Multi-Tap Transformer Phacoemulsification Driver
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Solution Overview
Problem
Existing ultrasonic phacoemulsification handpieces are limited to operating at a single frequency, requiring multiple handpieces for different cutting modes, which complicates procedures and leads to inefficient power delivery and distortion due to single output filter designs that struggle with maintaining consistent gain and rejecting third harmonic frequencies across multiple frequencies.
Innovation Solution
A system with a multi-tap transformer and configurable filter circuit that allows operation at multiple frequencies by switching passive electrical components, such as capacitors and inductors, to modify the tuned circuit response, ensuring consistent power delivery and minimizing third harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fixed output filter is used for a handpiece operating at multiple frequencies, then device complexity and cost are minimized, but third harmonic distortion increases and gain consistency deteriorates across different frequencies
Solution Approach 1:
The filter circuit transitions from a static single-frequency design to a dynamic multi-frequency design. The patent implements switchable filter configurations that can be dynamically adjusted based on the operating frequency (26 kHz or 38 kHz), allowing the system to optimize filter characteristics for each frequency while maintaining manageable complexity through controlled reconfiguration rather than permanent multi-frequency design.
Solution Approach 2:
The patent changes the electrical parameters of the filter circuit by switching between different capacitor and inductor configurations. Specifically, it adjusts the total capacitance and inductance values based on the operating frequency to maintain appropriate cutoff frequencies and impedance matching, thereby achieving consistent gain and harmonic rejection across multiple frequencies without requiring a completely different filter for each frequency.
2Reliability
If class AB linear drivers are used for multi-frequency handpiece operation, then frequency response flatness is maintained, but power efficiency deteriorates and heat generation increases
Solution Approach 1:
The patent replaces the linear class AB amplification mechanism with a switching class D amplification mechanism. This substitution transforms the continuous linear operation into pulsed switching operation with PWM modulation, dramatically improving power efficiency by minimizing the time the output transistors spend in the high-dissipation linear region while maintaining accurate frequency response through precise switching control and filtering.
Solution Approach 2:
The class D driver employs periodic switching action through pulse width modulation (PWM) to deliver power to the handpiece. Instead of continuous linear amplification, the system uses periodic on/off switching with variable duty cycles to control power delivery, which significantly reduces average power dissipation and heat generation while maintaining the required frequency response flatness through the filtering action of the tuned circuit.
3Loss of energy
If the driver operates in ON/OFF mode with digital signal, then power efficiency improves, but harmonic distortion increases requiring additional filtering
Solution Approach 1:
The patent introduces a tuned L-C filter circuit as an intermediary between the class D switching driver and the handpiece. This filter acts as a mediator that selectively passes the fundamental frequency while attenuating harmonic frequencies generated by the switching action. The filter is specifically designed with resonant frequency matching to the operating frequency (26 kHz or 38 kHz) to provide maximum impedance at harmonic frequencies, thereby reducing harmonic distortion delivered to the handpiece while maintaining the power efficiency benefits of class D operation.
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
Enables efficient operation of the ultrasonic handpiece at multiple frequencies, reducing procedural complexity and power inefficiencies, while maintaining accurate voltage and current control, thereby improving cutting efficiency and reducing distortion.
Implementation Method 1
a multi-tap transformer configured to receive the first sinusoidal signal at a first input tap and the second sinusoidal signal at a second input tap
Implementation Method 2
The operational frequencies are on or about the resonant frequencies of the handpiece
Implementation Method 3
The handpiece's ultrasonically actuated tip emulsifies the damaged lens
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
A system for performing an ocular surgical procedure is provided. The system includes a multiple frequency signal source, a configurable tuned output filter connected to the multiple frequency signal source, and a multiple frequency ultrasonic handpiece. The multiple frequency signal source operates at a first frequency and is configured to drive the configurable filter and the multiple frequency ultrasonic handpiece at the first frequency. The multiple frequency signal source operates at a second frequency and is configured to drive the configurable filter and the multiple frequency ultrasonic handpiece at the second frequency, and the design addresses third harmonic frequency issues for the multiple frequency ultrasonic handpiece. Switchable passive components, such as inductors, resistors, and/or capacitors may be employed in the configurable tuned output circuit, or alternately multiple similar circuits may be employed. Alternately, a multi-tap transformer may be provided.