Common LED power supply

There are many types of LED power supply. The quality and price of various power supplies vary greatly. This is also one of the important factors affecting product quality and price. LED power supply can generally be divided into three categories, switching constant current source, linear IC power supply, and resistance-capacitance step-down power supply.


1. The switching constant current source uses a transformer to change the high voltage to low voltage, and performs rectification and filtering to output a stable low voltage direct current. The switching constant current source is divided into isolated power supply and non-isolated power supply. Isolation refers to the isolation of output high and low voltage, and the safety is very high, so the requirement for the insulation of the shell is not high. Non-isolated safety is slightly worse, but the cost is relatively low. Traditional energy-saving lamps use a non-isolated power supply and use an insulated plastic shell for protection. The safety of the switching power supply is relatively high (generally the output is low voltage), and the performance is stable. The disadvantage is that the circuit is complicated and the price is high. The switching power supply has mature technology and stable performance, and is currently the mainstream power supply for LED lighting.

 2. Linear IC power supply uses one IC or multiple ICs to distribute voltage. There are few types of electronic components, power factor and power supply efficiency are very high, no electrolytic capacitor is needed, long life and low cost. The disadvantage is that the output high voltage is non-isolated, and there is stroboscopic, and the enclosure is required to be protected against electric shock. All use linear IC power supplies in the market claims that there are no electrolytic capacitors and ultra-long life. IC power supply has high reliability, high efficiency and low cost advantages, and is an ideal LED power supply in the future.

3. The RC step-down power supply uses a capacitor to provide driving current through its charging and discharging. The circuit is simple, the cost is low, but the performance is poor, and the stability is poor. It is very easy to burn out the LED when the grid voltage fluctuates, and the output is high-voltage non-isolated. Insulating protective shell. Low power factor and short life, generally only suitable for economical low-power products (within 5W). For products with high power, the output current is large, and the capacitor cannot provide large current, otherwise it is easy to burn out. In addition, the country has requirements for the power factor of high-power lamps, that is, the power factor above 7W is required to be greater than 0.7, but the resistance-capacitance step-down power supply is far from reaching (usually between 0.2-0.3), so high-power products should not be used RC step-down power supply. In the market, almost all low-end products with low requirements use RC step-down power supplies, and some low-end, high-power products also use RC step-down power supplies.

Post time: Aug-06-2021
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