CN203722861U - LED (light emitting diode) control circuit - Google Patents
LED (light emitting diode) control circuit Download PDFInfo
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- CN203722861U CN203722861U CN201320775558.8U CN201320775558U CN203722861U CN 203722861 U CN203722861 U CN 203722861U CN 201320775558 U CN201320775558 U CN 201320775558U CN 203722861 U CN203722861 U CN 203722861U
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- 238000010586 diagram Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
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- 230000007423 decrease Effects 0.000 description 2
- 238000005538 encapsulation Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
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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 LED (light emitting diode) control circuit, and the circuit comprises a control unit, a triode Q1, a triode Q2, a resistor R2, a resistor R3, an LED group, and a power supply. The control interface of the control unit is connected with the base electrode of the triode Q1. The emitter electrode of the triode Q1 is connected with the base electrode of the triode Q2. The base electrode of the triode Q2 is connected with one end of the resistor R2, and the collector electrode of the triode Q2 is connected with the base electrode of the triode Q1. The emitter electrode of the triode Q2 is connected with one end of the resistor R3. The other end of the resistor R3 is connected with the base electrode of the triode Q1, thereby forming a loop. The other end of the resistor R2 is connected with the emitter electrode of the triode Q2, and is also grounded. The collector electrode of the triode Q1 is connected with the negative electrode of the LED group. The positive electrode of the LED group is connected with the power supply. According to the utility model, the control of the LED brightness and the LED power supply are relatively independent. The circuit provided by the utility model can enable a current passing through the LED not to be changed when the supply voltage of the LED changes.
Description
Technical field
The utility model relates to light-emitting diode control technology field, particularly a kind of LED control circuit.
Background technology
LED lamp is indispensable a kind of device in modern consumption electronic product, and the outstanding role of LED product is its Presentation Function.For example, the demonstration of equipment working state (the operating state differences of the different representatives of color), device power state shows etc.The use of LED is very simple, but how to ensure in the unsettled situation of power supply, and the brightness constancy of LED is not but an easy thing.For example, what consumption electronic product generally adopted is powered battery, and along with the consumption of battery electric quantity, voltage must decline, and this will make LED brightness step-down, and the user that brightness step-down must affect product experiences.Meanwhile, how to be also the difficult problem of pendulum in face of technical staff for the supply power voltage of LED provides multiple choices.Therefore, design and a kind ofly can ensure that LED brightness preservation in the situation that of change in voltage is constant, and make the supply power voltage of LED have the technical scheme of more selection just to seem very necessary.
Utility model content
In view of the above problems, the utility model provides a kind of a kind of LED control circuit that overcomes the problems referred to above or address the above problem at least in part.
According to an aspect of the present utility model, a kind of LED control circuit is provided, this circuit comprises: control unit, transistor Q1, transistor Q2, resistance R 2, resistance R 3, LED group and power supply;
The control interface of control unit is connected with the base stage of transistor Q1.
The emitter of transistor Q1 is connected with transistor Q2 base stage.
The base stage of transistor Q2 is connected with one end of resistance R 2.
The collector electrode of transistor Q2 is connected with the base stage of transistor Q1.
The emitter of transistor Q2 is connected with one end of resistance R 3.
The base stage of the other end of resistance R 3 and transistor Q1 is connected to form loop.
The other end of resistance R 2 is connected with the emitter of transistor Q2 and ground connection.
The collector electrode of transistor Q1 is connected with the negative pole of LED group.
The positive pole of LED group is connected with power supply.
In an embodiment of the present utility model, this circuit further comprises: the first current-limiting circuit; The control interface of control unit is connected with the base stage of transistor Q1 and one end of resistance R 3 by the first current-limiting circuit.
In an embodiment of the present utility model, the first current-limiting circuit is the resistance R 1 being connected between the control interface of described control unit and one end of described resistance R 3.
In an embodiment of the present utility model, to control LED group bright by export high level on control interface for control unit, controls LED group go out by output low level on control interface.
In an embodiment of the present utility model, control unit is by changing in the brightness of control interface output pulse width modulation (PWM) ripple control LED group.
