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LED drive power, the difference between with and without ic!
LED 驱动芯片，实际上是个 PWM 控制芯片，在组成电路正常工作后，通过后面电流检测电阻上检测 LED 的电流而得到的电压反馈到芯片，控制内部的 PWM 占空比，以适应 LED 自身特性变化而引起的电流、电压波动，使 LED 得到的电流保持恒定。 Sanfang Xinli Electronic's LED driver chip is actually a PWM control chip. After the component circuit works normally, the voltage obtained by detecting the LED current on the current detection resistor is fed back to the chip to control the internal PWM duty cycle to adapt The current and voltage fluctuations caused by changes in the characteristics of the LED itself keep the current obtained by the LED constant. 是特性敏感的半导体器件，又具有负温度特性，因而在应用过程中需要对其进行稳定工作状态和保护，从而产生了驱动的概念。 LEDs are sensitive semiconductor devices with negative temperature characteristics, so they need to be stable and protected in the application process, which leads to the concept of driving.
驱动器原理与作用： Principle and function of LED driver:
驱动器是指驱动 LED 发光或 LED 模块组件正常工作的电源调整电子器件。 The LED driver refers to a power adjustment electronic device that drives an LED to emit light or a normal operation of the LED module assembly. LED PN 结的导通特性决定，它能适应的电源的电压和电流变动范围十分狭窄，稍许偏离就可能无法点亮 LED 或者发光效率严重降低，或者缩短使用寿命甚至烧毁芯片。 Due to the conduction characteristics of the LED PN junction, the range of voltage and current variations of the power supply it can adapt to is very narrow. A slight deviation may fail to light up the LED or reduce the luminous efficiency severely, or shorten the service life or even burn the chip. LED ， LED 驱动器就是这种可以驱使 LED 在最佳电压或电流状态下工作的电子组件。 The current industrial frequency power supply and common battery power supply are not suitable for directly supplying LEDs . LED drivers are such electronic components that can drive LEDs to work under optimal voltage or current conditions.
、 LED 器件对驱动电源的要求近乎于苛刻， LED 不像普通的白炽灯泡，可以直接连接 220V 的交流市电。 1. The requirements of LED devices for driving power are nearly harsh. Unlike ordinary incandescent light bulbs, LEDs can be directly connected to 220V AC mains. 是低电压驱动，必须要设计复杂的变换电路，不同用途的 LED 灯，要配备不同的电源适配器。 LED is a low-voltage driver. It is necessary to design a complex conversion circuit. Different LED lamps must be equipped with different power adapters. When designing a good power supply, factors such as efficiency conversion, effective power, constant current accuracy, power supply life, and electromagnetic compatibility must be considered, because the role of the power supply in the entire lamp is as important as the human heart.
、由于 LED 是特性敏感的半导体器件，又具有负温度特性， LED 驱动电源（也叫驱动器）就是在应用过程中对其进行稳定工作状态的保护。 2. As LED is a sensitive semiconductor device and has negative temperature characteristics, LED driving power supply (also called driver) is to protect the stable working state during the application process.
LED 功率水平的限制，通常需同时驱动多个 LED 以满足亮度需求，因此，需要专门的驱动电路来点亮 LED ，下面简单说下目前主流的几种 LED 驱动方式： Due to the limitation of LED power level, it is usually necessary to drive multiple LEDs at the same time to meet the brightness requirements. Therefore, special driving circuits are required to light up the LEDs . The following briefly describes the current mainstream LED driving methods:
、隔离反激电路：利用反激电路，通过变压器在副边产生直流电平，再通过光耦将此电平的纹波反馈回原边，从而自激稳定。 1. Isolation flyback circuit: The flyback circuit is used to generate a DC level on the secondary side through the transformer, and then this level of ripple is fed back to the primary side through the optocoupler, thereby self-excitation and stability. This type of circuit meets the safety certification requirements, and the output constant current accuracy is better, and the conversion efficiency is higher. However, due to the need for an optocoupler and a secondary-side constant current control circuit, the system is complicated, bulky, and expensive. It has gradually been replaced by the original plan.
、原边方案：原边方案就是通过完全在交流原边控制输出的电源和电流，最精确可以做到 5% 的恒流精度，副边仅需简单的输出电路即可。 2. Primary side scheme: The primary side scheme is to control the output power and current completely on the AC primary side. The most accurate can achieve 5% constant current accuracy. The secondary side only needs a simple output circuit. The primary side mainly relies on the feedback of the auxiliary side to control the output voltage, the control of the primary side current by the current limiting resistor, and at the same time multiplying the turns ratio to control the accuracy of the output current. The primary solution inherits the advantages of the isolated flyback circuit, and has a simple structure, which can achieve small size and low cost. It has become the mainstream driver.
、阻容降压：利用电容在交流下的阻抗来限制输入电流，从而获得直流电平给 LED 供电。 3 , resistance-capacity buck: use the impedance of the capacitor under AC to limit the input current, so as to obtain the DC level to power the LED . This drive method has a simple structure and low cost, but there is a potential safety hazard in entering a non-isolated solution. And the conversion efficiency is very low, and constant current control cannot be achieved
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