CN103327677A - Constant current controlling method of LED drive circuit and drive circuit of constant current controlling method - Google Patents
Constant current controlling method of LED drive circuit and drive circuit of constant current controlling method Download PDFInfo
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- CN103327677A CN103327677A CN2012100941294A CN201210094129A CN103327677A CN 103327677 A CN103327677 A CN 103327677A CN 2012100941294 A CN2012100941294 A CN 2012100941294A CN 201210094129 A CN201210094129 A CN 201210094129A CN 103327677 A CN103327677 A CN 103327677A
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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
Abstract
The invention relates to a current controlling method of an LED drive circuit. The constant current controlling method of the LED drive circuit is characterized in that standard constant-current source currents are accurately copied, a current mirror image pipe of a current copying circuit and a drive pipe of a mirror image amplifying drive circuit are adjusted to put the two pipes in the totally identical circuit state, namely the voltage difference between a grid and a source electrode and the voltage difference between a drain electrode and a source electrode of the two pipes are totally equal so as to amplify mirror images of the standard constant-current source currents. The drive pipe of the mirror image amplifying drive circuit is adjusted so that the voltage difference between the drain electrode and the source electrode of the drive pipe is approximate to a saturation voltage drop value. The LED constant-current drive circuit is composed of a current copying circuit, a standard constant-current source circuit, a mirror image amplifying drive circuit and a loaded circuit. The constant current controlling method of the LED drive circuit has the advantages of reducing power consumption of the LED constant-current drive circuit, saving electricity by 15% to 35%, improving the loading capacity of a single-channel drive circuit and a chip, simplifying capsulation of the chip and achieving the objective that load currents accurately amplify the mirror images of a standard constant-current source. The driving efficiency is high.
Description
Technical field
The present invention relates to control method and drive circuit that a kind of electric light source constant current drives, particularly a kind of constant current control method and drive circuit thereof that can reduce power consumption and reference current be carried out the led drive circuit of accurate mirror image amplification.
Background technology
At present, the driving of led light source mainly contains resistance step-down driving, linear voltage stabilization/constant-current supply driving, charge pump driving, these several modes of DC-DC conversion driving.In the occasion that constant current need to be provided for LED, the drive circuit of its LED is to be made of operational amplifier OP1, driving tube MN11 and resistance R s, and resistance is used for that constant current detects to load circuit.The operational amplifier positive input connects reference voltage Vref, and negative input is connected to the Nodes of driving tube source electrode and resistance, and resistance other end ground connection consists of negative feedback loop.The output of operational amplifier is connected with the grid of driving tube, and the drain electrode of driving tube is that led light source is connected with load circuit, for led light source provides constant current.Although this drive circuit circuit structure is simple, but the electric current that flows through resistance R s equals Vref/Rs, is the electric current that flows through in the LED lamp string, therefore exists: 1, the electric energy of resistance R s consumption is large, account for drive circuit chip 15%～35%, reduced the efficient of led drive circuit.2, the too much energy consumption of resistance R s can produce corresponding heat, has increased the heat radiation difficulty of making drive circuit chip.3, the resistance R s of drive circuit has limited LED and has driven the single pass maximum load capacity of chip.4, resistance R s has limited maximum port numbers that the load capacity of led light source drive circuit chip under the condition of same size size namely can have.
It is 02107078.4 led drive circuit that Chinese invention patent discloses a kind of application number, and the circuit that this invention provides makes part LEDs wherein luminous by adopting by the time partitioning scheme, reduces the power consumption of led drive circuit with this.For realizing the accurate mirror image of electric current, the threshold value place that this circuit uses a PMOS and NMOS that drain electrode and the source electrode pressure reduction of mirror image driving tube is arranged on metal-oxide-semiconductor, the threshold value of PMOS and NMOS easily has deviation, so there is certain defective in this drive circuit aspect reduction power consumption and the accurate mirror image of electric current.
It is 200810217219.1 multipath LED drive circuit that Chinese invention patent discloses a kind of application number, main by accurate current source, for the multichannel mirror image amplification module that described accurate electric current is amplified and copies to multichannel output, be used for the active output-stage circuit formation of carrying out accuracy controlling is exported on each road.This circuit has been realized the accurate mirror image of electric current is amplified, and also the source-drain electrode pressure reduction of output driving tube can be set to optimum value, but the adjustment pipe of active output-stage circuit exists power consumption, has increased simultaneously the area of domain in the integrated circuit.
