High-Q Coil Driver for Implantable Stimulator Data Transmission
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Solution Overview
Problem
High-Q coils used for power transmission to implantable medical devices result in slow rise and fall times of modulated signals, leading to unreliable data reception by microstimulators, as they are efficient for power but inefficient for data modulation.
Innovation Solution
A control unit with both low-voltage and high-voltage drivers is used to drive a high-Q external coil, employing Manchester encoding and amplitude modulation, along with an auto-tuning circuit and adjustable capacitor to achieve sharp rise and fall times for reliable data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high Q coil is used for power transmission, then power transmission efficiency is improved, but the rise time and fall time of modulated signals become slow, resulting in unreliable data reception
Solution Approach 1:
The system segments the coil operation into two distinct modes: a high Q coil mode for efficient power transmission and a separate modulation mode for reliable data communication. The control unit switches between these modes, using the high Q coil's natural resonance for power delivery while employing Manchester encoding and amplitude modulation with sharp rise/fall times for data transmission, thereby resolving the contradiction between power efficiency and data reliability
Solution Approach 2:
The system dynamically changes the operational parameters of the coil by switching between high Q resonance mode for power transmission and a modulation mode with controlled rise/fall times for data communication. The control unit adjusts the driving characteristics to achieve sharp transitions for data signals while maintaining high Q characteristics for power efficiency, thus resolving the parameter conflict
2Reliability
If a high power modulation amplifier is used to improve signal rise time, then data transmission reliability is improved, but the power consumption increases, which is not compatible with low power requirements of implantable microstimulators
Solution Approach 1:
Instead of using a high power amplifier that provides excessive power, the system employs a low power amplifier with optimized circuitry that provides just enough power to achieve the required sharp rise and fall times for data modulation. The control unit carefully manages the amplifier operation to maintain low power consumption while ensuring reliable data transmission through proper signal shaping
Solution Approach 2:
The system replaces the conventional approach of using high power amplifiers with a low power amplifier design that uses electronic signal processing techniques. The control unit employs Manchester encoding and amplitude modulation with optimized circuitry to achieve sharp signal transitions without requiring high power, thus substituting the mechanical/power-based approach with an electronic/control-based solution
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 configuration ensures reliable modulation of data signals with sharp rise and fall times, improving the integrity of data transmission to microstimulators while maintaining efficient power transfer.
Implementation Method 1
the external device generally referred to as a BION control unit (BCU) comprises a charger and a controller wherein the functionality of the charger and the controller may be combined and provided through a multi-turn loop antenna in the form of a single coil. This BCU coil is in turn coupled with the coil in the microstimulator providing the inductive coupling and transmission of power and modulated signal to the microstimulator
Data Source
AI summary
A system, method and power/data transmission device comprising a coil having a high Q, a low-voltage driver and a high-voltage driver switchably coupled to the coil. The low-voltage driver and the high-voltage driver are controlled by a microcontroller and switch at about the same time thereby providing a modulated data signal for transmission. Furthermore, the system includes at least one implantable microstimulator coupled to the transmission device.