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公开(公告)号：US20230111992A1
公开(公告)日：2023-04-13
申请号：US17497233
申请日：2021-10-08
Applicant: GaN Systems Inc.
Inventor： Xuechao LIU , Di CHEN , Yajie QIU
Abstract: An AC/DC Switching Mode Power Supply (SMPS) comprises a PFC stage, an isolated LLC DC/DC converter stage, and a control circuit that provides feedback/control signals to PFC and LLC controllers, to enable a plurality of operating modes, dependent on a sensed peak AC input voltage and required output voltage Vo. The PFC provides a first DC bus voltage Vdc (e.g. 200V) for low line AC input and a second DC bus voltage (e.g. 400V) for high line or universal AC input. A multi-mode LLC converter is operable in a half-bridge mode or a full-bridge mode. For low line AC input, output voltage Vo, and PFC output Vdc, the LLC operates in full-bridge mode; for high line input, output voltage Vo and PFC output 2×Vdc, the LLC operates in half-bridge mode; for universal AC input, output voltage 2×Vo, and PFC output 2×Vdc, the LLC operates in full-bridge mode.
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公开(公告)号：US20230110761A1
公开(公告)日：2023-04-13
申请号：US17942672
申请日：2022-09-12
Applicant: GaN Systems Inc.
Inventor： Yajie QIU , Xuechao LIU
Abstract: An AC input AC/DC Switching Mode Power Supply (SMPS) with Power Factor Correction (PFC) comprises a boost follower circuit (BFC), a hybrid bulk capacitance circuit (HBCC) and driver and control circuitry. The BFC senses the peak AC input voltage and adjusts a PFC output voltage Vdc dependent on the AC input voltage, to improve low line efficiency and reduce losses. The BFC may provide a stepless or step regulation mode to follow the AC input line voltage. The driver and control circuitry coordinates operation of the BFC and HBCC. The driver and control circuitry comprises comparator circuitry, which enables selective connection of bulk capacitors of different voltage ratings, responsive to a sense voltage from the BFC, to meet requirements for ripple voltage and hold-up times for different Vdc. This solution provides a reduction in capacitor height and volume, with associated improvement in the power density of an isolated AC/DC power supply.
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公开(公告)号：US20210234471A1
公开(公告)日：2021-07-29
申请号：US17230390
申请日：2021-04-14
Applicant: GaN Systems Inc.
Inventor： Yajie QIU , Xuechao LIU
Abstract: A bulk capacitor circuit for an AC input AC/DC Switching Mode Power Supply, such as an AC/DC adapter/charger without active power factor correction, is provided, comprising a plurality of bulk capacitors having different voltage ratings, and driver and control circuitry comprising AC input voltage sensing and comparator circuitry, which enables selective connection of one or more of the plurality of bulk capacitors, responsive to a sensed AC input voltage range. A startup circuit provides power to the driver circuit initially, so that the AC input voltage can be determined before power-up and enabling of the DC/DC converter. This solution provides for a reduction in capacitor volume, with associated improvement in the power density of an isolated AC/DC power supply, while the startup circuit ensures that an appropriate bulk capacitance is connected at startup for low line AC input, to maintain the ripple voltage in an appropriate range for reliable operation.
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公开(公告)号：US20210184567A1
公开(公告)日：2021-06-17
申请号：US17070309
申请日：2020-10-14
Applicant: GaN Systems Inc.
Inventor： Yajie QIU , Xuechao LIU
Abstract: A circuit for a multi-voltage input AC/DC charger, such as a Universal AC input AC/DC charger, is provided, comprising a plurality of capacitors having different voltage ratings that are connected in parallel, and a switching circuit comprising input voltage sensing and comparator drive circuitry, to allow for selective connection of one or more of the plurality of capacitors, responsive to a sensed input voltage. Since bulk capacitors occupy a significant proportion of the volume of an AC/DC charger, this solution provides for a reduction in system volume, with associated improvement in the power density of an isolated AC/DC charger.
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