Tag Archives: Recolux Lighting

Main indicators and parameters of LED selection缩略图

Main indicators and parameters of LED selection

1, brightness
LED light brightness is the most concerned about the topic of the user, brightness can be explained from two aspects.
Brightness L: luminous flux of the luminous body in a specific direction unit stereo angle unit area. Unit: Nitro (cd/㎡).
Luminous flux φ: the sum of the amount of light emitted by the luminous body per second. Unit: lumens (Lm), said the luminous body of how much light, the more luminescence the greater the number of lumens.
Usually LED lights are marked with luminous flux, users can judge the brightness of LED lights according to the luminous flux. The higher the luminous flux, the higher the brightness of the light.
2, wavelength
Wavelength consistent LED, the same colour. There is no LED spectrophotometer producers are difficult to produce products with pure colour.
3, colour temperature
Colour temperature is a unit of measurement to identify the colour of the light, expressed in K value. Yellow light is "3300k below", white light is "5300k above", there is a kind of intermediate colour "3300k-5300k".
4, leakage current
LED is a unidirectional conductive light emitter, if there is a reverse current, it is called leakage, leakage current is large LED, short life.
5, anti-static ability
Antistatic ability of the LED, long life, and therefore high prices. The market market many fake and shoddy products in this one do very bad, this is also expected how many years of life, greatly shortened the root cause.

Main indicators and parameters of LED selection插图

The choice of LED lamps and lanterns includes the appearance, heat dissipation, light distribution, glare, installation and so on. We do not talk about the parameters of the lamps and lanterns today, only about the light source: you really will pick a good LED light source? Light source parameters are: current, power, luminous flux, light decay, light colour, colour rendering. Our focus today is to talk about the last two, first briefly talk about the first four.

  First of all, we often say: "I want how many watts of light", this habit is the continuation of the previous traditional light source, then the light source only a few fixed wattage, basically only in those wattage inside the choice, can not be freely adjusted. And now the LED, drive current slightly change, the power immediately changed! Are you still asking for power? Beware! The same LED light source, with too much current to drive the time, the power is up, but it will cause a decline in luminous efficacy, light attenuation increase. See the chart below:

  In general, redundancy = waste, but for LED operating current, it is saving. In the case of driving current to the rated allowable maximum, reduce the driving current by 1/3, the sacrifice of luminous flux is very limited. Yet the benefits are enormous:

  Light attenuation is greatly slowed;

  Lifetime substantially extended;

  Significant improvement in reliability;

  Higher power utilisation.

  Therefore, a good LED light source, drive current should be used about 70% of the maximum rated current.

  In this case, the designer should directly request the luminous flux, as for what wattage to use, should be decided by the manufacturer itself. This will promote the manufacturers to pursue efficiency and stability, rather than just go to push up the wattage of the light source, at the expense of efficiency and longevity.

  The above mentioned includes these parameters: current, power, luminous flux, light decay. There is a close correlation between them, the use of attention: which is what you really need?

  Light colour

  Traditional light source era, when it comes to colour temperature, we only care about "yellow light, white light", not too concerned about the problem of light colour deviation. Anyway, the traditional light source colour temperature on those kinds of, choose one on the line, generally will not run off where. To the LED era, we found that: LED light colour of any kind. Even with the same batch of lamp beads, there may be deviations to a thousand strange, red, green and green lively ~~~

  They say LED is good, energy saving and environmental protection. But you make it? LED to do a bad business really quite a lot! The following is a large project sent by a V friend of a famous domestic brand of LED lamps and lanterns application scene, look at the people of this light distribution, the colour temperature consistency, the ghost of blue light ……

  In view of this mess, there is a conscientious LED lamps and lanterns factory to the customer commitment: "Our lamps and lanterns, colour temperature deviation ± 150K within! , there are also design companies to do product selection, specifications on the note: "lamp bead colour temperature requirement deviation ± 150K or less".

  The basis of this 150K is cited in the traditional literature concluded that: "the colour temperature deviation ± 150K or less, the human eye is difficult to detect". They think: the provisions of the colour temperature "± 150K or less", you can avoid the occurrence of red and green things. In fact, really "not so simple" ……

Lamp beads, drivers, housing, size, luminous flux, a few metres of illumination, rated power, actual power, power factor, colour rendering index, colour temperature, ambient temperature and light failure.
Main parameters of led lamp beads:
Small power lamp beads: red and yellow: 1.8-2.4V. blue green and white: 3-3.6V. rated current are 20mA.
High-power lamp beads: 1 watt: 3-3.6V, 350 mA.

1, LED with the aspect of very square, can be used in lighting, and indicator, decoration and so on.
2, LED lamp current is DC, LED lamp voltage is not the same, each has its own voltage, such as white light, green light, blue light, are in the 3-3.5V, its normal luminous brightness is 20MM on it, you use 9V voltage plus light up, then, with {(9 - lamp voltage) / 0.02A (mA to A) = to connect the resistor, connected to the 12V is also the same.
3, red light voltage is 1.8-2.1V wavelength 610-620
Green light voltage is 3.0-3.5V wavelength 520-530
Blue light voltage is 3.0-3.5V wavelength 460-470
White light voltage is 3.0-3.5V no wavelength

Although some factories, power plants and other enterprises and institutions have not used LED lights for industrial lighting, but for LED lights, I believe that you will not have heard of the arrival of the LED lighting era, incandescent lamps and energy-saving lamps will be eliminated, which is the inevitable result of technological progress.

  LED lights and traditional lights in the performance is a big difference, especially industrial lighting led lights. So users in the procurement of how to choose a good, suitable for industrial lighting LED lights, the following industrial lighting LED lights on several parameters for a brief introduction.

Main indicators and parameters of LED selection插图2

  1, brightness

  LED lamp brightness is the user's most concerned about the problem, brightness can be explained from two aspects.

  Brightness L: luminous flux of the luminous body in a specific direction unit stereo angle unit area. Unit: Nitrode (cd/㎡).

  Luminous flux φ: the sum of the amount of light emitted by the luminous body per second. Unit: lumens (Lm), said the luminous body of how much light, the more luminescence the greater the number of lumens.

  Usually LED lights are marked with luminous flux, users can judge the brightness of LED lights according to the luminous flux. The higher the luminous flux, the higher the brightness of the light.

  2, wavelength

  Wavelength consistent LED, the same colour. No LED spectrophotometer manufacturers are difficult to produce products with pure colour.

  3、Colour temperature

  Colour temperature is a unit of measurement to identify the colour of the light, expressed in K value. Yellow light is "3300k below", white light is "5300k above", there is a kind of intermediate colour "3300k-5300k". Of course, the user can choose the appropriate colour temperature according to the lighting application environment and operator needs.

  4, leakage current

  LED is a unidirectional conductive light emitter, if there is a reverse current, it is called leakage, leakage current is large LED, short life.

  5, anti-static ability

  Anti-static ability of the LED, long life, and therefore high prices. Many fake and shoddy products on the market do a very bad job on this one, which is expected to be how many years of life, the root cause of the greatly shortened.

  6, life expectancy

  The key to different qualities is the life expectancy, life expectancy is determined by the light decay. Small light decay, long life, the real quality of the LED lights have been done almost no light decay, which is the industry's top level, the industry's vast majority of LED light manufacturers can not reach.

  7, design

  Each product will have a different design, different design for different purposes, the reliability of the LED lamp design aspects include: electrical safety, fire safety, applicable environmental safety, mechanical safety, health safety, safe use of time and other factors.

  8、Protection level

  IP is the abbreviation of Ingress, Protection, IP rating is for the electrical equipment shell of foreign body intrusion protection level, such as: explosion-proof appliances, waterproof and dust-proof appliances, the source of the International Electrotechnical Commission's standard IEC60529.

