What is switching power supply? What's the usage? What is the principle?

Operating principle of switching power supply

In the linear power supply, the power transistor is working, and the linear power supply is PWM switching power supply which leads to the closure or disconnection. In the two states of closure and disconnection, when the voltage of the power transistor is relatively small, a large current will be generated. When the switching power supply is closed, it is the reverse. The voltage is large, and the current will be particularly small. The controller that controls the working principle of the switching power supply, It is to better maintain stability, so as to bring safety to people's living environment.
 

Switching power supply working mode

As the name implies, switching power supply uses electronic switching devices (such as transistors, field effect transistors, silicon controlled thyristors, etc.).

Through the control circuit, the electronic switching devices can be continuously "turned on" and "turned off", and the electronic switching devices can pulse modulate the input voltage, so as to realize the DC/AC, DC/DC voltage conversion, and the output voltage can be adjusted and automatically stabilized.

Switching power supply generally has three working modes: fixed frequency and pulse width mode, fixed frequency and variable pulse width mode, and variable frequency and pulse width mode. The former 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 output voltage of switching power supply also has three working modes: direct output voltage mode, average output voltage mode and amplitude output voltage mode.

Similarly, 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.

According to the way switching devices are connected in the circuit, switching power supply can be generally divided into three categories: series switching power supply, parallel switching power supply, transformer switching power supply. Among them, transformer switching power supply (hereinafter referred to as transformer switching power supply) can be further divided into push-pull, half bridge, full bridge and other types; According to the excitation and output voltage phase of the transformer, it can be divided into forward, flyback, single and double excitation, etc; If divided from the purpose, it can also be divided into more categories.