US 11,909,255 B2
Battery charging cut-off circuit
Xiqun Zhu, Cupertino, CA (US); Sung Kee Baek, San Ramon, CA (US); Wingo Cheong, Fremont, CA (US); Steven Anthony Granzella, Saratoga, CA (US); Joel Goergen, Soulsbyville, CA (US); and Charles Calvin Byers, Wheaton, IL (US)
Assigned to CISCO TECHNOLOGY, INC., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Mar. 24, 2022, as Appl. No. 17/702,944.
Application 17/702,944 is a division of application No. 17/097,611, filed on Nov. 13, 2020, granted, now 11,342,762.
Application 17/097,611 is a division of application No. 15/871,999, filed on Jan. 16, 2018, granted, now 10,868,431, issued on Dec. 15, 2020.
Prior Publication US 2022/0216712 A1, Jul. 7, 2022
Int. Cl. H02J 9/06 (2006.01); H02J 7/00 (2006.01)
CPC H02J 9/061 (2013.01) [H02J 7/00309 (2020.01); H02J 7/00306 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A battery backup unit (BBU) cut-off and recharge circuit comprising:
a mechanical relay switch with self-latch capability;
a power entry connection connected to a main power supply, wherein power from said power entry connection flows to application circuits for an electronic device, and said mechanical relay switch with said self-latch capability is positioned between a BBU and said power entry connection; and
a microcontroller, wherein said microcontroller is operative to:
detect a loss of power from said main power supply,
open said mechanical relay switch with said self-latch capability to enable said BBU to discharge through said power entry connection to said application circuits,
detect a status of charge (SOC) for said BBU, and
upon detecting that said SOC is under a predefined threshold, set said BBU cut-off and recharge circuit to a lockdown state by closing said mechanical relay switch with said self-latch capability.