Summary of the invention
The object of the present invention is to provide a kind of constant current control method of led drive circuit, the power consumption of the reduction led drive circuit of the method maximizing, and realized that the accurate mirror image of electric current amplifies, and has improved the load capacity of chip.
Another object of the present invention is to provide a kind of LED constant-current drive circuit of realizing the method.
The object of the present invention is achieved like this: a kind of constant current control method of led drive circuit, it is characterized in that benchmark constant-current source electric current is accurately copied, and make the output current of current replication circuit equal benchmark constant-current source electric current; Adjust the current mirror image tube of current replication circuit and the driving tube of mirror image amplification driving circuit, make two pipes be in identical circuit state, the i.e. grid of two pipes and source electrode, drain electrode equates fully with pressure reduction between the source electrode, realizes that benchmark constant-current source electric current is carried out current mirror to be amplified; Gather the voltage of driving tube in the mirror image amplification driving circuit, adjust the supply voltage of load circuit, make voltage difference between driving tube drain electrode and the source electrode near the saturation pressure depreciation, thereby further reduce the led drive circuit power consumption.
A kind of LED constant-current drive circuit is characterized in that the current replication circuit input is connected with the benchmark constant-current source, and output is connected with the mirror image amplification driving circuit, and the output of mirror image amplification driving circuit is connected with load circuit.
Described current replication circuit comprises operational amplifier OP2, current mirror image tube MN22 and resistance R 1, R2, operational amplifier OP2 positive input terminal is connected to benchmark constant-current source I1 and earth resistance R1 Nodes, form the reference voltage of operational amplifier, negative input end is connected to current mirror image tube MN22 source electrode and resistance R 2 Nodes, form negative feedback loop, the output of operational amplifier OP2 is connected with the grid of current mirror image tube MN22, and the drain electrode of current mirror image tube MN22 is connected with constant-current source I2.
Described mirror image amplification driving circuit comprises driving tube MN12, constant-current source I2, constant-current source I3 and resistance R 3, R4, the grid of driving tube MN12 is connected with the current mirror image tube MN22 grid of current replication circuit by resistance R 3, constant-current source I3 one end is connected to grid and resistance R 3 Nodes of driving tube MN12, other end ground connection, constant-current source I2 is connected in the drain electrode of driving tube MN12 by resistance R 4.
The driving tube drain electrode of mirror image amplification driving circuit is connected with boost module, and the driving tube drain voltage is arranged on the reference voltage V of boost module
Dsat(max) locate, boost module also is connected with load circuit, adjusts the voltage at load two ends by boost module.V wherein
Dsat(max) be the maximum saturation voltage of driving tube.
The present invention compared with prior art has following characteristics: be amplified to load circuit by the constant-current source electric current is carried out accurate ratio, like this current detection circuit can be set, reduced the power consumption of LED lamp drive circuit, can save 15%～35% electric energy, improved drive efficiency, load capacity with the single channel drive circuit has improved 15%～35% simultaneously, and can simplify the heat abstractor in the integrated circuit (IC) chip manufacturing process of this circuit.By the pressure reduction between the grid of current mirror image tube and the source electrode and the grid of driving tube are arranged to equate fully with the pressure reduction between the source electrode, pressure reduction between the drain electrode of current mirror image tube and the source electrode and the drain electrode of driving tube are arranged to equate fully with the pressure reduction between the source electrode, have realized the accurate mirror image of benchmark constant-current source electric current is amplified.
Description of drawings
Fig. 1 is the circuit theory diagrams of LED constant-current drive circuit of the present invention.
Embodiment
The invention will be further described below in conjunction with accompanying drawing:
Constant current control method of the present invention has adopted benchmark constant-current source electric current has accurately been copied, make the output current of current replication circuit equal benchmark constant-current source electric current, simultaneously by the current mirror image tube of adjustment current replication circuit and the driving tube of mirror image amplification driving circuit, make two pipes be in identical circuit state, the i.e. grid of two pipes and source electrode, drain electrode equates fully with pressure reduction between the source electrode, realizes that benchmark constant-current source electric current is carried out current mirror to be amplified.Gather the voltage of driving tube in the mirror image amplification driving circuit, adjust the supply voltage of load circuit, make voltage difference between driving tube drain electrode and the source electrode near the saturation pressure depreciation, further reduce the led drive circuit power consumption.
