LED in the external circuit to provide a certain current and voltage can be lit, LED lamp beads due to different processes, its operating voltage between 0.7-12V, the current varies between a few milliamps to a few amps. In order to work stably, it is necessary to provide a reliable power supply when used in a large area, and the common power supplies are as follows.

1. DC power supply

LED is a kind of diode, need DC voltage to drive, so the most basic LED power supply is DC power supply. Commonly available batteries, power adapters and so on. When using ordinary household AC power to drive LEDs, you need to rectify the circuit will be converted to DC power. You can use a bridge rectifier circuit or rectifier chip.

In fact, the led itself is a diode, can be used directly with ac, at this time the led will be ac half wave rectification, due to the voltage ripple is very large, there will be serious strobe.

2. Dimmable LED driver power supply

Usually use a simple electronic voltage converter and voltage regulator circuit to realize. If you need to adjust the light-emitting brightness, LED driver power supply can also be added to the brightness control function, by changing the output current to adjust the brightness of the LED. This kind of power supply is usually used for small power, very common in household lighting.

3. Switching power supply

In order to obtain a stable DC voltage to drive the LED, generally use switching regulator power supply, through the DC-DC conversion circuit, the input voltage will be converted to meet the requirements of the LED fwd voltage stable DC voltage.

Switching power supply is a more sophisticated power supply, due to the frequency adjustable, switching power supply supply voltage is wider, the output range is also very wide. However, to be used for LEDs, it needs to be designed for voltage and current stabilization to achieve a stable output through the output feedback circuit.

Switching power supply is the most widely used in industrial applications is the power supply, the back of the mentioned current-limited power supply and constant-current power supply, basically based on the switching power supply for the alienation of the design. In high-power applications, the power can reach several kilowatts, this time with a reliable air-cooled or water-cooled system for heat dissipation.

4. Current-limited LED driver power supply 

As LED is a current driver, so LED driver power supply usually has a current limiting function, so that the LED work in the appropriate forward current, to avoid excessive current damage.

5. Constant current LED driving power supply

More accurate LED driver power supply can use feedback control circuit, realize the output current of constant current control, not affected by the input voltage changes, to ensure that the LED work in the best current conditions.