CN207266348U - Constant current driver circuit for LED - Google Patents
Constant current driver circuit for LED Download PDFInfo
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- CN207266348U CN207266348U CN201721339561.XU CN201721339561U CN207266348U CN 207266348 U CN207266348 U CN 207266348U CN 201721339561 U CN201721339561 U CN 201721339561U CN 207266348 U CN207266348 U CN 207266348U
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- constant current
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Abstract
It the utility model is related to a kind of constant current driver circuit for LED.The circuit includes a switching buck LED drive chip, input capacitance group, output capacitance group, sampling resistor group, loop inductance and circuit diode.Input capacitance group is arranged on power input, one end connection input power, other end ground connection, and the one end for connecting input power is connected with sampling resistor group；Sampling resistor group, LED and loop inductance are sequentially connected with；The power switch output pin connection of loop inductance connection driving chip；The power switch output pin of circuit diode connection driving chip and one end of input capacitance group；The power input pin connection for one end connection driving chip that sampling resistor group is connected with input capacitance group, the driving boosting pin connection of the other end and driving chip；Output capacitance is in parallel with LED；And input capacitance group is made of two capacitances in parallel, sampling resistor group is made of two resistance in parallel.It carries out constant current-supplying, and supply current is not affected by temperature.
Description
Technical field
It the utility model is related to electronic technology field, more particularly to a kind of LED light constant-current drive circuit.
Background technology
It is mark obstacle that aviation obstruction beacon (AviaT1ion ObsT1rucT1ion lighT1), which is also known as navigational lighting aid equipment,
The extraordinary lamps and lanterns of thing, are under the jurisdiction of navigational lighting aid equipment Industry, and aviation obstruction beacon is the lamp kind scope under it.In view of light pollution
With the difference of general purpose headlamp, under middle high light intensity, aviation obstruction beacon is not used generally and is always on, but uses flicker side
Formula.Aero-obstruction lantern with low light intensity is generally always on working method.Its flicker frequency of the aviation obstruction beacon of senior middle school's light intensity is not generally low
In 20 times per minute, not higher than 70 times per minute.
LED can be used as light source in aviation obstruction beacon, but the stability requirement to illumination is higher, it is necessary to which LED outputs are bright
Spend constant, stable working state.
Utility model content
Based on this, it is necessary to provide a kind of constant current driver circuit for LED of powered stable.
To realize that a kind of constant current driver circuit for LED of the utility model aim offer, including a switching buck LED are driven
Dynamic chip, input capacitance group, output capacitance group, sampling resistor group, loop inductance and circuit diode；
The input capacitance group is arranged on power input, one end connection input power, other end ground connection, and connects input
One end of power supply is connected with the sampling resistor group；
The sampling resistor group, LED and the loop inductance are sequentially connected with；
The loop inductance is not opened with one end that the LED is connected and the power supply of the switching buck LED drive chip
Close output pin connection；
Described circuit diode one end connects the power switch output pin of the switching buck LED drive chip, separately
One end connects one end that the sampling resistor group connects the input capacitance group；
One end that the sampling resistor group is connected with the input capacitance group connects the switching buck LED drive chip
Power input pin connection, the driving of the other end and the switching buck LED drive chip pin that boosts is connected；
The output capacitance is in parallel with the LED；And
The input capacitance group is made of two capacitances in parallel, and the sampling resistor group is by two resistance groups in parallel
Into.
In one of embodiment constant current driver circuit for LED, the circuit diode is Schottky diode.
In one of embodiment constant current driver circuit for LED, the switching buck LED drive chip model MP2489,
Two resistances of the sampling resistor group are respectively 0.56 Ω and 0.51 Ω.
In one of embodiment constant current driver circuit for LED, current monitoring chip and monitored resistance group are further included；
The monitored resistance string formation is coupled between the sampling resistor group and the LED, and with the current monitoring chip
Two pins connection, detect the electric current that the LED passes through.
In one of embodiment constant current driver circuit for LED, the input control of the switching buck LED drive chip is drawn
Foot connects external LED control chip by a triode and a resistance of series connection.
In one of embodiment constant current driver circuit for LED, a capacitance is nonpolarity ceramics in the input capacitance group
Capacitance, another is high frequency decoupling capacitance.
In one of embodiment constant current driver circuit for LED, the output capacitance is nonpolarity ceramic condenser.
The beneficial effects of the utility model include：A kind of constant current driver circuit for LED provided by the utility model, input capacitance
Group, sampling resistor group output capacitance and loop inductance are sequentially connected with and are carried out by switching buck LED drive chip for LED
Constant current-supplying.For LED current it is constant after, no matter how temperature change, how C-V characteristic moves to left, and electric current is all constant, knot
Temperature also would not vicious circle.Extend LED service lifes, and LED brightness outputs are constant.