  The protection level is mostly expressed as IP followed by two numbers, which are used to specify the level of protection. The first number indicates the extent to which the equipment is resistant to fine dust, or the degree to which people are protected from hazards in a sealed environment. This represents the level of protection against the ingress of solid foreign objects, with the highest level being 6. The second number indicates the extent to which the device is waterproof. It represents the level of protection against water ingress, with the highest level being 8.

  Of course, the parameters of LED lights are more than these, such as strobe, heat dissipation, light efficiency, etc. are relevant parameters to judge the quality of LED lights.

  Users should understand that the choice of LED lamps can not be like choosing incandescent lamps only look at the wattage, LED lamp wattage has been unable to accurately interpret the brightness of the LED lamps, high luminous efficacy of the low wattage may also be brighter than the high wattage of the LED lamps. This is the LED era, only with the appropriate parameters to choose a good quality of industrial lighting LED lights. Feel free to ask questions about recolux LED lighting equipment!

Advantages of LED linear lights in practical applications缩略图

Advantages of LED linear lights in practical applications

The biggest highlight of LED linear light is to form visual extensibility, with lines outlining the layering of space, it may be placed on the roof, walls, cabinets and other corners, as if it is very inconspicuous, but the soft and warm light emitted is in control of the atmosphere of the space, bringing us the feeling of being wrapped in love.

Advantages of LED linear lights in practical applications插图

For example, in the aisle along the contours of the wall alignment linear lights, highlighting the beauty of geometric lines, guiding the line of sight along the light and go. Being there, it's as if you're traveling through the flowing lights.

LED linear light is a small hand to create the atmosphere, providing a romantic and cozy ambient light for the space.
For example, the layout of linear lights in the ceiling, so that the light is free to roam, to provide high lighting for the space, to break the depressing sense of dim ceiling, elevating the space, creating a bright and comfortable atmosphere.

Advantages of LED linear lights in practical applications插图2

For example, in the wall or a variety of cabinet installation of linear lights, uniform and detailed lighting so that the entire space is no longer monotonous, to meet the demand for medium lighting or low lighting, creating a romantic and cozy atmosphere.

Advantages of LED linear lights in practical applications插图4

LED linear lights can fit the decorative style of the space, personalized custom modeling.
For example, modern minimalist decorating style can let the linear light spread from the wall to the ceiling, fully white at the same time, increase the sense of advanced space; can also use linear lights to decorate the ceiling, as far as the eye is irresistible gentle light.

For more information about LED linear lights, please feel free to contact recolux industrial suppliers.

5 common problems with linear light strips, recolux can help you solve them缩略图

5 common problems with linear light strips, recolux can help you solve them

Are linear light strips bright enough? Do I have to do a suspended ceiling? How to fix it if it breaks? I heard that aluminum channel light strip wall is easy to crack? …… linear light strip is decorative, advanced design, and can also be used as basic lighting, more and more people like. Although it seems that the threshold of installation is high, in fact, the realization is not so difficult. Today recolux will answer the linear light problems that may be encountered.

5 common problems with linear light strips, recolux can help you solve them插图

Question:1: Is the linear light strip bright enough?

Linear light strip is beautiful for all to see, many people's biggest worry is that the linear light is not bright enough.

First of all, the conclusion: want to use linear strip light as a basic lighting, brightness is completely no problem.

There are more and more cutting-edge design cases only use linear strip light as the main lighting of the space. The point is: as long as you choose the right lamp, good design, linear strip light can carry the responsibility of the basic lighting of the space.

It is becoming more and more common to use linear strip as the main lighting in space design.

If you want to use strip light as auxiliary lighting, both decorative and basic brightness. This is the most common demand, it is recommended to choose 1cm wide, 6w/m style. This style of linear light has beautiful proportions and appropriate brightness.

It will not be very bright and is suitable for auxiliary lighting. Bedroom lighting, corridor lighting only with this type of strip, the brightness is not a problem; but the living room only with this type of strip, it will feel too dark, usually need to be used with downlights or floor lamps and other key lighting sources together.