Alternatively, LED group comprises a LED or comprises the LED of multiple series connection or comprise the LED of multiple parallel connections or comprise the LED that multiple connection in series-parallel mix.
In an embodiment of the present utility model, this circuit further comprises: the second current-limiting circuit; LED group is connected to the collector electrode of transistor Q1 by the second current-limiting circuit.
In an embodiment of the present utility model, the second current-limiting circuit is the resistance R 4 being connected between negative pole and the collector electrode of transistor Q1 of LED group.
In this LED control circuit that the utility model provides, LED brilliance control is to realize by control unit, power supply only for LED to power supply, LED brilliance control and LED power supply are relatively independent, therefore the supply power voltage of LED can have multiple choices.Meanwhile, in the technical program is that control unit is controlled, and can export by control unit the brightness variation of PWM ripple control LED.And the technical solution of the utility model realized in the time that LED supply power voltage changes, the electric current of the LED that makes to flow through remains unchanged, and ensures the constant of LED brightness.Compare with other LED intednsity circuits, the technical program simplicity of design, stable performance, with low cost, be applicable to various LED drive circuits.
Brief description of the drawings
Fig. 1 is the theory diagram of a kind of LED control circuit of providing of the utility model;
Fig. 2 is the circuit diagram of a kind of LED control circuit of providing of embodiment of the utility model.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing, the utility model execution mode is described in further detail.
Fig. 1 is the theory diagram of a kind of LED control circuit of providing of the utility model.Referring to Fig. 1, core concept of the present utility model is specifically to control light on and off state and the brightness variation of LED group by control unit (MCU shown in Fig. 1), and the power supply of LED is responsible for LED group to power, LED brilliance control and LED power supply are relatively independent, therefore, LED supply power voltage also can have multiple choices.
In an embodiment of the present utility model, can specifically control by MCU the light on and off state of LED group, meanwhile, the PWM waveform that can also export by MCU in an embodiment of the present utility model is as required realized the control of LED group brightness.
Further, this circuit for adjusting the electric current of LED group, makes the electric current in LED group trend towards stablizing by two homotype triode Q1 and Q2 and closed feedback loop of the composition of interlock circuit separately thereof.
Fig. 2 is the circuit diagram of a kind of LED control circuit of providing of embodiment of the utility model.
Referring to Fig. 2, this LED control circuit in the utility model comprises: control unit, transistor Q1, transistor Q2, resistance R 1, resistance R 2, resistance R 3, resistance R 4, LED group and power supply.In Fig. 2, do not draw control unit, but illustrated the control interface of control unit.
The control interface of control unit is connected with one end of resistance R 1;
The other end of resistance R 1 is connected with the base stage of transistor Q1.
The emitter of transistor Q1 is connected with transistor Q2 base stage.
The base stage of transistor Q2 is connected with one end of resistance R 2.
The collector electrode of transistor Q2 is connected with the base stage of transistor Q1.
The emitter of transistor Q2 is connected with one end of resistance R 3.
The base stage of the other end of resistance R 3 and transistor Q1 is connected to form loop.
The other end of resistance R 2 is connected with the emitter of transistor Q2 and ground connection.
The collector electrode of transistor Q1 is connected with one end of resistance R 4; The other end of resistance R 4 is connected with the negative pole of described LED group; The positive pole of LED group is connected with power supply.
It should be noted that, in an embodiment of the present utility model, Q1 and Q2 are all NPN type triode, and concrete model is determined according to side circuit.LED1 is light-emitting diode, and concrete model is determined according to side circuit.The resistance of resistance R 1, resistance R 2, resistance R 3 and resistance R 4 is determined according to the parameter of each related elements in side circuit, the precision encapsulation no requirement (NR) of resistance R 1, resistance R 2, resistance R 3 and resistance R 4.
Resistance R 1 is the first current-limiting circuit; it is mainly the control interface in order to protect MCU; because if the words that resistance R 2 resistances are very little; when Q1 conducting; may burn control interface, therefore resistance R 1 is not to arrange, when the resistance of resistance R 2 and R3 is enough greatly time; can save the setting of resistance R 1, simplify circuit.Similarly, resistance R 4 is the second current-limiting circuit, is mainly used for protecting LED group, neither arrange, and when the resistance of resistance R 2 and R3 is enough greatly time, the setting that also can save resistance R 4.Specifically can arrange according to circuit and product needed.
