Fingerswitch circuitry to reduce RF leakage current
First Claim
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1. An electrosurgical unit, comprising:
- a radiofrequency generator configured to generate electrosurgical energy, the radiofrequency generator including a detection circuit, the detection circuit having;
a resistor ladder having at least three resistors;
a single isolation transformer in electrical communication with the resistor ladder; and
the detection circuit being configured to detect a change in impedance across the isolation transformer and correlate the change in impedance to one of a plurality of predetermined energy thresholds.
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Abstract
An electrosurgical unit having detection circuitry for reducing radiofrequency leakage current in an electrosurgical unit. The electrosurgical unit includes a radiofrequency generator configured to generate electrosurgical energy, the radiofrequency generator including a detection circuit having a resistor ladder and an isolation transformer in electrical communication with the resistor ladder. The detection circuit is configured to detect a change in impedance across the isolation transformer and correlate the change in impedance to one of a plurality of predetermined energy thresholds.
198 Citations
10 Claims
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1. An electrosurgical unit, comprising:
a radiofrequency generator configured to generate electrosurgical energy, the radiofrequency generator including a detection circuit, the detection circuit having; a resistor ladder having at least three resistors; a single isolation transformer in electrical communication with the resistor ladder; and the detection circuit being configured to detect a change in impedance across the isolation transformer and correlate the change in impedance to one of a plurality of predetermined energy thresholds. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electrosurgical unit, comprising:
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a radiofrequency generator configured to generate electrosurgical energy, radiofrequency generator including a detection circuit, the detection circuit having; three finger switch conductors, each of the three finger switch conductors being configured to be in electrical communication with a corresponding finger switch on the electrosurgical hand piece, each finger switch having an open position and a closed position; each of the three finger switch conductors including at least one load resistor, the at least one load resistor in each of the three finger switch conductors collectively defining a resistor ladder and having a different resistance than any other load resistors; a single isolation transformer in electrical communication with the three finger switch conductors and the resistor ladder; a first radiofrequency oscillator configured to generate radiofrequency energy at a first frequency, the radiofrequency generator including a second radiofrequency oscillator configured to generate radiofrequency energy at a second frequency greater than the first frequency; a current sensing resistor disposed between the first radiofrequency oscillator and the isolation transformer, the current sensing resistor being configured to measure a change in current across the isolation transformer; a difference amplifier in communication with the current sensing resistor; a Sallen key filter in communication with the difference amplifier; and the detection circuit configured to detect a change in impedance across the isolation transformer when any one of the corresponding finger switches is placed in the closed position and to correlate the change in impedance to one of a plurality of predetermined energy thresholds, the plurality of predetermined energy thresholds including at least four predetermined energy thresholds, and wherein each of the four predetermined energy thresholds includes a 12 bit ADC value.
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Specification