LED Drive Power

- Jan 24, 2019-

LED drive power converts the power supply to a specific voltage and current to drive the LED's light-emitting voltage converter, usually:

Inputs for LED drive power include high-voltage power frequency AC (ie, mains), low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as the output of electronic transformers).

The output of the LED driver is mostly a constant current source that changes the voltage as the LED's forward voltage drop changes. The core components of the LED power supply include a switch controller, an inductor, a switching component (MOSfet), a feedback resistor, an input filter component, an output filter component, and the like.

According to different occasions, there must be input overvoltage protection circuit, input undervoltage protection circuit, LED open circuit protection, overcurrent protection and other circuits.

Classified by drive

(1)Constant current type

The output current of the constant current driving circuit is constant, and the DC voltage of the output varies within a certain range according to the magnitude of the load resistance. The load resistance is small, the output voltage is low, the load resistance is larger, and the output voltage is also The higher;

The constant current circuit is not afraid of load short circuit, but it is forbidden to completely open the load;

The constant current driving circuit drives the LED, which is ideal, but relatively high in price;

Attention should be paid to the maximum withstand current and voltage values used, which limits the number of LEDs used.

(2)Voltage regulator

When the parameters in the voltage stabilizing circuit are determined, the output voltage is fixed, and the output current changes as the load increases or decreases;

The voltage regulator circuit is not afraid of the load open circuit, but it is forbidden to completely short the load;

Driving the LED with a voltage-stabilized driving circuit, each string needs to be added with a suitable resistor to make each string of LEDs display brightness average;

The brightness is affected by the rectified voltage changes.

LED drive power features

(1)High reliability

High efficiency, LED is an energy-saving product, and the efficiency of driving power supply is high. It is very important to dissipate heat from the power supply installed in the fixture. The power source has high efficiency, its power consumption is small, and the heat generated in the lamp is small, which reduces the temperature rise of the lamp. It is beneficial to delay the light decay of LEDs.