Fig. 1 is a kind of LED lamp drive circuit schematic diagram of realizing the method, mainly comprises benchmark constant-current source 1, current replication circuit 2, mirror image amplification driving circuit 3, load circuit 4, Boost boost module 5.The operational amplifier OP2 positive input terminal of current replication circuit is connected to benchmark constant-current source I1 and earth resistance R1 Nodes, form the reference voltage of operational amplifier, negative input end is connected to current mirror image tube MN22 source electrode and resistance R 2 Nodes of current replication circuit, form negative feedback loop, in order to determine the electric current on the current mirror image tube, the output of operational amplifier OP2 is connected with the grid of current mirror image tube MN22, and the drain electrode of current mirror image tube MN22 is connected with constant-current source I2.In current replication circuit, benchmark constant-current source I1 produces pressure drop V1 at the first resistor R1, reference voltage access positive input as operational amplifier OP2, the output of operational amplifier OP2 is connected to the grid of current mirror image tube MN22, in order to driven current mirror image tube MN22, operational amplifier OP2, current mirror image tube MN22 and resistor R2 consist of degeneration factor, the electric current that flows through at current mirror image tube MN22 like this equals benchmark constant-current source I1, realizes mirror image pipe MN22 accurately copying constant-current source I1 electric current.
The grid of the driving tube MN12 of mirror image amplification driving circuit is connected with the current mirror image tube MN22 grid of current replication circuit by resistance R 3, constant-current source I3 one end is connected to driving tube MN12 grid and resistance R 3 contact places, other end ground connection, constant-current source I2 is connected in the drain electrode of driving tube MN12 by resistance R 4.For guaranteeing that the electric current on the driving tube MN12 is the accurate mirror image amplification of the upper electric current of current mirror image tube MN22, driving tube MN12 must be in source electrode, the drain and gate of current mirror image tube MN22 in the identical circuit state, being the grid of pressure reduction between grid and the source electrode of driving tube MN12 and current mirror image tube MN22 equates fully with pressure reduction between the source electrode, and the pressure reduction between the drain electrode of driving tube MN12 and the source electrode and the drain electrode of current mirror image tube MN22 equate fully with pressure reduction between the source electrode.Because the source voltage of driving tube MN12 need to be compared the grid voltage of driving tube MN12 like this current mirror image tube MN22 and reduce V11 than the low V11=I1 * R2 of source voltage of current mirror image tube MN22 with drain voltage.In drive circuit, meet constant-current source I3 with resistance R3, and resistance R 3=R2, constant-current source electric current I 3=I1, like this grid voltage of driving tube MN12 just than the grid voltage of current mirror image tube MN22 low I1 * R2=V11.In like manner, resistance R 4 flows through the electric current that equals constant-current source I1 size because R4=R2=R3, I2=2 * I1=2 * I3, thus the drain voltage of driving tube MN12 just than the drain terminal voltage of current mirror image tube MN22 low I1 * R2=V11.Pressure reduction between the grid that has so just guaranteed driving tube MN12 and the source electrode and the grid of current mirror image tube MN22 equate fully with pressure reduction between the source electrode, pressure reduction between the drain electrode of driving tube MN12 and the source electrode and the drain electrode of current mirror image tube MN22 equate fully with pressure reduction between the source electrode, thereby realized that driving tube MN12 amplifies the accurate mirror image of current mirror image tube MN22 electric current.
The drain electrode of mirror image amplification driving circuit is connected with the input IN of boost module, and the OUT end of boost module is connected to the two ends of load circuit, the drain voltage of driving tube MN12 is limited to the V of boost module
Dsat(max) locate.Gather the drain electrode of driving tube MN12 and the voltage difference between the source electrode by boost module, adjust the voltage of load circuit, make the voltage of load circuit reach optimum value, thereby make voltage difference between driving tube drain electrode and the source electrode near the saturation pressure depreciation, further reduce power consumption.
