| 摘要: |
| 设计了一种基于集成开关电源控制芯片DPA426R的高频DC／DC变换器，输出5 V／14 A。电路采用单端正激拓扑结构，反馈环路为电压控制模式。针对开关变换器的主要功能模块电路进行了设计和工作原理分析。为了提高开关电源的功率密度，初级控制电路的设计基于高集成度的电源管理芯片DPA426R，输出整流电路采用自驱动同步整流结构，应用LCD无损复位电路对高频变压器进行磁通复位，并利用DPA426R的内部集成电路实现了输入过压／欠压保护、限流保护、开环故障保护、热关断保护等功能。实验结果表明，设计的开关变换器输出电压精度高，纹波小，效率最高达到88 %，适用于低压大电流的负载设备。 |
| 关键词: 开关电源 同步整流 单端正激 低压大电流 无损复位 DC／ＤＣ变换器 设计 |
| DOI： |
| 分类号: |
| 基金项目:重庆市自然科学基金资助项目（2008BB2314） |
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| Low-voltage high-current DC-DC converter based on DPA426R |
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WANG Bin
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College of Automation，Chongqing University，Chongqing 400030，China
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| Abstract: |
| A 5V／14A high-frequency DC-DC converter is designed based on IC DPA426R，which adopts the single-ended forward topology and voltage control mode. The circuit design and operating principle of its main functional modules are analyzed. Its primary control circuit is designed based on IC DPA426R to improve its power density，the self-driven synchronous rectifier is adopted in its output circuit，the LCD lossless reset circuit is applied to reset the flux of high-frequency transformer，and the built-in integrated circuits of DPA426R are used to realize the protective functions：line over／under-voltage，overload，open-loop fault and thermal shutdown. Experimental results show that the output voltage of the designed converter has high precision，small ripple and up to 88% efficiency，suitable for low-voltage high-current load devices. |
| Key words: switching power supply synchronous rectification single-ended forward low-voltage high-current lossless reset DC-DC converters design |
