Cochlear Implant Current Source Compliance Detection
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Solution Overview
Problem
Cochlear implant current sources often enter an out-of-compliance state due to high electrode impedance or commanded output current pulses, leading to signal distortion and audio quality degradation, which conventional systems fail to address effectively.
Innovation Solution
The system includes a mirrored current source and a reference load that forces the mirrored current source into an out-of-compliance state, generating a dynamic reference voltage for comparison with the actual current source output, allowing for detection of compliance states and dynamic voltage adjustments to maintain compliance and conserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the current source operates with limited supply voltage, then power consumption is reduced, but the current source enters an out-of-compliance state leading to signal distortion and audio quality degradation
Solution Approach 1:
The patent applies preliminary action by proactively detecting the compliance state of the current source before it actually enters an out-of-compliance condition. The system continuously monitors voltage headroom and predicts when the current source will become non-compliant, allowing the processor to adjust stimulation parameters in advance to prevent signal distortion and maintain audio quality while optimizing power consumption.
2Length of stationary object
If the electrode impedance is high, then the cochlear implant can stimulate deeper neural structures, but the current source enters an out-of-compliance state due to lack of voltage headroom
Solution Approach 1:
The patent implements feedback by continuously monitoring the compliance state of the current source and using this information to dynamically adjust stimulation parameters. The system measures the actual current output and compares it with the commanded current, detecting when high electrode impedance causes the current source to become non-compliant. Based on this feedback, the processor adjusts voltage and current parameters to maintain compliance while still achieving deep neural stimulation.
3Power
If the commanded output current pulses are increased, then the stimulation intensity is improved, but the current source enters an out-of-compliance state due to insufficient voltage headroom
Solution Approach 1:
The patent applies dynamics by making the voltage supply adaptive and variable rather than fixed. The system dynamically adjusts the voltage headroom allocated to the current source based on real-time detection of compliance state. When high stimulation intensity is commanded, the system increases voltage headroom to maintain compliance. When lower intensity is sufficient, the system reduces voltage to conserve power, creating a dynamic balance between stimulation intensity and power consumption.
Data Source
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AI summary
An exemplary cochlear implant may include 1) a current source tied to a voltage supply and having an output that is electrically coupled to an electrode included in a plurality of electrodes, 2) a mirrored current source associated with the current source and that is commanded to output a commanded current, 3) a reference load coupled to an output of the mirrored current source and that forces the mirrored current source into an out-of-compliance state in which the mirrored current source outputs a reference current that is a predetermined percentage lower than the commanded current, the reference current resulting in a dynamic reference voltage at the output of the mirrored current source, and 4) a comparator that compares a voltage at the output of the current source with the dynamic reference voltage, and outputs a signal based on the comparison. Corresponding systems and methods are also described.