Controlled Commutation Circuit for Multiplexed Electrodes
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Solution Overview
Problem
Existing active implantable medical devices face challenges in safely selecting and configuring electrodes post-implantation due to the risk of inducing fibrillation from excessive voltage application, particularly when using multiplexer/demultiplexer circuits and switches controlled by coded pulse sequences.
Innovation Solution
A controlled commutation circuit with a micropulse detection mechanism that quickly opens switches and decodes a modulated signal to actuate switches safely, using a fast comparator and a signal sequence that includes a micropulse to prevent excessive voltage application, ensuring all switches are open before delivering coded pulses, thereby minimizing the risk of fibrillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiplexer/demultiplexer circuits with switches are used to control electrode configuration, then electrode selection flexibility is improved, but the risk of inducing fibrillation from excessive voltage application increases
Solution Approach 1:
The patent applies preliminary action by opening all switches before delivering the coded pulse sequence. The micropulse signal is detected first, which triggers the opening of all switches in advance. This ensures that no electrode is inadvertently connected to excessive voltage during the subsequent coded pulse delivery, thereby preventing fibrillation while maintaining electrode selection flexibility
Solution Approach 2:
The patent uses an intermediary approach by introducing a micropulse signal as a mediator between the coded pulse sequence and the switch control. This micropulse detection mechanism acts as a safety intermediary that verifies the switch state before full voltage is applied, preventing direct exposure of electrodes to excessive voltage during the transition phase
2Extent of automation
If coded pulse sequences are used to control switch configuration, then automated electrode programming is improved, but the risk of voltage application errors increases
Solution Approach 1:
The patent applies preliminary action by detecting the micropulse signal before processing the coded pulse sequence. This preliminary detection ensures that all switches are opened in advance, creating a safe initial state before the automated coded programming begins. This prevents voltage application errors during the automated transition of electrode configurations
Solution Approach 2:
The patent implements feedback by using the micropulse detection as a verification step before executing the coded pulse sequence. The system feedbacks on the switch state through micropulse detection, ensuring that the switches are in the correct open state before delivering the automated electrode programming commands, thereby reducing voltage application errors
3Object-affected harmful factors
If switches are opened quickly to prevent fibrillation, then safety is improved, but the complexity of the commutation control circuit increases
Solution Approach 1:
The patent applies self-service by using the micropulse signal itself to trigger the switch opening mechanism. The micropulse detection circuit automatically initiates the switch opening sequence without requiring external complex control signals. This self-service approach simplifies the commutation control circuit by eliminating the need for separate fast-opening control logic while still achieving rapid switch opening for fibrillation prevention
Data Source
AI summary
A circuit for controlled commutation of multiplexed electrodes, for an active implantable medical device. This circuit is located in a lead equipped with multiplexed sensing/pacing electrodes. This circuit decodes a signal generated by a generator, commanding a series of switches, which ensures selective coupling of the various electrodes to the proximal and distal terminals of the generator. This signal is a modulated signal comprising a coded series of logic pulses defining a particular configuration for coupling the lead electrodes to the proximal or distal terminal of the generator. The signal comprises a micropulse, that precedes the coded series of logic pulses and has an amplitude and duration lower than the amplitude and duration of each of the logic pulses. The detection of this micropulse activates, in response, all the circuit switches to an open position over a duration (PHASE 1) at least equal to the duration of reception of the coded series of logic pulses.