发明授权
- 专利标题: Zero voltage switching flyback converter for primary switch turn-off transitions
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申请号: US15334170申请日: 2016-10-25
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公开(公告)号: US09899931B1公开(公告)日: 2018-02-20
- 发明人: Kuang Ming Chang , Lin Chen , Qihong Huang
- 申请人: Alpha and Omega Semiconductor Incorporated
- 申请人地址: US CA Sunnyvale
- 专利权人: Alpha and Omega Semiconductor Incorporated
- 当前专利权人: Alpha and Omega Semiconductor Incorporated
- 当前专利权人地址: US CA Sunnyvale
- 代理机构: Innovation Counsel LLP
- 主分类号: H02M3/335
- IPC分类号: H02M3/335 ; H02M1/08 ; H02M1/44 ; H02M1/32 ; H02M1/00
摘要:
A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.
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IPC分类: