Microprocessor controlled electrosurgical generator
First Claim
1. An electrosurgical generator comprising:
- terminal means responsive to application of a cutting signal thereto for selectively delivering the cutting signal to a surgical site;
signal generator means for providing a high frequency signal;
adjustable gain amplifier means responsive to said high frequency signal for applying said high frequency signal to said terminal means as said cutting signal at an amplitude determined by the gain of said amplifier means; and
gain control means for adjusting the gain of said amplifier means, said gain control means comprising;
means for generating an alternating signal having a first predetermined frequency;
control means for providing a control signal of variable duty cycle by inhibiting said alternating signal during a selected portion of each alternating signal cycle; and
further means responsive to the duty cycle of said control signal for adjusting the gain of said amplifer means;
wherein said control means comprises;
a rectifier bridge for converting said alternating signal from a signal having successive half-cycles of alternating polarity to a signal having successive half-cycles with the same polarity, said rectifier bridge including first and second controlled rectifier means connected to conduct during opposite half-cycles of said alternating signal in response to respective applied first and second trigger signals;
means for establishing a variable binary word; and
trigger generator means for providing said first and second trigger signals at variable times during respective half-cycles of said alternating signal as a prescribed function of said established binary word.
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Accused Products
Abstract
A microprocessor controlled electrosurgical generator provides plural ground-isolated and mutually isolated monopolar r-f cutting signals for respective surgical pencils to permit plural surgeons to use the same generator while maintaining independent control over output power and mode selection. A bipolar output signal is also isolated from ground and from the monopolar signals so that the removal of the dispersive patient return pad is not required when changing between monopolar and bipolar operation. Adjustment of the r-f cutting signal power level is effected by providing an adjustable d.c. bias level for an output amplifier. The d.c. bias level is derived from an a.c. control signal which is duty-cycle modulated in accordance with selected r-f power level settings. Digital phase control is employed to change the control signal duty cycle by subdividing the control signal cycle into precise count intervals and triggering a gate to pass the control signal through a rectifier to a filter for only the selected number of count intervals in each cycle as determined by a pre-settable counter. Negative feedback of the cutting signal to the input terminal of the output amplifier provides system stability during open circuit operation.
491 Citations
20 Claims
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1. An electrosurgical generator comprising:
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terminal means responsive to application of a cutting signal thereto for selectively delivering the cutting signal to a surgical site; signal generator means for providing a high frequency signal; adjustable gain amplifier means responsive to said high frequency signal for applying said high frequency signal to said terminal means as said cutting signal at an amplitude determined by the gain of said amplifier means; and gain control means for adjusting the gain of said amplifier means, said gain control means comprising; means for generating an alternating signal having a first predetermined frequency; control means for providing a control signal of variable duty cycle by inhibiting said alternating signal during a selected portion of each alternating signal cycle; and further means responsive to the duty cycle of said control signal for adjusting the gain of said amplifer means; wherein said control means comprises; a rectifier bridge for converting said alternating signal from a signal having successive half-cycles of alternating polarity to a signal having successive half-cycles with the same polarity, said rectifier bridge including first and second controlled rectifier means connected to conduct during opposite half-cycles of said alternating signal in response to respective applied first and second trigger signals; means for establishing a variable binary word; and trigger generator means for providing said first and second trigger signals at variable times during respective half-cycles of said alternating signal as a prescribed function of said established binary word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An electrosurgical generator comprising:
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terminal means responsive to application of a cutting signal thereto for selectively delivering the cutting signal to a surgical site; signal generator means for providing a high frequency signal; adjustable gain amplifier means responsive to said high frequency signal for applying said high frequency signal to said terminal means as said cutting signal with a variable peak amplitude determined by the gain of said amplifier means; and gain control means for adjusting the gain of said amplifier means, said gain control means comprising; manually adjustable means for providing a selectively adjustable signal representing a desired power level of said cutting signal; means for generating an alternating signal having a first predetermined frequency; control means responsive to said selectively adjustable signal for providing a control signal of variable duty cycle by inhibiting said alternating signal during a selected portion of each alternating signal cycle as a function of said desired power level; and further means responsive to the duty cycle of said control signal for adjusting the gain of said amplifier means to vary the peak amplitude of said cutting signal; wherein the gain of said amplifier means is a function of a d.c. level of a bias signal; and wherein said further means comprises; means for converting the control signal to a d.c. signal having a d.c. level proportional to the control signal duty cycle; and
means for applying said d.c. signal to said amplifier means as said bias signal. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification