Unidirectional Monophasic Pulse Generation for TMS
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Solution Overview
Problem
Conventional transcranial magnetic stimulation (TMS) devices face challenges in generating unidirectional monophasic pulses at high frequencies, leading to inefficiencies and safety issues due to high voltage roll-off and the use of semiconductor switches like thyristors, which result in bidirectional pulses that can reduce therapeutic effectiveness.
Innovation Solution
A method using a device with an adjustable voltage bank and semiconductor switching devices like IGBTs to generate unidirectional monophasic triangular pulses by controlling the voltage levels, allowing for energy recovery and minimizing roll-off, thereby creating a pulse suitable for therapeutic applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional semiconductor switches like thyristors are used in TMS devices, then the device can operate at high frequencies, but the pulse becomes bidirectional which reduces therapeutic effectiveness
Solution Approach 1:
The patent extracts only the beneficial first half of the bidirectional pulse (the unidirectional monophasic portion) by using a diode to block the second half. This allows the system to maintain high-frequency operation while delivering only the therapeutically effective unidirectional component to the brain, eliminating the counterproductive negative phase.
Solution Approach 2:
The pulse waveform is segmented into two distinct phases: a first half that delivers therapeutic stimulation and a second half that is blocked by the diode. This segmentation allows the system to operate at high frequencies while ensuring only the beneficial portion of each cycle reaches the brain, resolving the contradiction between frequency and therapeutic effectiveness.
2Force
If high voltage is used to generate strong magnetic fields, then the magnetic field strength is sufficient for therapy, but energy is dissipated as heat due to roll-off
Solution Approach 1:
The patent recovers energy that would otherwise be dissipated as heat during the second half of the pulse cycle. By using a diode to block this phase and incorporating energy recovery circuitry, the system captures and stores the energy from the collapsing magnetic field, preventing its conversion to heat and making it available for subsequent pulses.
Solution Approach 2:
The patent converts the potentially harmful energy dissipation into a beneficial resource. The energy that would normally be lost as heat during the second half of the pulse is instead recovered and stored, then reused to power subsequent pulses. This reduces overall energy consumption and minimizes heat generation while maintaining therapeutic magnetic field strength.
3Stability of the object's composition
If bidirectional pulses are delivered to the brain, then the pulse completes the full electrical cycle, but the second half reduces the net therapeutic effect
Solution Approach 1:
The patent extracts only the beneficial first half of the bidirectional pulse by using a diode to block the second half. This allows the system to maintain high-frequency operation while delivering only the therapeutically effective unidirectional component to the brain, eliminating the counterproductive negative phase.
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 method effectively generates unidirectional monophasic pulses that reduce energy dissipation as heat, enhancing therapeutic efficacy while minimizing adverse effects, as demonstrated by improved depression treatment outcomes in clinical studies.
Implementation Method 1
a coil through which said energy is passed, such that passage of said energy creates a magnetic field around said coil, and wherein said coil is positioned near an individual's brain such that said magnetic field thereby induces a current flow in said individual's brain
Data Source
AI summary
Method of generating a unidirectional monophasic triangular pulse using a device having a voltage bank with an adjustable voltage level; use of such a pulse to induce a current flow in an individual's brain. A voltage control device of the device comprises one or more switches, such as IGBTs, and/or one or more inductors. Energy from the voltage bank is discharged into a magnetic coil of the device. When the energy in the coil reaches a predetermined peak level, the voltage of the voltage bank is rapidly changed from a first level to a second level, such that the majority of the energy in the coil is recovered while the voltage level is at the second level. In some embodiments, the first level is 5 times the second level. In some embodiments, the second level is 5 times the first level.