What issues need to be considered when designing LED driver circuits?

LED has many advantages such as environmental protection, long life, high photoelectric efficiency, etc. In recent years, the application in various industries has been developed rapidly, and the driving circuit of LED has become a key factor in product application. In theory, the service life of the LED is more than 100,000 hours, but in the actual application process, due to the improper design of the drive circuit design and drive mode, the LED is extremely vulnerable to damage.

When designing an LED drive circuit, you need to know the LED current and voltage characteristics. Due to different LED manufacturers and LED specifications, current and voltage characteristics are different. Now taking the typical specifications of white LED as an example, according to the LED current and voltage changes, the general application of forward voltage is about 3.0-3.6V, the typical value is 3.3V, the current is 20mA, when the forward voltage across the LED exceeds 3.6 After V, the forward voltage has only a small increase, but its forward current may multiply and increase the temperature of the LED luminous body too quickly, thereby accelerating the LED light attenuation, shortening the life of the LED, and even burning in severe cases. Bad LED. According to the change characteristics of the voltage and current of the LED, strict requirements are imposed on the design of the driving circuit.

At present, many manufacturers of LED light products (such as guardrails, lamp cups, and projection lights) use resistance-capacitance buck, and then add a voltage stabilizing diode to supply power to the LED. This way is simple and cheap to drive the LED, but there are very many The big defect is the low efficiency first. It consumes a lot of power on the buck resistor, and may even exceed the power consumed by the LED, and cannot provide a large current drive. Because the larger the current, the larger the buck capacitor is required, so the consumption is decreasing. The greater the energy on the piezoresistor. Secondly, the ability to stabilize the voltage is extremely poor, and it cannot be guaranteed that the current through the LED will not exceed its normal working requirements. When designing the product, the voltage across the LED will be reduced to drive the power, which is at the cost of reducing the brightness of the LED. The LED brightness is not stable when the resistance-capacitance buck is used to drive the LED. When the power supply voltage decreases, the LED brightness becomes darker. When the power supply voltage increases, the LED brightness becomes brighter.

According to the characteristics of LED current and voltage changes, it is feasible to use constant voltage to drive LEDs. Although commonly used voltage stabilizing circuits have the disadvantages of insufficient voltage stabilizing accuracy and poor current stabilizing ability, they may be over-precisely designed in the application of certain products. , Its advantages are still irreplaceable by other driving methods.

The constant current drive mode is an ideal LED drive mode. It can avoid the current fluctuation caused by the change of the LED forward voltage, and the constant current makes the brightness of the LED stable. Therefore, many manufacturers use constant current to drive LEDs. Another LED driving method is feasible, which is neither constant voltage nor constant current, but through the design of the circuit, when the LED forward voltage increases, the drive current is reduced, ensuring the safety of LED products. Of course, the increase of the forward voltage can only be within the range of the LED, too high will damage the LED.

The ideal LED driving method is to use constant voltage and constant current, and cascade multiple LEDs in series. But the cost of the drive increases. In fact, each driving method has advantages and disadvantages. According to the requirements of LED products and application occasions, it is reasonable to choose the LED driving method and accurately design the driving power supply.

 

If you want to know more, our website has product specifications for LED driver, you can go to ALLICDATA ELECTRONICS LIMITED to get more information

What is the development status and trend of led display?

 Over the past few years, with the further release of the market, the entire LED display industry has regained its vitality, and market competition has intensified. However, in contrast, more and more companies have entered the LED display industry. With this overall increase in competition, it is even more difficult to occupy a position in the LED display industry and become a leader.

In recent years, the steps of industrial transformation and upgrading have been accelerated, but the threshold for entering the LED display industry has not been raised year-on-year, which has also caused the current industrial situation: on the one hand, there are an increasing number of small and medium-sized screen companies with mixed fish and dragons; On the one hand, the threshold for creating a well-known brand in the industry is getting higher and higher; it is well known that the LED display industry has not born a well-known brand with a non-industry background for a long time.

　　 This situation has also caused multi-LED display practitioners to fall into a development puzzle: in the end, the market is getting better and better, will it cause many industry recruits and veterans to re-enter this industry? Or is it that the market is getting harder and harder, so it hasn't been a long time since a new brand from 0 to 1 has risen?

LED display development trend

　  1. Development towards energy saving trend

　  Energy saving and environmental protection has always been a new proposition for future life. The LED display itself is very energy-saving. Its characteristics are: high light efficiency, long life, easy control, and maintenance-free. It is a new generation of solid cold light source, with soft light, gorgeous, colorful, low loss, low energy consumption, and is a green and environmentally friendly product. But the power consumption is not small when made into LED display screen. Large LED screens are all large screens and require many points to form. Reducing the power consumption of LED display screens and realizing real energy saving must be an important development trend of LED display.

　　2. Development towards light and thin trend

      At present, almost everyone in the industry advertises that their boxes are light and thin. Indeed, thin and light boxes are an inevitable trend to replace iron boxes. In the past, the weight of the iron box itself is not low, and the weight of the steel structure makes the whole very heavy. In this way, many floors of the building are difficult to withstand such heavy attachments. The load-bearing balance of the building and the pressure of the foundation are not acceptable, and it is not easy to disassemble and transport. The cost is greatly increased, so the thin and light box is not allowed by all manufacturers. A trend that does not update.

　 3. Towards the trend of patent protection

    The LED industry is fiercely competitive, and almost every company is competing for the market, grabbing customers, and expanding its scale, but few companies really focus on product research and development. In fact, in order to maintain technological competitiveness and reduce the risk of technology spillovers, patents are good. Way of protection. As the industry slowly matures, regulates, and protects its intellectual property rights and intangible assets through patent applications, it is also an inevitable development trend for the LED large-screen industry.

4. To the trend of rapid and accurate splicing

　　This is mainly for LED rental display. The characteristic of leasing is that it is often disassembled and assembled to meet temporary needs, so the display boxes must be able to be spliced quickly and accurately. Hanchuang LED rental screen is super light and thin. Light and thin design is the demand of LED rental screens. LED display screens require frequent disassembly and handling because of the particularity of their application places. The thinner and lighter the LED rental screen is, the more convenient the transportation is, and it can also save more costs. Therefore, rapid and accurate installation is also bound to be the development trend of LED display screens.

　　 5. Towards the trend of standardization

　　 LED display screens have sprung up like mushrooms, but only a few can be recognized by the industry. Since many small enterprises were established, because of their small size, small capital, and incapable of keeping up with their R&D capabilities, they tried to take shortcuts, sloppy design, and even plagiarized designs from large companies. The customer has a headache, and this behavior is extremely irresponsible to the customer. Therefore, the standardization of LED large-screen products is also an inevitable trend.

　　 6. The trend towards smaller pitches

 Small pitch has always been one of the products of the heat. At present, the indoor small pitch has broken through a few points, and the outdoor small pitch has also broken below P2. With the development of technology, the pitch will become smaller and smaller.

 

If you want to know more, our website has product specifications for led display, you can go to ALLICDATA ELECTRONICS LIMITED to get more information