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The structure and principle of switching power supply

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Switching power supply can be seen everywhere for many years and is an indispensable power supply mode for our modern information industry. Switching power supply is a kind of power supply that uses modern power electronics technology to control switching time ratio and maintain stable output voltage. This paper mainly describes the schematic diagram and working mode of switching power supply for your reference.

In a linear regulated power supply. The power transistor is working. In the linear power supply is off or off PWM switching power supply, in the off, off two states, the voltage of the force transistor is small, produce large current, turn off the switching power supply, on the contrary, the voltage is large, the current is particularly small, control the controller of the working principle of the switching power supply

Schematic diagram of switching power supply, the working mode of switching power supply, as the name implies, switching power supply is the use of electronic switching equipment (such as transistors, field effect tube, thyristor, etc.)

Through the control circuit, the electronic switching equipment constantly open and close, so that the electronic switching equipment to the input voltage pulse modulation, realize dc /AC, DC/DC voltage changes, the output voltage can be harmonized automatic stability.

Power transformers generally have three working modes: frequency, pulse width fixed fixed frequency, pulse width variability mode, frequency, pulse width variability mode. The former working mode is mainly used for DC/AC frequency conversion power supply, or DC/DC working voltage conversion; The latter two working modes are mainly used for power switch adjustable voltage regulated power supply. In addition, the output voltage of the power transformer also has three working modes: immediate output voltage method, mean output voltage method, amplitude value output voltage method. Similarly, the former working mode is mostly used for DC /AC inverter or DC/DC voltage conversion; The latter two working modes are mostly used for switching stabilized power supply.

According to the method of connecting power switch components in the power circuit, power transformers can be roughly divided into three categories: series power transformers, parallel power transformers, transformer power transformers and so on. Among them, transformer switching power supply (hereinafter referred to as transformer switching power supply) can be divided into push-pull type, half-bridge type, full bridge type and other transformer excitation and output voltage phase, can be divided into forward excitation, flyback, single excitation, double excitation and other uses。

Switching power supply structure is mainly composed of main circuit, control circuit, detection circuit and auxiliary power supply. The functions of each part are as follows

The main circuit can be divided into impulse current limiting section, input filter section, rectifier and filter section, inverter section, output rectifier and filter section. Among them, the impact current limiting part bears the impact current limiting switch power supply access moment input side; Type filter part to bear filtering noise; The rectifier and filter part undertakes the ac rectifier of the power network for DC power supply; Part of the inverter is responsible for changing the DC power generated by the rectifier into high frequency AC current. The output rectifier and filter part undertake to produce a stable and reliable DC power supply.

The control part assumes the operation of the inverter to make the output smooth and present various safeguards for the power supply circuit.

The inspection power supply circuit is responsible for presenting various main parameters and data information in operation.

Auxiliary switching power supply is used to complete the mobile phone software (remote control) operation of the switching power supply, and power supply system for the normal operation of the power circuit.

Scope of application of power transformer

Power transformer products widely used in mechanical automation of industrial production, military, machinery and equipment, scientific research equipment, LED lighting, industrial automation, communications equipment, electrical equipment, instrumentation equipment, medical equipment, semiconductor refrigeration system of warm, air purification machine, electronics refrigerators, LCD, LED lamps and lanterns, communication equipment, audio-visual products, Security monitoring system, LED light bag, main box, electronic products and instrument equipment and other industries.