CN207166828U - LED light adjusting circuits and LED display device - Google Patents
LED light adjusting circuits and LED display device Download PDFInfo
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- CN207166828U CN207166828U CN201721021557.9U CN201721021557U CN207166828U CN 207166828 U CN207166828 U CN 207166828U CN 201721021557 U CN201721021557 U CN 201721021557U CN 207166828 U CN207166828 U CN 207166828U
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Abstract
A kind of LED light adjusting circuits and LED display device, LED light adjusting circuits with least LED series winding connects all the way, including LED constant current driving chip, dimming unit and boosting unit, the LED constant current driving chip have：Multiple LEDs drive pin, are connected with the negative pole respectively with LED string described in each road；Enabled pin, the switch controlling signal for access chip；PWM brightness adjustment control pins, it is connected with the enabled pin；PWM output pins, it is connected with the boosting unit, controls the boosting unit to supply the LED string after being boosted to the power supply；Output current sets pin, and the PWM dim signals are accessed by the dimming unit, wherein, the dimming unit adjusts the current value of the LED driving pin according to the PWM dim signals.The PWM outputs for being limited to undesirable PWM dim signals and then having influence on LED drive chip are avoided, causes the brightness of rear class LED lamp bead to be in course of adjustment and the problem of saltus step and excessive output ripple occurs.
Description
Technical field
The utility model belongs to LED backlight actuation techniques field, more particularly to a kind of LED backlight drive circuit and LED show
Show equipment.
Background technology
At present, 4 traditional road PWM dimming LED (Light Emitting Diode) driving chips, LED drivings are changed by changing the dutycycle of pwm signal
The PWM of chip is exported to realize that the electric current for changing 4 paths of LEDs passages exports.But it is constrained to the technology energy between different MCU chips
Power, the output for being not necessarily preferable pwm signal and then having influence on LED drive chip of PWM dim signals, causes rear class LED
Lamp bead brightness, which can be in course of adjustment, there is the problem of saltus step and excessive output ripple.
Utility model content
The purpose of this utility model is to provide a kind of LED backlight drive circuit and LED display device, it is intended to solves tradition
PWM dimming LED (Light Emitting Diode) lamp bead brightness can be in course of adjustment and the problem of saltus step and excessive output ripple occur.
A kind of LED light adjusting circuits, with least all the way LED series winding connect, the circuit include LED constant current driving chip, adjust
Light unit and the boosting unit being connected with the positive pole of LED string described in power supply and each road, wherein, the LED constant current is driven
Dynamic chip has：
Multiple LEDs drive pin, are connected with the negative pole respectively with LED string described in each road；
Enabled pin, the switch controlling signal for access chip；
PWM brightness adjustment control pins, PWM dim signals are accessed, and be connected with the enabled pin；
PWM output pins, it is connected with the boosting unit, controls the boosting unit to be supplied after being boosted to the power supply
To the LED string；And
Output current sets pin, and the PWM dim signals are accessed by the dimming unit, wherein, the light modulation is single
Member exports to the output current voltage for setting pin according to the duty cycle adjustment of the PWM dim signals, with described in regulation
LED drives the current value of pin.
Preferably, the dimming unit is included with current-limiting resistance, the first divider resistance, the second divider resistance and an electric capacity,
Wherein：
The PWM dim signals are accessed in described current-limiting resistance one end, and the other end is by the capacity earth, described first point
It is in parallel with the electric capacity after piezoresistance and second divider resistance series connection, first divider resistance and second partial pressure electricity
The public termination output current of resistance sets pin.
Preferably, in addition to clamp resistance, the clamp resistance are connected to the enabled pin and the PWM brightness adjustment controls
Between pin.
Preferably, the LED driving pin is 4.
Preferably, the boosting unit includes Boost circuit.
Preferably, the PWM brightness adjustment controls pin also accesses PWM dim signals.
In addition, a kind of LED display device is additionally provided, including above-mentioned LED light adjusting circuits.
Above-mentioned LED light adjusting circuits and LED display device are by using the switching signal of LED chip by the original of LED chip
Brightness adjustment control pin clamper, abandon traditional utilization PWM dim signals and be input to former brightness adjustment control pin change PWM output pins
Dutycycle to change the voltage of LED string to realize the scheme of light modulation, use instead and PWM dim signals are changed into out effective voltage connect
Enter to output current to set pin to adjust the driving current of LED driving pin to realize that LED is dimmed, avoid and be limited to not
Preferable PWM dim signals and then the PWM outputs for having influence on LED drive chip, cause the brightness of rear class LED lamp bead to adjust
Occurs the problem of saltus step and excessive output ripple in journey.
