最新多路输出单端反激式开关电源设计

多路输出单端反激式开关电源设计

电子设备对电源的要求日益增高，促进了开关电源技术的不断发展。本文介绍了基于美国PI公司生产的单片开关电源芯片TOPSwitch系列设计的多输出的AC/DC开关电源。

设计电路选用TOPSwitch系列芯片的TOP244Y，该芯集成了PWM控制器、MOSFET功率开关管和欠电压、过电压等保护电路，芯片的开关频率为132kHZ，最大占空比为78%。设计电路的开关电源输出功率为25W时，实现了12V/1.2A,5V/2A和

30V/20mA三路直流电压输出，效率为80%以上。

论文介绍了开关电源相关内容，反激式开关电源的原理和应用技术，为电路设计提供了理论指导，并且提出了反激式开关电源的设计规划。仔细分析反激式开关电源之后，选择了电路所需的元器件的型号和参数，最终完成电路图的设计。最后使用芯片专属的优化设计软件PI Expert对反激式开关电源进行优化设计。设计结果为，优化设计之前电源的效率为78%左右，实际输出直流电压的最大误差为3.5%，经过优化之后最大误差降为0.36%，且电源效率提高到90%以上。反激式开关电源的直流输出回路接有EMI 滤波器，有效地降低了开关电源的输出纹波。

关键词：开关电源；反激式；多路输出；TOPSwitch-GX

Title Design of Multi-output Single-ended Fly-back Converter

Abstract

Electronic devices demanded on power increasingly higher to promote the continuous development of converter technology. This paper introduced the small power multi output

AC/DC converter design based on the chip of TOP-Switch produced by American company Power Integrations.

The converter design used TOP244Y as switching chip, which had PWM control circuit and power MOSFET, the chip’s switching frequency was 132 kHz, the maximum duty cycle was 78%. When the output power was 25W, switching power served three DC outputs

12V/1.2A, 5V/2A and 30V/20mA and the efficiency was 80%.

The paper introduced some related content about the converter and the theory and technology of fly-back converter, to provide a theoretical guidance for circuit design. And then the paper proposed a fly-back converter supply design plan. And next, I designed a fly-back switching power circuit, and selected circuit’s components and parameters. Finally using PI Expert to optimize this fly-back switching power, I received some result about the designed circuit. Before the optimization, the efficiency was 78%, and the actual outp ut DC voltage’s maximum error was 3.5%, after the optimization, maximum error decreased to 0.36%, and the efficiency increased to 90%. And the fly-back switching power circuit had output EMI filter, decreased output ripple of switching power effectively.

Keywords: Switching power supply；Fly-back；Multiple output；TOPSwitch-GX

目次

1 绪论 (1)

1.1 开关电源研究的目的和意义 (1)

1.2 开关电源研究现状及发展前景 (1)

1.3 开关电源的新技术新理论 (2)

2 反激式开关电源的原理 (5)

2.1 反激式开关电源介绍 (5)

2.2开关电源的芯片简介 (6)

2.3 PWM反馈控制方式 (7)

2.4反激式开关电源的设计规划 (8)

3反激式开关电源的电路设计 (10)

3.1开关电源的EMI设计 (10)

3.2 整流电路设计 (12)

3.3高频变压器的设计 (14)

3.4 反馈电路设计 (17)

3.5 多路输出电压电路设计 (20)

3.6 保护电路设计 (21)

3.7 反激式开关电源的电路图 (22)

4 反激式开关电源电路的优化设计 (24)

4.1 PI Expert辅助设计软件介绍 (24)

4.2直流输出优化设计 (24)

4.3高频变压器的优化设计 (25)

4.4 反激式开关电源优化设计 (26)

结论 (28)