Classification and basic principles of switching power supplies
The field of switch mode power supply technology is developing related power electronic devices while developing switch frequency conversion technology. The two mutually promote and drive the development of switch mode power supplies towards the direction of light, small, thin, low-noise, high reliability, and anti-interference with an annual growth rate exceeding two digits. Switching power supplies can be divided into two categories: AC/DC and DC/DC. DC/DC converters have now been modularized, and the design technology and production process have been mature and standardized both domestically and internationally, and have been recognized by users. However, the modularity of AC/DC, due to its own characteristics, encounters complex technical and process manufacturing problems in the process of modularization. The following elaborates on the structure and characteristics of two types of switching power supplies.
DC/DC conversion
DC/DC conversion is the process of converting a fixed DC voltage into a variable DC voltage, also known as DC chopping. There are two working modes of a chopper: one is the pulse width modulation mode, where Ts remains unchanged and ton is changed (universal), and the other is the frequency modulation mode, where ton remains unchanged and Ts is changed (prone to interference).
Basic principles of switch mode power supply
1. The AC power input is rectified and filtered into DC;
2. Control the switching transistor through high-frequency PWM (pulse width modulation) signal and apply the DC to the primary of the switching transformer;
3. The secondary of the switching transformer induces high-frequency voltage, which is rectified and filtered to supply the load;
4. The output part is fed back to the control circuit through a certain circuit to control the PWM duty cycle, in order to achieve stable output.
