公开(公告)号：US12136885B2

公开(公告)日：2024-11-05

申请号：US18436023

申请日：2024-02-08

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00 ,  H02M1/08

Abstract: A resonant half-bridge flyback power converter includes: a first transistor and a second transistor which form a half-bridge circuit; a transformer and a resonant capacitor connected in series and coupled to the half-bridge circuit; and a switching control circuit configured to generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer to generate an output voltage. The first driving signal is configured to magnetize the transformer. The second driving signal includes at most one pulse between two consecutive pulses of the first driving signal. The switching control circuit generates a skipping cycle period when an output power is lower than a predetermined threshold. A resonant pulse of the second driving signal is skipped during the skipping cycle period. The skipping cycle period is increased in response to the decrease of the output power.

公开(公告)号：US11962247B2

公开(公告)日：2024-04-16

申请号：US17673062

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/33 ,  H02M1/00 ,  H02M1/08 ,  H02M3/335

CPC classification number: H02M3/33571 ,  H02M1/0058 ,  H02M1/083 ,  H02M3/33592 ,  H02M1/0009

Abstract: A resonant half-bridge flyback power converter includes: a first transistor and a second transistor which form a half-bridge circuit; a transformer and a resonant capacitor connected in series and coupled to the half-bridge circuit; and a switching control circuit configured to generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer to generate an output voltage. The first driving signal is configured to magnetize the transformer. The second driving signal includes at most one pulse between two consecutive pulses of the first driving signal. The switching control circuit generates a skipping cycle period when an output power is lower than a predetermined threshold. A resonant pulse of the second driving signal is skipped during the skipping cycle period. The skipping cycle period is increased in response to the decrease of the output power.

公开(公告)号：US12184183B2

公开(公告)日：2024-12-31

申请号：US17673158

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00 ,  H02M1/08

Abstract: A flyback power converter includes: a first transistor switching a transformer for generating a primary switching current and an output voltage; and a second transistor generating a circulated current to achieve ZVS (zero voltage switching) of the first transistor; wherein the flyback power converter actively forces at least one switching cycle to be operated in a DCM (discontinuous conduction mode) operation when the primary switching current is determined to have been operating in a non-DCM operation for a predetermined number of switching cycles. The flyback power converter generates a demagnetized signal which emulates the demagnetized time of the transformer for controlling the second transistor during the non-DCM operation. The flyback power converter calibrates the demagnetized signal according to the demagnetized time during the actively fored DCM operation.

公开(公告)号：US20220271674A1

公开(公告)日：2022-08-25

申请号：US17673062

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00

Abstract: A resonant half-bridge flyback power converter includes: a first transistor and a second transistor which form a half-bridge circuit; a transformer and a resonant capacitor connected in series and coupled to the half-bridge circuit; and a switching control circuit configured to generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer to generate an output voltage. The first driving signal is configured to magnetize the transformer. The second driving signal includes at most one pulse between two consecutive pulses of the first driving signal. The switching control circuit generates a skipping cycle period when an output power is lower than a predetermined threshold. A resonant pulse of the second driving signal is skipped during the skipping cycle period. The skipping cycle period is increased in response to the decrease of the output power.

公开(公告)号：US20240223093A1

公开(公告)日：2024-07-04

申请号：US18436023

申请日：2024-02-08

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00 ,  H02M1/08

CPC classification number: H02M3/33571 ,  H02M1/0058 ,  H02M1/083 ,  H02M3/33592 ,  H02M1/0009

Abstract: A resonant half-bridge flyback power converter includes: a first transistor and a second transistor which form a half-bridge circuit; a transformer and a resonant capacitor connected in series and coupled to the half-bridge circuit; and a switching control circuit configured to generate a first driving signal and a second driving signal to control the first transistor and the second transistor respectively for switching the transformer to generate an output voltage. The first driving signal is configured to magnetize the transformer. The second driving signal includes at most one pulse between two consecutive pulses of the first driving signal. The switching control circuit generates a skipping cycle period when an output power is lower than a predetermined threshold. A resonant pulse of the second driving signal is skipped during the skipping cycle period. The skipping cycle period is increased in response to the decrease of the output power.

公开(公告)号：US12009753B2

公开(公告)日：2024-06-11

申请号：US17673298

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00 ,  H02M1/08

CPC classification number: H02M3/33571 ,  H02M1/0058 ,  H02M1/083 ,  H02M3/33592 ,  H02M1/0009

Abstract: A half-bridge flyback power converter: a first transistor, a second transistor and a third transistor which form a half-bridge circuit. The first transistor is turned on for generating a negative circulated current for achieving zero voltage switching of the second transistor. The second transistor is turned on for magnetizing a transformer. The third transistor is turned on during a demagnetized time period to generate an output voltage. The physical size of the first transistor is smaller than physical size of the third transistor.

公开(公告)号：US20220271676A1

公开(公告)日：2022-08-25

申请号：US17673298

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00

Abstract: A half-bridge flyback power converter: a first transistor, a second transistor and a third transistor which form a half-bridge circuit. The first transistor is turned on for generating a negative circulated current for achieving zero voltage switching of the second transistor. The second transistor is turned on for magnetizing a transformer. The third transistor is turned on during a demagnetized time period to generate an output voltage. The physical size of the first transistor is smaller than physical size of the third transistor.

公开(公告)号：US20220271675A1

公开(公告)日：2022-08-25

申请号：US17673158

申请日：2022-02-16

Applicant: Richtek Technology Corporation

Inventor： Ta-Yung Yang ,  Ying-Chieh Su ,  Yu-Chang Chen

IPC: H02M3/335 ,  H02M1/00 ,  H02M1/08

Abstract: A flyback power converter includes: a first transistor switching a transformer for generating a primary switching current and an output voltage; and a second transistor generating a circulated current to achieve ZVS (zero voltage switching) of the first transistor; wherein the flyback power converter actively forces at least one switching cycle to be operated in a DCM (discontinuous conduction mode) operation when the primary switching current is determined to have been operating in a non-DCM operation for a predetermined number of switching cycles. The flyback power converter generates a demagnetized signal which emulates the demagnetized time of the transformer for controlling the second transistor during the non-DCM operation. The flyback power converter calibrates the demagnetized signal according to the demagnetized time during the actively fored DCM operation.