Pulse Generator Circuit Biphasic Pulse Transient Management
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Solution Overview
Problem
Implantable electronic stimulator devices face challenges in accurately producing biphasic current pulses due to parasitic capacitances in semiconductor switches, which cause switching transients and affect the delivery of prescribed stimulation therapy.
Innovation Solution
A pulse generator circuit with a controller that actuates semiconductor switches to deliver biphasic current pulses between output ports, incorporating an energy discharge circuit to manage and dissipate residual energy, thereby eliminating transient spikes and ensuring accurate pulse delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor switches are used in the pulse generator circuit, then the device can deliver biphasic current pulses for stimulation therapy, but parasitic capacitances in the switches cause switching transients that prevent accurate production of prescribed current pulses
Solution Approach 1:
The patent applies preliminary action by pre-charging a dedicated capacitor to the battery voltage before the bipolar pulse sequence begins. This pre-charged capacitor then serves as a stable voltage source during pulse delivery, eliminating the need for the battery to switch polarity and thereby preventing switching transients. The capacitor is charged in advance through a diode from the battery, ensuring it is ready to deliver precise current pulses without affecting the battery's polarity.
Solution Approach 2:
The patent introduces an intermediary element - a dedicated capacitor - that mediates between the battery and the tissue load. This capacitor acts as a buffer that decouples the battery from the rapid polarity switching required for bipolar pulses. The capacitor absorbs the switching transients and provides a stable voltage reference, allowing the semiconductor switches to operate without causing accuracy degradation in the delivered current pulses.
2Device complexity
If semiconductor switches with parasitic capacitances are used, then the pulse generator can be compact and efficient, but residual energy in the circuit causes transient spikes that affect therapy accuracy
Solution Approach 1:
The patent extracts the energy storage function from the semiconductor switches and places it in a dedicated capacitor. By taking out the parasitic capacitance effect from the switches and concentrating it in a controlled capacitor element, the circuit can manage and dissipate residual energy more effectively. This extracted energy storage function allows for deliberate discharge paths that prevent unwanted transient spikes while maintaining the compactness of the overall device.
Solution Approach 2:
The patent implements discarding and recovering by providing dedicated discharge paths for the capacitor and any residual energy in the circuit. After the bipolar pulse sequence is complete, the capacitor is deliberately discharged through controlled paths that prevent transient spikes. Any residual energy in the semiconductor switches is also dissipated through predetermined resistive paths, ensuring that no unwanted transients affect the next pulse delivery cycle.
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 effectively delivers biphasic electrical stimulation therapy by eliminating transient spikes and ensuring accurate pulse delivery, enhancing the reliability of the treatment by managing parasitic capacitances and residual energy in the pulse generator circuit.
Implementation Method 1
The energy discharge circuit is coupled to the battery and configured to receive an electrical charge from the battery and deliver the electrical charge through an energy output port
Implementation Method 2
Parasitic capacitances may develop in semiconductor switches of pulse generator circuits. Such parasitic capacitances may prevent the pulse generator from accurately producing current pulses
Data Source
AI summary
An electronic stimulator device comprises a battery, first and second output ports, and an energy discharge circuit. The energy discharge circuit is coupled to the battery and configured to receive an electrical charge from the battery and deliver the electrical charge through an energy output port. A first switch is connected between the energy output and the first output port. A second switch is connected between the second output port and electrical ground. A third switch is connected between the second output port and the energy output. A fourth switch is connected between the first output port and electrical ground. A controller comprising a processor is configured to actuate the first, second, third and fourth switches between open and close states to deliver a biphasic current pulse between the first and second output ports.