Realize that method of the present invention is not limited to above-mentioned drive circuit, the resistance R 1 of drive circuit, R2, R3, R4 can substitute with switching capacity, the equating fully of the pressure reduction between the pressure reduction between the grid that also can realize driving tube MN12 and current mirror image tube MN22 and the source electrode, drain electrode and the source electrode.In addition, the resistance value of the current value of constant-current source and resistance can be adjusted according to the side circuit needs.The proportionate relationship of the W/L value of current mirror image tube and the W/L value of driving tube also can be adjusted according to the load needs.
Claims (5)
1. the constant current control method of a led drive circuit is characterized in that benchmark constant-current source electric current is accurately copied, and makes the output current of current replication circuit equal benchmark constant-current source electric current; Adjust the current mirror image tube of current replication circuit and the driving tube of mirror image amplification driving circuit, make two pipes be in identical circuit state, the i.e. grid of two pipes and source electrode, drain electrode equates fully with pressure reduction between the source electrode, realizes that benchmark constant-current source electric current is carried out current mirror to be amplified; Gather the voltage of driving tube in the mirror image amplification driving circuit, adjust the supply voltage of load circuit, make voltage difference between driving tube drain electrode and the source electrode near the saturation pressure depreciation, further reduce the led drive circuit power consumption.
2. a LED constant-current drive circuit is characterized in that the current replication circuit input is connected with the benchmark constant-current source, and output is connected with the mirror image amplification driving circuit, and the output of mirror image amplification driving circuit is connected with load circuit.
3. LED constant-current drive circuit according to claim 2, it is characterized in that described current replication circuit comprises operational amplifier OP2, current mirror image tube MN22 and resistance R 1, R2, operational amplifier OP2 positive input terminal is connected to benchmark constant-current source I1 and earth resistance R1 Nodes, form the reference voltage of operational amplifier, negative input end is connected to current mirror image tube MN22 source electrode and resistance R 2 Nodes, form negative feedback loop, the output of operational amplifier OP2 is connected with the grid of current mirror image tube MN22, and the drain electrode of current mirror image tube MN22 is connected with constant-current source I2.
4. LED constant-current drive circuit according to claim 2, it is characterized in that described mirror image amplification driving circuit comprises driving tube MN12, constant-current source I2, constant-current source I3 and resistance R 3, R4, the grid of driving tube MN12 is connected with the current mirror image tube MN22 grid of current replication circuit by resistance R 3, constant-current source I3 one end is connected to driving tube MN12 grid and resistance R 3 Nodes, other end ground connection, constant-current source I2 is connected in the drain electrode of driving tube MN12 by resistance R 4.
5. LED constant-current drive circuit according to claim 2, the driving tube drain electrode that it is characterized in that the mirror image amplification driving circuit is connected with boost module, boost module also is connected with load circuit, adjusts the voltage at load two ends by boost module, makes the driving tube drain voltage be arranged on the V of boost module
Dsat(max) locate.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2012100941294A CN103327677A (en) | 2012-03-23 | 2012-03-23 | Constant current controlling method of LED drive circuit and drive circuit of constant current controlling method |
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| CN2012100941294A CN103327677A (en) | 2012-03-23 | 2012-03-23 | Constant current controlling method of LED drive circuit and drive circuit of constant current controlling method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107548219A (en) * | 2017-10-19 | 2018-01-05 | 东莞市翔实信息科技有限公司 | Linear constant current electric light drive circuit, integrated circuit and control system |
| CN107977042A (en) * | 2017-11-30 | 2018-05-01 | 深圳麦格米特电气股份有限公司 | A kind of power circuit and adapter |
| CN111601429A (en) * | 2020-06-03 | 2020-08-28 | 西安中颖电子有限公司 | Constant current driving circuit |
| CN115379619A (en) * | 2022-10-13 | 2022-11-22 | 合肥灿芯科技有限公司 | LED common-cathode driving chip |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107548219A (en) * | 2017-10-19 | 2018-01-05 | 东莞市翔实信息科技有限公司 | Linear constant current electric light drive circuit, integrated circuit and control system |
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| CN111601429A (en) * | 2020-06-03 | 2020-08-28 | 西安中颖电子有限公司 | Constant current driving circuit |
| CN115379619A (en) * | 2022-10-13 | 2022-11-22 | 合肥灿芯科技有限公司 | LED common-cathode driving chip |
| CN115379619B (en) * | 2022-10-13 | 2023-04-11 | 合肥灿芯科技有限公司 | LED common-cathode driving chip |
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Application publication date: 20130925 |