What is led driver power conversion
LED driver refers to the power adjustment electronic device that drives the led to emit light or the LED module assembly to work normally. Due to the conduction characteristics of the LED PN junction, the voltage and current variation range of the power supply it can adapt to is very narrow. If it deviates slightly, the LED may not be lit or the luminous efficiency may be seriously reduced, or the service life may be shortened or even the chip may be burned. The current power frequency power supply and the common battery power supply are not suitable for directly supplying the LED. The LED driver is an electronic component that can drive the led to work under the optimal voltage or current state.
In many systems (including many regulators deployed in the automotive power output system), the design of power conversion controller is a difficult and complex work. This paper describes the advantages, trade-offs and applications of different switching topologies used by LED drivers in order to simplify the selection process.
LEDs are different from traditional electric lamps with filament or gas components. With a specific semiconductor junction, LED manufacturers can generate light of a specific color over the entire visible light range, as well as infrared and ultraviolet rays. In automotive applications, LEDs can improve the safety of day and night driving. The improvement of efficiency can prolong the battery life of electric vehicles, and the use of multiple LEDs in a single system can avoid the failure of a single component.
Because of its versatility, LEDs can be driven in many different ways. Since the output of the LED has good lighting control, the LED load is different from the traditional load of the power system. LEDs emit light only by precisely controlling the current through the semiconductor junction, and the relative voltage from the port to the system ground (or the chassis in the automobile system) is irrelevant. Therefore, the LED system can take advantage of the different topologies provided by the switching technology.
So how to choose the correct switching topology for the LED system? Take automobile LED driver as an example. The choice of specific switch topology in the automotive system is related to the whole system design; Minimum input voltage, maximum string voltage, chassis loop capacity, short-circuit output capacity, maximum input current, output / LED current and PWM dimming shall be considered.
The buck LED driver regulates the current in the LED string by a voltage higher than the total voltage of the LED string. The buck LED driver can be safely short circuited to the system ground to ensure its intrinsic safety. They have the ability of chassis reflow (one line for power supply) and can easily adapt to matrix or animation applications.
The buck LED driver needs to have several key characteristics: fixed frequency operation, high efficiency through excellent switching control and low resistance switching, high accuracy over the entire analog dimming range, and proper design of spread spectrum frequency modulation for excellent EMI.
Automotive LED lighting systems can be driven by switching regulators in many different ways. According to different applications, lighting designers can design complete subsystems according to different lighting requirements of the whole vehicle by selecting switch topology and configuration. Selecting the correct power transfer switch topology and configuration for the system can optimize the complexity, efficiency, EMI and safety requirements.