Cranial Nerve Current Stimulator With Dual-Circuit Noise Control
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Solution Overview
Problem
Current methods for stimulating cranial nerve cells with current signals face challenges in accurately providing currents without noise, as existing technologies struggle to generate precise currents that effectively interact with cranial nerve cells while minimizing interference.
Innovation Solution
A current stimulator is designed with a first current generation circuit using current mirroring and a second current generation circuit driven by a clock, which generates currents with specific impedance ratios to match the load impedance of cranial nerve cells, allowing for precise control of current magnitudes and modes through transistor pairs and a switched capacitor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single current generation circuit is used, then the device structure is simple, but the current precision and noise reduction capability are insufficient
Solution Approach 1:
The current generation function is divided into two separate circuits: a first current generation circuit using current mirroring for generating baseline current, and a second current generation circuit using switched capacitor for generating precise adjustment current. This segmentation allows each circuit to specialize in specific current generation tasks, improving overall current precision while maintaining manageable device complexity through functional decomposition.
Solution Approach 2:
The patent combines two different current generation methodologies (current mirroring and switched capacitor) into a unified current stimulator system. The first and second current generation circuits are merged through parallel connection, where their outputs are combined to achieve both high precision and low noise performance that neither circuit could achieve alone.
2Power
If high current magnitude is generated, then the stimulation effect is strong, but the noise level increases
Solution Approach 1:
The switched capacitor circuit acts as an intermediary between the current mirroring circuit and the cranial nerve cell. It generates a precise adjustment current that can be added to or subtracted from the baseline current, allowing fine control of the total current magnitude while maintaining low noise through the capacitor's charge transfer mechanism rather than direct high-current switching.
Solution Approach 2:
The switched capacitor circuit uses periodic clock signals to charge and discharge the capacitor, transferring charge in discrete steps. This periodic action allows precise current control through frequency and duty cycle modulation, enabling strong stimulation effects when needed while operating at lower average power levels to minimize noise generation.
3Manufacturing precision
If the output impedance is increased to match the load impedance ratio, then the current control precision is improved, but the circuit complexity increases
Solution Approach 1:
The patent applies different impedance characteristics to different parts of the current generation system. The first current generation circuit is designed with high output impedance to provide stable baseline current, while the second circuit uses switched capacitor with controlled impedance to provide precise adjustment. This local differentiation of impedance properties optimizes current control precision for each functional block without requiring the entire system to be complex.
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 stimulator effectively generates currents in the range of picoampere to microampere units with high accuracy, reducing noise and enabling precise interaction with cranial nerve cells, thereby improving signal analysis and observation.
Implementation Method 1
a first current generation circuit configured to generate a first current, injectable into a cranial nerve cell, through a current mirroring based on a plurality of transistor pairs
Implementation Method 2
a second current generation circuit, driven by a clock, configured to generate a second current smaller than the first current by controlling a charge rate based on a voltage difference between terminals of a capacitor
Implementation Method 3
a first transistor pair configured to output a positive current, and a second transistor pair configured to output a negative current
Data Source
AI summary
A current stimulator includes a first current generation circuit configured to generate a first current, injectable into a cranial nerve cell, through a current mirroring based on a plurality of transistor pairs; and a second current generation circuit, driven by a clock, configured to generate a second current smaller than the first current by controlling a charge rate based on a voltage difference between terminals of a capacitor. A first output impedance of the first current generation circuit and a second output impedance of the second current generation circuit have a magnitude greater than or equal to a predetermined ratio to a load impedance corresponding to the cranial nerve cell.