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公开(公告)号:US20210111634A1
公开(公告)日:2021-04-15
申请号:US16888923
申请日:2020-06-01
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor: Wei-Hsu Chang , Ta-Yung Yang , Yu-Chang Chen , Chao-Chi Chen , Chuh-Ching Li , Li-Di Lo , Hao-Wen Chung
IPC: H02M3/335 , G01R19/165 , H03M1/12
Abstract: A flyback power converter includes a primary side controller circuit for controlling a primary side switch; and a secondary side controller circuit for generating an SR (Synchronous Rectification) signal to control an SR switch. The SR signal includes an SR pulse and a ZVS (Zero Voltage Switching) pulse. The SR pulse controls the SR switch for synchronous rectification at the secondary side. The secondary side controller circuit samples and holds a voltage at a first end of the SR switch as a first voltage at a timing between the end of the ZVS pulse and the beginning of the SR pulse, and determines a length of the ZVS pulse so as to control the SR switch to be conductive for a ZVS time period, whereby the primary side switch achieves ZVS. The first voltage is proportional to an input voltage.
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公开(公告)号:US11139742B2
公开(公告)日:2021-10-05
申请号:US16879692
申请日:2020-05-20
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor: Wei-Hsu Chang , Ta-Yung Yang , Yu-Chang Chen , Chao-Chi Chen , Chuh-Ching Li , Li-Di Lo , Hao-Wen Chung
Abstract: A switching controller circuit for controlling a flyback power converter includes: a power transformer, a primary side controller circuit and a secondary side controller circuit. The power transformer is coupled between the input voltage and the output voltage in an isolated manner. The primary side controller circuit controls a primary side switch of the flyback power converter. The secondary side controller circuit generates a synchronous rectification (SR) signal, to control an SR switch of the flyback power converter. The SR signal includes an SR pulse and a soft switching (SS) pulse. The SR pulse controls the SR switch to be ON for an SR period, to achieve synchronous rectification at the secondary side. The SS pulse controls the SR switch to be ON for an SS period, to achieve soft switching of the primary side switch.
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公开(公告)号:US11018597B2
公开(公告)日:2021-05-25
申请号:US16783224
申请日:2020-02-06
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor: Ta-Yung Yang , Chao-Chi Chen , Chen-Hung Tsai , Chuh-Ching Li
Abstract: A flyback power converter circuit includes: a transformer; a primary side switch, for controlling a primary winding to convert an input voltage to an output voltage and an internal voltage; a primary side control circuit, which is powered by the internal voltage; the primary side control circuit generates a switching signal according to a feedback signal, to operate the primary side switch; a secondary side control circuit, which generates the feedback signal according the output voltage; and a dummy load circuit, which is coupled to the output voltage, wherein when the output voltage drops to or is lower than a predetermined threshold, the dummy load circuit generates a dummy load current, to determine the feedback signal, so that the internal voltage is not undesirably low. When the output voltage exceeds the predetermined threshold, the dummy load circuit adjusts the dummy load current to zero current.
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公开(公告)号:US11139744B2
公开(公告)日:2021-10-05
申请号:US16888923
申请日:2020-06-01
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor: Wei-Hsu Chang , Ta-Yung Yang , Yu-Chang Chen , Chao-Chi Chen , Chuh-Ching Li , Li-Di Lo , Hao-Wen Chung
IPC: H02M3/335 , G01R19/165 , H03M1/12 , H02M1/00
Abstract: A flyback power converter includes a primary side controller circuit for controlling a primary side switch; and a secondary side controller circuit for generating an SR (Synchronous Rectification) signal to control an SR switch. The SR signal includes an SR pulse and a ZVS (Zero Voltage Switching) pulse. The SR pulse controls the SR switch for synchronous rectification at the secondary side. The secondary side controller circuit samples and holds a voltage at a first end of the SR switch as a first voltage at a timing between the end of the ZVS pulse and the beginning of the SR pulse, and determines a length of the ZVS pulse so as to control the SR switch to be conductive for a ZVS time period, whereby the primary side switch achieves ZVS. The first voltage is proportional to an input voltage.
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公开(公告)号:US20210126543A1
公开(公告)日:2021-04-29
申请号:US16879692
申请日:2020-05-20
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor: Wei-Hsu Chang , Ta-Yung Yang , Yu-Chang Chen , Chao-Chi Chen , Chuh-Ching Li , Li-Di Lo , Hao-Wen Chung
Abstract: A switching controller circuit for controlling a flyback power converter includes: a power transformer, a primary side controller circuit and a secondary side controller circuit. The power transformer is coupled between the input voltage and the output voltage in an isolated manner. The primary side controller circuit controls a primary side switch of the flyback power converter. The secondary side controller circuit generates a synchronous rectification (SR) signal, to control an SR switch of the flyback power converter. The SR signal includes an SR pulse and a soft switching (SS) pulse. The SR pulse controls the SR switch to be ON for an SR period, to achieve synchronous rectification at the secondary side. The SS pulse controls the SR switch to be ON for an SS period, to achieve soft switching of the primary side switch.
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