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公开(公告)号：US20200067305A1
公开(公告)日：2020-02-27
申请号：US16113655
申请日：2018-08-27
Applicant: CISCO TECHNOLOGY, INC.
Inventor： Xiqun Zhu , Sung Kee Baek
Abstract: In one embodiment, a hot swap inrush current limiter circuit includes a pair of paths connecting an input and a load, a first capacitor connected in series with a switch between the paths, a first resistor connected to one of the paths and to a junction between the switch and the first capacitor, a second capacitor connected in series with a second resistor between the paths, with a gate of the switch connected to a junction between the second capacitor and the second resistor, a first diode connected in parallel with the second capacitor, and a second diode connected in parallel with the second resistor to allow for discharge of the second capacitor when input power is off. A method is also disclosed herein.
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公开(公告)号：US20200041579A1
公开(公告)日：2020-02-06
申请号：US16600361
申请日：2019-10-11
Applicant: Cisco Technology, Inc.
Inventor： Xiqun Zhu , Sung Kee Baek , Robert Gregory Twiss
IPC: G01R31/42 , G01R31/02 , G01R19/165 , H02J3/00 , H02J13/00
Abstract: To reduce the rate at which a false alternating current (“AC”) loss alarming signal is generated, but at the same time detect an actual AC loss situation in a timely manner, the disclosed method describes an AC line power loss detection and active verification method. If the AC line input voltage dips momentarily lower than a standard sine wave amplitude, the AC line may not be considered lost as long as it still has energy to drive a load. The method inserts a momentary load across the AC line and compares the AC line voltage before and after the extra load is applied. If the AC power is present, this extra loading will increase the AC loading current momentarily, but will not affect the AC line voltage. However, if the AC power is lost, such loading will lower the AC line voltage, indicating a loss of power.
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公开(公告)号：US11777394B1
公开(公告)日：2023-10-03
申请号：US17724985
申请日：2022-04-20
Applicant: Cisco Technology, Inc.
Inventor： Xiqun Zhu , Sung Kee Baek , Joel Goergen , Doug Paul Arduini , Ruqi Li
IPC: H02M1/00
CPC classification number: H02M1/0048 , H02M1/0043
Abstract: A control method improves the efficiency profile of a power supply across a wide range of output loading. The method includes obtaining a measure of output power for a power supply, which includes one or more output modules and an auxiliary power supply. The method determines whether a maximum power rating of the auxiliary power supply is sufficient to provide the measure of output power. Responsive to a determination that the maximum power rating of the auxiliary power supply is sufficient to provide the measure of output power, the controller of the power supply directs the auxiliary power supply to provide the output power.
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Patent Agency Ranking
公开(公告)号：US11682904B2
公开(公告)日：2023-06-20
申请号：US17484847
申请日：2021-09-24
Applicant: Cisco Technology, Inc.
Inventor： Xiqun Zhu , Sung Kee Baek , Robert Gregory Twiss
Abstract: A method comprises, at a power balancing circuit for three-phase AC power: feeding three power phases to respective loads; measuring power drain on the three power phases by the respective loads; based on measuring, detecting an unbalanced power drain across the three power phases due to a relatively light power drain on one or more lightly loaded power phases and a relatively high power drain on one or more heavily loaded power phases; computing an amount of power to be drained from the one or more lightly loaded power phases and to be fed to the one or more heavily loaded power phases to balance the power drain across the three power phases; and transferring the amount of power from the one or more lightly loaded power phases to the one or more heavily loaded power phases to balance the power drain across the three power phases.
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公开(公告)号：US11522442B1
公开(公告)日：2022-12-06
申请号：US17444089
申请日：2021-07-30
Applicant: Cisco Technology, Inc.
Inventor： Ruqi Li , Sung K. Baek , Douglas P. Arduini , Xiqun Zhu
Abstract: Embodiments herein describe control circuitry for operating a PFC converter in an AC-DC power supply under light loading conditions. The embodiments herein improve the power factor by identifying an optimized phase offset (γ) between an AC reference voltage and an AC reference current used to control the PFC converter. In one embodiment, the control circuitry iteratively changes the phase offset between the reference voltage and current and measures its impact on the power factor. The control circuitry then selects the phase offset that results in the best power factor to use when operating the PFC converter under light loading conditions.
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公开(公告)号：US11342762B2
公开(公告)日：2022-05-24
申请号：US17097611
申请日：2020-11-13
Applicant: Cisco Technology, Inc.
Inventor： Xiqun Zhu , Sung Kee Baek , Wingo Cheong , Steven Anthony Granzella , Joel Goergen , Charles Calvin Byers
IPC: H02J7/00
Abstract: In one embodiment, a battery backup unit (BBU) cut-off and recharge circuit includes: a first transistor, a power entry connection connected to a main power supply, where power from the power entry connection flows to application circuits for an electronic device, and the first transistor is positioned between a BBU and the power entry connection, and a microcontroller, where the microcontroller is operative to: detect a loss of power from the main power supply, turn on the first transistor to enable the BBU to discharge through the power entry connection to application circuits, detect a status of charge (SOC) for the BBU, and upon detecting that the SOC is under a predefined threshold, set the BBU cut-off and recharge circuit to a lockdown state by turning off the first transistor.
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公开(公告)号：US10971923B2
公开(公告)日：2021-04-06
申请号：US16113655
申请日：2018-08-27
Applicant: CISCO TECHNOLOGY, INC.
Inventor： Xiqun Zhu , Sung Kee Baek
Abstract: In one embodiment, a hot swap inrush current limiter circuit includes a pair of paths connecting an input and a load, a first capacitor connected in series with a switch between the paths, a first resistor connected to one of the paths and to a junction between the switch and the first capacitor, a second capacitor connected in series with a second resistor between the paths, with a gate of the switch connected to a junction between the second capacitor and the second resistor, a first diode connected in parallel with the second capacitor, and a second diode connected in parallel with the second resistor to allow for discharge of the second capacitor when input power is off. A method is also disclosed herein.
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公开(公告)号：US20190222035A1
公开(公告)日：2019-07-18
申请号：US15871999
申请日：2018-01-16
Applicant: Cisco Technology, Inc.
Inventor： Xiqun Zhu , Sung Kee Baek , Wingo Cheong , Steven Anthony Granzella , Joel Goergen , Charles Calvin Byers
IPC: H02J7/00
CPC classification number: H02J7/0021
Abstract: In one embodiment, a battery backup unit (BBU) cut-off and recharge circuit includes: a first transistor, a power entry connection connected to a main power supply, where power from the power entry connection flows to application circuits for an electronic device, and the first transistor is positioned between a BBU and the power entry connection, and a microcontroller, where the microcontroller is operative to: detect a loss of power from the main power supply, turn on the first transistor to enable the BBU to discharge through the power entry connection to application circuits, detect a status of charge (SOC) for the BBU, and upon detecting that the SOC is under a predefined threshold, set the BBU cut-off and recharge circuit to a lockdown state by turning off the first transistor.
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