Automatic control circuit for use in an electrosurgical generator
First Claim
Patent Images
1. A system for controlling an output of an electrosurgical generator comprising:
- a drive circuit for generating an output, the output being responsive to a feedback signal and operatively coupled to at least one electrode of the electrosurgical generator;
at least one sensing circuit operatively coupled to the at least one electrode for generating a first signal corresponding to a value of a voltage waveform present on the at least one electrode and a second signal corresponding to a value of a current waveform present on the at least one electrode;
a processing circuit for receiving the first and second signals, wherein the processing circuit implements a heterodyne polyphase demodulation and decimation filter for determining magnitudes and a power factor based on the voltage waveform and the current waveform, wherein the heterodyne polyphase demodulation and decimation filter includes a plurality of outputs, each of which is multiplied by a complex heterodyne of the form ejrθ
k where r ranges from 0 to the total number of filters of the heterodyne polyphase demodulation and decimation filter minus one, θ
is 2π
divided by the total number of filters, and k is the ratio of a modulating frequency θ
to a decimation frequency or an integer number of periods of the modulating frequency at an output sample rate, and wherein the modulating frequency is chosen in order to modulate the first signal and the second signal to a baseband frequency;
a determining circuit in communication with the processing circuit for generating an output signal as a function of a phase difference between the voltage waveform and the current waveform and/or real power; and
a control circuit for generating the feedback signal, the feedback signal representative of a difference between a value of the output signal and a reference value, the feedback signal operatively coupled to the drive circuit.
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Abstract
An automatic control circuit for an electrosurgical generator is herein disclosed. The automatic control circuit includes voltage and current sensing circuits, a processing circuit, a dosage calculating circuit, and control circuit. Samples of the voltage and current outputs are supplied to the processing circuit and the dosage calculating circuit to generate a dosage output signal. The dosage output signal is compared to a reference signal to generate a feedback signal that controls a drive circuit.
75 Citations
13 Claims
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1. A system for controlling an output of an electrosurgical generator comprising:
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a drive circuit for generating an output, the output being responsive to a feedback signal and operatively coupled to at least one electrode of the electrosurgical generator; at least one sensing circuit operatively coupled to the at least one electrode for generating a first signal corresponding to a value of a voltage waveform present on the at least one electrode and a second signal corresponding to a value of a current waveform present on the at least one electrode; a processing circuit for receiving the first and second signals, wherein the processing circuit implements a heterodyne polyphase demodulation and decimation filter for determining magnitudes and a power factor based on the voltage waveform and the current waveform, wherein the heterodyne polyphase demodulation and decimation filter includes a plurality of outputs, each of which is multiplied by a complex heterodyne of the form ejrθ
k where r ranges from 0 to the total number of filters of the heterodyne polyphase demodulation and decimation filter minus one, θ
is 2π
divided by the total number of filters, and k is the ratio of a modulating frequency θ
to a decimation frequency or an integer number of periods of the modulating frequency at an output sample rate, and wherein the modulating frequency is chosen in order to modulate the first signal and the second signal to a baseband frequency;a determining circuit in communication with the processing circuit for generating an output signal as a function of a phase difference between the voltage waveform and the current waveform and/or real power; and a control circuit for generating the feedback signal, the feedback signal representative of a difference between a value of the output signal and a reference value, the feedback signal operatively coupled to the drive circuit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for controlling an output of an electrosurgical generator comprising:
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a drive circuit for generating an output, the output being responsive to a feedback signal from at least one electrode operatively coupled to the electrosurgical generator; at least one sensing circuit operatively coupled to the at least one electrode that generates a first signal corresponding to a value of a voltage waveform present on the at least one electrode and a second signal corresponding to a value of a current waveform present on the at least one electrode; a processing circuit for receiving the first and second signals, wherein the processing circuit implements a heterodyne polyphase demodulation and decimation filter for determining magnitudes and a power factor based on the voltage waveform, the current waveform, and/or real power, wherein the heterodyne polyphase demodulation and decimation filter includes a plurality of outputs, each of which is multiplied by a complex heterodyne of the form ejrθ
k, where r ranges from 0 to the total number of filters of the heterodyne polyphase demodulation and decimation filter minus one, θ
is 2π
divided by the total number of filters, and k is the ratio of a modulating frequency θ
to a decimation frequency or an integer number of periods of the modulating frequency at an output sample rate, and wherein the modulating frequency is chosen in order to modulate the signal to a baseband frequency, and wherein the modulating frequency is chosen to modulate the first signal and the second signal to a baseband frequency; anda determining circuit in communication with the processing circuit that generates an output signal as a function of a phase difference between the voltage waveform and the current waveform and/or the real power. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification