Switching power supply schematic diagram switching power supply working principle introduction

With the continuous development of China's electronic power technology, the power switches used in homes or other places have achieved a major breakthrough in physical development. At present, switching power supply is widely used in all electronic and electrical equipment, and it is the most indispensable power supply method in the current electronic information industry. What about switching power supply schematic, is how it happened? Interested friends, you can explore and investigate together small series Oh! Let decoration home network Xiaobian to tell you about it.

As the name suggests, Switching Power Supplies use electronic switching devices (such as transistors, FETs, thyristors, etc.), through the control circuit, so that the electronic switching device is constantly "on" and "off", let the electronic switch The device modulates the input voltage to achieve DC/AC, DC/DC voltage conversion, and adjustable output voltage and auto-regulation.

The switching power supply is generally composed of a pulse width modulation (PWM) control IC and a MOSFET. Compared with Linear Power Supplies, switching Power Supplies increase in cost as output power increases, but the growth rates vary. The linear power supply cost is higher than the switching power supply at a certain output power point, which is called the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating. This cost reversal point is increasingly moving to the low output power end, which provides a broad space for development of switching power supplies.

Second, the working principle of switching power supply - structure

The switching power supply is roughly composed of a main circuit, a switching power supply control circuit, a detection circuit, and an auxiliary power supply.

1, the main circuit

Inrush current limiting: Limits the inrush current on the input side of the power supply.

Input filter: Its function is to filter the clutter in the grid and to prevent the clutter generated by the machine from feeding back to the grid.

Rectification and filtering: directly rectify the grid AC power to a smoother DC.

Inverter: The rectified DC power is changed to high frequency AC, which is the core part of the high frequency switching power supply.

Output rectification and filtering: Provides a stable and reliable DC power supply according to the load requirements.

2, the control circuit

On the one hand, sampling from the output, comparing with the set value, then controlling the inverter, changing its pulse width or pulse frequency to stabilize the output, on the other hand, according to the data provided by the test circuit, the protection circuit provides identification and provides The control circuit performs various protection measures on the power supply.

3, detection circuit

Provides various parameters and various meter data in operation in the protection circuit.

4, auxiliary power supply

Software (remote) startup of the power supply, power supply for protection circuits and control circuits (chips such as PWM).

Third, the working principle of switching power supply - classification

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

Switching power supply can be divided into two major categories: AC/DC and DC/DC. The DC/DC converter has been modularized, and the design technology and production process have been matured and standardized at home and abroad. The modularization of AC/DC is due to Its own characteristics make it difficult to encounter technical and process manufacturing problems in the process of modularization.

The working principle of the switching power supply introduced by Xiaobian may not be well understood by everyone. If you want to know more about the schematic diagram of the switching power supply, please continue to pay attention to the decoration home network.

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