CN205510461U

CN205510461U - From LED drive device that adjusts luminance

Info

Publication number: CN205510461U
Application number: CN201521139708.1U
Authority: CN
Inventors: 宋露露; 杨诗凤
Original assignee: Wuhan Polytechnic University
Current assignee: Wuhan Polytechnic University
Priority date: 2015-12-28
Filing date: 2015-12-28
Publication date: 2016-08-24
Anticipated expiration: 2025-12-28

Abstract

The utility model discloses a from LED drive device that adjusts luminance, this drive device comprises wave filter, constant voltage circuit, constant current circuit, light sensor and controller. Its median filter is the EMI wave filter, and the constant voltage circuit is L6562 single -stage PFC constant voltage circuit, and constant current circuit is HV9910 step -down constant current circuit, and light sensor is BH1710 numeral light intensity sensor, and the controller is AT89C2051 microprocessor. Light sensor BH1710 gathers and sends the control center for main device for controller AT89C2051 through I2C communication protocol after the ambient light intensity information, and control center received data and handles, then changes the PWM incoming signal's of constant current circuit HV9910's PWMD foot duty cycle according to data, and then reaches purpose with an automatic light meter. This equipment circuit is simple, low cost, maneuverability are strong, measures illuminance data dorsal radix and adjusts the luminous luminance of LED according to the algorithm, has fine supporting role to reducing the electric power energy resource consumption.

Description

A kind of from dimming LED (Light Emitting Diode) driving equipment

Technical field

This utility model relates to LED drive circuit field, drives equipment particularly to one from dimming LED (Light Emitting Diode).

Background technology

Along with the energy is needed by the day by day exhausted of the non-renewable resources such as oil, coal, natural gas in recent years and the mankind The increase day by day asked, energy-saving and emission-reduction cause the great attention of people.LED is as a kind of novel illumination light source Technology has received much concern, various countries also begin to put into effect relevant policies limit electric filament lamp, the production and sales of daylight lamp, Then help LED.LED light source has the highest usefulness, and consumed energy relatively reduces 80% with the electric filament lamp of light efficiency, The most mercurous and glass, is acknowledged as green energy conservation pioneer.

Additionally, the luminosity of LED is mainly affected by forward current, utilize this characteristic, it is achieved to LED Light modulation, be possible not only to adjust light visual effect, moreover it is possible to reduce further energy consumption 20% to 50%.Learning Classroom, school, stadiums, street lamp etc. illuminate place, and owing to daylight affects, the brightest illumination can cause electric energy wave Take, and the darkest illumination can cause visual fatigue, affect the normal study and work of people, even draw Send out security incident.As can be seen here, illumination photometry accurately, suitable brightness of illumination in productive life the most very Important.

The advantage energy-conservation in order to preferably play LED illumination, it is big for adding dimming function in LED driver Gesture is become.Generally, the dimming mode of LED driver has 3 kinds: controllable silicon light modulation, simulation light modulation, PWM Light modulation.Every kind of dimming mode has its advantage and limitation.PWM light modulation is to make on-off circuit with relative to people Sufficiently high frequency work for eye identification ability, by the cycle is set and dutycycle to change output electric current average Value, its output electric current only has two states: maximum rated operating current and zero current.Simulation light modulation is by changing The amplitude becoming output electric current realizes dimming function, and thyristor regulating just comes real by the output of regulation power supply Existing dimming function.

PWM light modulation can ensure that the color temperature constant of LED, and the efficiency of driver is higher, and can carry out essence Really control.Simulation dims relative PWM light adjusting circuit simply, easily realize, but LED colour temperature can be made to occur Change, simultaneously efficiency low, output current precision be difficult to regulation, dimming scope limited.Thyristor regulating just utilizes Existing controllable silicon dimmer, by changing the silicon controlled angle of flow, regulation output realizes light modulation, its Advantage is to change original daylight lamp lighting network control.But shortcoming is more serious: it can seriously reduce driver effect Rate and power factor, also can make LED produce flicker simultaneously.

Therefore, LED luminosity how is regulated, it is provided that while one comfortable visual environment of people, Effectively reduce electric power energy consumption, it has also become be badly in need of solving the technical problem that.

Utility model content

In view of the foregoing defects the prior art has, the purpose of this utility model is to provide a kind of from dimming LED (Light Emitting Diode) Driving equipment, this circuitry is simple, with low cost, workable, according to algorithm after measurement illumination data Regulation LED luminosity, has good assosting effect to reducing electric power energy consumption.