Question 2: Must I do the ceiling? Installation difficulty?
If you want the light strip as the main lighting, the space is no longer with the downlight situation. It is recommended to choose 5cm wide, 20w/m style as the main lighting. recolux suggests: light strips as the main lighting on the lighting design layout requirements are relatively high, the need for different combinations of light strips, but also combined with the lifestyle of the occupants of the design, it is recommended to consult a professional recolux.

Even if you use this higher brightness of the strip as the main lighting, in order to ensure that the sofa, coffee table, desktop and other areas to do fine operation with sufficient illumination, it is recommended that you still need to match the specialized accent lighting light source, such as floor lamps, table lamps, chandeliers, etc., you can not use downlights.

Of course not, not necessarily all linear strip light need to do ceiling. Commonly several types of linear strip light installation, do not need to do ceiling type or quite a few:

① ceiling structure hiding lights (need to suspend the ceiling). Usually there is a slit on the edge of the ceiling, as a light strip installation and light outlet. This design maintains the minimalist flatness of the ceiling while maximizing the beauty of the linear light strip.

  • Ceiling Structure Hidden Light
    ②Curtain box hidden light (without ceiling). As the name implies, the linear strip light will be hidden in the curtain box, many households come with a curtain box, eliminating the need for many troublesome installation of the strip light. The combination of light and curtain fabric, adding a warm and cozy quiet atmosphere.
  • Curtain box hidden lights
    If you don't have a curtain box, it's not a problem to make a curtain box. Curtain boxes do not exist to hide lights, but it makes the top of the curtains more beautiful, to avoid light leakage at the same time, it is also an excellent place to hide lights, but also save the trouble of doing the ceiling, a multi-purpose.
  • Add curtain box is very simple, improve the value, avoid light leakage, but also hide the light
    ③ Localized ceiling to hide the light (need to be localized ceiling). Partial ceiling is one of the most traditional way to hide the light, do not need to do the whole ceiling, usually around the ceiling to do partial ceiling, can hide the light, also installed embedded spotlights. The advantage is that it can provide soft and not harsh basic lighting, the disadvantage is that it is easy to dust, and the design is not so simple and beautiful.
  • Partial Ceiling Hidden Lights
    ④ Aluminum groove light strip to hide the light (without ceiling). Aluminum groove strip is now more popular practice of light strips. If the ceiling has a suspended ceiling, it will be installed in the ceiling groove; if the ceiling does not have a suspended ceiling, it can be installed directly in the ceiling groove (without affecting structural safety). Advantage is that the installation location is not restricted, and the design is more indirect and beautiful, the disadvantage is that if you do not do the ceiling, slotting up relative trouble.

Aluminum groove light strip to hide the light, do not need to do the ceiling
In general, linear strip light does not have to rely on the ceiling to exist (specific installation methods can see @ egg brother past articles). There are still a lot of ways to play with linear light strips without making a suspended ceiling. Especially with aluminum channel light strip (aluminum channel light strip has many types, not to be repeated here), the installation limitations of the light strip, the installation difficulty is greatly reduced.

The need to do the ceiling situation, it looks more troublesome. But whether it is a partial ceiling or full ceiling, may have to take into account the hiding of the central air conditioning, embedded lamps and lanterns, hidden pipeline and other needs, by the way, hide a linear light strip is a very simple thing, and can make the ceiling role to play to the extreme.

5 common problems with linear light strips, recolux can help you solve them插图2

Question 3: How to repair the linear strip when it breaks? How to hide the transformer?

Today's mainstream light source are LED, higher stability, longer life, the light source itself is actually not easy to get out of the problem. However, the household linear strip light is usually low voltage strip, household high voltage to low voltage, it is necessary to use a transformer. The current transformer technology is also more mature, less prone to problems, but the stability is not as high as the durable LED light source. Usually linear strip light problems, mostly because of the transformer.

