公开(公告)号：US10003187B2

公开(公告)日：2018-06-19

申请号：US15439725

申请日：2017-02-22

Applicant: CISCO TECHNOLOGY, INC.

Inventor： Weizhong Tang ,  Sung Kee Baek ,  Craig Zimmerman

IPC: H02H7/12 ,  H03K17/082

CPC classification number: H02H7/1213 ,  G06F1/26 ,  G06F11/16 ,  G06F11/2015 ,  H03K17/0822 ,  H04M19/08

Abstract: Aspects of the subject technology relate to a system and method for preventing voltage sagging using an Oring-FET in a redundant power supply configuration. Each redundant power supply includes an Oring-FET and a voltage comparator. The voltage comparator receives and compares an input voltage and an output voltage of the Oring-FET during power up. In the event input voltage is less than the output voltage, the Oring-FET is deemed to be operating properly and provides output to a communicatively coupled system bus in response to the input voltage reaching a predetermined voltage threshold level. In the event the input voltage is approximately equal to the output voltage, the voltage comparator assists in preventing inrush current from flowing from the communicatively coupled system bus and prevents voltage sagging on the communicatively coupled system bus when another redundant power supply configuration is providing power to the communicatively coupled system bus.

公开(公告)号：US20180074136A1

公开(公告)日：2018-03-15

申请号：US15261860

申请日：2016-09-09

Applicant: Cisco Technology, Inc.

Inventor： Xiqun Zhu ,  Sung Kee Baek ,  Robert Gregory Twiss

IPC: G01R31/42 ,  H02J3/00 ,  H02J13/00

CPC classification number: G01R31/42 ,  G01R19/16547 ,  G01R31/026 ,  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.