Switching Power Supply Basic Components
The working process of a switching power supply is fairly easy to understand and has three distinct features:
Switching: the power electronics operate in a switching state rather than a linear state.
High frequency: the power electronics operate at a high frequency rather than at a low frequency close to the industrial frequency.
DC: the switching power supply outputs DC instead of AC, and can also output high-frequency AC such as an electronic transformer.
Switching power supply basic components
1,Main circuit
Inrush current limiting: Limit the inrush current on the input side at the moment of power on.
Input filter: its role is to filter the presence of grid noise and impede the machine generated by the noise feedback back to the grid.
Rectification and Filtering: Directly rectify the AC power from the grid to a smoother DC power.
Inverting: change the rectified DC into high-frequency AC, which is the core part of high-frequency switching power supply.
Output rectification and filtering: provide stable and reliable DC power supply according to the needs of the load.
2,Control circuit
On the one hand, it takes samples from the output, compares with the set value, and then goes to control the inverter, changes its pulse width or pulse frequency, and makes the output stable, on the other hand, according to the data provided by the test circuit, it is identified by the protection circuit, and provides the control circuit to carry out all kinds of protection measures for the power supply.
3,Test circuit
Provide the protection circuit is running in a variety of parameters and a variety of instrumentation data.
4,Auxiliary power supply
It realises software (remote) start-up of the power supply and supplies power for the protection circuit and control circuit (PWM and other chips).
Switching power supply classification:
People in the field of switching power supply technology is the side of the development of related power electronic devices, while the development of switching inverter technology, the two promote each other to promote the switching power supply to more than double-digit growth rate each year towards the light, small, thin, low noise, high reliability, anti-interference direction of development. Switching power supply can be divided into two categories: AC/DC and DC/DC.
Miniature low power switching power supply
Switching power supply is moving towards mass and miniaturisation. Switching power supply will gradually replace the transformer in the life of all applications, low-power miniature switching power supply applications to be first embodied in the digital display meter, smart meter, mobile phone charger and so on. At this stage, the country is vigorously promoting the construction of smart grid, the requirements of the power meter has increased significantly, switching power supply will gradually replace the transformer in the power meter above the application.
Inverting series switching power supply
The difference between inverting series switching power supply and general series switching power supply is that the output voltage of this inverting series switching power supply is negative voltage, which is exactly opposite to the positive voltage output of general series switching power supply; and because the energy storage inductor L only outputs the current to the load when the switch K is turned off, therefore, under the same conditions, the output current of inverting series switching power supply is twice as small as that of series switching power supply. The current is twice as small as that of the series switching power supply under the same conditions.