Brief description of the drawings
Fig. 1 is an a kind of specific embodiment electrical block diagram of constant current driver circuit for LED of the utility model.
Embodiment
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing to this reality
Illustrated with the embodiment of new flying obstacle lamp power circuit and aviation obstruction beacon.It should be appreciated that this place
The specific embodiment of description only to explain the utility model, is not used to limit the utility model.
It should be noted that term " first " described herein, " second " be only used for description purpose, and it is not intended that
Indicate or imply relative importance or the implicit quantity for indicating indicated technical characteristic.Thus, " first ", " are defined
At least one this feature can be expressed or be implicitly included to two " feature.In the description of the utility model, " multiples' " contains
Justice is at least two, such as two, three etc., unless otherwise specifically defined.
As shown in Figure 1, a kind of constant current driver circuit for LED of one of embodiment, including a switching buck LED drive
Dynamic chip, input capacitance group, output capacitance group, sampling resistor group, loop inductance and circuit diode.
Input capacitance group is arranged on power input, one end connection input power, other end ground connection, and connects input power
One end be connected with sampling resistor group.Sampling resistor group, LED and loop inductance L3 are sequentially connected with, in circuit connection afterwards, inductance
The one end not being connected with LED and power switch output pin (the MP2489 chips shown in Fig. 1 of switching buck LED drive chip
The first pin -- SW pins) connection.
The SW pins of circuit diode D3 one end connecting valve voltage-dropping type LED drive chip, the other end and sampling resistor group
Connect one end of input capacitance group.One end connecting valve voltage-dropping type LED driving cores that sampling resistor group is connected with input capacitance group
The power input pin connection of piece, the other end are connected with the driving boosting pin of switching buck LED drive chip.Output capacitance
C15 is in parallel with LED.
And in the present embodiment, as shown in Figure 1, input capacitance group is made of two capacitance C12, C13 in parallel, sampling
Resistance group is made of two resistance R15, R16 in parallel.Switching buck LED drive chip can be connected exterior by pin
LED control chips, the processor that can be such as controlled by pulse to LED.
More preferably, as shown in Figure 1, the input control pin of switching buck LED drive chip passes through a triode Q2
An and resistance R18 connection external LED control chip (MCU) of series connection.
In the constant current driver circuit for LED of the present embodiment, input capacitance group, sampling resistor group output capacitance and loop inductance
It is sequentially connected with and constant current-supplying is carried out for LED by switching buck LED drive chip.For LED current it is constant after, no matter
How temperature changes, and how C-V characteristic moves to left, and electric current is all constant, and junction temperature also would not vicious circle.Extend LED and use the longevity
Life, and LED brightness outputs are constant.
In an instantiation, DC/DC drive circuits select opening for Monolithic Power Systems (MPS) companies
Voltage-dropping type LED drive chip MP24892 is closed, its unit for electrical property parameters is as follows：
1. input voltage VIN:DC6-45V；
2. output current IOUT:1A；
3. switching frequency fMAX:600kHz。
And in the drive circuit shown in Fig. 1, current monitoring chip and monitored resistance group are further included, by two variable resistors
RP1, RP2 are formed.Monitored resistance string formation is coupled between sampling resistor group and LED, and is connected with two pins of current monitoring chip
Connect, the electric current that detection LED passes through.In order to monitor whether LED load is working properly in real time, and the ADC that can be sent into MCU is examined in real time
Survey, selected the high-side current monitor ZXCT1009 chips of DIODES companies, coordinate MP24892 chips to use, its electrical property
Parameter is as follows：
1. operating voltage：2.5-20V；
2. detect voltage VSENSE:2.5V。
In the constant-current drive circuit shown in Fig. 1, resistance R15, R16 setting LED output currents of sampling resistor group, and this
Two resistances are respectively 0.56 Ω and 0.51 Ω in embodiment；L3 sets the working frequency of MP24892, and general setting scope is
Between 200kHz-600kHz；3 feet of MP24892 are EN/DIM, there is two functions：One, this pin is connected to the PWM of MCU by Q2
Pin, produces PWM by MCU and adjusts LED luminance；Two, the light on and off of low and high level control LED are exported by MCU；RP1、RP2、
Whether electric current and voltage when R17, R19 setting LED normal works, detection LED work normally, and the voltage detected is sent into MCU
ADC, so as to judge the working status of LED.
Correlation computations formula is as follows：
The 1st, LED output currents are set
RSENSE=202mV/ILED
In present design, the Ω of sampling resistor R15//R16, i.e. 0.56 Ω // 0.51, after being calculated according to formula, output
Electric current is about 750mA.
