Working principle of small switching power supply
Switching power supply works is:
1. AC power input rectified filter into a DC;
2. Through the high-frequency PWM (pulse width modulation) signal control switch, the DC added to the switch transformer primary;
3. Switching transformer secondary induction of high frequency voltage, the rectifier filter supply load;
4. The output part of the circuit through a certain feedback to the control circuit, control PWM duty cycle, in order to achieve the purpose of stable output.
AC power input generally through the Euler circle of a class of things, filter out the interference on the grid, but also filter out the power of the power grid interference;
In the same power, the higher the switching frequency, the smaller the size of the switching transformer, but the higher the requirements of the switch;
The transformer transformer secondary can have multiple windings or a winding with multiple taps to get the desired output;
Generally should also increase the number of protection circuits, such as no-load, short circuit protection, or may burn the switching power supply.
Mainly for industrial and some household appliances, such as televisions, computers and so on.
Switching power supply is used to control the switch through the circuit for high-speed pass and cut off. The conversion of direct current into high-frequency alternating current is provided to the transformer for transformer, resulting in the required group or groups of voltages! The reason for the high frequency AC is that the high frequency AC is much more efficient than the 50HZ in the transformer transformer circuit. So the switch transformer can be done very small, and the work is not very hot! The The cost is very low. If not 50Hz into high-frequency switching power supply does not make sense
Small switching power supply works is to control the switching transistor through and turn off the time ratio, to maintain a stable output voltage of a power supply, switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. Switching power and linear power compared to the cost of both the output power increases with the growth, but the growth rate of the two different. Linear power costs at an output power point, but higher than the switching power supply, which is called the cost of reversal point.
