Analysis of working principle of switching power supply
Release Time:2016-04-27 Source:Original Views:8232
What is the working principle of switching power supply?
Switching power supply is used to control the speed of the switch tube through the circuit and the cut-off.
The direct current is converted into a high frequency alternating current to provide a transformer for the transformer, thereby generating a set or a plurality of groups of voltage required! Conversion to high frequency AC power is the reason for the high frequency AC transformer circuit in the efficiency of more than 50HZ a lot. So the switch transformer can do is very small, and the work is not very hot!! The cost is very low. If you do not turn the 50HZ into a high frequency switch, the power supply will have no meaning.
The working flow of the switching power supply is:
Power supply, input filter, full bridge rectifier, DC filter, switching tube (oscillation inverter), switching transformer, output rectifier and filter.
AC power input through the rectifier filter into DC
By high frequency PWM (pulse width modulation) signal control switch tube, the DC to switch transformer
Switching transformer secondary induction out of the high-frequency voltage, the supply load through the rectifier filter
Output part of the circuit through a certain feedback to the control circuit to control the PWM duty cycle, in order to achieve the purpose of stable output
AC power input when the general need to pass through the coil of a class of things, filter out the interference on the power grid, but also filter out the power supply to the grid interference;
In the same power, the higher the switching frequency, the smaller the size of the switching transformer, but the higher the requirement of the switch tube;
The secondary can have a plurality of windings or a winding with a plurality of taps to obtain the required output;
Generally should also add some protection circuit, such as no-load, short circuit protection, or may burn the switch power supply.
Mainly used in industrial and household appliances, such as TV sets, computers, etc.