# US 2022/0046352 A1 · Wireless audio device battery pre-loading and pre-charging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0046352 A1 - Document ID: US20220046352A1 - Status: Published application - Kind: A1 - Application number: 16/988,105 - Filed: 2020-08-07 - Published: 2022-02-10 - Earliest claimed: 2020-08-07 - Assignees: Bose Corporation - Applicants: Bose Corporation - Inventors: Taha Mehrabi; Daniel D. Najemy; Steve Torku; Suganya Subramanian - Web page: https://patentgrep.com/patent/US20220046352A1 ## CPC - H02J 7/82: Control of state of charge [SOC] - H04R 1/1025: Accumulators specially adapted for earpieces; Arrangements specially adapted for charging thereof - H02J 7/875: {Charging or discharging for charge maintenance, battery initiation or rejuvenation} - H02J 7/96: in response to battery voltage - H02J 50/12: of the resonant type - H04R 1/1016: {Earpieces of the intra-aural type} - H04R 2420/07: Applications of wireless loudspeakers or wireless microphones - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A portable charging case is provided. The case includes a charging interface configured to establish a power transfer connection with a wireless audio device having a battery. The case includes charging circuitry configured to determine a voltage of the battery. The charging circuitry is further configured to, if the voltage is less than or equal to an undervoltage lockout, charge the battery in pre-charging mode. In pre-charging mode, the charging circuitry is configured to apply a constant pre-charging voltage to the battery. The charging circuitry is further configured to switch from pre-charging mode to standard charging mode when the voltage exceeds the undervoltage lockout value. The charging circuit is further configured to determine the voltage by (1) powering on, via a case power source, the wireless audio device; (2) applying, pre-charge load to the device battery; (3) retrieving the voltage; and (4) transmitting the voltage to the case. ## Claims ### Claim 1 A portable charging case, comprising: a charging interface configured to establish a power transfer connection with a wireless audio device, wherein the wireless audio device comprises a device battery; and charging circuitry configured to: determine a device battery voltage of the device battery; if the device battery voltage is greater than an undervoltage lockout value, charge the device battery, via the power transfer connection, in standard charging mode; and if the device battery voltage is less than or equal to the undervoltage lockout value, charge the device battery, via the power transfer connection, in pre-charging mode. ### Claim 2 (depends on 1) The portable charging case of claim 1, wherein the charging circuitry is further configured to switch from pre-charging mode to standard charging mode when the device battery voltage is greater than the undervoltage lockout value. ### Claim 3 (depends on 1) The portable charging case of claim 1, wherein the charging circuitry is further configured to switch from pre-charging mode to standard charging mode after charging the device battery in pre-charging mode for a predetermined time interval. ### Claim 4 (depends on 1) The portable charging case of claim 1, wherein the charging circuit in standard charging mode is configured to apply a varying standard charging voltage to the device battery to maintain a constant charging current. ### Claim 5 (depends on 1) The portable charging case of claim 1, wherein the charging circuit in pre-charging mode is configured to apply a constant pre-charging voltage to the device battery. ### Claim 6 (depends on 5) The portable charging case of claim 5, wherein the constant pre-charging voltage is approximately 2.2 V. ### Claim 7 (depends on 1) The portable charging case of claim 1, wherein the charging circuit is configured to determine the device battery voltage by: powering on, via a case power source of the portable charging case, a device microcontroller of the wireless audio device; applying, via the device microcontroller, pre-charge load to the device battery; retrieving, via the device microcontroller, the device battery voltage; and transmitting the device battery voltage from the device microcontroller to a case microcontroller of the portable charging case. ### Claim 8 (depends on 7) The portable charging case of claim 7, wherein the pre-charge load comprises one or more resistors. ### Claim 9 (depends on 1) The portable charging case of claim 1, wherein the undervoltage lockout value is approximately 1.0 V. ### Claim 10 (depends on 1) The portable charging case of claim 1, wherein the pre-charging mode is disabled if the device battery voltage is below a minimum charging voltage. ### Claim 11 (depends on 1) The portable charging case of claim 1, wherein the minimum charging voltage is 0.5 V. ### Claim 12 (depends on 1) The portable charging case of claim 1, wherein the case power source is a case battery. ### Claim 13 An audio system, comprising: a first wireless audio device comprising a first device battery; and a portable charging case comprising: a first charging interface configured to establish a first power transfer connection with the first wireless audio device; and charging circuitry configured to: determine a first device battery voltage of the first device battery; if the first device battery voltage is greater than an undervoltage lockout value, charge the first device battery via the first power transfer connection in standard charging mode; and if the first device battery voltage is less than or equal to the undervoltage lockout value, charge the first device battery via the power transfer connection in pre-charging mode. ### Claim 14 (depends on 13) The audio system of claim 13, further comprising a second wireless audio device, wherein the second wireless audio device comprises a second device battery, and wherein the portable charging case further comprises a second charging interface configured to establish a second power transfer connection with the second wireless audio device. ### Claim 15 (depends on 14) The audio system of claim 14, wherein the charging circuitry is further configured to: determine a second device battery voltage of the second device battery; if the second device battery voltage is greater than the undervoltage lockout value, charge the second device battery via the second power transfer connection in standard charging mode; and if the second device battery voltage is less than or equal to the undervoltage lockout value, charge the second device battery via the second power transfer connection in pre-charging mode. ### Claim 16 (depends on 13) The audio system of claim 13, wherein the first wireless audio device is an earbud. ### Claim 17 (depends on 13) The audio system of claim 13, wherein the first device battery is an NiMH battery. ### Claim 18 A method for charging a wireless audio device, comprising the steps of: forming, via a charging interface of a portable charging case, a power transfer connection between the wireless audio device and the portable charging case; determining, via charging circuitry of the portable charging case, a device battery voltage of a device battery of the wireless audio device; if the device battery voltage is greater than an undervoltage lockout value, charging the device battery, via the power transfer connection, in standard charging mode; and if the device battery voltage is less than or equal to the undervoltage lockout value, charging the device battery, via the power transfer connection, in pre-charging mode. ### Claim 19 (depends on 18) The method of claim 18, wherein determining a device battery voltage of a device battery of the wireless audio device comprises the steps of: powering on, via a case power source of the portable charging case, a device microcontroller of the wireless audio device; applying, via the microcontroller of the wireless audio device, pre-charge load to the device battery; retrieving, via the microcontroller of the wireless audio device, the voltage of the device battery; and transmitting the voltage of the device battery from the device microcontroller to a case microcontroller of the portable charging case. ### Claim 20 (depends on 18) The method of claim 18, wherein charging the device battery in pre-charging mode comprises the step of applying a constant pre-charging voltage to the device battery.