# US 12,005,249 B2 · Method for regulating TETS power transfer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,005,249 B2 - Document ID: US12005249B2 - Status: Granted - Kind: B2 - Application number: 17/174,717 - Filed: 2021-02-12 - Published: 2022-08-18 - Granted: 2024-06-11 - Earliest claimed: 2021-02-12 - Assignees: Medtronic, Inc. - Applicants: Medtronic, Inc. - Inventors: Jacob A. Roe; Joel B. Artmann; Jonathan P. Roberts; David J. Peichel - Web page: https://patentgrep.com/patent/US12005249B2 ## CPC - A61M 60/873: specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging - A61M 60/178: drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices - A61M 60/216: including a rotating member acting on the blood, e.g. impeller - A61M 60/508: Electronic control means, e.g. for feedback regulation - H02J 50/12: of the resonant type - A61M 2205/33: Controlling, regulating or measuring - A61M 2205/52: with memories providing a history of measured variating parameters of apparatus or patient - H02J 7/02: for charging batteries from AC mains by converters - H02J 2105/46: Medical devices, medical implants or life supporting devices - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract In an implanted medical device system, an internal controller, external power transmitter and methods for regulation of TETS power for an implanted medical device system are disclosed. According to one aspect, a method in an external power transmitter of an implanted medical device system includes determining a current in an external coil of the external power transmitter, multiplying the determined current by a supply voltage to determine a power delivered to the external coil, and controlling the power delivered to the external coil by adjusting the current in the external coil. ## Claims ### Claim 1 An external power transmitter of an implanted medical device system, the external power transmitter comprising processing circuitry configured to: determine a current in an external coil of the external power transmitter; multiply the current by a supply voltage to determine a power delivered to the external coil; control the power delivered to the external coil by adjusting the current in the external coil; and adjust the power to account for resistive losses in the external coil. ### Claim 2 (depends on 1) The external power transmitter of claim 1, wherein the processing circuitry is further configured to control the power by adjusting a duty cycle of a pulse-width-modulated bridge circuit. ### Claim 3 (depends on 2) The external power transmitter of claim 2, wherein the processing circuitry is further configured to determine the current while the pulse-width-modulated bridge circuit is active. ### Claim 4 (depends on 3) The external power transmitter of claim 3, wherein the processing circuitry is further configured to estimate the current in the external coil based at least in part on peak coil current, a pulse width of the pulse-width-modulated bridge circuit, and an approximation of the current as a sine wave. ### Claim 5 (depends on 1) The external power transmitter of claim 1, wherein the processing circuitry is further configured to use the supply voltage to compensate a current proportional integral derivative (PID) controller to maintain a constant power over different supply voltages. ### Claim 6 (depends on 1) The external power transmitter of claim 1, wherein processing circuitry is further configured to determine the current by by continuously measuring a current output of a bridge circuit. ### Claim 7 (depends on 1) The external power transmitter of claim 1, wherein the processing circuitry is further configured to determine the current by measuring a peak current in the external coil. ### Claim 8 A method in an external power transmitter of an implanted medical device system, the method comprising: determining a current in an external coil of the external power transmitter; multiplying the current by a supply voltage to determine a power delivered to the external coil; controlling the power delivered to the external coil by adjusting the current in the external coil; and adjusting the power to account for resistive losses in the external coil. ### Claim 9 (depends on 8) The method of claim 8, wherein controlling the power comprises adjusting a duty cycle of a pulse-width-modulated bridge circuit. ### Claim 10 (depends on 9) The method of claim 9, wherein determining the current is performed while the pulse-width-modulated bridge circuit is active. ### Claim 11 (depends on 10) The method of claim 10, wherein determining the current in the external coil comprises estimating the current based at least in part on peak coil current, a pulse width of the pulse-width-modulated bridge circuit, and an approximation of the current as a sine wave. ### Claim 12 (depends on 8) The method of claim 8, further comprising using the supply voltage to compensate a current proportional integral derivative (PID) controller to maintain a constant power over different supply voltages. ### Claim 13 (depends on 8) The method of claim 8, wherein determining the current comprises continuously measuring a current output of a bridge circuit. ### Claim 14 (depends on 8) The method of claim 8, wherein determining the current includes measuring a peak current in the external coil. ### Claim 15 A current control loop in an external device of an implanted medical device system, the current control loop including: an H-bridge circuit configured to output a current to an external coil of the external device; processing circuitry configured to: determine the current to the external coil based on a current output of the H bridge circuit; multiplying the current by a supply voltage applied to the external coil to determine a power delivered to the external coil; and controlling the power delivered to the external coil by adjusting the current in the external coil, the adjusting being by controlling a pulse width modulation (PWM) duty cycle of the H-bridge circuit in response to the determined current; and a current proportional integral derivative (PID) controller configured to control the PWM duty cycle of the H-bridge circuit. ### Claim 16 (depends on 15) The current control loop of claim 15, further comprising a current sensor configured to measure the current of the external coil, the processing circuitry being configured to compare the measured current to a current that is based on a difference between a voltage across an internal coil of the implanted medical device system and a target voltage. ### Claim 17 (depends on 15) The current control loop of claim 15, wherein the current output of the H-bridge circuit is further based on a supply voltage provided by a power supply external to the external device.