Brief introduction of switching power supply principle and design scheme

With the wide application of switching power supplies in computers, communications, aerospace, instrumentation and household appliances, the demand for them is increasing, and higher efficiency, volume, weight and reliability of the power supply have been proposed. Claim. Switching power supplies have gradually replaced low-efficiency and heavy linear power supplies in many aspects with their advantages of high efficiency, small size, and light weight. The development of power electronics technology, especially the rapid development of high-power devices IGBT and MOSFET, has increased the operating frequency of the switching power supply to a very high level, making it highly stable and cost-effective.

Introduction of switching power supply:

Switching power supply (English: SwitchingModePowerSupply), also known as switching power supply, switching converter, is a high-frequency electric energy conversion device. Its function is to convert a level of voltage into the voltage or current required by the user through different forms of architecture.

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2. Design of switching power supply based on 51 single chip computer numerical control Buck

Features:

Hardware system composition: STC12C5A60S2 single-chip microcomputer + IR2104 driver + Buck circuit + 1602 LCD + button;

LCD display: input voltage, preset output voltage, output current, working status (overcurrent, input undervoltage, input overvoltage)

Default output mode: constant voltage output;

Output voltage range: 0-input voltage*90%, if the actual input voltage is 40V, the maximum output voltage is 36V

Working mode: Buck step-down;

Rectification mode: non-synchronous rectification;

Switching frequency: 43Khz;

Maximum conversion efficiency: 89%;

Maximum output current: 1.0A;

Over-current protection: over-current protection value 1.2A, cut off when over-current;

Ripple range: ≤200mV;

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3. High-power switching power supply circuit scheme

Mature program. The instantaneous power can be reached, more than 150W. Work in the small power range for a long time. Around 80W.

It is suitable for a short time and the power is large. The general working power is relatively small.

Output two 15V1A and one 60V.

Can input 220V. If 110V is input, the starting resistance can be changed. And a same resistor will do.

The scheme is verified, but the filtering is separated from the power supply.

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4. Circuit design of DC-DC switching power supply based on 51 single chip microcomputer

This document is the circuit design of the DC-DC switching power supply based on 51 single-chip microcomputer. There is a complete design circuit schematic diagram, which can be directly imitated by the drawing board, and small partners in need can download it directly.

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5. Isolated low-cost switching power supply circuit scheme

LP2702A is a high-efficiency and high-precision non-isolated step-down switching power supply constant voltage control driver chip. It is suitable for the non-isolated Buck topology structure of 85VAC~265VAC full-range input voltage, especially suitable for the driving of power supplies such as small household appliances and white goods. LP2702A integrates a 500V power switch and adopts a unique constant voltage control mode. The system can work in inductor current discontinuous mode and inductor current continuous mode. The scheme design is flexible, the peripheral application is simple, and the lower system cost can be used for greater output power.

JW3510 is a micro-power isolated flyback converter, through sampling and isolating the output voltage waveform directly from the primary side flyback, without the need for a third winding or an optical isolator for adjustment. The output voltage can be programmed with an external resistor. In addition, internal compensation and soft start further reduce the external component count. JW3510 operates from 3.0V to 42V within the input voltage range, and outputs a stable voltage of 5V.

The switching power supply is based on LP2702A's low-cost non-isolated step-down AC 220V, filtered to obtain an unstable voltage of about 12V. Then through the JW3510 isolation circuit to convert the stable 5V for subsequent circuit use, this module is safe and reliable, with short-circuit protection, over-current protection, when the load is too large, the power supply will appear intermittently on and off abnormal conditions. It also has the characteristics of low cost and small size.

Original title: Pay tribute to the classics, 10 switching power supply solutions tell you what is the evergreen tree in the electronics industry