EP1051948A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Automatic activation of electrosurgical generator bipolar output
Assignee: Covidien AG
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Filing: 2000-04-25
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Granted: —
•
Expires: 2020-04-25
Abstract
Abstract An automatic circuit that controls a surgical instrument having a pair of bipolar electrodes. The circuit comprises means for measuring the current between the pair of electrodes, an impedance detection circuit in electrical communication with the current measuring means, a comparator in electrical communication with the impedance detection circuit and a controller electrically connected to the comparator. The impedance detection circuit calculates the impedance between the electrodes based on the measured current and generates a first signal indicative of the calculated impedance. The comparator processes the first signal and generates an activation signal if the calculated impedance falls within a predetermined range of impedance values and generates a deactivation signal if the calculated impedance exceeds a deactivation threshold. The controller receives the activation and deactivation signals and transmits a first control signal to a radiofrequency energy output stage to activate the electrodes in response to the activation signal and transmits a second control signal to the radiofrequency output stage to deactivate the electrodes in response to the deactivation signal.
Inventors
- 👤 David Keppel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 15:40
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/1206; A61B2018/00636; A61B2018/00666; A61B2018/00696; A61B2018/00702; A61B2018/00708; A61B2018/00773; A61B2018/00827; A61B2018/00875; A61B2018/1246; A61B2018/126; A61B2018/1273
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
166 words
An automatic circuit that controls a surgical instrument having a pair of bipolar
electrodes, the circuit comprising: means for measuring the current between the pair of electrodes;
an impedance detection circuit in electrical communication with the current measuring
means for calculating the impedance based on the measured current, the impedance
detection circuit generating a first signal indicative of the calculated impedance; a comparator in electrical communication with the impedance detection circuit,
the comparator processing the first signal and generating an activation signal if the
calculated impedance falls within a predetermined range of impedance values and
generating a deactivation signal if the calculated impedance exceeds a deactivation
threshold; and a controller in electrical communication with the comparator for receiving the
activation and deactivation signals and transmitting a first control signal to a
radiofrequency energy output stage to activate the electrodes in response to the activation
signal and transmitting a second control signal to the radiofrequency output stage to
deactivate the electrodes in response to the deactivation signal.
Claim 2
Dependent Claim
39 words
The circuit of claim 1, further comprising a filter in electrical communication with the
current measuring means for blocking from the impedance detection circuit current from
the radiofrequency output stage which would otherwise interfere with the current
measuring means.
Claim 3
Dependent Claim
44 words
The circuit of claim 2, wherein the first signal is an analog signal and the automatic
circuit further comprises an analog to digital converter for receiving the first signal and
converting it to a digital signal, the digital signal being transmitted to the comparator.
Claim 4
Dependent Claim
47 words
The circuit of claim 3, wherein the current measuring means further comprises an
oscillator and a transformer for electrically coupling the bipolar electrodes to the
oscillator, a voltage across a primary winding of the transformer varying in accordance
with a variation of impedance between the bipolar electrodes.
Claim 5
Dependent Claim
26 words
The circuit of claim 4, further comprising an amplifier in electrical communication
with the oscillator, the oscillator and amplifier driving the transformer at a constant
voltage.
Claim 6
Dependent Claim
23 words
The circuit of claim 5, wherein the oscillator and transformer are driven at a
frequency of about 60 kHz to about 90 kHz.
Claim 7
Dependent Claim
21 words
The circuit of claim 1, wherein the activation range of impedance values is from
about 20 Ohms to about 500 Ohms.
Claim 8
Dependent Claim
13 words
The circuit of claim 7, wherein the deactivation threshold is about 2000 Ohms.
Claim 9
Dependent Claim
20 words
The circuit of claim 8, wherein the activation range of impedance values is from
about 20 to about 500 Ohms.
Claim 10
Dependent Claim
92 words
An electrosurgical system including a generator for use with bipolar electrodes
comprising: a current monitor for measuring the current between the bipolar electrodes;
an impedance detection circuit in electrical communication with the current monitor to
calculate the impedance between the electrodes based on the measured current; a comparator for comparing the calculated impedance to an activation range of
impedance values; and a controller for automatically activating the generator if the calculated impedance
falls within the activation range of impedance values and deactivating the generator if the
calculated impedance exceeds a deactivation threshold.
Claim 11
Dependent Claim
31 words
The system of claim 10, further comprising a filter for blocking energy from the
bipolar output from the impedance detection circuit, the filter being in electrical
communication with the current monitor.
Claim 12
Dependent Claim
48 words
The circuit of claim 11, further comprising a transformer in electrical communication
with the impedance detection circuit wherein the transformer is driven at a constant
voltage and the voltage of a primary winding of the transformer varies in accordance with
a variation of the impedance between the electrodes.
Claim 13
Dependent Claim
31 words
The system of claim 11, wherein the impedance detection circuit is in electrical
communication with a transformer, the transformer transmitting a voltage signal
proportional to the tissue impedance between the electrodes.
Claim 14
Dependent Claim
36 words
The system of claim 13, further comprising in analog to digital converter in electrical
communication with the impedance detection circuit for converting an analog impedance
signal from the impedance detection circuit to a digital impedance signal.
Claim 15
Dependent Claim
38 words
The system of claim 14, wherein the comparator and the controller form part of a
microprocessor and the microprocessor receives and processes the digital impedance
signal and generates a digital control signal for activating and deactivating the generator.
Claim 16
Dependent Claim
21 words
The system of claim 10, wherein the activation range of impedance values is from
about 20 Ohms to about 500 Ohms.
Claim 17
Dependent Claim
13 words
The system of claim 16, wherein the deactivation threshold is about 2000 Ohms.
Claim 18
Dependent Claim
21 words
The system of claim 18, wherein the activation range of impedance values is from
about 20 Ohms to about 500 Ohms.
References Cited (Backward Citations)
No citation records indexed.
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