Brief description of the drawings
Fig. 1 is the LED light adjusting circuit circuit theory diagrams that the utility model preferred embodiment provides.
Embodiment
In order that the purpose of this utility model, technical scheme and advantage are more clearly understood, below in conjunction with accompanying drawing and implementation
Example, the utility model is further elaborated.It should be appreciated that specific embodiment described herein is only explaining
The utility model, it is not used to limit the utility model.
Referring to Fig. 1, the LED light adjusting circuits in the utility model preferred embodiment may be provided at any LED display device,
LED light adjusting circuits with least all the way LED string 200 be connected with realize light modulation.
LED light adjusting circuits include LED constant current driving chip 101, dimming unit 102 and with power supply V+ and each road
The boosting unit 103 of the positive pole connection of LED string 200.
Wherein, LED constant current driving chip 101 has enabled pin ENA, PWM brightness adjustment control pin DIM, GND grounding lead
Pin, FREQUENCY CONTROL pin RI, output current set pin ISET, light-modulating mode selection pin BF/DMO, soft start and compensated back
Pass pin COMP, linear voltage stabilization output pin VCC, supply input pin VIN, PWM output pin GATE, current detecting pin
CS, overvoltage protection input pin OVP, multiple LEDs driving pin LED1~LED4 (present embodiment is by taking 4 tunnels as an example).
Each LED driving pin LED1~LED4 is connected with the negative pole respectively with each paths of LEDs lamp string 200；Enabled pin
ENA is used for the switch controlling signal BKE_EN1 of access chip 101；PWM brightness adjustment controls pin access PWM dim signals BKL_
DIM, and be connected with enabled pin ENA with clamper；PWM output pins GATE is connected with boosting unit 103, controls boosting unit
LED string 200 is supplied after 103 pairs of power supply V+ boostings；Output current sets pin ISET to be accessed by dimming unit 102
PWM dim signals BKL_DIM.Wherein, dimming unit 102 is exported to defeated according to PWM dim signals BKL_DIM duty cycle adjustment
Go out the voltage that electric current sets pin ISET, to adjust LED driving pin LED1~LED4 current value, so as to realize LED
The light modulation of string 200.
In the present embodiment, dimming unit 102 is included with current-limiting resistance R354, the first divider resistance R352, the second partial pressure electricity
Hinder a R348 and electric capacity C296.PWM dim signal BKL_DIM, the current-limiting resistance R354 other ends are accessed in current-limiting resistance R354 one end
Be grounded by electric capacity C296, the first divider resistance R352 and the second divider resistance R348 series connection after it is in parallel with electric capacity C296, first
Divider resistance R352 and the second divider resistance R348 public termination output current sets pin ISET.
In the present embodiment, in addition to clamp resistance R335, clamp resistance R335 are connected to enabled pin ENA and PWM light modulation
Between controlling switch.
In the present embodiment, boosting unit 103 include Boost circuit, be connected with Boost circuit output end filter circuit,
The output voltage detecting circuit of Boost circuit output end connection and the sampling resistor being connected with the switching tube in Boost circuit.
In one embodiment, the PWM output pins of outside controller connect electric capacity by current-limiting resistance R354 resistance
Under C296, the output current that another way connects the first divider resistance R352 to LED constant current driving chip 101 sets pin ISET,
According to the specifications of LED constant current driving chip 101 (such as AP3064, AP3062) it is recognised that 4 paths of LEDs driving pin LED1
~LED4 output is determined by 5 pin-output current setting pin ISET curent change.
Assuming that when outside controller output PWM dim signals BKL_DIM is 0V, current-limiting resistance R354 is 10K Ω, then
Divider resistance R352 (56K Ω) and divider resistance R348 (56K Ω) is parallel relationship,.By calculating output current, pin is set
ISET input resistance=1/ (1/56+1/56)=28k Ω, further 4 paths of LEDs driving pin LED1~LED4 electric currents are about
For the ≈ 128mA of ILED=3000X 1.2/28.If outside controller output PWM dim signals BKL-DIM is 1V, first count
Point counting piezoresistance R352 this all the way electric current again calculating partial pressure resistance R34 8 this both electric currents are added and then are multiplied by 3000 and draw 4 all the way
Paths of LEDs drives pin LED1~LED4 electric currents.
PWM dim signals BKL-DIM dutycycle so can be just exported by the controller outside changing, changes PWM and adjusts
Optical signal BKL-DIM DC voltage value, finally change 4 paths of LEDs driving pin LED1~LED4 output current value.This circuit
Solve the problems, such as that different controller output PWM dim signal different wave shapes have influence on the output of LED constant current driving chip 101.Carry
The compatibility of LED constant current driving chip 101 is risen, after LED constant current driving chip 101 caused by when solving PWM waveform adjustment
Level output ripple excessive problem.
Above-mentioned LED light adjusting circuits and LED display device are in use, the PWM light modulations of original LED constant current driving chip 101
Controlling switch DIM is switched on and off control signal BKE_EN1 high level and is clamped to high level, is arranged to maximum output.Abandon traditional
Former brightness adjustment control pin, which is input to, using PWM dim signals BKL_DIM changes PWM output pins GATE dutycycle to change
The voltage of LED string 200 is used instead to realize the scheme of light modulation and PWM dim signals BKL_DIM is changed out into effective voltage is linked into
Output current sets pin ISET to adjust LED driving pin LED1~LED4 driving current to realize that LED is dimmed, and avoids
It is limited to undesirable PWM dim signals BKL_DIM and then has influence on the PWM outputs of LED drive chip, causes rear class LED
Lamp bead brightness, which can be in course of adjustment, there is the problem of saltus step and excessive output ripple.
Only described above is preferred embodiment of the present utility model, all at this not to limit the utility model
All any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model
Protection domain within.
Claims (7)
1. a kind of LED light adjusting circuits, and at least LED series winding connects all the way, it is characterised in that the circuit includes LED constant current drive
Dynamic chip, dimming unit and the boosting unit being connected with the positive pole of LED string described in power supply and each road, wherein, it is described
LED constant current driving chip has：
Multiple LEDs drive pin, are connected with the negative pole respectively with LED string described in each road；
Enabled pin, the switch controlling signal for access chip；
PWM brightness adjustment control pins, it is connected with the enabled pin；
PWM output pins, it is connected with the boosting unit, controls the boosting unit to supply institute after being boosted to the power supply
State LED string；And
Output current sets pin, and the PWM dim signals are accessed by the dimming unit, wherein, the dimming unit root
Voltage that pin be set is exported to the output current according to the duty cycle adjustment of the PWM dim signals, to adjust the LED
Drive the current value of pin.
2. LED light adjusting circuits as claimed in claim 1, it is characterised in that the dimming unit is included with current-limiting resistance, first
Divider resistance, the second divider resistance and an electric capacity, wherein：
The PWM dim signals are accessed in described current-limiting resistance one end, and the other end passes through the capacity earth, the first partial pressure electricity
Resistance and second divider resistance are in parallel with the electric capacity after connecting, first divider resistance and second divider resistance
The public termination output current sets pin.
3. LED light adjusting circuits as claimed in claim 1, it is characterised in that also including clamp resistance, the clamp resistance connection
Between the enabled pin and the PWM brightness adjustment controls pin.
4. LED light adjusting circuits as claimed in claim 1, it is characterised in that the LED driving pin is 4.
5. LED light adjusting circuits as claimed in claim 1, it is characterised in that the boosting unit includes Boost circuit.
6. LED light adjusting circuits as claimed in claim 1, it is characterised in that the PWM brightness adjustment controls pin also accesses PWM tune
Optical signal.
7. a kind of LED display device, it is characterised in that including the LED light adjusting circuits described in any one of claim 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721021557.9U CN207166828U (en) | 2017-08-15 | 2017-08-15 | LED light adjusting circuits and LED display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721021557.9U CN207166828U (en) | 2017-08-15 | 2017-08-15 | LED light adjusting circuits and LED display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207166828U true CN207166828U (en) | 2018-03-30 |
Family
ID=61716692
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721021557.9U Active CN207166828U (en) | 2017-08-15 | 2017-08-15 | LED light adjusting circuits and LED display device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107277985A (en) * | 2017-08-15 | 2017-10-20 | 合肥惠科金扬科技有限公司 | LED light adjusting circuits and LED display device |
| CN112533323A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | LED driver and method for enhancing dimming stability thereof |
-
2017
- 2017-08-15 CN CN201721021557.9U patent/CN207166828U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107277985A (en) * | 2017-08-15 | 2017-10-20 | 合肥惠科金扬科技有限公司 | LED light adjusting circuits and LED display device |
| CN112533323A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | LED driver and method for enhancing dimming stability thereof |
| CN112533323B (en) * | 2020-12-15 | 2022-11-11 | 广东新昇电业科技股份有限公司 | LED driver and method for enhancing dimming stability thereof |
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