Electrosurgical generator and method for cross-checking output power

• US 20060020261A1
• Filed: 08/05/2005
• Published: 01/26/2006
• Est. Priority Date: 11/19/2002
• Status: Active Grant

• Current Assignee: Jim Pantera, Tim Refior
• Original Assignee: Jim Pantera, Tim Refior
• Inventors: Pantera, Jim, Refior, Tim
• Granted Patent: US 7,972,329 B2
• Time in Patent Office: Days
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00892 Voltage

Abstract

The functionality and the output power delivered are evaluated in an electrosurgical generator by calculating first and second values related to the output power delivered by using separate first and second computations. The two calculated values are compared, and an error condition is indicated when the two values differ by a predetermined amount. The separate computations, coupled with the other separate activities of measuring, averaging and sampling the output current and voltage measurements, serve as an effective basis for detecting errors caused by malfunctions or equipment failure. The error condition may be used to as a basis to terminate the output power delivery or indicate the error.

Claims

1. An electrosurgical generator which delivers electrosurgical output power and which regulates the amount of output power delivered from feedback information, comprising:

a plurality of sensors connected to sense current and voltage of the output power delivered and operative to supply current and voltage measurement signals related to the amount of current and voltage sensed;

a control processor receptive of the current and voltage measurement signals and which performs a first computation based on the current and voltage measurement signals to derive the feedback information and to derive a first value related to the output power delivered;

a monitor processor receptive of the current and voltage measurement signals and which performs a second computation separate from the first computation to derive a second value related to the output power delivered;

a communication path connecting the control and monitor processors over which the control and monitor processors communicate information including the first and second values, one of the control or monitor processors receiving the first and second values being a comparison processor;

the comparison processor executing a comparison procedure for comparing the first and second values and delivering an error condition signal when the first and second values differ by a predetermined amount; and

the electrosurgical generator responding to the assertion of the error condition signal by one of either issuing an error indication or terminating the delivery of output power.

5. An electrosurgical generator as defined in claim 1, further comprising:

a system processor which oversees functionality of the control and monitor processors, the system processor connected to the communication path to communicate with the control and monitor processors, the system processor rather than the monitor or control processors being the comparison processor which issues the error indication.

6. An electrosurgical generator as defined in claim 5, wherein:

the control processor executes the first calculation;

the monitor processor executes the second calculation; and

the control and monitor processors send the first and second values to the system processor over the communication path.

7. An electrosurgical generator as defined in claim 5, further comprising:

an alarm connected to the system processor and responsive to the error condition signal to deliver an alarm.

8. An electrosurgical generator as defined in claim 5, wherein:

the system controller responding to the assertion of the error condition signal by logging an error occurrence.

9. A method as defined in claim 5, wherein:

the system processor responds to the error condition signal by incrementing a count number with each instance where the first and second values differ by more than the predetermined amount;

the system processor indicates the error condition upon the count number reaching a predetermined threshold.

10. A method as defined in claim 9, wherein:

the system processor resets the count number to a predetermined count value upon the first and second values not differing by the predetermined amount within a predetermined number of most recent comparisons.

11. A method as defined in claim 9, wherein:

the system processor increments the count number only with each instance where the first and second values differ by the predetermined amount within a predetermined number of most recent comparisons.

13. A method as defined in claim 1, further comprising:

sensing the output voltage and the output current separately for use in the first and second computations; and

calculating the first value using values of the sensed output voltage and the sensed output current which are separate from values of the sensed output voltage and the sensed output current used in calculating the second value.

14. A method as defined in claim 13, further comprising:

sensing the output current by sensing a plurality of current values for each of the first and second computations;

sensing the output voltage by sensing a plurality of voltage values for each of the first and second computations;

performing a root mean square computation on each of the sensed pluralities of current values and on each of the sensed pluralities of voltage values to obtain a root mean square current value of each of the pluralities of sensed current values and to obtain a root mean square voltage value of each of the pluralities of sensed voltage values; and

using the root mean square current values and the root mean square voltage values in the first and second computations to calculate the first and second values.

15. A method as defined in claim 13, wherein the electrosurgical generator includes a control processor which controls the delivery of the electrosurgical output power and also includes a monitor processor which monitors functions of the electrosurgical generator, and further comprising:

performing the first calculation using the control processor; and

performing the second calculation using the monitor processor.

2. An electrosurgical generator as defined in claim 2, wherein the plurality of sensors includes:

a first current sensor for supplying a first current sense measurement signal used in performing the first computation;

a second current sensor for supplying a second current sense measurement signal used in performing the second computation;

a first voltage sensor for supplying a first voltage sense measurement signal used in performing the first computation; and

a second voltage sensor for supplying a second voltage sense measurement signal used in performing the second computation.

3. An electrosurgical generator as defined in claim 2, wherein the control and monitor processors are digital processors.

4. An electrosurgical generator as defined in claim 3, further comprising:

a first analog to digital converter (ADC) connected to the first current and voltage sensors and operative to convert the first current and voltage sense measurement signals, respectively, into digital form;

a first direct memory access (DMA) controller;

a first buffer connected to the first ADC and to the first DMA controller, the first DMA controller placing the digital form of the first current and voltage sense measurement signals into the first buffer;

the control processor connected to the first buffer to read the digital form of the first current and voltage sense measurement signals from the first buffer to perform the first computation;

a second analog to digital converter (ADC) connected to the second current and voltage sensors and operative to convert the second current and voltage sense measurement signals, respectively, into digital form;

a second direct memory access (DMA) controller;

a second buffer connected to the second ADC and to the second DMA controller, the second DMA controller placing the digital form of the second current and voltage sense measurement signals into the second buffer; and

the monitor processor connected to the second buffer to read the digital form of the second current and voltage sense measurement signals from the second buffer to perform the second computation.

12. A method of evaluating functionality of an electrosurgical generator which delivers electrosurgical output power established by an output current and an output voltage, comprising:

sensing the output voltage and the output current;

calculating with a first computation a first value related to the output power delivered by using the sensed output current and the sensed output voltage;

calculating with a second computation separate from the first computation a second value related to the output power delivered by using the sensed output current and the sensed output voltage;

comparing the first and second values; and

indicating an error condition when the first and second values differ by a predetermined amount.

16. A method as defined in claim 12, further comprising:

terminating delivery of the electrosurgical output power upon indicating an error condition.

17. A method as defined in claim 12, further comprising:

incrementing a count number with each instance where the first and second values differ by more than the predetermined amount; and

indicating the error condition upon the count number reaching a predetermined threshold.

18. A method as defined in claim 17, further comprising:

resetting the count number to a predetermined count value upon the first and second values not differing by the predetermined amount within a predetermined number of most recent comparisons.

19. A method as defined in claim 17, further comprising:

incrementing the count number only with each instance where the first and second values differ by the predetermined amount within a predetermined number of most recent comparisons.