1. Triac/phase-cut dimming led driver
Triac/phase-cut dimming is a kind of physical dimming. Starting from AC phase 0, the input voltage is chopped until the triac/phase-cut dimming is turned on before there is voltage input. The principle is to adjust the conduction angle of each half wave of the alternating current to change the sine waveform, thereby changing the effective value of the alternating current, so as to achieve the purpose of dimming. Thyristor dimmers have the advantages of high adjustment accuracy, high efficiency, small size, light weight, and easy long-distance operation. They dominate the market, and most manufacturers' products are this type of dimmer. The advantages of using Triac/phase-cut dimmers in LED lighting are: low dimming cost, and the disadvantage is that the Triac/phase-cut dimming performance is poor, which usually leads to a reduction in the dimming range. Because of the properties of Triac/phase-cut half-control switches, only The function of turning on the current, but not completely turning off the current, even if it is adjusted to the lowest level, there is still a weak current passing, and the characteristics of LED micro-current light-emitting, so that there is a large amount of thyristor dimming, and the LED still has a weak light-emitting phenomenon after turning off. , has become a difficult problem in the promotion of LED dimming methods. 2. PWM dimming LED Driver Pulse width modulation (PWM) is a very effective technology that uses the digital output of a microprocessor to control analog circuits. It is widely used in many fields from measurement and communication to power control and conversion, and LED lighting. By controlling the analog circuit digitally, the cost and power consumption of the system can be greatly reduced. In addition, many microcontrollers and DSPs have included PWM controllers on the chip, which makes the realization of digital control easier. In short, PWM is a method of digitally encoding analog signal levels. Through the use of high-resolution counters, the duty cycle of the square wave is modulated to encode the level of a specific analog signal. The PWM signal is still digital, because at any given moment, the full-scale dc power supply is either completely present or completely absent. The voltage or current source is applied to the analog load in a repetitive pulse sequence of on or off. When it is on, it is when the DC Power Supply is added to the load, and when it is off, it is when the power supply is disconnected. As long as the bandwidth is sufficient, any analog value can be encoded using PWM. The figure above shows three different PWM signals. 3. 0-10V dimming led driver 0-10V dimming is also called 0-10V signal dimming. It is an analog dimming method. It is different from the thyristor power supply in that there are two more 0-10V interfaces on the 0-10V power supply (+10V and -10V), it is to control the output current of the power supply by changing the voltage of 0-10V to achieve dimming. It is brightest at 10V, and off at 0V. And 1-10V is only the dimmer is 1-10V, when the resistance dimmer is adjusted to the minimum 1V, the output current is also 10%, if the output current will reach the power output at 10V, the brightness will also be 100%, 1 -10V does not have the function of a switch, and the lamp cannot be adjusted to the lowest shutdown function.
October 28, 2020