The 2nd, inductance parameters are set
According to formula, VOUTFor 2.2-2.4V, 2.3V, V are takenINFor 12V, ILEDFor 750mA, FSWRecommendation is 200-
Between 600kHz, this programme takes 300kHZ, and inductance L is about 30uH inductance after calculating, and actual value L3 is 33uH.
The 3rd, diode parameters are set
When internal metal-oxide-semiconductor turns off, Schottky diode need to be used to provide electric current for inductance, this programme selects Schottky two
Pole pipe D3 (SS24/2A/40V).
The 4th, input capacitance parameter is set
Input capacitance can be reduced from surge current caused by power input and switching noise, it is recommended to use 10uF-22uF is low
ESR capacitors.This programme selects nonpolarity ceramic condenser and high frequency decoupling capacitance, location number C12, C13, the design parameter to be：
X7R/1206/50V/10uF。
The 5th, output capacitance parameter is set
In order to reduce the peak point current at LED both ends, i.e. 30% less than average value.This programme selects nonpolarity ceramic electrical
Hold, design parameter is：X7R/0805/16V/22uF.
PCB layouts pay attention to
In addition, in terms of pcb board layout, critical IN, RS pin by MP24892 of sampling resistor, it is possible to reduce output electricity
Stream error；In addition, the cabling in the SW pins circuit of input circuit, i.e. input capacitance-Schottky diode-chip internal metal-oxide-semiconductor
It is as short as possible.
Embodiment described above only expresses the several embodiments of the utility model, its description is more specific and detailed,
But it should not be interpreted as limiting the scope of the present invention.It should be pointed out that for the common of this area
For technical staff, without departing from the concept of the premise utility, various modifications and improvements can be made, these all belong to
In the scope of protection of the utility model.Therefore, the protection domain of the utility model patent should be determined by the appended claims.
Claims (7)
1. a kind of constant current driver circuit for LED, it is characterised in that including switching buck LED drive chip, an input capacitance
Group, output capacitance group, sampling resistor group, loop inductance and circuit diode；
The input capacitance group is arranged on power input, one end connection input power, other end ground connection, and connects input power
One end be connected with the sampling resistor group；
The sampling resistor group, LED and the loop inductance are sequentially connected with；
The loop inductance is not defeated with one end that the LED is connected and the power switch of the switching buck LED drive chip
Go out pin connection；
Described circuit diode one end connects the power switch output pin of the switching buck LED drive chip, the other end
Connect one end that the sampling resistor group connects the input capacitance group；
One end that the sampling resistor group is connected with the input capacitance group connects the electricity of the switching buck LED drive chip
Source input pin connection, the other end are connected with the driving boosting pin of the switching buck LED drive chip；
The output capacitance is in parallel with the LED；And
The input capacitance group is made of two capacitances in parallel, and the sampling resistor group is made of two resistance in parallel.
2. constant current driver circuit for LED according to claim 1, it is characterised in that the circuit diode is Schottky two
Pole pipe.
3. constant current driver circuit for LED according to claim 1, it is characterised in that the switching buck LED drive chip
Model MP2489, two resistances of the sampling resistor group are respectively 0.56 Ω and 0.51 Ω.
4. constant current driver circuit for LED according to claim 1, it is characterised in that further include current monitoring chip and monitoring electricity
Resistance group；
The monitored resistance string formation is coupled between the sampling resistor group and the LED, and with the two of the current monitoring chip
A pin connection, detects the electric current that the LED passes through.
5. constant current driver circuit for LED according to claim 1, it is characterised in that the switching buck LED drive chip
Input control pin pass through a triode and a resistance of series connection and connect external LED control chip.
6. constant current driver circuit for LED according to claim 1 a, it is characterised in that capacitance in the input capacitance group
For nonpolarity ceramic condenser, another is high frequency decoupling capacitance.
7. constant current driver circuit for LED according to claim 1, it is characterised in that the output capacitance is nonpolarity ceramics
Capacitance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721339561.XU CN207266348U (en) | 2017-10-17 | 2017-10-17 | Constant current driver circuit for LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721339561.XU CN207266348U (en) | 2017-10-17 | 2017-10-17 | Constant current driver circuit for LED |
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| Publication Number | Publication Date |
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| CN207266348U true CN207266348U (en) | 2018-04-20 |
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ID=61917630
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|---|---|---|---|
| CN201721339561.XU Active CN207266348U (en) | 2017-10-17 | 2017-10-17 | Constant current driver circuit for LED |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110281839A (en) * | 2019-07-05 | 2019-09-27 | 台州学院 | A kind of automobile long-and-short distant light automatic control system based on Bluetooth technology |
-
2017
- 2017-10-17 CN CN201721339561.XU patent/CN207266348U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110281839A (en) * | 2019-07-05 | 2019-09-27 | 台州学院 | A kind of automobile long-and-short distant light automatic control system based on Bluetooth technology |
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