, improves the efficient of drive circuit.
In order to realize above-mentioned utility model purpose, the utility model discloses a kind of average linear led drive circuit, comprise a rectifier bridge that is connected with input ac voltage, one LED load, be connected a power switch after this LED load and the filter capacitor parallel connection, this drive circuit also comprises a compensating network and a Voltage Feedback network, when the output dc voltage through this rectifier bridge is higher than filter capacitor voltage, the drain voltage of power switch rises, reduce or turn-off electric current in the described power switch by feedback network, by compensating network, make that the mean value of electric current equals the LED load current in the power switch.
Further, this drive circuit also comprises an operational amplifier, the drain voltage of network based this power switch of this Voltage Feedback and the voltage of this compensating network obtain an output voltage, when the voltage of this power switch drain electrode hangs down, output voltage equals the voltage of this compensating network, when the voltage of this power switch drain electrode was higher, output voltage was less than the voltage of this compensating network.
Further, the negative input end of this operational amplifier connects a sampling resistor, and positive input terminal connects a reference voltage, and the output of this operational amplifier is connected with this compensating network.
Further, this drive circuit also comprises a driver, the input of this driver and this Voltage Feedback network connection, its output is connected with the gate leve of this power switch, and this driver is converted to the output voltage of Voltage Feedback network the driving voltage of power switch gate pole.
Further, this power switch is field effect transistor or bipolar transistor.
Further, this compensating network comprises a resistance R 2, capacitor C 2 and capacitor C 3, and is in parallel with this capacitor C 3 after this resistance R 2 is connected with this capacitor C 2.This compensating network can also only be comprised of capacitor C 3.
Further, this Voltage Feedback network is by resistance R 3, resistance R 4, resistance R 5, resistance R 6, triode Q1 and buffer 201 forms, and an end of this resistance R 3 is connected with buffer 201, and the other end is by driver 400 or directly connect the gate pole of this power switch, this resistance R 3 directly connects the gate pole of this power switch, the collector electrode of this triode Q1 is connected with this resistance R 3, and emitter is connected with an end of this resistance R 4, the other end ground connection of this resistance R 4, one end of this resistance R 5 is connected with the drain electrode of this power switch, the other end is connected with the base stage of this triode Q1, and an end of this resistance R 6 is connected other end ground connection with the base stage of this resistance R 5 with this triode Q1.
Further, this power switch is in series by the first power switch and the second power switch, the gate pole of this first power switch connects the output of this Voltage Feedback network, the drain electrode of this first power switch is connected with the source electrode of this second power switch, the drain electrode of this second power switch connects the negative input end of this Voltage Feedback network, and the gate pole of this second power switch is connected with a power supply.
Compared with prior art, average linear led drive circuit provided by the utility model can be controlled the electric current of drive circuit intelligently, so that system power dissipation reduces, efficient is improved.Especially in wider input voltage situation, this drive circuit can both keep higher conversion efficiency.
Description of drawings
Can describe in detail and appended graphic being further understood by following utility model about advantage of the present utility model and spirit.
Fig. 1 is the structural representation of employed linear led drive circuit in the prior art;
Fig. 2 is the structural representation of the shown average linear led drive circuit of the utility model;
Fig. 3 is the work typical waveform schematic diagram of the shown average linear led drive circuit of the utility model;
Fig. 4 is the compensating network of the shown average linear led drive circuit of the utility model and the circuit diagram of Voltage Feedback network;
Fig. 5 is the structural representation of another execution mode of the shown average linear led drive circuit of the utility model.
Embodiment
Describe specific embodiment of the utility model in detail below in conjunction with accompanying drawing.
Lower and easily produce the technical problem of thrashing for solving existing led drive circuit efficient in the prior art, the utility model proposes a kind of average linear led drive circuit.This average linear led drive circuit directly is parallel to LED load two ends with a filter capacitor, when the input voltage after the rectification during a little more than filter capacitor voltage, current flowing in the power switch, when the input voltage after the rectification is higher than filter capacitor voltage when more, electric current in minimizing even the switch-off power switch, the mean value of electric current equals the LED load current in this power switch, thereby realizes the purpose that high efficiency LED drives.
As shown in Figure 2, Fig. 2 is the structural representation of the shown average linear led drive circuit of the utility model.In the average linear led drive circuit provided by the utility model, filter capacitor C1 and LED load are directly in parallel, are connected to rectifier bridge 100 positive output ends.The drain D of power switch M1 connects filter capacitor C1 and LED load, and the source S of power switch connects the inverting input of sampling resistor R1 and operational amplifier 500, another termination electricity ground of sampling resistor R1.The in-phase input end of operational amplifier 500 connects the anode of reference voltage 600, the negative terminal connection circuit ground of reference voltage 600, the output termination compensating network 300 of operational amplifier 500, the drain D voltage signal of the voltage signal of compensating network 300 and power switch connects Voltage Feedback network 200, and the output signal of Voltage Feedback network 200 meets the gate pole G of power switch M1 by driver 400.Driver 400 is converted to the output voltage of Voltage Feedback network the driving voltage of power switch gate pole.In another better embodiment, this driver 400 also can omit, and the output signal of Voltage Feedback network 200 directly connects the gate pole G of power switch.This power switch M1 can be field effect transistor, also can be bipolar transistor.When this power switch was bipolar transistor, the driving signal was current signal.
