Transformer Charging Circuit for Implantable Medical Devices
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Solution Overview
Problem
The miniaturization of implantable medical devices (IMDs) is hindered by the need for complex circuitry that increases power consumption and footprint, despite advancements in technology, as battery-powered IMDs require efficient power management to prolong their lifespan.
Innovation Solution
A charging circuit utilizing a single primary transformer winding and a single secondary winding, coupled with a diode to maintain charging polarity, dynamically configures capacitors in various stacking configurations (parallel, series, or combination) to optimize charging and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex circuitry is used to improve technical performance, then device capability is enhanced, but power consumption increases and device size increases
Solution Approach 1:
The patent combines multiple capacitor charging functions into a single transformer winding system. Instead of using separate windings for each capacitor, the invention uses one primary winding and one secondary winding that can charge multiple capacitors through dynamic configuration, thereby reducing component count and power consumption while maintaining the ability to deliver complex therapy waveforms.
Solution Approach 2:
The patent employs dynamic switching circuitry that can reconfigure capacitors between series and parallel connections based on therapeutic requirements. This dynamic reconfiguration allows the device to adapt its electrical characteristics for different therapy types (e.g., pacing, cardioversion, defibrillation) without requiring separate dedicated circuits for each function, thus reducing overall power consumption and device complexity.
2Adaptability or versatility
If complex circuitry is used to improve technical performance, then device capability is enhanced, but device footprint increases
Solution Approach 1:
The patent merges multiple charging circuits into a single transformer system with dynamic capacitor configuration. This consolidation reduces the number of discrete components needed, thereby minimizing the circuit footprint while preserving the capability to deliver diverse therapeutic waveforms through software-controlled switching.
Solution Approach 2:
The single transformer winding system is designed to serve multiple functions by dynamically reconfiguring capacitor connections. The same hardware infrastructure supports pacing, cardioversion, and defibrillation therapies, making the circuit universal and eliminating the need for separate dedicated circuits for each therapy type.
3Reliability
If multiple transformer windings are used to charge capacitors, then charging reliability is improved, but component count increases
Solution Approach 1:
The patent combines multiple capacitor charging functions into a single transformer winding system. Instead of using separate windings for each capacitor, the invention uses one primary winding and one secondary winding that can charge multiple capacitors through dynamic configuration, thereby reducing component count while maintaining charging reliability through intelligent switching control.
4Productivity
If higher supply voltage is used for capacitor charging, then charging speed is improved, but component stress increases and size increases
Solution Approach 1:
The patent employs dynamic switching circuitry that can reconfigure capacitors between series and parallel connections based on therapeutic requirements. By switching between configurations, the system optimizes charging conditions and reduces voltage stress on individual components while maintaining efficient charging performance.
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
This approach reduces the supply voltage required for charging, decreases the size and stress on charging components, and enhances the reliability of IMDs by minimizing the component count and footprint, while also allowing for more efficient therapy delivery with dynamically configurable waveforms.
Implementation Method 1
A charging circuit is provided that includes a transformer having a single primary winding and a single secondary winding
Implementation Method 2
A diode is coupled between the secondary transformer winding and the plurality of capacitors to maintain a predetermined charging polarity
Implementation Method 3
The plurality of capacitors are coupled in a first stacking configuration prior to charging the capacitors to a predetermined voltage level
Data Source
AI summary
Recent advancements in power electronics technology have provided opportunities for enhancements to implantable medical device circuits. The enhancements have contributed to increasing circuit miniaturization and increased efficiency in the operation of the implantable medical devices. Stimulation therapy waveforms generated by the circuits include a stepped leading-edge that may be shaped having a varying slope and varying amplitudes associated with each of the segments of the slope. A charging circuit having a single primary transformer winding and a single secondary transformer winding that is coupled to a plurality of capacitors is utilized to generate the therapy stimulation waveforms. The stimulation waveform of the present disclosure may be dynamically shaped as a function of an individual patient's response. Such stimulation waveforms facilitate achieving lower capture thresholds which reduces the device's supply consumption thereby increasing longevity of the device and facilitate a reduction of tissue damage.