CN108401331A - A kind of constant-current charge LED drive circuit of low cost - Google Patents
A kind of constant-current charge LED drive circuit of low cost Download PDFInfo
- Publication number
- CN108401331A CN108401331A CN201810394742.5A CN201810394742A CN108401331A CN 108401331 A CN108401331 A CN 108401331A CN 201810394742 A CN201810394742 A CN 201810394742A CN 108401331 A CN108401331 A CN 108401331A
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- Prior art keywords
- diode
- constant
- triode
- drive circuit
- led
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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- Circuit Arrangement For Electric Light Sources In General (AREA)
- Led Devices (AREA)
Abstract
The present invention relates to field of LED drive technologies, specifically disclose a kind of constant-current charge LED drive circuit of low cost, power input equipped with access power supply, is additionally provided with first resistor, second resistance, the first diode, the second diode, lighting inductive switch, triode and light emitting diode.A kind of constant-current charge LED drive circuit of low cost provided by the invention, is built using components such as triode, diodes, realizes the brightness stability of LED, ensure that the brightness of LED still remains unchanged in the case where LED supply voltages fluctuate；The present invention directly drives LED by the external low level feedback point modulating signal received, is not take up the ports MCU, saves system MCU port resource；The present invention is built using the cheap electronic component such as resistance, diode, triode, if compared to available circuit in order to realize that scheme of the LED constant current driving using LDO voltage stabilizing chips, cost are greatly reduced, cost performance higher.
Description
Technical field
The present invention relates to field of LED drive technology more particularly to a kind of constant-current charge LED drive circuits of low cost.
Background technology
Currently, in automotive air-conditioning controller, the point modulating signal of part light emitting diode (hereinafter referred to as LED) is from outer
The low level feedback signal of portion's equipment such as seat heating indicator light, rear defrosting indicator light etc., the principle relationship block diagram realized is such as
Shown in Figure of description 1：When air-conditioner controller receives external low level modulating signal such as seat heating lighting feedback signal
After be entered into its MCU and be detected, realized by controlling LED drive circuit after MCU detections to LED is bright or goes out control
System.
LED drive circuit therein is built by discrete component, and circuit diagram is main as shown in Figure of description 2
To include triode Q4, light emitting diode D4 etc..MCU is by the presence or absence of test point modulating signal, by its output end MCU_5V_EN1
It exports corresponding low and high level and further controls triode ON and cut-off, to control the light on and off of LED.Work as MCU_5V_EN1
5V is inputted, LED (D4) is lighted, and triode Q4 is operated in saturation region；When MCU_5V_EN1 inputs 0V, LED (D4) point off, triode
Q4 is operated in cut-off region.In that case, can exist as following drawbacks：
1, vehicle power supply voltage can have a certain range of fluctuation in normal output, or be tested in starting impulse
In, it may appear that the case where mains ripple, if LED is in illuminating state at this time, flow through LED electric current easy to produce it is larger
Variation, to generate apparent brightness change, the bad experience of the flickers such as LED is brought to user vehicle, cannot achieve LED light perseverance
Stream driving.Also, in the case that the ports MCU are in short supply, system can not distribute the ports MCU and be driven for low level detection and LED
The control of dynamic circuit, and the external low level feedback point modulating signal by receiving is needed to directly drive LED；
2, in the foregoing circuit using MCU2 resource mouth, if in order to overcome the problems, such as that constant current drives and passes through LDO
Voltage stabilizing chip realizes voltage stabilizing, by constant resistance current limliting, and then realizes constant current driving, but the program needs additional LDO voltage stabilizings
Chip, it is with high costs.
Invention content
The technical issues of present invention provides a kind of constant-current charge LED drive circuit of low cost, solution is existing discrete member
The LED drive circuit that part is built cannot achieve the LED constant current driving of low cost.
In order to solve the above technical problems, the present invention provides a kind of constant-current charge LED drive circuit of low cost, is equipped with access
The power input of power supply, be additionally provided with first resistor, second resistance, the first diode, the second diode, lighting induction open
Pass, triode and light emitting diode；
One end of the first resistor connects the power input with the negative pole end of first diode, and described first
The other end of resistance connects the emitter of the triode, and the positive terminal of first diode connects the base stage of the triode
With one end of the second resistance, the positive concatenated light emitting diode of collector forward direction connection of the triode with it is described
One end of the other end and the lighting inductive switch of the second resistance, the lighting inductive switch are connected after second diode
The other end ground connection.
