Patent US7077853B2 successfully refreshed from Google Patents.
US7077853B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for calculating transducer capacitance to determine transducer temperature
Assignee: Ethicon Endo Surgery Inc
•
Filing: 2001-10-10
•
Granted: 2006-07-18
•
Expires: 2021-10-10
Abstract
Abstract A method for calculating the capacitance of a transducer (C 0 ) without knowing the exact resonance frequency of a transducer/blade combination is achieved by sweeping across a broad frequency range which contains resonant and non-resonant frequencies where C 0 can be measured. A pre-defined frequency range is set independently of the resonance frequency of a specific transducer/blade combination. C 0 of the transducer/blade is measured at several different frequencies within the pre-defined frequency range to ensure that invalid C 0 measurements are disregarded, and the temperature of the transducer is calculated based on valid C 0 measurements. The determined transducer temperature, based on C 0 measurements, can be used to optimize performance and/or provide a safety shutdown mechanism for the generator.
Inventors
- 👤 Kenneth S. Kramer
- 👤 Eitan T. Wiener
- 👤 William T. Donofrio
- 👤 Kevin Houser
- 👤 Foster B. Stulen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:25
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/32; A61B17/320068; A61B2017/00017; A61B2017/00022; A61B2017/00084; A61B2017/00115; A61B2017/00119; A61B2017/320069; A61B2017/320071; A61B2017/320089
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
186 words
A method for determining temperature of a transducer of an ultrasonic hand piece, comprising the steps of: determining a shunt capacitance of the transducer comprising the steps of; applying an ultrasonic drive signal to the transducer across a pre-defined frequency range; measuring the hand piece impedance at fixed frequency intervals to obtain a measured impedance at each frequency interval; performing a curve fit based on each measured impedance at each frequency interval to obtain a curve fit equation; solving the curve fit equation at equally spaced frequency values to obtain a group of distinct impedance values; calculating a shunt capacitance based on each distinct impedance value; discarding a maximum and a minimum calculated shunt capacitance value to obtain a residual group of shunt capacitances; and averaging the residual group of shunt capacitances to obtain a final shunt capacitance value of the hand piece; calculating the temperature of the transducer based on the shunt capacitance of the transducer; and providing a warning to a user of the hand piece if one of the temperature of the transducer and a rate of change of the temperature is excessive.
Claim 2
Independent Claim
186 words
A method for determining temperature of a transducer of an ultrasonic hand piece, comprising the steps of: determining a shunt capacitance of the transducer comprising the steps of; applying an ultrasonic drive signal to the transducer across a pre-defined frequency range; measuring the hand piece impedance at fixed frequency intervals to obtain a measured impedance at each frequency interval; performing a curve fit based on each measured impedance at each frequency interval to obtain a curve fit equation; solving the curve fit equation at equally spaced frequency values to obtain a group of distinct impedance values; calculating a shunt capacitance based on each distinct impedance value; discarding a maximum and a minimum calculated shunt capacitance value to obtain a residual group of shunt capacitances; and averaging the residual group of shunt capacitances to obtain a final shunt capacitance value of the hand piece; calculating the temperature of the transducer based on the shunt capacitance of the transducer; and providing a warning to a user of the hand piece if one of the temperature of the transducer and a rate of change of the temperature is excessive.
Claim 3
Dependent Claim
169 words
The method of claim 1 , wherein said determining step comprises the steps of: applying an ultrasonic drive signal to the hand piece/blade across a pre-defined frequency range; measuring a first hand piece shunt capacitance when a user first activates the hand piece/blade; measuring a second hand piece/blade shunt capacitance when the surgeon deactivates the hand piece/blade; calculating a time difference between when the hand piece/blade is activated and deactivated using a time when the first measured hand piece/blade shunt capacitance is obtained and a time when the second measured hand piece/blade shunt capacitance is obtained; computing a rate of change value of the hand piece/blade shunt capacitance using the calculated time difference; determining whether the rate of change value of the hand piece/blade shunt capacitance is greater than a predetermined threshold above a value stored in memory; and providing a warning to the user, if the rate of change value of the hand piece/blade shunt capacitance is greater than the predetermined threshold above the value stored in memory.
Claim 4
Dependent Claim
19 words
The method of claim 2 , wherein the predefined frequency range is from approximately 34 kHz to 44 kHz.
Claim 5
Dependent Claim
60 words
The method of claim 2 , wherein said computing step comprises the step of: dividing a difference between the first measured hand piece/blade shunt capacitance and the second measured hand piece/blade shunt capacitance by a difference in time between when the first measured hand piece/blade shunt capacitance is obtained and when the second measured hand piece/blade shunt capacitance is obtained.
Claim 6
Dependent Claim
21 words
The method of claim 2 , wherein the predetermined threshold is a shunt capacitance rate of change value stored in memory.
Claim 7
Dependent Claim
13 words
The method of claim 5 , wherein the predetermined threshold is 120 pF/min.
Claim 8
Dependent Claim
62 words
The method of claim 1 , wherein the curve fit is performed in accordance with the relationship: C 0 = 1 2 π f Z HP , where a, b and c are constants which are calculated via the curve fit and f 0 is a fixed frequency at which the hand piece impedance is measured.
Claim 9
Dependent Claim
19 words
The method of claim 1 , wherein the pre-defined frequency range is from approximately 34.5 kHz to 44.5 kHz.
Claim 10
Dependent Claim
14 words
The method of claim 1 , wherein the fixed frequency Interval is 50 Hz.
Claim 11
Dependent Claim
169 words
The method of claim 1 , wherein the shunt capacitance is calculated in accordance with the relationship: C o = - ( 1 f o ) * ( Z HP 2 - 1 R p 2 ) 1 2 - ( C v1 * C v2 ) ( C v1 + C v2 ) + 1 ( f 0 z ≠ L t ) - C c - C pcb , where C 0 is the shunt capacitance, f 0 is a fixed frequency at which the hand piece impedance is measured, Z HP is the hand piece impedance at the fixed frequency F 0 , R p is a value of a limiting resistor, C v1 and C v2 are values of voltage dividing capacitors, L t is a value stored in memory of the generator which represents a transducer tuning inductor, C c is a capacitance of a hand piece cable and C pcb is a contribution of capacitance from a printed circuit board in the generator.
Claim 12
Dependent Claim
17 words
The method of claim 1 , wherein the group of distinct impedance values comprises eleven impedance values.
Claim 13
Dependent Claim
19 words
The method of claim 1 , wherein the equally spaced frequency values are spaced apart at 1000 Hz intervals.
References Cited (Backward Citations)
US2917691A
Cited
US3608553A
Cited
US3781717A
Cited
US4689515A
Cited
US5001649A
Cited
US5180363A
Cited
US5425704A
Cited
US5026387A
Cited
US5112300A
Cited
US5400267A
Cited
US5449370A
Cited
US5707369A
Cited
US5735280A
Cited
US5630420A
Cited
US6655386B1
Cited
US5879364A
Cited
US6090123A
Cited
US6017354A
Cited
US5968007A
Cited
US6019775A
Cited
US6066135A
Cited
JP2000175926A
Cited
US6454781B1
Cited
US6626926B2
Cited
US6679899B2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2009-07-17 | 2010-01-16 | 2010-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-07-17 | 2014-01-16 | 2014-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-07-17 | 2018-01-16 | 2018-07-18 | $7700.00 | Window Closed / Lapsed |