Because input voltage is electric main, so the instantaneous value of input sinusoidal voltage is higher than filter capacitor C1 voltage sometimes, sometimes be lower than filter capacitor C1 voltage.When the input voltage after the rectification rises to when being higher than filter capacitor C1 voltage, begin to produce a positive voltage on the power switch C1 drain D, this moment, power switch M1 had electric current to flow through, produce a voltage signal at sampling resistor R1, this voltage signal has reflected the electric current that flows through LED load and filter capacitor C1.Operational amplifier 500 compares the voltage signal on the sampling resistor R1 and reference voltage, and exports a curtage error signal.Compensating network is processed the output error signal of operational amplifier 500, obtains an error voltage service voltage feedback network 200.Voltage Feedback network 200 receives the drain D signal of error voltage and power switch M1, processes the gate pole G of rear drive power switch M1.
When the voltage on the power switch M1 drain D is higher, if larger electric current is crossed in the afterflow of power switch M1 relaying, then can produce larger power loss, reduce the efficient of system.Voltage Feedback network 200 is by the voltage on the detection power switch M1 drain D in the utility model, when drain voltage is higher, reduce the gate drive voltage of power switch M1, thereby reduce or turn-offed electric current among the power switch M1, realize the purpose of intelligent drives.
Although the electric current on the sampling resistor R1 and voltage are discontinuous, operational amplifier and compensating network can be controlled by the average current on the power switch M1 with its integration at last, and its size equals reference voltage value divided by sampling resistor R1 value.
Fig. 3 is the work typical waveform schematic diagram of the shown average linear led drive circuit of the utility model.Shown when input voltage is sinusoidal waveform the time dependent schematic diagram of waveform of power switch M1 electric current, power switch M1 drain voltage and power switch M1 gate voltage among Fig. 3.
Fig. 4 is an embodiment according to the shown compensating network of the utility model and Voltage Feedback network.As shown in Figure 4, this compensating network 300 is by resistance R 2, and capacitor C 2 and capacitor C 3 consist of.It is in parallel with capacitor C 3 after resistance R 2 is connected with capacitor C 2.In another kind of better embodiment, compensating network 300 also can only be made of capacitor C 3.
The voltage of the network based power switch M1 drain electrode of Voltage Feedback and the voltage of compensating network 300 obtain an output voltage, when the voltage of power switch drain electrode hangs down, output voltage equals the voltage of compensating network 300, when the voltage of power switch drain electrode was higher, output voltage was less than the voltage of compensating network.
When the drain voltage of power switch M1 is higher, begin current flowing between the base stage of Q1 and the emitter, thereby also begin current flowing between collector electrode and the emitter, this electric current produces pressure drop at R3, the output voltage of Voltage Feedback network is reduced, thereby realize the gate voltage reduction of power switch M1 and the purpose of power switch M1 current reduction.
It is pointed out that in another kind of better embodiment, power switch M1 can be realized by two power switch series connection sometimes.As shown in Figure 5, Fig. 5 is the structural representation that uses the average linear led drive circuit of two power switchs.Wherein M2 is high-voltage circuit breaker, and M1 is low-voltage power switch.The gate pole of M2 connects a system drive level, and the gate signal of M1 connects the output drive signal of Voltage Feedback network.Its mode of operation and control logic and Fig. 4 are similar, do not repeat them here.
Owing to having adopted linear led drive circuit of the present utility model, control intelligently the electric current of drive circuit, so that system power dissipation reduces, efficient is improved.Especially in wider input voltage situation, this drive circuit can both keep higher conversion efficiency.
Described in this specification is preferred embodiment of the present utility model, and above embodiment is only in order to the technical solution of the utility model to be described but not to restriction of the present utility model.All those skilled in the art comply with design of the present utility model by the available technical scheme of logical analysis, reasoning, or a limited experiment, all should be within scope of the present utility model.
Claims (9)
1. average linear led drive circuit, comprise a rectifier bridge that is connected with input ac voltage, one LED load, it is characterized in that, be connected a power switch after described LED load and the filter capacitor parallel connection, described drive circuit also comprises a compensating network and a Voltage Feedback network, when the output dc voltage through described rectifier bridge is higher than described filter capacitor voltage, the drain voltage of described power switch rises, reduce or turn-off electric current in the described power switch by described feedback network, by described compensating network, make the mean value of electric current in the described power switch equal described LED load current.
