​The basic types of switching power supply

As the name suggests, switching power supply is the use of electronic switching devices (such as transistors, field-effect tubes, silicon thyristors, etc.), through the control circuit, so that the electronic switching devices are constantly "on" and "off", so that the electronic switching devices on the input voltage for pulse modulation, to achieve DC/AC, DC/DC voltage conversion, as well as adjustable output voltage and automatic voltage regulation. Below we will introduce the basic types of switching power supplies.

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Self-excited and other-excited switching power supplies

Pulse width modulated and pulse frequency modulated switching power supplies

Typical operation of switching tubes

Self-excited and other-excited switching power supplies

According to the excitation method of switching devices, they can be divided into self-excited and other-excited switching power supplies. The self-excited switching power supply does not require a dedicated oscillation circuit, using the switching regulator tube as the oscillation tube, and only needs to set up a positive feedback circuit to make the circuit start working, so the circuit is relatively simple. In contrast, the other-excited switching power supply requires a dedicated oscillator and start-up circuit, and the circuit structure is more complex.

Pulse width modulated and pulse frequency modulated switching power supplies

The output of the switching power supply is related to the on-time of the switching tube, which is determined by the duty cycle of the switching pulses. Pulse width control switching power supply voltage regulator circuit in the process of changing the width of the switching pulse to stabilize the output voltage, the operating frequency of the switching tube does not change. Pulse frequency control switching power supply in the process of voltage regulation control, changing the duty cycle of the switching pulse at the same time, the operating frequency of the switching tube also changes, so-called the frequency modulation - wide regulator.

Pulse width modulation and pulse frequency modulation of the two control methods also have something in common: First, they both use the time ratio control principle of voltage regulation, to regulate the pulse duty cycle. Although the use of different ways, the control objectives are the same. Second, when the load changes from light to heavy, or the input voltage changes from high to low, respectively, the output voltage is kept stable by increasing the pulse width and increasing the frequency.

The typical operation mode of switching tube

According to the connection and operation of the switching tube classification, the switching regulator power supply can be divided into four types: single-ended, push-pull, half-bridge, and full-bridge. The single-ended type uses only one switching transistor, the push-pull or half-bridge type uses two switching transistors, and the full-bridge type uses four switching transistors. At present, color TVs, monitors, and fax machines, and other switching power supplies often use the single-ended type, while microcomputer switching power supplies are used in the half-bridge type.

With people entering the 21st century, electrical equipment has entered many people's homes, but switching power supplies has become an indispensable application material in people's lives. The switching power supply produced by Zhejiang Ximeng Electronic Technology Co., Ltd. has low energy consumption and high efficiency. It can output voltage in a wide range. In addition, the production cost is relatively low, and the noise generated when working is relatively small. It is a good choice to buy a switching power supply from our company.