3W LED internal power source at low cost

Abstract

The invention relates to a 3W LED internal power source at a low cost. The 3W LED internal power source is characterized by comprising a primary rectifying and filtering circuit, a single end flyback type converting circuit and a secondary rectifying and filtering circuit; the single end flyback type converting circuit comprises a DC-DC flyback control device SFL600, a transformer T and a resistance-capacitance circuit; the DC-DC flyback control device SFL600 is of a wide range dynamic responding type and is provided with three pins P1, P2 and P3, the pin P2 is connected with a primary side sampling resistor R1, the pin P3 is connected with a capacitor C1, the pin P1 is connected with an RCD clamping circuit and a duplex-winding flyback transformer T, and power is supplied to an LED array through the secondary rectifying and filtering circuit after the duplex-winding flyback transformer T converts high voltage and low frequency in the forestage into low voltage and high frequency in a post stage. The 3W LED isolated internal power source is low in cost, high in reliability.

Description

technical field [0001] The invention relates to an LED power supply, in particular to a low-cost 3W LED built-in power supply. Background technique [0002] LED is a photoelectric direct conversion element with high photoelectric conversion efficiency, because it is not Edison's filament heating and light emitting principle, there is no thermal energy conversion process, only the current is generated by the small internal resistance in the PN pole of the LED Minimal thermal effect. So LED is the most ideal energy-saving illuminant today. LED has no filament and is a pure semiconductor light-emitting element, so it has a very high service life. Its service life is 150 times that of ordinary incandescent lamps and 75 times that of fluorescent tube energy-saving lamps. Generally, qualified LEDs have a service life of more than 30,000 to 60,000 hours. If the working current of the LED is effectively controlled, the service life can reach 80,000 to 100,000 hours. LED is a sem...

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Problems solved by technology

Compared with the three, the resistance-capacitance step-down has a good cost advantage, but because of its influence with the fluctuation of the power grid, the output current also changes accordingly, and the instability is too strong; the cost of the non-isolated circuit is between the resistance-capacity step-down and the isolated power supply Between, but its input end and load end are not isolated by a transformer, which has a certain safety factor; AC-DC isolated power supply, the cost is high, but because of the electrical isolation control of its input end and load end, it has high safety

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