CN106376143B - A kind of circuit of the multiple LED pixel points of single channel constant current drive control - Google Patents
A kind of circuit of the multiple LED pixel points of single channel constant current drive control Download PDFInfo
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- CN106376143B CN106376143B CN201610976707.5A CN201610976707A CN106376143B CN 106376143 B CN106376143 B CN 106376143B CN 201610976707 A CN201610976707 A CN 201610976707A CN 106376143 B CN106376143 B CN 106376143B
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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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Abstract
A kind of circuit of the multiple LED pixel points of single channel constant current drive control, including being serially connected the LED light string formed by more than two LED lamp beads, further include the logic control circuit for driving the LED light string, the logic control circuit include it is more than two with LED lamp bead one-to-one correspondence and with the electronic switch of corresponding LED lamp bead parallel connection and the driver be connected for controlling electronic switch.Working principle of the present invention: multiple LED lamp beads are cascaded, and are driven with constant-current source all the way, an electronic switch in parallel again in every LED lamp bead, so that it may accomplish that every LED lamp bead is individually lighted or extinguished.As long as the switching speed of electronic switch is sufficiently fast, the average current for flowing through every LED lamp bead can be adjusted by adjusting the duty ratio in each electronic switch period, to control the output power of each LED pixel point, the independent light on and off and light modulation of every LED lamp bead are realized.
Description
Technical field
The present invention relates to LED illumination lamp fields, more particularly to need to export a kind of constant current for controlling multiple LED pixel points
Driving circuit.
Background technique
LED illumination lamp on the market at present, most of is all to drive LED with constant-current drive circuit and adjust LED to drive
Streaming current, constant current driving in general 1 tunnel can only drive 1 paths of LEDs lamp string, and LED multi-path lamp string just needs multi-path constant-current drive circuit.
This constant current drive scheme must use multi-path constant-current drive circuit when being used in control Matrix LED pixel, and N number of pixel just needs
N number of constant-current drive circuit, just seeming to compare takes up space and higher cost.
Summary of the invention
Technical problem to be solved by the invention is to provide a kind of electricity of the multiple LED pixel points of single channel constant current drive control
Road reduces the cost of LED lattice pixels driving circuit and simplifies circuit structure.
In order to solve the above technical problems, the technical scheme is that a kind of multiple LED pixels of single channel constant current drive control
The circuit of point further includes for driving the LED light string including being serially connected the LED light string formed by more than two LED lamp beads
Logic control circuit, the logic control circuit include it is more than two with LED lamp bead one-to-one correspondence and with corresponding LED lamp bead simultaneously
The electronic switch of connection and the driver be connected for controlling electronic switch.Working principle of the present invention: multiple LED lamp beads are connected on one
It rises, is driven with constant-current source all the way, an electronic switch in parallel again in every LED lamp bead, so that it may accomplish every LED lamp bead list
Solely lights or extinguish.As long as the switching speed of electronic switch is sufficiently fast, so that it may by adjusting each electronic switch period
Duty ratio flows through the average current of every LED lamp bead to adjust, to control the output power of each LED pixel point, realizes every
The independent light on and off and light modulation of LED lamp bead.
As an improvement, the electronic switch is metal-oxide-semiconductor.
As an improvement, the electronic switch is N-channel MOS pipe.
As an improvement, the N-channel MOS pipe drain electrode and LED lamp bead anode connect, the source electrode of N-channel MOS pipe with
The cathode of LED lamp bead connects, and driver controls the grid of N-channel MOS pipe by pwm signal.
As an improvement, the driver is half-bridge driver.
As an improvement, the grid of N-channel MOS pipe and the cut-in voltage at source electrode both ends are Vgs, high side LED lamp bead the two poles of the earth pair
The voltage of GND is Vdg；When Vdg is greater than the supply voltage VDD of half-bridge driver, half-bridge driver is by high side N-channel MOS pipe
Vgs voltage raise.
As an improvement, when all light of LED light string, if the cathode voltage of LED lamp bead is plus its N-channel MOS pipe in parallel
Conducting voltage is greater than the voltage value of VDD, then the grid of N-channel MOS in parallel is connected to the upper bridge end of half-bridge driver.
As an improvement, the upper bridge of half-bridge driver, which is driven through bootstrap capacitor C1 and bootstrap diode D1, makes half-bridge driver
The voltage value of pin HB remain that the voltage than pin HS is higher by the voltage value of a Vgs, pin HS respectively with N-channel
The source electrode of metal-oxide-semiconductor is connected with the cathode of corresponding high side LED lamp bead；If the pin HI of half-bridge driver exports high level at this time,
The pin HO that half-bridge driver is connect with the grid of N-channel MOS pipe then exports the voltage of HB；The lower bridge output of half-bridge driver is straight
It connects and is powered by VDD, if the pin LI of half-bridge driver exports high level, half-bridge driver N-channel corresponding with downside LED lamp bead
The pin LO of metal-oxide-semiconductor grid connection then exports the voltage of VDD, guarantees that the voltage value of VDD has to be larger than the conducting of N-channel MOS pipe
Voltage.
As an improvement, when pin HI exports high level, signal after the Bootstrap of the upper bridge of half-bridge driver
N-channel MOS, the conducting of N-channel MOS pipe are accessed, corresponding lamp bead LED lamp bead does not work；When pin HI exports low level, half-bridge is driven
Dynamic device is failure to actuate, and N-channel MOS pipe is not turned on, corresponding LED lamp bead all light；Then pass through the duty ratio of adjustment pin HI high level
It is flowed through to adjust the duty ratio of half-bridge driver output signal to adjust the turn-on time in N-channel MOS each period to change
The average current size of corresponding LED lamp bead.
The beneficial effect of the invention compared with the existing technology is:
Multiple LED lamp beads are cascaded, and are driven with constant-current source all the way, an electronics in parallel again in every LED lamp bead
Switch, so that it may accomplish that every LED lamp bead is individually lighted or extinguished；As long as the switching speed of electronic switch is sufficiently fast, so that it may
To adjust the average current for flowing through every LED lamp bead by the duty ratio for adjusting each electronic switch period, so that control is every
The output power of a LED pixel point, realizes the independent light on and off and light modulation of every LED lamp bead, i.e. single channel constant current drive control is multiple
LED pixel point reduces the cost of LED lattice pixels driving circuit and simplifies circuit structure.
Detailed description of the invention
Fig. 1 is logical circuitry of the present invention.
Fig. 2 is application circuit of the present invention.
Specific embodiment
The invention is further explained in the following combination with the attached drawings of the specification.
As shown in Figure 1, a kind of circuit of the multiple LED pixel points of single channel constant current drive control, including by more than two LED light
Pearl is serially connected the LED light string of composition and the logic control circuit for driving the LED light string.As shown in Fig. 2, the present embodiment
LED light string be made of six LED lamp beads, be LED1-LED6 respectively, wherein LED1-LED3 be high side LED lamp bead, LED4-
LED6 is downside LED lamp bead；Each LED lamp bead is a pixel, also can be set according to actual needs the quantity of pixel.
The logic control circuit includes six and corresponds and the electronic switch in parallel with corresponding LED lamp bead and be used for LED lamp bead
Control the driver of electronic switch conducting；In the present embodiment, electronic switch selects N-channel MOS pipe Q1-Q6 to replace, and selects
Three half-bridge driver U1-U3 drive N-channel MOS to be connected, and half-bridge driver output signal is controlled with pwm signal.
Guarantee N-channel MOS pipe normal switch, must just be added and open in the grid G of N-channel MOS pipe and source S both ends
Voltage Vgs, general Vgs > 5 ~ 10V.But there are PN junction voltage Vf, Vf=3 ~ 4V for LED chip itself；With the increasing of LED serial number
Add, high side LED lamp bead the two poles of the earth also correspondingly increase GND voltage Vdg, when Vdg is greater than half-bridge driven supply voltage VDD, with regard to nothing
Method guarantees N-channel MOS pipe grid source plate voltage Vgs, and the N-channel MOS pipe of high side can not be normally-open, this just needs to drive using half-bridge
Dynamic circuit raises the Vgs voltage of the N-channel MOS pipe of high side.
As shown in Fig. 2, the upper bridge driving of half-bridge driver U1 can make pin by bootstrap capacitor C1 and bootstrap diode D1
The voltage value of HB remains that the voltage (i.e. the S pole tension of N-channel MOS pipe Q1) than pin HS is higher by the voltage value of a Vgs,
If at this time PWM6 export high level, the pole G of pin HO(N channel MOS tube Q1) output pin HB voltage.Half-bridge driver U1
Lower bridge output directly powered by VDD, if PWM3 export high level, the pole G of pin LO(N channel MOS tube Q4) export VDD's
Voltage, so the voltage value of VDD has to be larger than the conducting voltage of N-channel MOS pipe.When LED pixel point all light, if LED lamp bead
Cathode voltage is greater than the voltage value of VDD plus the conducting voltage of its N-channel MOS pipe in parallel, just must be N-channel MOS in parallel
The pole G of pipe is connected to the upper bridge end of half-bridge driver.
As shown in Fig. 2, when the PWM6 of half-bridge driver U1 exports high level, by the bootstrapping of bridge on half-bridge driver U1
Signal is accessed N-channel MOS pipe Q1, N-channel MOS pipe Q1 conducting after boosting, lamp bead LED1 does not work；When PWM6 exports low level
When, half-bridge driver U1 is failure to actuate, and N-channel MOS pipe Q1 is not turned on, lamp bead LED1 all light.It can be by adjusting PWM6 high level
Duty ratio is come when adjusting conducting of the duty ratio of half-bridge driver U1 output signal to adjust N-channel MOS pipe Q1 each period
Between change the average current size for flowing through lamp bead LED1.Other five LED lamp beads are also similarly to control, to realize with one
Road constant-current drive circuit drives six LED and every LED can individually adjust its electric current.
Claims (2)
1. a kind of circuit of the multiple LED pixel points of single channel constant current drive control, including group is serially connected by more than two LED lamp beads
At LED light string, it is characterised in that: further include the logic control circuit for driving the LED light string, logic control electricity
Road includes more than two with LED lamp bead one-to-one correspondence and the electronic switch in parallel with corresponding LED lamp bead and for controlling electronic cutting
Close the driver of conducting；
The driver is half-bridge driver；
The grid of N-channel MOS pipe and the cut-in voltage at source electrode both ends are Vgs, and high side LED lamp bead the two poles of the earth are to the voltage of GND
Vdg；When Vdg is greater than the supply voltage VDD of half-bridge driver, half-bridge driver lifts the Vgs voltage of high side N-channel MOS pipe
It is high；
When all light of LED light string, if the cathode voltage of LED lamp bead is greater than plus the conducting voltage of its N-channel MOS pipe in parallel
The voltage value of VDD, then the grid of N-channel MOS in parallel is connected to the upper bridge end of half-bridge driver；
The upper bridge of half-bridge driver is driven through bootstrap capacitor and bootstrap diode make half-bridge driver pin HB voltage value
Remain that the voltage than pin HS is higher by the voltage value of a Vgs, pin HS respectively with the source electrode of N-channel MOS pipe and corresponding
High side LED lamp bead cathode connection；If the pin HI of half-bridge driver exports high level, half-bridge driver and N-channel at this time
The pin HO of the grid connection of metal-oxide-semiconductor then exports the voltage of HB；The lower bridge output of half-bridge driver is directly powered by VDD, if half
The pin LI of bridge driver exports high level, half-bridge driver N-channel MOS tube grid connection corresponding with downside LED lamp bead
Pin LO then exports the voltage of VDD, guarantees that the voltage value of VDD has to be larger than the conducting voltage of N-channel MOS pipe；
The electronic switch is N-channel MOS pipe；
The drain electrode of the N-channel MOS pipe and the anode of LED lamp bead connect, and the source electrode of N-channel MOS pipe and the cathode of LED lamp bead connect
It connects, driver controls the grid of N-channel MOS pipe by pwm signal；
Pin HI and pin LI is separately connected PWM light modulation input terminal；The bootstrap capacitor of pin HB connection half-bridge driver and bootstrapping
Diode；The grid G of the N-channel switch metal-oxide-semiconductor at the both ends pin HO connection high side LED；The N at the both ends pin LO connection downside LED
The grid G of channel switches metal-oxide-semiconductor；The source S and bootstrap capacitor of the N-channel switch metal-oxide-semiconductor at the both ends pin HS connection high side LED.
2. a kind of circuit of the multiple LED pixel points of single channel constant current drive control according to claim 1, it is characterised in that:
When pin HI exports high level, signal is accessed N-channel MOS, N-channel after the Bootstrap of the upper bridge of half-bridge driver
Metal-oxide-semiconductor conducting, corresponding lamp bead LED lamp bead do not work；When pin HI exports low level, half-bridge driver is failure to actuate, N-channel
Metal-oxide-semiconductor is not turned on, corresponding LED lamp bead all light；Half-bridge driver is then adjusted by the duty ratio of adjustment pin HI high level
The duty ratio of output signal flows through being averaged for corresponding LED lamp bead to adjust the turn-on time in N-channel MOS each period to change
Size of current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610976707.5A CN106376143B (en) | 2016-11-08 | 2016-11-08 | A kind of circuit of the multiple LED pixel points of single channel constant current drive control |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610976707.5A CN106376143B (en) | 2016-11-08 | 2016-11-08 | A kind of circuit of the multiple LED pixel points of single channel constant current drive control |
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| Publication Number | Publication Date |
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| CN106376143A CN106376143A (en) | 2017-02-01 |
| CN106376143B true CN106376143B (en) | 2019-04-30 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107493635A (en) * | 2017-09-22 | 2017-12-19 | 浙江晶日照明科技有限公司 | A kind of more pixel drive systems of LED |
| CN108777434B (en) * | 2018-05-15 | 2019-12-13 | 维沃移动通信有限公司 | Vertical cavity surface emitting laser and electronic equipment |
| CN109257852B (en) * | 2018-11-14 | 2024-07-23 | 钟友兴 | LED control circuit |
| CN109348601B (en) * | 2018-12-20 | 2023-06-16 | 青岛亿联客信息技术有限公司 | Color light driving circuit and driving method thereof |
| CN109507562B (en) * | 2018-12-24 | 2024-05-14 | 南昌易美光电科技有限公司 | Circuit board and method for lamp bead aging experiment |
| CN113395802B (en) * | 2020-03-13 | 2024-07-19 | 无锡力芯微电子股份有限公司 | LED display system and driving circuit of array type LED display panel thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102612235B (en) * | 2012-04-07 | 2014-03-12 | 李桂宏 | Light-emitting diode (LED) illuminating device comprising multistage constant current drive circuit |
| CN102740561B (en) * | 2012-06-04 | 2014-06-04 | 杭州展顺科技有限公司 | LED (Light Emitting Diode) driving circuit |
| CN104125692A (en) * | 2014-08-11 | 2014-10-29 | 矽力杰半导体技术(杭州)有限公司 | Multiway LED constant current controller and control method |
| CN104883789B (en) * | 2015-06-05 | 2017-09-19 | 罗成 | For the constant-current control circuit of LED display and the display device |
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