For reaching above-mentioned purpose, this utility model takes following scheme:

A kind of drive equipment from dimming LED (Light Emitting Diode), this driving equipment by wave filter, constant voltage circuit, constant-current circuit, Optical sensor and controller composition, it is characterised in that:

Wave filter is electromagnetic interface filter, is connected with constant voltage circuit, is used for suppressing AC network medium-high frequency to disturb, The circuit of this electromagnetic interface filter includes common mode capacitance C_y1、C_y2、C_y3、C_y4, common mode inductance L₁, differential mode Electric capacity C_x1、C_x2, varistor R_vAnd the critesistor NTC of negative temperature coefficient；

Constant voltage circuit is L6562 single-stage PFC constant voltage circuit, is connected with wave filter and constant-current circuit respectively, should Single-stage PFC constant voltage circuit includes switching tube, voltage stabilizing chip TL431 and photoelectrical coupler PC817；

Controller is AT89C2051 microprocessor, is connected with constant-current circuit and optical sensor respectively, controller Receive from the data of optical sensor and export control signal to constant-current circuit；

Optical sensor is BH1710 new digital light intensity sensor, is connected with controller, and this optical sensor uses Voltage stabilizing chip AMS1117 provides 3.3V running voltage, and the pin ADDR of optical sensor BH1710 connects Meeting GND to GND, pin DVI through 1 μ F electric capacity, pin SCL Yu SDA is respectively through the limit of 1k Ω Leakage resistance connects P3.2 Yu the P3.3 foot of controller AT89C2051；

Constant-current circuit is HV9910 blood pressure lowering constant-current circuit, is connected with constant-current circuit and LED array respectively, The PWMD pin of HV9910 is connected with the light modulation I/O port P1.0 pin of controller AT89C2051.

Preferably, common mode inductance L₁Be identical by two numbers of turn, constitute around to contrary winding, common mode capacitance It is safety electric capacity with differential mode capacitor.

This utility model has the advantages that:

1) compatible good, integrated circuit is without using special light modulation IC, simple in construction, and cost is relatively low.

2) realizing energy-conservation LED with an automatic light meter and drive equipment, it is more suitable for use in teaching building, street lamp, advertisement The places such as lamp, park, corridor.Can arrange with ambient brightness is the most dimmed, utilizes photosensitive probe signal anti- Feedback, makes LED illumination luminosity gradually strengthen.It not only can save mass energy, also as during work Decrease power and extend the service life of LED illumination device.

Accompanying drawing explanation

Fig. 1 is system theory of constitution figure；

Fig. 2 is filter circuit schematic diagram；

Fig. 3 is constant voltage circuit schematic diagram；

Fig. 4 is constant-current circuit schematic diagram；

Fig. 5 is optical sensor circuit schematic diagram；

Fig. 6 is controller circuitry schematic diagram.

Detailed description of the invention

Below in conjunction with the accompanying drawings embodiment of the present utility model is described further.

The schematic diagram of this driving equipment is as shown in Figure 1.This driving equipment is by wave filter, constant voltage circuit, Constant Electric Current Road, optical sensor and controller composition.Its median filter is electromagnetic interface filter, and constant voltage circuit is L6562 Single-stage PFC constant voltage circuit, constant-current circuit is HV9910 blood pressure lowering constant-current circuit, and optical sensor is BH1710 New digital light intensity sensor, controller is AT89C2051 microprocessor.Optical sensor BH1710 gathers I is passed through after environmental light intensity information²C communication protocol is sent to the control that controller AT89C2051 is main devices Center processed, control centre receives data and processes, and then changes constant-current circuit HV9910's according to data The dutycycle of the PWM input signal of PWMD foot, and then reach purpose with an automatic light meter.

Filter circuit schematic diagram is as shown in Figure 2.Electromagnetic interface filter is mainly used to suppress AC network medium-high frequency to do Disturb the impact on the equipment of driving, the shadow that the most also AC network is produced by suppression driving equipment due to HF switch Ring, interference predominantly common mode disturbances and differential mode interference.Common mode capacitance C_y1、C_y2、C_y3、C_y4And common mode inductance L₁For filtering common mode noise, L₁Be identical by two numbers of turn, constitute around to contrary winding.C_x1、C_x2 It is differential mode capacitor, is used for filtering differential mode interference.Common mode capacitance Y to be selected₂Safety electric capacity, differential mode capacitor selects X₁Safety electric capacity, R_vBeing varistor, NTC is the critesistor of negative temperature coefficient.

Constant voltage circuit schematic diagram is as shown in Figure 3.The peak current mode control chip that ST Microelectronics produces L6562 is widely used in active power factor (APFC) correcting circuit, and it is operated in critical (TM) Pattern, by control inductance peak point current so that input current follow input voltage change, with reach power because of The purpose of number correction.And single-stage PFC constant voltage circuit is by the boost inductance in APFC Replace with transformator, and carry out other improvement, the flyback topologies circuit of formation.

In the electronic circuit as shown in figure 3, as switching tube Q₂When opening, the exchange after electromagnetic interface filter is defeated Enter voltage through rectifier bridge rectification, input filter capacitor C₁Afterwards, transformator T it is added in₁Former limit inductance on, Inductive current linear rise, now transformer secondary commutation diode VD₅And VD₆Reversely cut-off, outfan By output capacitance C_oAnd C_o1Power supply.When primary current detects resistance R₁₂On voltage reach L6562 CS and draw During the reference voltage of foot, switching tube Q₂Turn off, now secondary commutation diode VD₅、VD₆Conducting, secondary Winding is load supplying through commutation diode, charges for output capacitance simultaneously.Flyback topologies structure is at switch When pipe is closed, transmit energy.Without electricity in the ZCD zero current detection pin of L6562 detects auxiliary winding During stream, illustrating that former limit inductance has completed magnetic reset, L6562 drives switching tube Q again₂Conducting, the most repeatedly.

The main output voltage of single-stage PFC constant voltage circuit is by voltage stabilizing chip TL431 and photoelectrical coupler PC817 Divider resistance R in the output feedback network of composition₁₅And R₁₇Arrange, when output voltage is more than designing During rated output voltage, resistance R₁₇On voltage more than the reference voltage 2.5V of TL431 pin, the most defeated Go out to hold feedback signal to feed back to the INV pin of L6562 by PC817, due to the reference voltage of INV pin For 2.5V, if the voltage of feedback signal is more than 2.5V, then just have electric current through R₆、C₇、R₇Group The network that compensates become flows into the COMP pin of L6562, when this electric current is more than 40 μ A, will enter Pressure guard mode, L6562 quits work, until this current reduction is to during less than 10 μ A, L6562 can be again Start.From output circuit for powering for controller AT89C2051, its output voltage is 5V, when main output During voltage constant, from output voltage substantially constant.

Input filter capacitor C after rectifier bridge in circuit₁Choose it is noted that: if select excessive, meeting The angle of flow making rectifier bridge becomes too small, can make the class sinusoidal voltage waveform of the MULT pin of L6562 simultaneously Becoming all the more unlike sine wave, the power factor reducing circuit increases total harmonic distortion (THD) simultaneously；If Capacitance selection too small, then do not have the effect of filtering, and this can strengthen the size of front end electromagnetic interface filter and become This.

Constant-current circuit schematic diagram is as shown in Figure 4.HV9910 is the general height that Supertex semiconductor company produces Brightness LED drive chip, is characterized in:

1) efficiency is more than 90%；

2) 8V～450V input voltage range；

3) constant-current LED driver；

4) electric current is exported from several milliamperes to more than 1A；

5) LED strip driven is from 1 to hundreds of；

6) PWM low frequency light modulation is carried out by enable pin.

Using Buck (blood pressure lowering) topological structure to realize LED constant current in this driving equipment to drive, its work is former Reason is: constant voltage V that L6562 single-stage PFC produces_oIt is linked into the VIN pin of this circuit, as switching tube Q When opening, input current is through overload LED, inductance L, switching tube Q, detection resistance R_csIt is flowed into ground. Now, inductive current linear rise, store energy, draw when the ohmically voltage of detection reaches HV9910 CS During foot detection voltage, switching tube is closed.Owing to inductance has the effect of obstruction curent change, when switching tube is closed Time, inductive current is by fly-wheel diode and output capacitance C_oPower for load LED together, now inductance electricity Stream is from peak point current linear decline, and the meansigma methods of inductive current is output electric current.

Less in order to make to flow through current ripples in LED strip, Buck transducer is operated in continuous mode.Because work Making when continuous mode, when dutycycle is more than 0.5, circuit there will be subharmonic oscillation, makes system unstable, Need to carry out harmonic compensation.And HV9910 chip does not have harmonic compensation function, during so using this chip, Input voltage to be ensured is more than 2 times of output voltage, so that dutycycle is less than 0.5, it is to avoid subharmonic occur Vibration.The light modulation pin PWMD of HV9910, when not dimming, is generally connected with VDD pin, and When carrying out PWM light modulation, PWMD pin is made to be connected with the light modulation I/O port of controller AT89C2051, When PWMD pin voltage is more than 2.4V, HV9910 normally works, when PWMD pin voltage is less than During 2.4V, HV9910 is disabled.Being dimmed by PWM, the electric current in LED only has two states: zero Electric current and the output-current rating of setting.

Utilize the pulsewidth of controller AT89C2051 regulation pwm signal, the i.e. average current of scalable LED I.e. export electric current.Output electric current can be adjusted to output-current rating from 0, i.e. dimming scope can be from 0～100%, HV9910 support the PWM light modulation of 100Hz～1kHz.

