First, constant current type:
1. Constant current drive circuit is ideal to drive LED, but the disadvantage is that the price is high
2. Although the constant current circuit is not afraid of load short circuit, it is strictly prohibited to completely open the load
3. The output current of the constant current drive circuit is constant, but the output DC voltage varies in a certain range with the size of the load resistance
4. The number of LEDs should be limited because they have the maximum withstand current and voltage
Second, voltage stabilizing type:
1. After the voltage stabilizing circuit determines various parameters, the output is a fixed voltage, but the output current changes with the increase or decrease of load
2. Although the voltage stabilizing circuit is not afraid of open load, it is strictly prohibited to completely short load
3. The voltage change after rectification will affect the brightness of LED
4. In order to make each string of LED display brightness driven by voltage stabilizing circuit uniform, it is necessary to add appropriate resistance
LED power supply can be divided into six categories according to circuit structure
First, conventional transformer step-down:
This power supply has the advantages of small volume, but the disadvantages are heavy weight and low power efficiency, generally 45% ~ 60%. It is rarely used because of its low reliability
Second, electronic transformer step-down:
The disadvantages of this power supply structure are low conversion efficiency, narrow voltage range, generally 180 ~ 240V and large ripple interference
Third, capacitor voltage reduction:
The LED power supply in this way is easily affected by the voltage fluctuation of the power grid, and the power efficiency is low. It is not suitable to use the LED when flashing, because the circuit depressurizes through the capacitor. When flashing, due to the role of charge and discharge, the instantaneous current through the LED is very large, which is easy to damage the chip
Fourth, resistance step-down:
This power supply mode has low power efficiency and low reliability of the system. Because the circuit reduces voltage through resistance, it is greatly disturbed by the change of grid voltage, it is not easy to make a regulated power supply, and the step-down resistance itself consumes a lot of energy
Fifth, RCC step-down switching power supply:
This led power supply has the advantages of wide voltage stabilizing range and high power efficiency, generally 70% ~ 80%, and is widely used. The disadvantages are that the switching frequency is not easy to control, the load voltage ripple coefficient is large, and the load adaptability is poor under abnormal conditions
Sixth, PWM controlled switching power supply:
At present, the LED power supply designed by PWM control mode is ideal, because the output voltage or current of this switching power supply is very stable. The power conversion efficiency is very high, generally up to 80% ~ 90%, and the output voltage and current are very stable. This led power supply mainly consists of four parts: input rectifier and filter part, output rectifier and filter part PWM voltage stabilizing control part and switching energy conversion part. Moreover, this circuit has perfect protection measures and belongs to high reliability power supply
Classification by output power
0.4W, 1.28w, 1.4W, 3W, 4.2w, 5W, 8W, 10.5w, 12W, 15W, 18W, 20W, 23W, 25W, 30W, 45W, 60W, 100W, 120W, 150W, 200W, 300W, etc.
Classification by output voltage
Dc4v, 6V, 9V, 12V, 18V, 24V, 36V, 42V, 48V, 54V, 81v, 105v, 135v, etc.
Classification by shape and structure
PCBA bare board and shell.
Classification by safety structure
Isolated and non isolated.
Classification by power factor
With and without power factor correction.
Classification by waterproof performance
Waterproof and non waterproof
Classification by incentive mode
Self excited and other excited.
Classification by conversion method
AC-DC and DC-DC.
LED fluorescent lamp driving power supply
By power
6W, 8W, 9W, 10W, 12W, 15W, 18W, 20W, 30W, etc;
By function
Ordinary type, multifunctional type with wireless remote control dimming, etc.
By safety structure
Isolated and non isolated.