Therefore, lighting designers will recommend: the installation of the transformer should not be sealed in the ceiling, to be hidden in easy maintenance places, such as central air conditioning access ports, lights in the slot, the top of the cabinet, curtain boxes and so on.
Transformers for linear light strips are recommended to be hidden in places that are easy to maintain.
If the location of the installation of the light strip is not good to hide the transformer, you can use a soft wire to pull the power out to connect the transformer, the transformer will be hidden in a place that is easy to maintain can be.

Flexible wire pulling power to connect the transformer, the transformer will be hidden in an easy maintenance place
Some partners may be worried: Although the LED is rarely a problem, but who can not guarantee 100%, if the lamp beads out of the problem, how to do?

In fact, this problem is very good solution. Low-voltage linear strip can be cut and spliced at will, if the lamp bead is damaged, cut and spliced again can be (with a special light strip interface). Aluminum groove lampshade can be easily dismantled and installed manually, maintenance is not difficult.

Linear strip can be cut and spliced, aluminum groove lampshade is easy to remove and install.

Question 4: How to choose the color temperature of linear strip light?

The lighting of home space is mainly comfortable, the color of home linear strip light is usually between 3000k-5000k. Within the same space or the same use scene, it is recommended to choose the same color temperature. If you use 3000k spotlights, it is best to choose the same color temperature to match the linear strip.

Color temperature of different lights
Different space scenes have different color temperature requirements. For example, the living room space on the brightness of the light requirements are higher, it is recommended to choose 3500k-4000k color temperature; bedroom needs more warm atmosphere, suitable for 3000k-3500k brightness. And as a decorative line of public space, you can choose 4000k-5000k and other a little whiter color temperature, visually more stylish.

As a basic lighting or ambient lighting light strip can choose a little warmer 3000k-4000k, decorative light strip can choose a little whiter 4000k-5000k

Question 5: Aluminum groove light strip on the wall, the wall will be easy to crack?

Aluminum groove light strip is the more mainstream type of household light strip, the installation is relatively simple: after grooving the light strip pre-buried fixed, paint can be.
More LED lighting problems welcome to recolux consulting, free to provide you with solutions!

Lighting the future: Recolux at Light+Building缩略图

Lighting the future: Recolux at Light+Building

From 3 to 8 March 2024, leading lighting solutions provider Recolux will present its latest innovations at the Light+Building trade fair in Frankfurt am Main. As a pioneer in the lighting industry, Recolux will showcase its cutting-edge smart lighting technology, sustainable energy solutions and unique design concepts.

Lighting the future: Recolux at Light+Building插图

Exhibition theme: Light up the future, lead with innovation
Recolux will use the theme of "Lighting the Future, Leading with Innovation" to highlight its pioneering position in the lighting industry. We will showcase a range of exciting new products, from smart lighting to sustainable energy, and innovative designs that seamlessly blend aesthetics and functionality.

Booth information: Hall 10.3 B71A
We warmly welcome you to visit our booth and experience Recolux's lighting technology and products. Our booth number is 10.3 B71A, making it easy for you to find us and explore our latest products.

Lighting the future: Recolux at Light+Building插图2

Brand Consistency: Innovation, Quality, Sustainability
Recolux will demonstrate brand consistency including innovative lighting technology, superior product quality and commitment to sustainability. Our products are designed to meet the needs of our customers and bring brilliance to their living and working environments.

Lighting the future: Recolux at Light+Building插图4

Discover new dimensions of future lighting
At Light+Building, Recolux will present its unique vision for the future of lighting. Through intelligent, innovative and efficient solutions, we will take you on a journey to explore new dimensions in the field of lighting. Recolux offers tailor-made lighting solutions for every environment.

Visit our booth for exclusive offers
As a thank you for visiting us, we offer exclusive discounts to customers who visit our booth during the show. This is your chance to experience first-hand the power of future lighting innovations.

Schedule a meeting to learn more
If you would like to meet us during the show or learn more about our products, please feel free to arrange a meeting in advance. You can book an appointment by visiting our official website www.recolux.com.