Optical sensor circuit schematic diagram is as shown in Figure 5.Voltage stabilizing chip AMS1117 is by 5V voltage voltage stabilizing in application Running voltage is provided for BH1710 to 3.3V.The pin ADDR of BH1710 is connected to GND, pin DVI Meet GND, pin SCL Yu SDA through 1 μ F electric capacity and meet AT89C2051 respectively through the current-limiting resistance of 1k Ω P3.2 Yu the P3.3 foot of single-chip microcomputer.BH1710 sensor built-in 16bit a/d converter, directly exports numeral Value, supports I²C communication protocol, application circuit is without more peripheral components, relatively simple easy-to-use.

Controller circuitry schematic diagram is as shown in Figure 6.The P3.2 pin of AT89C2051 single-chip microcomputer and P3.3 pin Simulation I²SCL and SDA signal line needed for C communication, and BH1710 sensor carries out data communication, comes It is obtained from the intensity of illumination data required for light modulation.Owing to the running voltage of BH1710 is 2.4V～3.6V, So for the single-chip microcomputer proper communication enabled and running voltage is 5V, needing to meet SDA and SCL signal line The pull-up resistor of 5.1k Ω, is connected on 5V power supply.P1.0 pin is for the PWMD of HV9910B chip The different duty pwm signal that foot exports needed for PWM square-wave signal, PWMD pin can be by single-chip microcomputer Internal 16bit intervalometer accurately controls to produce.

4th pin of microprocessor AT89C2051 and the 5th pin connect extraneous quartz oscillator. AT89C2051 is at V_ccThe crystal oscillator of 0～12MHz can be supported, at V during=2.7V～6V_ccDuring=4V～6V The crystal oscillator of 0～24MHz can be supported.Two load capacitances at crystal oscillator two ends choose capacitance for (30 ± 10) pF Electric capacity the most suitable.

Due to BH1710 light intensity sensor built-in 16bit AD, direct output digit signals, and support I²C Communication protocol, this makes the Single Chip Microcomputer (SCM) program design of driver become the easiest.Have only to AT89C2051 P3.2 Yu the P3.3 pin simulation I of single-chip microcomputer²In C communication, the sequential of SCL Yu SDA, reads from sensor Take the digital signal of its output.Then digital signal is processed, it is judged that, then by certain calculation Method revises the interruption frequency of single-chip microcomputer intervalometer, thus changes the dutycycle of the pwm signal of P1.0 pin, LED driver is made to realize with an automatic light meter.

Protection domain of the present utility model is not limited to the above embodiments, it is clear that those skilled in the art The present invention can be carried out various change and deformation without deviating from scope and spirit of the present invention.If these are changed Belonging in the range of this utility model claim and equivalent technologies thereof with deformation, intention the most of the present utility model is also Comprise these to change and deformation.

Claims

1. driving an equipment from dimming LED (Light Emitting Diode), this driving equipment is by wave filter, constant voltage circuit, constant-current circuit, optical sensor And controller composition, it is characterised in that:

Wave filter is electromagnetic interface filter, is connected with constant voltage circuit, is used for suppressing AC network medium-high frequency to disturb, and this EMI filters The circuit of device includes common mode capacitance C_y1、C_y2、C_y3、C_y4, common mode inductance L₁, differential mode capacitor C_x1、C_x2, varistor R_VAnd the critesistor NTC of negative temperature coefficient；

Constant voltage circuit is L6562 single-stage PFC constant voltage circuit, is connected with wave filter and constant-current circuit respectively, and this single-stage PFC is permanent Volt circuit includes switching tube, voltage stabilizing chip TL431 and photoelectrical coupler PC817；

Controller is AT89C2051 microprocessor, is connected with constant-current circuit and optical sensor respectively, and controller receives and passes from light The data of sensor also export control signal to constant-current circuit；

Optical sensor is BH1710 digital optical intensity sensor, is connected with controller, and this optical sensor uses voltage stabilizing chip AMS1117 Thering is provided 3.3V running voltage, the pin ADDR of optical sensor BH1710 is connected to GND, pin DVI and connects through 1 μ F electric capacity GND, pin SCL and SDA connect P3.2 and the P3.3 foot of controller AT89C2051 respectively through the current-limiting resistance of 1k Ω；

Constant-current circuit is HV9910 blood pressure lowering constant-current circuit, is connected with constant-current circuit and LED array respectively, the PWMD of HV9910 Pin is connected with the light modulation I/O port P1.0 pin of controller AT89C2051.

2. according to described in claim 1 from dimming LED (Light Emitting Diode) drive equipment, it is characterised in that: common mode inductance L₁It is by two The number of turn is identical, constitute around to contrary winding, and common mode capacitance and differential mode capacitor are safety electric capacity.