System and method for closed loop monitoring of monopolar electrosurgical apparatus
An electrosurgical system is disclosed comprising a generator configured to electrosurgical coagulation waveforms. The generator includes a closed loop control system for controlling the electrosurgical coagulation waveforms. The closed loop control system includes a sensor configured to sense a tissue property and/or an energy property and to transmit the tissue property and/or the energy property as one or more sensor signals having an amplitude. The control system also includes a gain controller configured to process the at least one sensor signal to reduce the amplitude of the sensor signals and to obtain a signal to noise ratio of the at sensor signals within a predetermine range. A microprocessor coupled to the generator and is configured to adjust the electrosurgical coagulation waveforms as a function of the sensor signals.
1. An electrosurgical system comprising:
a generator configured to generate at least one electrosurgical coagulation waveform, the generator includes a closed loop control system that controls the at least one electrosurgical coagulation waveform, the closed loop control system including:
a sensor configured to sense at least one of a tissue property and an energy property and transmit the at least one of a tissue property and an energy property to a gain controller as a voltage sensor signal having an amplitude;
the gain controller configured to process the voltage sensor signal to reduce the amplitude of the voltage sensor signal and obtain a signal to noise ratio of the voltage sensor signal within a predetermine range;
the gain controller being a voltage gain controller that includes:
a sensor voltage scaler control configured to scale the amplitude of the voltage sensor signal and to generate a scaled sensor signal;
a gain control configured to process a variable DC level control signal to generate a gain control signal; and
a multiplier coupled to the sensor voltage scaler and the gain control, the multiplier configured to multiply in real-time the scaled sensor signal and the gain control signal to normalize the voltage sensor signal independent of the amplitude thereof; and
a microprocessor coupled to the generator and configured to adjust the at least one electrosurgical coagulation waveform as a function of the voltage sensor signal.
2. An electrosurgical system according to claim 1 , wherein the voltage gain controller includes:
an anti-alias filter configured to substantially block a harmonic radio frequency.
3. An electrosurgical system according to claim 1 , wherein the microprocessor includes a buffer sized to store an integer multiple of a repetition rate of the voltage sensor signal.
4. An electrosurgical system according to claim 1 , wherein the microprocessor is configured to calculate at least one of a RMS value, a peak value, and crest factor of the voltage sensor signal and adjust the at least one electrosurgical coagulation waveform as a function thereof.
5. An electrosurgical system comprising:
a generator configured to generate at least one electrosurgical coagulation waveform, the generator includes a closed loop control system which controls the at least one electrosurgical coagulation waveform, the closed loop control system including:
a sensor configured to sense at least one of a tissue property and an energy property and transmit the at least one of a tissue property and an energy property to a gain controller as a current sensor signal having an amplitude;
the gain controller configured to process the current sensor signal to reduce the amplitude of the current sensor signal and obtain a signal to noise ratio of the current sensor signal within a predetermine range;
the gain controller being a current gain controller that includes:
a sensor current scaler control configured to scale the amplitude of the current sensor signal and to generate a scaled sensor signal;
a gain control configured to process a variable DC level control signal to generate a gain control signal;
a multiplier configured to generate a multiplied signal as a function of the real-time the gain control signal;
a summer configured to generate a difference signal as a function of the multiplied signal and the current sensor signal; and
an operational amplifier configured to amplify the difference signal to normalize the current sensor signal independent of the amplitude thereof; and
a microprocessor coupled to the generator and configured to adjust the at least one electrosurgical coagulation waveform as a function of the current sensor signal.
6. An electrosurgical system according to claim 5 , wherein the current gain controller includes:
an input limiter to provide surge protection for the operational amplifier.
7. An electrosurgical system according to claim 5 , wherein the current gain controller includes:
an anti-alias filter configured to substantially block a harmonic radio frequency.
8. An electrosurgical system according to claim 5 , wherein the microprocessor includes a buffer sized to store an integer multiple of a repetition rate of the current sensor signal.
