Inductive Charging Circuit Regulates Implantable Device Temperature
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Solution Overview
Problem
Existing inductive charging systems for implantable devices face challenges in regulating energy absorption to prevent excessive heat build-up and overcharging, often requiring a separate communications path and experiencing time lags in temperature management.
Innovation Solution
An inductive charging system that directly regulates energy absorption by tuning the receiving circuit's resonant frequency in real-time using sensors and microprocessors to reduce ohmic heating, eliminating the need for a separate communications path and allowing immediate temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate communications path (radio transceiver) is used to transmit temperature data from the implantable device to the external charging system, then temperature monitoring capability is improved, but device complexity increases and time lag is introduced
Solution Approach 1:
The patent combines the temperature monitoring function with the existing inductive charging circuitry. The receiver coil and associated circuitry that were previously used only for power transfer are now dual-purpose: they both charge the battery and sense temperature through their thermal response characteristics. This eliminates the need for a separate radio transceiver communication path while maintaining temperature monitoring capability.
Solution Approach 2:
The inductive charging system itself performs the temperature monitoring function without requiring external communication infrastructure. The receiver circuitry automatically detects temperature changes through its electrical characteristics and feeds this information back to the external charger, allowing the system to self-regulate without additional communication components.
2Temperature
If temperature data is transmitted via radio transceiver and processed by external charging system, then temperature control is achieved, but time lag is introduced reducing responsiveness
Solution Approach 1:
The patent establishes continuous temperature monitoring through the always-active inductive coupling between transmitter and receiver coils. Unlike periodic radio communication, the inductive link continuously transfers power and simultaneously provides continuous temperature feedback, eliminating dead time and enabling real-time temperature control without interruption or delay.
Solution Approach 2:
The system implements immediate feedback by using the receiver circuitry's electrical characteristics (which change with temperature) to continuously inform the external charger of temperature conditions. This allows the external charger to adjust its output in real-time based on actual receiver temperature, creating a tight control loop without the time delays inherent in radio transmission and processing.
3Productivity
If high power is supplied to the inductive coil for efficient charging, then charging speed is improved, but excessive heat build-up occurs causing damage to components
Solution Approach 1:
The patent uses the temperature-sensing capability of the receiver circuitry to provide real-time feedback to the external charging system. When the receiver detects elevated temperatures, it automatically signals the external charger to reduce power output, preventing excessive heat build-up. This closed-loop control allows the system to operate at high power when safe and automatically throttle back when temperature limits are approached, maximizing charging speed while protecting components.
Solution Approach 2:
The charging system dynamically adjusts power delivery based on real-time temperature conditions. Rather than using fixed power levels, the external charger modulates its output in response to continuous feedback from the receiver's temperature sensing, allowing optimal charging speed when conditions permit and automatic protection when temperatures rise, thus resolving the contradiction between charging speed and heat management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively limits temperature excursions and reduces ohmic heating within the implantable device, ensuring safe and efficient charging without the delays associated with data transmission and analysis.
Implementation Method 1
energy is transmitted to a receiving circuit disposed within the implant by magnetically coupling a transmitting coil in an external charging system to a receiving coil in the implantable device. An alternating current flowing in the transmitting coil induces an alternating current to flow in the receiving coil.
Implementation Method 2
The current in the receiving coil is converted to a form suitable for recharging a battery disposed within the implantable device, or in some cases directly powering the electro-mechanical pump.
Implementation Method 3
the implantable device includes a temperature sensor disposed to monitor the battery temperature and a radio transceiver configured to transmit battery temperature data to the external charging system.
Implementation Method 4
the power supplied to the inductive coil of the external charging system is cycled between high power (e.g., 120 mA) and low power (e.g., 40 mA) charging intervals responsive to the measured temperature within the implantable device.
Data Source
Figure 1~2B
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AI summary
Systems and methods are provided for regulating the transfer of energy inductively between an implantable device and an external charging system, wherein the energy transfer rate is regulated by varying an operating frequency of an inductive energy transfer circuit of the implantable device responsive a temperature measured within the implantable device.