Patent EP0136855A2 successfully refreshed from Google Patents.
EP0136855A2
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Electrosurgical generator
Assignee: Covidien AG
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Filing: 1984-09-10
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Granted: —
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Expires: 2004-09-10
Abstract
Abstract An electrosurgical generator having a source (12) of electrosurgical energy connected to a patient (24) and including control circuitry (16) for decreasing the-output power from the source with increasing patient impedance, the rate of power decrease being substantially greater than that which would result if the output voltage from the source were maintained constant over the range of increasing patient impedance. The control circuitry may, in particular, decrease the output power over the range of increasing patient impedance in accordance with the square of the impedance.
Inventors
- 👤 Frank Werner Harris
- 👤 Frederic Marshall Hulett Iii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 17:30
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/1206; A61B2018/00636; A61B2018/00696; A61B2018/00702; A61B2018/00773; A61B2018/00779; A61B2018/00827; A61B2018/00875; A61B2018/00892
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
63 words
An electosurgical generator comprising:- a source of electrosurgical energy; means adapted for connecting said source to a patient; and control means for decreasing the output power from said source with increasing patience impedance, the rate of power decrease being substantially greater that that which would result if the output voltage from the source were maintained constant over the range of increasing patient impedance.
Claim 2
Dependent Claim
63 words
An electosurgical generator comprising:- a source of electrosurgical energy; means adapted for connecting said source to a patient; and control means for decreasing the output power from said source with increasing patience impedance, the rate of power decrease being substantially greater that that which would result if the output voltage from the source were maintained constant over the range of increasing patient impedance.
Claim 3
Dependent Claim
29 words
A generator as in claim 1 where said control means decreases the output power over the range of increasing patient impedance in accordance with the square of said impedance.
Claim 4
Dependent Claim
91 words
An electrosurgical generator comprising:- an adjustable source of electrosurgical energy; means adapted for connecting said source to a load including a patient; and control means for adjusting the actual power delivered to said load from said source including:- means for determining the impedance of said load; means for computing a correction factor depending on the value of said impedance, said correction factor corresponding to a required load power; and means responsive to said correction factor for adjusting said source of electrosurgical power so that said actual power follows said required power.
Claim 5
Dependent Claim
91 words
An electrosurgical generator comprising:- an adjustable source of electrosurgical energy; means adapted for connecting said source to a load including a patient; and control means for adjusting the actual power delivered to said load from said source including:- means for determining the impedance of said load; means for computing a correction factor depending on the value of said impedance, said correction factor corresponding to a required load power; and means responsive to said correction factor for adjusting said source of electrosurgical power so that said actual power follows said required power.
Claim 6
Dependent Claim
25 words
A generator as in claim 3 where said control means includes a microprocessor for adjusting the actual power delivered to said load from said source.
Claim 7
Dependent Claim
34 words
A generator as in claim 3 including means for selecting a nominal power to be delivered to said load where said correction factor also depends on the nominal power to compute the correction factor.
Claim 8
Dependent Claim
16 words
A generator as in claim 5 where said nominal power extends from 0 to 70 watts.
Claim 9
Dependent Claim
29 words
A generator as in claim 3 including a heat sink for said source of electrosurgical energy, the heat sink having a capacity of not more than about four watts.
Claim 10
Dependent Claim
35 words
A generator as in claim 3 where, for all load impedances less than a predetermined value, said correction factor computing means so computes the correction factor that the current through said load remains substantially constant.
Claim 11
Dependent Claim
55 words
A generator as in claim 8 including means for selecting a nominal power to be delivered to said load and where said correction factor equals IMAX/ISEN where I MAX is the current through an impedance of said predetermined value having said nominal power applied thereto and I SEN is the actual current through said load.
Claim 12
Dependent Claim
14 words
A generator as in claim 8 where said predetermined value is about 70 ohms.
Claim 13
Dependent Claim
38 words
ll. A generator as in claim 3 where for all load impedances between predetermined first and second values, said correction factor computing means so computes the correction factor that the power delivered to said load remains substantially constant.
