Capacitive Voltage Multiplier for Implantable Pulse Generators
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Solution Overview
Problem
Existing voltage converters for implantable pulse generators face inefficiencies and electronic noise issues, particularly with inductive converters and limited efficiency at fractional multiples of supply voltage in capacitive converters, which affect power consumption and wireless communication.
Innovation Solution
A capacitive voltage multiplier with programmable outputs providing non-integer multiples of the battery voltage, including fractional outputs, and a controller for managing pulse generation and discharge, utilizing high-efficiency field effect transistors and a pre-charge period to minimize power consumption and electronic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an inductive voltage converter is used to convert DC from battery to AC for voltage conversion, then voltage conversion capability is achieved, but power consumption increases and electronic noise is introduced
Solution Approach 1:
The patent replaces the inductive converter (electromagnetic system requiring AC switching) with a capacitive voltage multiplier system that operates directly on DC voltage. This substitution eliminates the need for complex switching regulator circuitry to convert DC to AC, thereby reducing power consumption while maintaining voltage conversion capability through capacitive charge transfer mechanisms
Solution Approach 2:
The patent extracts and removes the inductive converter and its associated AC switching infrastructure from the system. By eliminating this component, the patent avoids the power losses and electronic noise generation inherent in inductive conversion, while achieving the desired voltage multiplication through a purely capacitive DC-to-DC conversion approach
2Adaptability or versatility
If an inductive up-converter is used for voltage conversion, then voltage multiplication is achieved, but electronic noise increases preventing wireless communication
Solution Approach 1:
The patent substitutes the inductive up-converter with a capacitive voltage multiplier that operates silently on DC voltage without electromagnetic switching. This replacement eliminates the electronic noise and radio frequency interference that would otherwise prevent wireless communication between the implantable pulse generator and external control unit
Solution Approach 2:
The patent removes the inductive converter from the system architecture, thereby eliminating the source of electronic noise and electromagnetic interference. This allows wireless communication to proceed without requiring periodic shutdowns to 'listen' for communication signals
3Loss of energy
If a capacitive voltage converter is used to provide integer multiples of supply voltage, then efficient operation is achieved at exact multiples, but efficiency deteriorates at fractional multiples
Solution Approach 1:
The patent segments the voltage multiplication process into discrete capacitive stages that can be selectively activated. By dividing the voltage conversion into modular capacitor charge and transfer steps, the system can efficiently generate not only integer multiples but also fractional multiples of the input voltage, thereby expanding voltage output flexibility without sacrificing efficiency
Solution Approach 2:
The patent implements dynamic control over the capacitive voltage multiplier stages, allowing selective activation of different capacitor combinations based on the desired output voltage. This dynamic reconfiguration enables efficient operation across a continuous range of voltage outputs including fractional multiples, rather than being limited to fixed integer multiples
4Adaptability or versatility
If high voltage field effect transistors are used in the voltage multiplier, then high voltage switching capability is achieved, but silicon area consumption increases and reliability decreases
Solution Approach 1:
The patent segments the high voltage handling function across multiple lower-voltage capacitive stages rather than relying on single high-voltage transistors. Each capacitor and switching element operates at a manageable voltage level, improving reliability while collectively achieving the required high voltage multiplication through series connection of the capacitor stages
Solution Approach 2:
The patent employs standard-voltage field effect transistors that are more reliable and smaller in size, accepting that each individual capacitor stage may require periodic discharge and reset. This approach trades the complexity of high-voltage transistor design for simpler, more reliable low-voltage components that can be rapidly switched and reset
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 solution enables efficient voltage selection and reduced power consumption, minimizing electronic noise and allowing for reliable wireless communication while providing precise control over stimulation pulses.
Implementation Method 1
A capacitive voltage multiplier with programmable outputs providing non-integer multiples of the battery voltage, including fractional outputs
Data Source
AI summary
In one embodiment, an implantable pulse generator comprises: pulse generating circuitry for generating pulses and delivering the pulses to outputs of the implantable pulse generator; a controller; wherein the pulse generating circuitry comprises a voltage multiplier for multiplying a battery voltage, the voltage multiplier including multiple outputs, wherein a first output of the multiple outputs provides a voltage that is programmably selectable from a plurality of voltages including non-integer multiples of the battery voltage, wherein a second output of the multiple outputs provides a voltage that is a fixed multiple of the battery voltage; wherein the controller controls the pulse generator circuitry to generate a first pulse for stimulation of the patient using a first output of the multiple outputs and controls the pulse generator circuitry to generate a second pulse to discharge output capacitors of residual charge from the first pulse using a second output of the multiple outputs.