Specifically, the input voltage of the power input is 9-16V, rated voltage 12V.
Specifically, the first resistor and the second resistance are current-limiting resistance, and the first resistor is single resistance or more
The equivalent resistance of a list resistor coupled in parallel.
Specifically, first diode is zener diode, and second diode is anti-reverse diode.
Specifically, the triode is PNP type triode.
Preferably, the PNP type triode is BC807-25.
Specifically, the power supply is powered by vehicle-mounted KL15 ignition leads or KL30 battery lines.
Specifically, the input voltage of the first resistor, the value standard of second resistance and the power input is most
Low value standard is when ensureing that the normal electricity of the light emitting diode is bright, and the triode is in amplification region.
The constant-current charge LED drive circuit of a kind of low cost provided by the invention, using components such as triode, diodes
It builds, adjusts the resistance value of first resistor as needed, then it is (constant in first resistor resistance value can to obtain constant different electric currents
In the case of, then the electric current for flowing through LED is invariable), to realize that client requires the difference of lamplight brightness, realize LED's
Brightness stability ensure that the brightness of LED still remains unchanged in the case where LED supply voltages fluctuate；
In the case that system MCU port is in short supply, available circuit can not distribute the ports MCU do it is low level detection and
The control of LED drive circuit, the present invention directly drive LED by the external low level feedback point modulating signal received, are not take up
The ports MCU save system MCU port resource；
The present invention is built using the cheap electronic component such as resistance, diode, triode, if compared to available circuit in order to
Realize that scheme of the LED constant current driving using LDO voltage stabilizing chips, cost are greatly reduced, cost performance higher.
Description of the drawings
Fig. 1 is the functional block diagram for the LED drive circuit that the prior art provided by the invention is built using separate type component；
Fig. 2 is a circuit connection diagram of Fig. 1 provided by the invention；
Fig. 3 is a kind of circuit connection of the constant-current charge LED drive circuit of low cost provided in an embodiment of the present invention
Figure；
Fig. 4 is the voltage wave that Fig. 3 embodiments provided by the invention are applied to its power input during starting impulse
Shape figure；
Fig. 5 is a parameter general chart corresponding with Fig. 4 provided in an embodiment of the present invention.
Specific implementation mode
Embodiments of the present invention are specifically illustrated below in conjunction with the accompanying drawings, embodiment is only given for illustrative purposes,
It can not be interpreted as limitation of the invention, including the type selecting of component and value size and attached drawing are only preferred embodiment, only
For reference with illustrate to use, the limitation to scope of patent protection of the present invention is not constituted, because not departing from spirit of that invention and model
On the basis of enclosing, many changes can be carried out to the present invention.
A kind of one circuit connection diagram of the constant-current charge LED drive circuit for low cost that inventive embodiments provide, such as Fig. 3
It is shown.In the present embodiment, the constant-current charge LED drive circuit of a kind of low cost is equipped with access power supply
The power input B+ of Battery, be additionally provided with first resistor R1, second resistance R2, the first diode D1, the second diode D2,
Lighting inductive switch SW1, triode Q and Light-emitting diode LED；One end of the first resistor R1 and the first diode D1
Negative pole end connect the power input B+, the other end of the first resistor R1 connects the emitter E of the triode Q,
The positive terminal of the first diode D1 connects one end of the base stage B and the second resistance R2 of the triode Q, three pole
Described second is connected after the collector C forward directions connection positive concatenated light emitting diode D and the second diode D2 of pipe Q
One end of the other end of resistance R2 and the lighting inductive switch SW1, the other end ground connection of the lighting inductive switch SW1.
In Fig. 3, in order to calculate voltage, be position mark A-F, Ubf indicates the voltage between then contact B, F, remaining similarly, Vf is indicated
Supply voltage.
