Biphasic Stimulation Integrated Circuit for Safe Neural Implant
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Solution Overview
Problem
Current implantable neural stimulators face challenges in providing biphasic stimulation safely and efficiently, as monophasic current densities can be injurious to nervous tissue, and existing biphasic devices often have larger physical footprints, leading to discomfort and limited safety for patients.
Innovation Solution
A system comprising an electrode, an inductively coupled antenna, a capacitor, a power supply, and a controller that selectively couples the capacitor plates to the electrode to provide biphasic stimulation signals with alternating polarities, allowing for safe and efficient neural stimulation with a small physical footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If monophasic current density is used for neural stimulation, then stimulation effectiveness is improved, but tissue safety deteriorates due to injurious effects on nervous tissue
Solution Approach 1:
The patent implements biphasic stimulation where current flows in one direction for a first period, then reverses direction for a second period. This periodic reversal of current polarity allows the nerve to experience stimulation during each phase while the reverse phase allows charge compensation and prevents cumulative injury, thus maintaining effectiveness while improving safety.
Solution Approach 2:
The patent converts the potentially harmful continuous current into beneficial alternating current by introducing a reverse polarity phase. The second phase with opposite polarity serves to compensate for charge accumulation during the first phase, transforming what would be injurious continuous stimulation into safe alternating stimulation that maintains therapeutic effect.
2Object-affected harmful factors
If existing biphasic stimulation devices are designed with adequate components, then stimulation safety is improved, but device size increases leading to patient discomfort
Solution Approach 1:
The patent merges multiple functions into a single integrated circuit that includes the capacitor, switching devices, and control logic. This integration eliminates the need for separate discrete components, significantly reducing the overall device footprint while maintaining the biphasic stimulation capability and safety features.
Solution Approach 2:
The integrated circuit performs multiple functions: storing energy in the capacitor, controlling the switching of current polarity, timing the phases, and interfacing with external power sources. This multi-functionality in a single chip reduces component count and device size while preserving safety through the biphasic mechanism.
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
The system enables safe biphasic neural stimulation with a net current density of up to 50 μA/mm2, reducing patient discomfort and improving safety by alternating current direction, while maintaining a compact size less than 1 mm3.
Implementation Method 1
an antenna configured to be inductively coupled to a transmitter
Implementation Method 2
a capacitor having a first plate and a second plate
Data Source
AI summary
A system for providing biphasic stimulation is disclosed. The system includes an electrode, an antenna coupled to a transmitter, a capacitor, a power supply, a backscatter load selectively coupled to the antenna via a switching device, a plurality of switches, and a controller configured to control the switching device to output, by the antenna, an acknowledgement signal to the transmitter responsive to receiving the power. The controller is further configured to control the plurality of switches to electrically couple a first plate of the capacitor to the electrode to provide a first nerve stimulation signal having a first polarity, and electrically couple a second plate of the capacitor to the electrode to provide a second nerve stimulation signal having a second polarity opposite the first polarity. The system further includes a housing encapsulating the antenna, the capacitor, the power supply, the backscatter load, the switches, and the controller.