Bipolar RF generator

• US 5,318,563 A
• Filed: 06/04/1992
• Issued: 06/07/1994
• Est. Priority Date: 06/04/1992
• Status: Expired due to Term

• Current Assignee: VFSC Delaware, Inc.
• Original Assignee: Valley Forge Scientific Corporation (Bausch Health Cos., Inc.)
• Inventors: Solt, David L., Acorcey, Robert R., Malis, Leonard I., DiJoseph, Frank, Klaus, Harry E., Malis, Jerry L.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US07/893,308
• Time in Patent Office: 733 Days
• Field of Search: 606/32-40, 128/419 R, 128/419 B
• US Class Current: 606/38
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/0066 without feedback, i.e. open loop control
• CPC Class Codes: A61B 2018/126 bipolar
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

An electrosurgical bipolar RF generator apparatus includes a bipolar electrode. An aperiodic sequence of uniform width bursts of a high frequency signal are electronically synthesized. Substantially identical decaying amplitude envelopes are impressed on the bursts of the high frequency signal. Each of the envelopes has a predetermined rate of change from a preselected initial amplitude. The impressed bursts of the high frequency signal are applied to the electrode. The electrical apparatus operates in a cut mode or a coagulation mode. The apparatus includes a power supply for providing a variable DC voltage, a short circuit detect circuit for detecting a short circuit at the bipolar electrode, and an open circuit detector for detecting an open circuit at the bipolar electrode.

Claims

1. An electrosurgical bipolar RF generator apparatus comprising a bipolar electrode, means for electronically synthesizing an aperiodic sequence of uniform width bursts of a high frequency signal, means for impressing substantially identical decaying amplitude envelopes on said bursts of a higher frequency signal, each of said envelopes having a predetermined rate of change from a preselected initial amplitude and means for applying said impressed bursts of said high frequency signal to said electrode, said electrosurgical apparatus operating in a cut mode or a coagulation mode, the improvement comprising:

a power supply for providing a variable DC voltage;

a coagulation waveform generator for receiving and modulating said DC voltage;

signal driving means for driving the flow of the modulated DC voltage at a predetermined rate;

amplifying means for receiving and amplifying said modulated DC voltage, said amplifying means comprising a plurality of drivers which are alternately driven to produce a predetermined voltage level having a predetermined impedance level; and

converting means for converting the alternately driven plurality of drivers and modulated DC voltage to an amplified RF voltage signal;

output means for identifying whether said amplified RF voltage signal is a cut signal or a coagulation signal as determined by an impedance requirement, said output means providing impedance matching between the amplified RF voltage signal and said bipolar electrode.

2. The electrosurgical apparatus according to claim 1, wherein said amplifying means is a bridge amplifier.

3. The electrosurgical apparatus according to claim 2, wherein the bridge amplifier is an H-type bridge amplifier.

4. The electrosurgical apparatus according to claim 2, wherein the bridge amplifier includes four drivers.

5. The electrosurgical apparatus according to claim 4, wherein each bridge amplifier driver comprises a MOSFET transistor.

6. The electrosurgical apparatus according to claim 1, wherein said output means is an RF transformer.

7. The electrosurgical apparatus according to claim 1, wherein the DC voltage signal is in the range of 0 to 225.

8. The electrosurgical apparatus according to claim 1, wherein the modulated DC voltage signal is a damped sinusoidal signal.

9. The electrosurgical apparatus according to claim 1, wherein said signal driving means drives the modulated DC voltage at a 1 MHz rate.

10. An electrosurgical bipolar RF generator apparatus comprising a bipolar electrode, means for electronically synthesizing an aperiodic sequence of uniform width bursts of a high frequency signal, means for impressing substantially identical decaying amplitude envelopes on said bursts of said high frequency signal, each of said envelopes having a predetermined rate of change from a preselected initial amplitude and means for applying said impressed bursts of said high frequency signal to said electrode, said electrosurgical apparatus operating in a cut mode or a coagulation mode, the improvement comprising:

a high voltage power supply comprising;

a voltage source which generates an AC voltage signal;

converting means for converting the AC voltage signal to a DC voltage signal;

electronic switching means for receiving the DC voltage signal;

a flyback transformer for receiving the DC voltage signal when the electronic switching means is conducting, the flyback transformer ramping linearly while the electronic switching means is conducting;

reference signal means for generating a reference voltage signal, said reference signal means corresponding to a desired output voltage signal;

comparing means for comparing the ramped DC voltage signal from the flyback transformer with said reference voltage signal, said comparing means determining if said ramped DC voltage signal exceeds said reference voltage signal;

control means for controlling said ramped DC voltage signal from said flyback transformer such that said ramped DC voltage signal is prevented from exceeding said reference voltage signal, said control means preventing said desired output voltage signal from exceeding said reference voltage signal.

11. The electrosurgical apparatus according to claim 10, wherein a change in the reference voltage signal results in a proportional change in the output voltage signal from the power supply.

12. The electrosurgical apparatus according to claim 10, wherein the reference voltage does not exceed three volts.

13. The electrosurgical apparatus according to claim 10, wherein the output voltage signal is preferably less than 225 volts.

14. The electrosurgical apparatus according to claim 10, wherein the control means comprises a pulse width modulation controller.

15. An electrosurgical bipolar RF generator apparatus comprising a bipolar electrode, means for electronically synthesizing a aperiodic sequence as a uniform width burst of a high frequency signal, means for impressing substantially identical decaying amplitude envelopes on said burst of said high frequency signal, each of said envelopes having a predetermined rate of change from a preselected initial amplitude, means for applying said impressed bursts of said high frequency signal to said electrode, the improvement to the electrosurgical apparatus comprising:

an open circuit detector including;

a waveform generator for producing a high frequency sinusoidal audio signal;

buffering means for buffering the audio signal;

voltage detecting means for detecting an output voltage signal at the bipolar electrode;

comparing means for comparing the output voltage signal sensed at the bipolar electrode with a threshold voltage;

impedance means for impeding the flow of the audio signal if the output voltage signal from the bipolar electrode exceeds the threshold voltage; and

power disabling means for disabling power to the bipolar electrode when the threshold voltage is exceeded wherein said disabling power is removed when the voltage signal no longer exceeds the threshold voltage.

16. The electrosurgical apparatus according to claim 15, wherein said high frequency sinusoidal audio signal is 3 volts peak to peak and 20 KHz.

17. The electrosurgical apparatus according to claim 15, further comprising signal level detecting means for detecting the signal level of the output voltage signal.