# US 11,909,255 B2 · Battery charging cut-off circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,255 B2 - Document ID: US11909255B2 - Status: Granted - Kind: B2 - Application number: 17/702,944 - Filed: 2022-03-24 - Published: 2022-07-07 - Granted: 2024-02-20 - Earliest claimed: 2018-01-16 - Assignees: Cisco Technology, Inc. - Applicants: Cisco Technology, Inc. - Inventors: Xiqun Zhu; Sung Kee Baek; Wingo Cheong; Steven Anthony Granzella; Joel Goergen; Charles Calvin Byers - Web page: https://patentgrep.com/patent/US11909255B2 ## CPC - H02J 9/061: {for DC powered loads} - H02J 7/65: against overtemperature - H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)} - H02J 7/63: against overdischarge - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) The BBU cut-off and recharge circuit according to claim 1, wherein at least said microcontroller is a plug-in module. ### Claim 3 (depends on 1) The BBU cut-off and recharge circuit according to claim 1, wherein said BBU is a plug-in module. ### Claim 4 (depends on 1) The BBU cut-off and recharge circuit according to claim 1, wherein: said microcontroller is powered from said main power supply; upon said loss of power from said main power supply, said microcontroller is powered by said BBU; and upon setting said BBU cut-off and recharge circuit to said lockdown state, said microcontroller is not powered. ### Claim 5 (depends on 1) The BBU cut-off and recharge circuit according to claim 1, wherein said microcontroller is further operative to: upon detecting that said SOC is under said predefined threshold, notify said application circuits that said lockdown state is being set; wait for a pre-defined period of time to allow said application circuits to shut down; and close said mechanical relay switch with said self-latch capability after said pre-defined period of time has elapsed. ### Claim 6 (depends on 5) The BBU cut-off and recharge circuit according to claim 5, wherein said microcontroller is further operative to: restart in response to power from said main power supply. ### Claim 7 (depends on 1) The BBU cut-off and recharge circuit according to claim 1, wherein said microcontroller is further operative to: upon detecting power from said main power supply, open said mechanical relay switch with said self-latch capability. ### Claim 8 A method for battery backup unit (BBU) cut-off and recharging, the method implemented on a microcontroller of a BBU cut-off and recharge circuit and comprising: detecting a loss of power from a main power supply, wherein power from a power entry connection connected to said main power supply flows to application circuits for an electronic device, and a mechanical relay switch with self-latch capability is positioned between a BBU and said power entry connection; opening said mechanical relay switch with said self-latch capability to enable said BBU to discharge through said power entry connection to said application circuits, detecting a status of charge (SOC) for said BBU, and upon detecting that said SOC is under a predefined threshold, setting said BBU cut-off and recharge circuit to a lockdown state by closing said mechanical relay switch with said self-latch capability. ### Claim 9 (depends on 8) The method of claim 8, wherein at least said microcontroller is a plug-in module. ### Claim 10 (depends on 8) The method of claim 8, wherein said BBU is a plug-in module. ### Claim 11 (depends on 8) The method of claim 8, wherein: said microcontroller is powered from said main power supply; upon said loss of power from said main power supply, said microcontroller is powered by said BBU; and upon setting said BBU cut-off and recharge circuit to said lockdown state, said microcontroller is not powered. ### Claim 12 (depends on 8) The method of claim 8, further comprising: upon detecting that said SOC is under said predefined threshold, notifying said application circuits that said lockdown state is being set; waiting for a pre-defined period of time to allow said application circuits to shut down; and closing said mechanical relay switch with said self-latch capability after said pre-defined period of time has elapsed. ### Claim 13 (depends on 12) The method of claim 12, further comprising: restarting in response to power from said main power supply. ### Claim 14 (depends on 8) The method of claim 8, further comprising: upon detecting power from said main power supply, opening said mechanical relay switch with said self-latch capability. ### Claim 15 A non-transitory tangible computer-interpretable medium encoded with instructions that, when executed by a microcontroller of a battery backup unit (BBU) cut-off and recharge circuit, cause the microcontroller to: detect a loss of power from a main power supply, wherein power from a power entry connection connected to said main power supply flows to application circuits for an electronic device, and a mechanical relay switch with self-latch capability is positioned between a BBU and said power entry connection; 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. ### Claim 16 (depends on 15) The non-transitory tangible computer-interpretable medium of claim 15, wherein at least said microcontroller is a plug-in module. ### Claim 17 (depends on 15) The non-transitory tangible computer-interpretable medium of claim 15, wherein said BBU is a plug-in module. ### Claim 18 (depends on 15) The non-transitory tangible computer-interpretable medium of claim 15, wherein: said microcontroller is powered from said main power supply; upon said loss of power from said main power supply, said microcontroller is powered by said BBU; and upon setting said BBU cut-off and recharge circuit to said lockdown state, said microcontroller is not powered. ### Claim 19 (depends on 15) The non-transitory tangible computer-interpretable medium of claim 15, wherein the instructions further cause the microcontroller to: upon detecting that said SOC is under said predefined threshold, notify said application circuits that said lockdown state is being set; wait for a pre-defined period of time to allow said application circuits to shut down; and close said mechanical relay switch with said self-latch capability after said pre-defined period of time has elapsed. ### Claim 20 (depends on 15) The non-transitory tangible computer-interpretable medium of claim 15, wherein the instructions further cause the microcontroller to: upon detecting power from said main power supply, open said mechanical relay switch with said self-latch capability.