As shown in Figure 2, in an embodiment of the present utility model, that control unit adopts is micro-control unit MCU.
LED in the utility model can be a LED, also can be the LED group that multiple LED are in series, also can be the LED of multiple parallel connections, can also be the LED group that mode that multiple LED mix by connection in series-parallel is formed by connecting, specifically can be by circuit and product demand and design.
As shown in Figure 2, in an embodiment of the present utility model, that control unit adopts is micro-control unit MCU.LED in the utility model can be a LED, can be also the LED group that multiple LED are in series.In an embodiment of the present utility model, adopt a LED to carry out exemplary illustration.
In the technical solution of the utility model, MCU is controlled, can control the state of the on and off of LED group by MCU.Particularly, in the time that needs are lighted LED1, the level that can draw high control interface by MCU is controlled the bright of LED1; In the time not needing to light LED1, can drag down control interface level by MCU and control going out of LED1, improve like this flexibility that LED light on and off state is adjusted.And this scheme also can realize in the time need to regulating the brightness of LED group, only need to regulate the duty ratio of the pulse width modulation (PWM) waveform that MCU exports by control interface, simple and convenient.
Further, the technical solution of the utility model can also realize under the state of lighting at LED1, makes the electric current that flows through LED1 keep constant.Particularly, referring to Fig. 2, draw high the level of control interface by MCU and light LED1.In the time of MCU output high level, triode Q1 and Q2 are operated in amplification region, and Q1 conducting now has electric current to flow through LED1, so LED1 is lit.In the time of mains voltage variations, Q1 emitter voltage can change, and the change in voltage of Q1 emitter must cause the variation of Q2 operating state.The variation of Q2 operating state, can cause again the variation of the upper voltage of R3, and the variation of the upper voltage of R3 causes again the variation of Q1 operating state.So just formed a closed feedback loop, the result of this feedback loop makes the electric current on LED1 trend towards stablizing.
The above-mentioned electric current that makes to flow through LED1 keeps the specific implementation process of constant thought as follows: if supply voltage becomes large, it is large that the electric current of the LED1 that flows through becomes, and the dividing potential drop on R2 becomes large so, and it is large that the dividing potential drop on R2 becomes, and causes the base current of Q2 to become large.Because Q2 is operated in amplification region, so Q2 collector current becomes large (I
c=β × I
bβ is constant).The collector current of Q2 becomes the voltage decreases that can make again greatly Q1 base stage.Q1 base voltage diminishes and can make the collector current of Q1 diminish, and the electric current of the LED1 that flows through so will diminish.The result of this process must make the electric current on LED1 trend towards stablizing.
In the time that supply voltage diminishes, analytic process is similar.If supply voltage diminishes, the electric current of the LED1 that flows through diminishes, and causes the electric current of Q2 base stage to diminish.Because Q2 is operated in amplification region, so Q2 collector current diminishes, the collector current of Q2 diminishes, and can make again the voltage of Q1 base stage become large, and Q1 base voltage becomes greatly can make Q1 collector current become large, and the electric current of the LED1 that flows through so will become large.The result of this process is to make the electric current on LED1 trend towards stablizing.
Also provide a kind of LED control method according to another aspect of the present utility model, the method comprises: make the control interface of described control unit be connected with the base stage of transistor Q1; Make the emitter of transistor Q1 be connected with transistor Q2 base stage.
Make the base stage of transistor Q2 be connected with one end of resistance R 2.
Make the collector electrode of transistor Q2 be connected with the base stage of transistor Q1.
Make the emitter of transistor Q2 be connected with one end of resistance R 3.Make the other end of resistance R 3 and the base stage of transistor Q1 be connected to form loop.Make the other end of resistance R 2 be connected with the emitter of transistor Q2 and ground connection; Make the collector electrode of transistor Q1 be connected with the negative pole of LED group.Make the positive pole of LED group be connected with power supply.
