There are many types of LED power supplies. The quality and price of various types of power supplies vary greatly, which is also one of the important factors affecting product quality and price.
LED drive power can usually be divided into three categories, namely switching constant current source, linear IC power supply, resistance-capacitor step-down power supply.
First, switch constant current source
A transformer is used to change the high voltage to low voltage and rectify and filter in order to output stable low voltage DC power.
Constant current driver LED is divided into isolated power supply and non-isolated power supply; isolation refers to the output high and low voltage isolation, high safety, so the insulation requirements of the shell is not high; However, the cost is relatively low. Traditional energy-saving lamps use non-isolated power supplies and are protected by insulated plastic shells.
(Switch constant current isolated power supply schematic diagram)
The switching power supply has relatively high safety (generally low voltage output) and stable performance, but its disadvantages are complicated circuits and higher prices. Switching power supply technology is mature and stable in performance. It is the mainstream power supply for LED lighting.
Second, linear IC power
Using one IC or multiple ICs to distribute the voltage, there are few types of electronic components, the power factor and power efficiency are very high, no electrolytic capacitor is needed, the life is long, and the cost is low. The disadvantage is that the output high voltage is non-isolated and there is flicker. The enclosure is required to be well protected against electric shock. The market claims that there is no (de) electrolytic capacitor on the market, and the long-life uses linear IC power. IC drive power has the advantages of high reliability, high efficiency, and low cost, and it is an ideal constant current led driver led driver in the future.
Constant Current Driver Led
Third, the resistance capacitor step-down power supply
A capacitor is used to provide driving current through its charge and discharge. The circuit is simple and low cost, but the performance is poor and the stability is poor. When the grid voltage fluctuates, it is easy to burn out the LED. At the same time, the output high voltage is non-isolated.
Low power factor, short life, generally only suitable for economical low power products (within 5W). High-power products have large output currents and capacitors cannot provide large currents, otherwise they will easily burn out. In addition, countries have requirements for the power factor of high-power lamps, that is, power factors above 7W require greater than 0.7, but the resistance-capacity step-down power supply is far away. Can't reach (usually between 0.2-0.3), so high-power products should not use resistance-capacitor step-down power supply.
Low-end products with low requirements in the market are almost all using resistance-capacitor step-down power supplies; in addition, some high-power low-cost products also use resistance-capacitor step-down power supplies.
In the mid-to-high-end market, switching constant current non-isolated power supplies are still the mainstream power supply in the market. Manufacturers generally conduct high-voltage isolation on the structural design.
In the low-end market, most manufacturers use resistance-capacitor step-down power supplies, and some manufacturers use linear IC power supplies (requires manufacturers to have certain design capabilities).
With different power supplies, the performance and price of the products are different. We should choose different products according to different markets.
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