Recolux looks forward to meeting you at the Light+Building exhibition to explore the future of the lighting industry together. Let us illuminate the future together and bring more brilliance to life and work!

LED controllable constant current source drive system design scheme缩略图

LED controllable constant current source drive system design scheme

LED as the third generation of lighting light source, has the advantages of low operating voltage, low power consumption, high luminous efficiency, long life, etc. LED is a non-linear device, when the LED on, as long as the LED voltage changes slightly, will make the current is too large leading to LED device heat damage. LED's operating characteristics of the quality of the power supply is very dependent on the degree of power supply, so the realization of a high-quality power supply is important to improve the quality of LED lighting, power utilization, extend the service life of LED. Power supply is of great significance to improve the lighting quality of LEDs, power utilization, and extend the service life of LEDs. The stability of the power supply mainly depends on the LED drive circuit design, constant current source drive is the best LED drive mode, the use of constant current source drive, LED current will not be affected by the voltage, ambient temperature changes, as well as the LED parameters of the dispersion, so as to keep the current constant, and give full play to the LED's various excellent characteristics. Currently widely used constant current source has two forms: one is a linear power supply to improve the constant current source, the other is a switching power supply constant current source. Linear power supply to improve the type of constant current source of linear loss, the scope of application is small; switching power supply type constant current source of poor reliability, adapt to the small range, and high cost. Therefore, economical and practical, reliable performance of CNC constant current source has been widely used. In this paper, for the small power LED in the existing lighting system in the drive mode of some of the deficiencies, the design of a highly efficient drive system, proposed a corresponding new type of drive system.

  1 LED characteristics

  1.1 LED volt-ampere characteristics

  The mathematical model of LED volt-ampere characteristics can be expressed as:

LED controllable constant current source drive system design scheme插图

  Where V is the LED starting voltage; RS indicates the slope of the volt-ampere curve; IF indicates the LED forward current; T indicates the ambient temperature; △VF/△T is the temperature coefficient of the LED forward voltage, which has a typical value of -2V/°C for most LEDs. From the mathematical model of the LED, in a certain ambient temperature conditions LED in the forward conduction after the forward voltage of the small changes will cause a large change in the LED current.

 1.2 LED temperature characteristics

  The size of the LED forward current is with the temperature changes, white LED operating current is generally about 200mA, when the ambient temperature once more than 50 ℃, white LED allowable forward current will be reduced and not up to the normal luminous brightness of the required operating current, in this case, if you still apply high current, it is easy to make the white LED aging.

  1.3 LED optical properties

  The luminous flux of the light source refers to the visible light energy passing through the 4π stereo angle per unit time. The relationship between white LED current and luminous flux is shown in Figure 1, with the increase of current, the luminous flux of the LED increases nonlinearly and gradually tends to saturation. The reason is mainly because with the increase in current and time, the internal temperature of the high-power LED rises, which occurs in the P/N junction region of the carrier composite probability decreases, resulting in a reduction in the LED luminous efficiency.

LED controllable constant current source drive system design scheme插图2

  2 system program selection and comparison

  2.1 Core controller selection

  Controller using the more common STC series microcontroller STC89C52, a high-performance 8-bit microprocessor with 8K-byte flash programmable erasable read-only memory (FPEROM-FalshProgrammableandErasableReadOnlyMemory). The device is fabricated using high-density non-volatile memory manufacturing technology and is compatible with the industry-standard MCS-51 instruction set and output pins. With the combination of a versatile 8-bit CPU and flash memory in a single chip, STC's STC89C52 is a highly efficient microcontroller that provides a flexible and inexpensive solution for many embedded control systems.

 2.2 Clock function module selection

  Program 1 uses the DS1302 clock chip. This chip has a small size, few pins, and is very easy to operate. The disadvantage is that the use of external backup battery and external crystal oscillator, the hardware line is more complex, the cost is higher.

