Ultrasonic Handpiece Driver With Linear Amplifier Headroom Control

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Solution Overview

Problem

Existing ultrasonic surgical tools require multiple control consoles to accommodate different handpieces with varying drive signal requirements, leading to increased operational costs and administrative burdens, and existing consoles often fail to generate optimal drive signals across a wide range of frequencies and voltages.

Innovation Solution

A console that can generate drive signals over a wide range of frequencies and voltages, minimizing energy loss and enabling rapid signal ramp-up, with features like MOSFET transistors and a processor to maintain headroom voltage, ensuring efficient operation of handpieces with different characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional control console is used with fixed frequency and voltage output, then the console structure is simple, but it cannot accommodate different handpieces with varying drive signal requirements

Engineering Contradiction:
Improvecompatibility with different handpiecesVSAvoidconsole structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic frequency and voltage control in the console through a processor that continuously adjusts drive signal parameters based on handpiece impedance feedback. The frequency can be varied between 20-100 kHz and voltage between 0-500 Vpp, allowing the same console to adapt to different handpiece requirements without hardware changes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The console changes operational parameters (frequency and voltage) dynamically to match different handpiece characteristics. The system measures handpiece impedance and adjusts the drive signal parameters accordingly, enabling one console to control multiple handpiece types with different resonant frequencies and power requirements.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the console generates optimal drive signals rapidly, then tissue removal efficiency improves, but energy loss increases

Engineering Contradiction:
Improvetissue removal efficiencyVSAvoidenergy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system employs feedback control by monitoring handpiece impedance and adjusting the drive signal in real-time. The processor continuously adapts the frequency and voltage based on impedance measurements, ensuring optimal power transfer and minimizing energy loss while maintaining high tissue removal efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The drive signal is applied in periodic cycles with rapid ramp-up and ramp-down phases. The console generates bursts of ultrasonic energy at optimal parameters followed by brief intervals, allowing efficient tissue removal while reducing overall energy consumption compared to continuous operation.

Inventive Principle:
Principle #19Periodic action

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 console provides efficient and responsive drive signals to various handpieces, reducing the need for multiple consoles and improving tissue removal efficiency by minimizing energy loss and time lag.

Implementation Method 1

an ultrasonic surgical tool includes a handpiece that contains at least one piezoelectric driver

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

Other ultrasonic tips remove tissue by inducing cavitation in the tissue and surrounding fluid. Cavitation occurs as a result of the tip head moving back and forth. Specifically, as a result of these vibrations, small cavities form in the fluid located immediately adjacent the tissue.

Methodology Applied
Scientific EffectCavitation: Cavitation

Implementation Method 3

The control console supplies an AC drive signal to the driver. The control console is able to source drive signals over both a wide range of frequencies and a wide range of potentials.

Methodology Applied
Scientific EffectElectrical amplification:

Data Source

PatentEP4371534B1System and method for driving an ultrasonic handpiece with a linear amplifier
Publication Date: 2025.10.29 STRYKER CORP
  • EP4371534B1 patent drawingFigure 1
  • EP4371534B1 patent drawingFigure 2
  • EP4371534B1 patent drawingFigure 3

AI summary

A control console (50) for supplying an AC drive signal to the power generating unit (344) of a powered surgical tool (330) is disclosed, wherein the console (50) includes a transformer (250) with: a primary winding (252) with opposed ends and a center tap to which a DC voltage is applied; and a secondary winding (258) across which the AC drive signal is induced for application to the tool power generating unit (344). The console (5) also includes transistors (162, 184) tied to the ends of the transformer primary winding (252) and ground that are selectively turned on/off to cause an AC voltage to develop across the primary winding (252), wherein the transistors (162, 184) are operated as active resistors. Also included is a variable DC power supply assembly regulating the level of the DC voltage applied to the center tap of the transformer primary winding (252). Further provided is a headroom monitor (190) connected to the ends of the transistors (162, 184) connected to the ends of the transformer primary winding (252), wherein said headroom monitor (190) is configured to, based on the voltages present at the ends of the transistors (162, 184), generate a headroom signal representative of the headroom voltages at the transistors (162, 184). The variable DC power supply assembly includes a processor (80) to which the headroom signal from said headroom monitor (190) is applied and said variable power supply assembly is configured to, based on the headroom signal, set the level of the DC voltage applied to the center tap of the transformer primary winding (252) so that saturation voltages are applied to the transistors (162, 184).