Current Stimulator Emulating Voltage Pulses via Switched Capacitors
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Solution Overview
Problem
Medical devices capable of delivering electrical stimulation therapy are often limited to either current mode or voltage mode, lacking the ability to seamlessly switch between the two, which can restrict treatment options for patients preferring specific modes of stimulation.
Innovation Solution
A system that enables a controlled-current stimulation device to emulate controlled-voltage pulses by selectively coupling electrodes to regulated and unregulated current paths, allowing for the production of specified voltage levels, thereby mimicking a voltage mode system without the need for duplicate circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a device is configured as a controlled-current system, then current level remains substantially constant over a range of power and load conditions, but the device cannot deliver controlled-voltage pulses
Solution Approach 1:
The controlled-current stimulation device is enhanced with voltage emulation capability, allowing a single device to provide both controlled-current and controlled-voltage stimulation modes. The system uses a switched-capacitor circuit that can be configured to deliver current pulses directly or to emulate voltage pulses by switching between different capacitor connections, thereby achieving multi-functionality without requiring separate dedicated circuits for each mode.
2Adaptability or versatility
If duplicate circuitry is added to enable both voltage and current mode stimulation, then stimulation mode flexibility improves, but device complexity and power consumption increase
Solution Approach 1:
The patent merges the voltage emulation functionality into the existing controlled-current circuit by using the same capacitors and switching elements. The switched-capacitor circuit serves dual purposes: delivering controlled current pulses and emulating controlled voltage pulses through different switching configurations. This eliminates the need for separate voltage-mode circuitry, reducing overall power consumption while maintaining both stimulation modes.
Solution Approach 2:
The same hardware components (capacitors, switches, current source) are made multi-functional to perform both current-mode and voltage-mode stimulation. The system dynamically reconfigures these components based on the desired stimulation mode, avoiding the power overhead of maintaining duplicate dedicated circuits for each mode simultaneously.
3Adaptability or versatility
If duplicate circuitry is added to enable both voltage and current mode stimulation, then stimulation mode flexibility improves, but additional circuit complexity is introduced
Solution Approach 1:
The voltage emulation functionality is integrated into the existing controlled-current circuit architecture by sharing capacitors and switching elements. The same current source and capacitor array used for current-mode stimulation are reconfigured through additional switching to provide voltage-mode emulation, thereby avoiding duplicate circuitry and minimizing additional complexity.
Solution Approach 2:
The system uses a universal switched-capacitor architecture where the same hardware components serve both current-mode and voltage-mode functions. The control logic dynamically reconfigures the circuit topology to achieve the desired stimulation mode, eliminating the need for separate dedicated circuits and reducing overall device complexity.
Data Source
AI summary
Techniques are described for generating electrical stimulation current pulses for delivery of electrical stimulation therapy via a current-controlled system that emulates voltage pulses generated via a voltage-controlled system. In one example, a method includes receiving user input specifying a voltage level of electrical stimulation to be delivered by one or more of a plurality of electrodes implanted within the patient, selectively coupling the one or more electrodes to respective regulated current paths to deliver the electrical stimulation to the patient, selectively coupling at least another of the plurality of electrodes implanted within the patient to an unregulated current path to deliver the electrical stimulation to the patient, determining a regulated current for each respective regulated current path in order to produce the specified voltage level at the one or more electrodes selectively coupled to the respective regulated current paths, and delivering the determined regulated currents via the respective regulated current paths.