9. An electrosurgical system according to claim 5 , wherein the microprocessor is configured to calculate at least one of a RMS value, a peak value, and crest factor of the current sensor signal and adjust the at least one electrosurgical coagulation waveform as a function thereof.
10. A closed loop control system for controlling at least one electrosurgical coagulation waveform, the closed loop control system including:
a sensor configured to sense at least one of a tissue property and an energy property and transmit the at least one of a tissue property and an energy property to a gain controller as a voltage sensor signal having an amplitude;
the gain controller configured to process the voltage sensor signal to reduce the amplitude of the sensor signal and to obtain a signal to noise ratio of the voltage sensor signal within a predetermine range;
the gain controller being a voltage gain controller that includes:
a sensor voltage scaler control configured to scale the amplitude of the voltage sensor signal and to generate a scaled sensor signal;
a gain control configured to process a variable DC level control signal to generate a gain control signal; and
a multiplier coupled to the sensor voltage scaler and the gain control, the multiplier configured to multiply in real-time the scaled sensor signal and the gain control signal to normalize the voltage sensor signal independent of the amplitude thereof; and
a microprocessor coupled to the generator configured to adjust the at least one electrosurgical coagulation waveform as a function of the voltage sensor signal.
11. A closed loop control system according to claim 10 , wherein the voltage gain controller includes:
an anti-alias filter configured to substantially block a harmonic radio frequency.
12. A closed loop control system for controlling at least one electrosurgical coagulation waveform, the closed loop control system including:
a sensor configured to sense at least one of a tissue property and an energy property and transmit the at least one of a tissue property and an energy property to a gain controller as a current sensor signal having an amplitude;
the gain controller configured to process the sensor signal to reduce the amplitude of the current sensor signal and to obtain a signal to noise ratio of the current sensor signal within a predetermine range;
the gain controller being a current gain controller that includes:
a sensor current scaler control configured to scale the amplitude of the current sensor signal and to generate a scaled sensor signal;
a gain control configured to process a variable DC level control signal to generate a gain control signal;
a multiplier configured to generate a multiplied signal as a function of the real-time the gain control signal;
a summer configured to generate a difference signal as a function of the multiplied signal and the current sensor signal; and
an operational amplifier configured to amplify the difference signal to normalize the current sensor signal independent of the amplitude thereof; and
a microprocessor coupled to the generator configured to adjust the at least one electrosurgical coagulation waveform as a function of the current sensor signal.
13. A closed loop control system according to claim 12 , wherein the current gain controller includes:
an input limiter to provide surge protection for operational amplifier.
14. An electrosurgical system according to claim 12 , wherein the current gain controller includes:
an anti-alias filter configured to substantially block a harmonic radio frequency.
15. A method for controlling at least one electrosurgical coagulation waveform, the closed loop control system including:
sensing at least one of a tissue property and an energy property and transmitting the at least one of a tissue property and an energy property as a sensor signal having an amplitude;
processing the sensor signal to reduce the amplitude of the sensor signal and to obtain a signal to noise ratio of the sensor signal within a predetermine range; and
adjusting the at least one electrosurgical coagulation waveform as a function of the sensor signal.
16. A method according to claim 15 , further comprising the steps of:
scaling the amplitude of the sensor signal to generate a scaled sensor signal;
processing a variable DC level control signal to generate a gain control signal; and
multiplying in real-time the sealed sensor signal and the gain control signal to normalize the sensor signal independent of the amplitude thereof.
17. A method according to claim 16 , further comprising the steps of
generating a difference signal as a function of the multiplied signal and the current sensor signal; and
amplifying the difference signal to normalize the current sensor signal independent of the amplitude thereof.
18. A method according to claim 15 , further comprising the step of:
calculating one of a RMS value, a peak value, and crest factor of the sensor signal and adjusting the at least one electrosurgical coagulation waveform as a function thereof.