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公开(公告)号：US11374489B2
公开(公告)日：2022-06-28
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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公开(公告)号：US11689098B2
公开(公告)日：2023-06-27
申请号：US17497233
申请日：2021-10-08
Applicant: GaN Systems Inc.
Inventor： Xuechao Liu , Di Chen , Yajie Qiu
CPC classification number: H02M1/4233 , H02M1/4241 , H02M3/33569 , H02M7/4815 , H02M3/01 , H02M7/02 , H02M7/04
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：US11431261B2
公开(公告)日：2022-08-30
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：US11545889B2
公开(公告)日：2023-01-03
申请号：US17536542
申请日：2021-11-29
Applicant: GaN Systems Inc.
Inventor： Yajie Qiu , Larry Spaziani
IPC: H02M1/38
Abstract: Disclosed is a method for deadtime optimization in a half-bridge switch or full-bridge switch wherein high-side and low-side switches comprise GaN transistors; a circuit for implementing the method; and a power switching system comprising a GaN half-bridge or a GaN full-bridge and a deadtime optimization system. The circuit comprises a drain current bump filter for generating a current charge output; and circuit elements for comparing the current charge output to a reference current charge Coss and generating a deadtime adjust signal. The deadtime adjust signal may be used to adjust deadtime to reduce or minimize deadtime, and deadtime losses, while avoiding cross-conduction.
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