In preferred the present embodiment, the input voltage of the power input B+ is 9-16V, rated voltage 12V；
The power supply Battery is powered by vehicle-mounted KL15 ignition leads or KL30 battery lines；
The first resistor R1 is current-limiting resistance, and the first resistor R1 is the equivalent of single resistance or multiple single resistor coupled in parallel
Resistance, by adjusting the value of first resistor R1, adjustment circuit needs stable electric current, realizes LED luminance adjustment；
The second resistance R2 is the current-limiting resistance of triode Q ground levels B, while being also the current limliting electricity of the first diode D1
Resistance prevents the electric current for flowing through D1 excessive so that damage；
The lighting inductive switch SW1 inductions are external low level feedback point modulating signal, are closed when effective, break when invalid
It opens；
The first diode D1 is zener diode, Ubf voltage stabilizations may be implemented by D1, at present the voltage stabilizing value of D1
5.6V is taken, according to the voltage stabilizing value for needing to adjust Uef of circuit, selects different voltage stabilizing values；
The second diode D2 is anti-reverse diode, when preventing interface A to power supply high voltage short circuit, damages circuit；
The triode Q is PNP type triode Q, when LED is lighted, is operated in amplification region, the PNP type triode Q is
BC807-25, or other PNP type triodes；
It is significant to note that the value standard of the first resistor R1, second resistance R2 and the power input B
+ the minimum value standard of input voltage be when ensureing that the normal electricity of the Light-emitting diode LED is bright, the triode Q is in and puts
Great Qu.
LED circuit is lighted and extinguishes control principle：When external low level feedback point modulating signal SW1 is effective, circuit is over the ground
Circuit is connected, and LED is lighted, and triode Q is operated in amplification region；When external low level feedback point modulating signal SW1 is invalid, circuit pair
Earth-return disconnects, and LED light is extinguished, and triode Q is operated in cut-off region.
LED constant current driving principle：The Ube of usual triode Q is a fixed value, and room temperature about takes -0.65V, the one or two pole
The voltage stabilizing value of pipe D1 is that 5.6V=Ufb obtains Ufe=5.6V-0.65V in conjunction with Ufb=Ueb+Ufe, Ueb=-Ube=0.65V
=4.95V, at this time first resistor R1 both end voltages Ufe do not change with the variation of supply voltage Vf and a steady state value.Stream
The electric current i.e. triode Q emitting stages electric current Ie=Ufe/R4 of first resistor R1 is crossed, Ufe is constant, and first resistor R1 hinders in circuit
It is worth constant, therefore Ie values are constant, Ie=1000* (4.95V/560 Ω) ≈ 8.8mA, Ie ≈ Ic ≈ 8.8mA, therefore flow through LED's
Electric current Ic is constant in 8.8mA or so, realizes the brightness stability of LED.It is constant by adjusting the value adjusting needs of first resistor R1
Electric current Ic, to realize that client requires the difference of lamplight brightness.
The embodiment of the present invention realizes that control LED current Ic is constant, needs to meet triode Q works by charging to LED constant current
Make in amplification region, when supply voltage Vf dynamic changes, LED current Ic still stablizes, and LED luminance still remains unchanged.Referring to
Fig. 4, Fig. 5 are the voltage that Fig. 4 embodiments provided by the invention are applied to its power input B+ during starting impulse respectively
Oscillogram and a corresponding parameter general chart, wherein Ub=Vf, US=Ub-Va1, UA=Ub-Va2.When simulating vehicle startup, if
Moment starts, and battery line voltage meeting transient state declines, and then slowly rises.(grade I requires measured piece applying in the experiment of grade I
During and after adding interference, it is functional to execute the institute that it is pre-designed, without abnormal phenomenon), there is not the brightness of LED light
Variation, this circuit can ensure through certain depot's starting impulse experiment.
The constant-current charge LED drive circuit of a kind of low cost provided in an embodiment of the present invention, using triode, diode etc.
Component is built, and is adjusted the resistance value of first resistor R1 as needed, then can be obtained constant different electric currents (in first resistor R1
In the case that resistance value is constant, then the electric current for flowing through LED is invariable), it is real to realize that client requires the difference of lamplight brightness
The brightness stability for having showed LED ensure that the brightness of LED still remains unchanged in the case where LED supply voltages fluctuate；
In the case that system MCU port is in short supply, available circuit can not distribute the ports MCU do it is low level detection and
The control of LED drive circuit, the present invention directly drive LED by the external low level feedback point modulating signal received, are not take up
The ports MCU save system MCU port resource；
The embodiment of the present invention is built using the cheap electronic component such as resistance, diode, triode, such as compared to available circuit
Fruit is in order to realize that scheme of the LED constant current driving using LDO voltage stabilizing chips, cost are greatly reduced, cost performance higher.
The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment
Limitation, it is other it is any without departing from the spirit and principles of the present invention made by changes, modifications, substitutions, combinations, simplifications,
Equivalent substitute mode is should be, is included within the scope of the present invention.
Claims (8)
1. a kind of constant-current charge LED drive circuit of low cost is equipped with the power input (B of access power supply (Battery)
+), it is additionally provided with first resistor (R1), second resistance (R2), the first diode (D1), the second diode (D2), lighting inductive switch
(SW1), triode (Q) and light emitting diode (LED)；
One end of the first resistor (R1) connects the power input (B+) with the negative pole end of first diode (D1),
The other end of the first resistor (R1) connects the emitter (E) of the triode (Q), the anode of first diode (D1)
End connects one end of the base stage (B) and the second resistance (R2) of the triode (Q), the collector (C) of the triode (Q)
The positive concatenated light emitting diode (D) of forward direction connection connect the second resistance (R2) afterwards with second diode (D2)
The other end and the lighting inductive switch (SW1) one end, the lighting inductive switch (SW1) the other end ground connection.
2. a kind of constant-current charge LED drive circuit of low cost as described in claim 1, it is characterised in that：The power supply is defeated
The input voltage for entering end (B+) is 9-16V, rated voltage 12V.
3. a kind of constant-current charge LED drive circuit of low cost as claimed in claim 2, it is characterised in that：First resistor
(R1) it is current-limiting resistance, the first resistor (R1) is the equivalent resistance of single resistance or multiple single resistor coupled in parallel.
4. a kind of constant-current charge LED drive circuit of low cost as described in claim 1, it is characterised in that：Described 1st
Pole pipe (D1) is zener diode, and second diode (D2) is anti-reverse diode.
5. a kind of constant-current charge LED drive circuit of low cost as described in claim 1, it is characterised in that：The triode
(Q) it is PNP type triode.
6. a kind of constant-current charge LED drive circuit of low cost as claimed in claim 5, it is characterised in that：The positive-negative-positive three
Pole pipe is BC807-25.
7. a kind of constant-current charge LED drive circuit of low cost as described in claim 1, it is characterised in that：The power supply electricity
Source (Battery) is powered by vehicle-mounted KL15 ignition leads or KL30 battery lines.
8. a kind of constant-current charge LED drive circuit of low cost as described in claim 1, it is characterised in that：First electricity
The minimum value standard of input voltage of resistance (R1), the value standard of second resistance (R2) and the power input (B+) is,
When ensureing that the normal electricity of the light emitting diode (LED) is bright, the triode (Q) is in amplification region.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810394742.5A CN108401331A (en) | 2018-04-27 | 2018-04-27 | A kind of constant-current charge LED drive circuit of low cost |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810394742.5A CN108401331A (en) | 2018-04-27 | 2018-04-27 | A kind of constant-current charge LED drive circuit of low cost |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108401331A true CN108401331A (en) | 2018-08-14 |
Family
ID=63099485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810394742.5A Pending CN108401331A (en) | 2018-04-27 | 2018-04-27 | A kind of constant-current charge LED drive circuit of low cost |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111796621A (en) * | 2020-07-16 | 2020-10-20 | 山东超越数控电子股份有限公司 | Constant current source control method based on linear voltage stabilizer and constant current source circuit |
| CN114567948A (en) * | 2022-04-01 | 2022-05-31 | 山东华天电气有限公司 | Energy-saving and high-reliability partitioned series light source driving circuit and working method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101998719A (en) * | 2009-08-26 | 2011-03-30 | 胡梦阳 | LED (Light Emitting Diode) control circuit of automobile lamp |
| JP2014151717A (en) * | 2013-02-06 | 2014-08-25 | Stanley Electric Co Ltd | Overvoltage protection device for vehicular lighting fixture |
-
2018
- 2018-04-27 CN CN201810394742.5A patent/CN108401331A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101998719A (en) * | 2009-08-26 | 2011-03-30 | 胡梦阳 | LED (Light Emitting Diode) control circuit of automobile lamp |
| JP2014151717A (en) * | 2013-02-06 | 2014-08-25 | Stanley Electric Co Ltd | Overvoltage protection device for vehicular lighting fixture |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111796621A (en) * | 2020-07-16 | 2020-10-20 | 山东超越数控电子股份有限公司 | Constant current source control method based on linear voltage stabilizer and constant current source circuit |
| CN114567948A (en) * | 2022-04-01 | 2022-05-31 | 山东华天电气有限公司 | Energy-saving and high-reliability partitioned series light source driving circuit and working method thereof |
| CN114567948B (en) * | 2022-04-01 | 2024-03-12 | 山东华天电气有限公司 | Energy-saving high-reliability partitioned series light source driving circuit and working method thereof |
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Application publication date: 20180814 |