2. average linear led drive circuit as claimed in claim 1 is characterized in that, described drive circuit also comprises a computing
Amplifier, the drain voltage of the network based described power switch of described Voltage Feedback and the voltage of described compensating network obtain an output voltage, when the voltage of described power switch drain electrode hangs down, output voltage equals the voltage of described compensating network, when the voltage of described power switch drain electrode was higher, output voltage was less than the voltage of described compensating network.
3. average linear led drive circuit as claimed in claim 2 is characterized in that the negative input end of described operational amplifier
Connect a sampling resistor, positive input terminal connects a reference voltage, the output of described operational amplifier and described compensating network
Connect.
4. average linear led drive circuit as claimed in claim 1 is characterized in that, described drive circuit also comprises a driving
Device, the input of described driver and described Voltage Feedback network connection, its output is connected with the gate leve of described power switch, and described driver is converted to the output voltage of Voltage Feedback network the driving voltage of power switch gate pole.
5. average linear led drive circuit as claimed in claim 1 is characterized in that, described power switch is field effect transistor or bipolar transistor.
6. average linear led drive circuit as claimed in claim 1 is characterized in that, described compensating network comprises a capacitor C 3.
7. average linear led drive circuit as claimed in claim 1 is characterized in that, described compensating network comprises a resistance R 2, capacitor C 2 and capacitor C 3, after described resistance R 2 is connected with described capacitor C 2 and described capacitor C 3 in parallel.
8. average linear led drive circuit as claimed in claim 1, it is characterized in that, described Voltage Feedback network is by resistance R 3, resistance R 4, resistance R 5, resistance R 6, triode Q1 and buffer 201 form, one end of described resistance R 3 is connected with buffer 201, the other end is by driver 400 or directly connect the gate pole of described power switch, and described resistance R 3 directly connects the gate pole of described power switch, and the collector electrode of described triode Q1 is connected with described resistance R 3, emitter is connected with an end of described resistance R 4, the other end ground connection of described resistance R 4, an end of described resistance R 5 is connected with the drain electrode of described power switch, and the other end is connected with the base stage of described triode Q1, one end of described resistance R 6 and described resistance R 5 be connected the base stage of triode Q1 and be connected other end ground connection.
9. average linear led drive circuit as claimed in claim 1, it is characterized in that, described power switch is in series by the first power switch and the second power switch, the gate pole of described the first power switch connects the output of described Voltage Feedback network, the drain electrode of described the first power switch is connected with the source electrode of described the second power switch, the drain electrode of described the second power switch connects the negative input end of described Voltage Feedback network, and the gate pole of described the second power switch is connected with a power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205341672U CN202918545U (en) | 2012-10-18 | 2012-10-18 | Average linear LED (Light Emitting Diode) drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205341672U CN202918545U (en) | 2012-10-18 | 2012-10-18 | Average linear LED (Light Emitting Diode) drive circuit |
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| Publication Number | Publication Date |
|---|---|
| CN202918545U true CN202918545U (en) | 2013-05-01 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012205341672U Expired - Lifetime CN202918545U (en) | 2012-10-18 | 2012-10-18 | Average linear LED (Light Emitting Diode) drive circuit |
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| CN (1) | CN202918545U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102938953A (en) * | 2012-10-18 | 2013-02-20 | 上海晶丰明源半导体有限公司 | Average linear LED (Light Emitting Diode) drive circuit |
| CN103269537A (en) * | 2013-05-28 | 2013-08-28 | 上海路千电子科技有限公司 | Multi-circuit current-limiting power supplying circuit, controlling method thereof and current-limiting power supplying method thereof |
-
2012
- 2012-10-18 CN CN2012205341672U patent/CN202918545U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102938953A (en) * | 2012-10-18 | 2013-02-20 | 上海晶丰明源半导体有限公司 | Average linear LED (Light Emitting Diode) drive circuit |
| CN103269537A (en) * | 2013-05-28 | 2013-08-28 | 上海路千电子科技有限公司 | Multi-circuit current-limiting power supplying circuit, controlling method thereof and current-limiting power supplying method thereof |
| CN103269537B (en) * | 2013-05-28 | 2015-04-01 | 上海路千电子科技有限公司 | Multi-circuit current-limiting power supplying circuit, controlling method thereof and current-limiting power supplying method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 5 room 504-511, room 2, Lane 666, Zhang Heng Road, Pudong New Area, China (Shanghai) free trade zone, Shanghai, China () Patentee after: SHANGHAI BRIGHT POWER SEMICONDUCTOR Co.,Ltd. Address before: 201204 Shanghai city Pudong New Area in 299 Lane Road, No. 10 Patentee before: Shanghai Bright Power Semiconductor Co.,Ltd. |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130501 |