  Program 2 uses DS12C887 clock chip. This chip, relatively large size, internal integration of rechargeable lithium batteries, but also integrated 32.768kHz standard crystal, can effectively maintain the continuity of time, very convenient to use, but expensive.

  Scheme 3 uses the timer of the microcontroller (crystal 11.0592M) to design the clock. The time is displayed on the 1602 LCD, and the hours, minutes and seconds of the clock are adjusted with a separate keyboard, and the timer can be set. Low cost, do not need to enable other chips and peripheral circuits in, but the program is more complex.

  Considering the cost-effective and circuit optimization issues, so choose program 3.

2.4 Constant current source module selection

  Scheme 1 uses a microcontroller to generate PWM signals, output to the Darlington tube, through the filter to eliminate ripple, to achieve the function of constant current source. Using PWM pulse to achieve constant current source can simplify the hardware circuit, easy to control and regulate, but the program is difficult to ensure the accuracy, to adapt to the design of the precision requirements of the higher technical difficulty, and the program is difficult to adapt to the application of a large range of current regulation, ripple and stability and other factors, it is difficult to achieve.

  Program 2 by the operational V / I conversion circuit constitutes a constant current circuit. Constant current circuit composed of operational amplifiers to get rid of the transistor constant current circuit is limited by the shortcomings of the process parameters. This scheme can realize 0~5V/0~500mA V/I conversion, and the conversion accuracy is high. If the input is controlled by a microcontroller with a digital potentiometer, a numerical control constant current source can also be easily realized.

LED controllable constant current source drive system design scheme插图4

  Program 3 through the specialized constant current / constant voltage chip LT1769 and a simple control line to achieve voltage-controlled current source program. This constant voltage chip has a high degree of integration, the use of the control system hardware and software have become relatively simple advantages. But the disadvantage is that the program is not flexible enough to achieve; due to the chip precision is not high, the device performance is limited to the performance of this dedicated chip performance indicators allowed. So this design is generally only suitable for precision requirements are not high, but the integration and portability requirements of high occasions, it has been proved that this is not to do the ideal CNC current source to realize the program.

  In view of the arguments and comparisons, the final choice of program 2.

 2.5 D / A converter selection

  For D / A converter, I use a very common 8-bit D / A converter DAC0832, its conversion time of 1 μs, the operating voltage of +5V ~ +15V, the reference voltage of ± 10V, and the microprocessor interface is fully compatible with the low price, simple interface, conversion control is easy, etc., in the application of microcontroller systems are widely used. Its D/A converter consists of 8-bit input latch, 8-bit DAC register, 8-bit D/A conversion circuit and conversion control circuit.

  3 Hardware circuit design

  3.1 System power supply circuit

  The power supply utilizes positive voltage integrated regulator LM7812 and negative voltage integrated regulator LM7912 to provide symmetrical positive/negative 12V regulated output, which is supplied to the op-amp, and then regulated to 5V output by LM7805, which is supplied to the microcontroller.

3.2 LED Driver Circuit

  The circuit can easily realize the voltage/current conversion. Operational amplifier U1A constitutes a comparator, U1C constitutes a voltage follower, playing the role of negative feedback. Input signal Vi compared with the feedback signal Vf, the output voltage V1 at the output of the comparator U1A, V1 control the output voltage V2 of the op-amp U1B, thus changing the output current IL of the transistor Q1, and the output IL affects the feedback voltage Vf, to reach the purpose of tracking the input voltage Vi. The output current IL is calculated as IL=Vf/R13, because the negative feedback makes Vi=Vf, so IL=Vi/R13. If R13 takes the value of 10Ω, the V/I conversion of 0~5V/0~500mA can be realized; if the performance parameters of the selected device are stable, and the amplification of the op-amps UA1 and UA2 is large enough, the conversion accuracy is higher. the voltage of V13 is controlled by the MCU. With the D / A output control, can easily realize the digital constant current source output.

For more LED lighting issues, please feel free to consult recolux for free

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