Claim 14
Dependent Claim
49 words
A generator as in claim 11 including means for selecting a nominal power to be delivered to said load and where said correction factor equals (P MAX /P LOAD ) 1/2 where P MAX is the nominal power and P LOAD is the actual power delivered to said load.
Claim 15
Dependent Claim
20 words
A generator as in claim 11 where said first and second predetermined values are respectively about 70 and 100 ohms.
Claim 16
Dependent Claim
35 words
A generator as in claim 3 where, for all load impedances greater than a predetermined value, said correction factor computing means so computes the correction factor that the voltage across said load remains substantially constant.
Claim 17
Dependent Claim
58 words
A generator as in claim 14 including means for selecting a nominal power to be delivered to said load and where said correction factor equals V MAX /V SEN where v MAX is the voltage across an impedance of said predetermined value having said nominal power applied thereto and V SEN is the actual voltage across said load.
Claim 18
Dependent Claim
14 words
A generator as in claim 14 where said predetermined value is about 100 ohms.
Claim 19
Dependent Claim
44 words
A generator as in claim 3 where, for all impedances greater than a predetermined value, said correction factor computing means so computes the correction factor that the power delivered to said load is proportional to the inverse of the square of the load impedance.
Claim 20
Dependent Claim
57 words
A generator as in claim 17 including means for selecting a nominal power to be delivered to said load and where said correction factor equals [(10,000P MAX /Z 2 LOAD )P LOAD ] 1/2 where P MAX is the nominal power, ZLOAD is the load impedance, and P LOAD is the actual power delivered to the load.
Claim 21
Dependent Claim
14 words
A generator as in claim 18 where said predetermined value is about 100 ohms.
Claim 22
Dependent Claim
129 words
An electrosurgical generator comprising:- an adjustable source of electrosurgical energy; means adapted for connecting said source to a load including a patient; and control means for adjusting the power delivered to said load from said source including:- means for selecting first and second modes of operation of said generator when said load impedance exceeds a predetermined value; means for maintaining the voltage across said load substantially constant for all values of load impedance in excess of said predetermined value in response to said first mode being selected, and means for reducing the power delivered to said load in accordance with the inverse of the square of the load impedance for all values of load impedance in excess of said predetermined value in response to said second mode being selected.
Claim 23
Dependent Claim
129 words
An electrosurgical generator comprising:- an adjustable source of electrosurgical energy; means adapted for connecting said source to a load including a patient; and control means for adjusting the power delivered to said load from said source including:- means for selecting first and second modes of operation of said generator when said load impedance exceeds a predetermined value; means for maintaining the voltage across said load substantially constant for all values of load impedance in excess of said predetermined value in response to said first mode being selected, and means for reducing the power delivered to said load in accordance with the inverse of the square of the load impedance for all values of load impedance in excess of said predetermined value in response to said second mode being selected.
Claim 24
Dependent Claim
25 words
A generator as in claim 20 where said control means includes a microprocessor for adjusting the actual power delivered to said load from said source.
Claim 25
Dependent Claim
71 words
A generator as in claim 20 where said means for adjusting the power delivered to said load includes:- means for computing a correction factor which is a function of the impedance of said load and the selected mode of operation; and means responsive to the correction factor for adjusting said source of electrosurgical current so that either said first or second mode of operation is implemented depending on the selected mode.
Claim 26
Dependent Claim
103 words
A generator as in claim 21 including means for selecting a nominal power to be delivered to said load and where said correction factor for said first mode of operation equals VMAX/VSEN where V MAX is the voltage across an impedance of said predetermined value having said nominal power applied thereto and VSEN is the actual voltage across said load and where the correction factor for said second mode of operation equals [(10,000P MAX /Z 2 LOAD )P LOAD ] 1/2 where PMAX is the nominal power, ZLOAD is the load impedance, and P LOAD is the actual power delivered to the load.
Claim 27
Dependent Claim
14 words
A generator as in claim 20 where said predetermined value is about 100 ohms.
References Cited (Backward Citations)
No citation records indexed.
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