[{"title":"( 2 个子文件 704KB ) 单周期控制无桥PFC电路设计与参数计算(2000W,85~264V输入,400V输出)","children":[{"title":"核心实践.docx <span style='color:#111;'> 37.92KB </span>","children":null,"spread":false},{"title":"789448005575.pdf <span style='color:#111;'> 117.07KB </span>","children":null,"spread":false}],"spread":true}]