Switching power supply schematic diagram switching power supply working principle introduction

With the continuous development of China's electronic power science and technology technology, no matter in the home or other places used by the power switch, have been a larger breakthrough in the substantive development. At present, the switching power supply, almost widely used in all electronic and electrical equipment, is now the most indispensable electronic information industry in a power supply. So about the switching power supply schematic, what is going on? Interested friends, you can come to explore with the editor to explore oh! Let us give you an introduction to it.

One, switching power supply principle of operation - Introduction

As the name suggests, switching power supply is the use of electronic switching devices (such as transistors, field effect tubes, thyristors, etc.), through the control circuit, so that the electronic switching devices constantly "on" and "off". "Off", so that the electronic switching device on the input voltage pulse modulation, so as to realize the DC/AC, DC/DC voltage conversion, as well as the output voltage can be adjusted and automatic voltage regulation.

Switching power supplies are generally composed of pulse width modulation (PWM) control ICs and MOSFETs. Switching power supply and linear power supply compared to the cost of both with the increase in output power and growth, but the rate of growth of the two are different. Linear power supply cost at a certain output power point, but higher than the switching power supply, this point is called the cost reversal point. With the development of power electronics technology and innovation, so that the switching power supply technology is also constantly innovating, this cost reversal point increasingly to the low output power end of the move, which provides a broad space for the development of switching power supply.

Two, switching power supply principle of operation - structure

Switching power supply is roughly by the main circuit, switching power supply control circuit, detection circuit, auxiliary power supply is composed of four major components.

1, the main circuit

Inrush current limiting: Limit the inrush current of the input side at the moment of power on.

Input filter: Its function is to filter the stray waves in the power grid and prevent the stray waves generated by the machine from being fed back to the power grid.

Rectification and filtering: Directly rectify the AC power from the grid into a smoother DC power.

Inverter: Rectified DC power into high-frequency AC power, 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, sampling from the output, compared with the set value, and then go to control the inverter, change its pulse width or pulse frequency, so that the output is stable, on the other hand, according to the data provided by the test circuit, identified by the protection circuit, to provide the control circuit of the power supply to carry out a variety of protective measures.

3, test circuit

Provide protection circuit is running in a variety of parameters and a variety of instrumentation data.

4, auxiliary power supply

To realize the power supply software (remote) start, for the protection circuit and control circuit (PWM and other chips) work power supply.

Three, switching power supply principle of operation - classification

Switching power supply generally has three modes of operation: frequency, pulse width fixed mode, fixed frequency, pulse width variable mode, frequency, pulse width variable mode. The former mode is mostly used for DC/AC inverter power supply, or DC/DC voltage conversion; the latter two modes are mostly used for switching regulator power supply. In addition, the switching power supply output voltage also has three working modes: direct output voltage mode, average output voltage mode, amplitude output voltage mode. Similarly, the former mode of operation is mostly used for DC/AC inverter power supply, or DC/DC voltage conversion; the latter two modes of operation are mostly used for switching regulated power supply.

Switching power supply can be divided into two categories of AC/DC and DC/DC, DC/DC converter has now achieved modularity, and the design technology and production processes at home and abroad have matured and standardized; AC/DC modularity, because of its own characteristics make the process of modularity, encountered a more complex technology and manufacturing process problems.

Small introduction to the working principle of switching power supply, you may not understand very well, if you want to be more specific about the switching power supply schematic diagram, please continue to pay attention.