Implantable Pulse Generator Switching Energy Storage Devices
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Solution Overview
Problem
Conventional implantable pulse generators require high peak voltages for defibrillation, necessitating robust components and increasing costs, while existing solutions do not effectively reduce the peak voltage for efficient defibrillation.
Innovation Solution
An implantable pulse generator design that uses a switching device to connect and disconnect energy storage devices in series, generating output pulses with a rectangular waveform by selectively supplying energy from individual or combined storage devices, thereby reducing peak voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional energy storage devices are used to generate output pulses, then defibrillation function is provided, but peak voltage becomes excessively high (exceeding 1300 V) requiring robust and expensive components
Solution Approach 1:
The energy storage system is divided into multiple separate energy storage devices (first energy storage device and second energy storage device) instead of using a single large capacitor. Each device can be optimized for lower voltage operation, and they are connected in series only when needed for shock delivery, thereby reducing the voltage rating requirements for individual components and associated circuitry.
Solution Approach 2:
The circuit configuration is made dynamic through the use of a switching device that can change the connection topology between energy storage devices. The switching device connects the first and second energy storage devices in series during shock delivery to achieve high voltage, but allows them to operate independently during normal charging and monitoring, thereby reducing peak voltage stress on components.
2Reliability
If high peak voltage is used for defibrillation, then effective shock delivery is achieved, but component cost and complexity increase
Solution Approach 1:
By segmenting the energy storage into multiple devices, each component can be manufactured with lower voltage ratings, which are cheaper and less complex than a single high-voltage component. The segmentation allows standard low-voltage components to be used in combination to achieve the required therapeutic effect.
Solution Approach 2:
The switching device operates periodically to connect energy storage devices in series only during the brief shock delivery phase, while during the majority of the time (charging and monitoring phases), the devices operate independently at lower voltages. This periodic series connection reduces the average voltage stress on components, allowing the use of less expensive components with lower voltage ratings.
3Device complexity
If conventional capacitor discharge is used, then simple circuit design is maintained, but output pulse waveform becomes exponentially decaying with high peak voltage
Solution Approach 1:
The circuit transitions from a static capacitor discharge configuration to a dynamic configuration using a switching device. This allows the circuit topology to change based on operational needs: during shock delivery, the switching device connects energy storage devices in series to produce a controlled rectangular waveform, while during normal operation, the devices operate independently, maintaining relatively simple circuit behavior.
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 achieves therapeutically effective defibrillation with reduced peak voltage, simplifying the pulse generator's construction and lowering component requirements, while delivering a defined shock over time.
Implementation Method 1
The first switching device is electrically connected, at a first circuit node, to the at least one first energy storage device and is configured to connect, in a closed state, the at least one first energy storage device with the at least one second energy storage device and to disconnect, in an open state, the at least one first energy storage device from the at least one second energy storage device
Implementation Method 2
an arrangement of energy storage devices, for example, in the shape of capacitors, are used to generate an output pulse based on a discharging of the energy storage devices
Implementation Method 3
The shock generation circuitry is configured to generate said output pulse by supplying energy to the output circuitry, in the open state of the first switching device, from the at least one first energy storage device via the first connection line and, in the closed state of the first switching device, from the at least one first energy storage device and the at least one second energy storage device via the second connection line
Data Source
AI summary
An implantable pulse generator comprises a pulse generation device generating an output pulse, the pulse generation device comprising a control unit, shock generation circuitry and output circuitry. The shock generation circuitry comprises a first energy storage device, a second energy storage device and a switching device. The switching device is electrically connected to the first energy storage device, and is configured to connect, in a closed state, the first energy storage device with the second energy storage device, and to disconnect, in an open state, the first energy storage device from the second energy storage device. The shock generation circuitry configured to generate an output pulse by supplying energy to the output circuitry, in the open state, from the first energy storage device via a first connection line and, in the closed state, from the first energy storage device and the second energy storage device via a second connection line.