H-Bridge Control Circuit for Neuromodulation Safety
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Solution Overview
Problem
Current constant-current electro-stimulation therapeutic instruments face challenges in accurately controlling pulse width due to slow connection and disconnection speeds of MOS transistors, leading to potential safety hazards from charge imbalance across the load during neuromodulation therapy.
Innovation Solution
An H-bridge control circuit with additional switching diodes and voltage stabilizing components is introduced, isolating low and high voltages using capacitors, and employing a booster circuit and current sampling to ensure safe and accurate neuromodulation by preventing charge discharge and stabilizing transistor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high resistance values (above 100K) are used for resistors R13 and R16 to protect PMOS transistors from high voltage damage, then transistor safety is improved, but the charging and discharging time of gate capacitance increases, making connection and disconnection speed extremely slow
Solution Approach 1:
The patent introduces a voltage transformer circuit as an intermediary between the high-voltage power supply and the PMOS transistor gate control. This transformer isolates the high voltage from the low-voltage control circuitry, allowing the use of lower resistance values in the gate control circuit without exposing the PMOS transistors to damaging high voltages. The transformer acts as a mediator that transfers control signals while preventing direct high-voltage exposure to sensitive components.
Solution Approach 2:
The patent divides the control circuit into separate voltage domains using the voltage transformer. The primary side handles high-voltage isolation while the secondary side provides low-voltage fast switching control. This segmentation allows each part of the circuit to operate at optimal resistance values for its voltage level, resolving the contradiction between safety and speed.
2Measurement precision
If conventional H-bridge circuit control mode is used with high-voltage power supply and constant current source, then accurate neuromodulation electro-stimulation therapy is achieved, but charge accumulates at two ends of the load during stimulation intervals, creating safety hazards
Solution Approach 1:
The patent converts the potentially harmful charge accumulation into a beneficial feature by using it to drive the next stimulation pulse. The capacitor stores the charge that would normally be wasted during intervals, then releases it to enhance the next pulse delivery. This transforms what was a safety hazard into an energy-efficient mechanism that maintains therapeutic accuracy while eliminating charge imbalance issues.
Solution Approach 2:
Instead of dissipating the accumulated charge during stimulation intervals through parasitic diodes, the patent recovers this energy by redirecting it through the capacitor to the load during the next stimulation phase. This recovery mechanism prevents charge imbalance safety hazards while maintaining the accuracy required for neuromodulation therapy.
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 solution enhances the safety and accuracy of neuromodulation by preventing charge imbalance, allowing for precise control of pulse width and ensuring the reliability of the therapeutic instrument.
Implementation Method 1
a capacitor, one end of which is connected to a control signal and the other end of which is connected to a gate of the PMOS transistor
Implementation Method 2
a switching diode is arranged between the drain of the PMOS transistor and the load, an anode of the switching diode is electrically connected to the drain of the PMOS transistor, and a cathode of the switching diode is electrically connected to the load
Data Source
AI summary
Disclosed is an H-bridge control circuit for an electro-stimulation therapeutic instrument for neuromodulation. The H-bridge control circuit includes an H-bridge circuit and a constant current source, where the H-bridge circuit includes a first positive channel metal oxide semiconductor (PMOS) transistor, a second PMOS transistor, a first negative channel metal oxide semiconductor (NMOS) transistor and a second NMOS transistor. Corresponding switching diodes are additionally arranged between the first PMOS transistor and a load and between the second PMOS transistor and the load to avoid an influence of safety of the therapeutic instrument by discharging charges during an interval of stimulation; and moreover, a resistance-capacitance (RC) circuit is additionally arranged between the first PMOS transistor, the second PMOS transistor and a control device such that connection and disconnection of the PMOS transistor can be controlled.