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The difference between LED switching power supply and ordinary switching power supply
2019-10-14 22:34:12
The difference between LED switching power supply and ordinary switching power supply
LED switching power supply
High frequency LED switching power supply is the direction of its development, high frequency makes switching power small, and make switching power into a wider range of applications, especially in the field of high-tech applications, promote the miniaturization and portability of high-tech products. In addition, the development and application of switching power supply are of great significance in energy saving, resource saving and environmental protection.
The main electronic components used in LED switching power supply are LED diode, IGBT and MOSFET. SCR has a small number of applications in switching power input rectifier circuit and soft start circuit. GTR drive is difficult and the switching frequency is low, so it is gradually replaced by IGBT and MOSFET.
Three conditions for LED switching power supply
1, switch is: power electronic devices work in the switching state instead of the linear state
2. High frequency: power electronic devices work at high frequency instead of low frequency close to power frequency
Dc: the switching power supply outputs dc instead of ac
Ordinary switching power supply
Switching power supply is a kind of power supply that USES modern power electronic technology to control the time ratio of switching tube on and off and maintain stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. At present, switching power supply is widely used in almost all electronic devices with the characteristics of small, light and high efficiency. It is an indispensable power source for the rapid development of electronic information industry.
The difference between LED switching power supply and ordinary switching power supply
The biggest difference is that LED power source is constant current source, general switching power source is constant voltage source.
The difficulty in designing LED switching power supply is size and price.
LED power supply: 1 requirements must be constant current. Low temperature, low heat and long life. 3 small volume. Waterproof, anti-corrosion and anti-static. 5 high-frequency pollution. The high frequency pollution of ordinary power supply and low quality LED power supply is serious. Even with inductance and large capacitance filtering, the waveform of output dc is very complicated. Poor power, the power itself may not be bad, but LED life and light decay are greatly reduced.
In fact, LED power circuit is mostly composed of switching power circuit and feedback circuit. After sampling from the load, the feedback circuit adjusts the duty cycle or frequency of the pulse to control the output of the switching circuit.
switching power circuit and feedback circuit