In an embodiment of the present utility model, to control LED group bright by export high level on control interface for control unit, controls LED group go out by output low level on control interface.
In sum, in this LED control circuit that the utility model provides, LED brilliance control is to realize by control unit, and LED passes through Power supply, LED brilliance control and LED power supply are relatively independent, and therefore the supply power voltage of LED can have multiple choices.Meanwhile, in the technical program is that control unit is controlled, controls the light on and off state of LED by controlled MCU, and can export by control unit the brightness variation of PWM ripple control LED.Further, the technical solution of the utility model is in the time that LED supply power voltage changes, and the electric current of the LED that makes to flow through remains unchanged, and realizes the constant of LED brightness with this.
The foregoing is only preferred embodiment of the present utility model, be not intended to limit protection range of the present utility model.All any amendments of doing, be equal to replacement, improvement etc. within spirit of the present utility model and principle, be all included in protection range of the present utility model.
Claims (8)
1. a LED control circuit, is characterized in that, described circuit comprises: control unit, transistor Q1, transistor Q2, resistance R 2, resistance R 3, LED group and power supply;
The control interface of described control unit is connected with the base stage of described transistor Q1;
The emitter of described transistor Q1 is connected with described transistor Q2 base stage;
The base stage of described transistor Q2 is connected with one end of described resistance R 2;
The collector electrode of described transistor Q2 is connected with the base stage of described transistor Q1;
The emitter of described transistor Q2 is connected with one end of described resistance R 3;
The base stage of the other end of described resistance R 3 and described transistor Q1 is connected to form loop;
The other end of described resistance R 2 is connected with the emitter of described transistor Q2 and ground connection;
The collector electrode of described transistor Q1 is connected with the negative pole of described LED group;
The positive pole of described LED group is connected with described power supply.
2. circuit as claimed in claim 1, is characterized in that, described circuit further comprises: the first current-limiting circuit;
The control interface of described control unit is connected with the base stage of described transistor Q1 and one end of resistance R 3 by the first current-limiting circuit.
3. circuit as claimed in claim 2, is characterized in that, described the first current-limiting circuit is the resistance R 1 being connected between the control interface of described control unit and one end of described resistance R 3.
4. circuit as claimed in claim 1, is characterized in that, to control described LED group bright by export high level on control interface for described control unit, controls described LED group go out by output low level on control interface.
5. circuit as claimed in claim 1, is characterized in that, described control unit is by changing in the brightness of LED group described in the control of control interface output pulse width modulation (PWM) ripple.
6. the circuit as described in any one in claim 1 to 5, is characterized in that, described LED group comprises a LED or comprises the LED of multiple series connection or comprise the LED of multiple parallel connections or comprise the LED that multiple connection in series-parallel mix.
7. circuit as claimed in claim 6, is characterized in that, described circuit further comprises: the second current-limiting circuit;
Described LED group is connected to the collector electrode of described transistor Q1 by the second current-limiting circuit.
8. circuit as claimed in claim 7, is characterized in that, described the second current-limiting circuit is the resistance R 4 being connected between negative pole and the collector electrode of described transistor Q1 of described LED group.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320775558.8U CN203722861U (en) | 2013-11-28 | 2013-11-28 | LED (light emitting diode) control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320775558.8U CN203722861U (en) | 2013-11-28 | 2013-11-28 | LED (light emitting diode) control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203722861U true CN203722861U (en) | 2014-07-16 |
Family
ID=51161978
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320775558.8U Expired - Lifetime CN203722861U (en) | 2013-11-28 | 2013-11-28 | LED (light emitting diode) control circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN203722861U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103716957A (en) * | 2013-11-28 | 2014-04-09 | 青岛歌尔声学科技有限公司 | Light emitting diode (LED) control circuit and method |
-
2013
- 2013-11-28 CN CN201320775558.8U patent/CN203722861U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103716957A (en) * | 2013-11-28 | 2014-04-09 | 青岛歌尔声学科技有限公司 | Light emitting diode (LED) control circuit and method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140716 |