Blanking Switch for Physiological Signal Sensing
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Solution Overview
Problem
Sensing physiological signals in proximity to a stimulation site during electrical stimulation therapy is challenging due to the overwhelming amplitude of stimulation signals, which saturate the sensing circuits and obscure the physiological signals, especially in neurological stimulation systems where the recharge phase dominates and leaves insufficient time to detect physiological signals.
Innovation Solution
A method and device that blank or limit the stimulation signal during its phase to prevent saturation, allowing for the accurate detection of physiological signals by using blanking switches or signal limiters in the sensing circuitry, ensuring that the sensing circuitry can capture physiological data between stimulation pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physiological signals are sensed in proximity to the stimulation site during stimulation therapy, then the usefulness of physiological signal sensing is improved, but the stimulation signals saturate the sensing circuits and obscure the physiological signals
Solution Approach 1:
The patent segments the stimulation signal into distinct phases (stimulation phase and recharge phase) and applies different handling strategies to each phase. During the stimulation phase, blanking is applied to prevent saturation, while during the recharge phase, physiological signal sensing is enabled. This temporal segmentation allows the system to manage the harmful stimulation signals while capturing useful physiological data.
Solution Approach 2:
The patent employs periodic blanking of the sensed signal during the stimulation phase, synchronized with the periodic stimulation waveform. The blanking occurs only during specific time windows (stimulation phase) while allowing signal acquisition during other windows (recharge phase), creating a periodic pattern of signal suppression and acquisition that matches the stimulation rhythm.
2Object-affected harmful factors
If the recharge phase is blanked out to avoid saturation, then the harmful stimulation signal impact is reduced, but there is inadequate time remaining to sense the physiological signal
Solution Approach 1:
The patent implements periodic blanking that is synchronized to the stimulation waveform, selectively suppressing signals only during the stimulation phase while maintaining sensing capability during the recharge phase. This periodic approach ensures that physiological signal sensing occurs systematically during available time windows without being overwhelmed by stimulation artifacts.
Solution Approach 2:
The blanking function is dynamically controlled based on the phase of the stimulation waveform. The system transitions between blanking and non-blanking states according to the timing requirements, enabling adaptive signal acquisition that maximizes physiological signal detection while minimizing stimulation signal interference.
3Object-affected harmful factors
If the amplitude of the stimulation signal is reduced, then the saturation effect is minimized, but the stimulation therapy effectiveness is compromised
Solution Approach 1:
The patent extracts and removes the harmful stimulation signal components from the sensed signal during the stimulation phase through blanking. By selectively eliminating only the problematic stimulation artifacts while preserving the recharge phase for physiological signal acquisition, the system maintains full stimulation therapy effectiveness without compromising signal detection capability.
Data Source
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AI summary
A device for sensing a physiological signal while stimulation therapy is being provided wherein the stimulation therapy involves application of a stimulation signal comprising a stimulation phase and a passive or active recharge phase, comprising: a sensing electrode; a blanking switch; an electrically conductive pathway connected between the sensing electrode and a blanking switch; a sensing amplifier; a controller configured to maintain the blanking switch in a non-conducting state during a stimulation phase of a stimulation signal and to maintain the blanking switch in a conducting state during at least a portion of the recharge phase.