Electrosurgical apparatus with high speed energy recovery
A circuit for controlling the discharging of stored energy in an electrosurgical generator includes a pulse modulator which controls an output of a power supply. At least one comparator is configured to provide an error signal to the pulse modulator based on a comparison between an output signal generated by the power supply and a feedback signal generated in response to the application of energy to tissue. A discharge circuit is configured to control the discharge of the output of the power supply to an inductive load disposed in parallel with the output of the power supply based on the comparison between the output signal and the feedback signal. The discharge circuit provides a rapid response and time rate control of the delivered electrosurgical energy by controlling the power supply and delivered RF energy in real time, based on a feedback signal generated in response to the application of energy to tissue.
1. A method for controlling the discharging of stored energy in an electrosurgical generator comprising the steps of:
applying energy stored in an output of a power supply to tissue;
generating at least one control signal based on at least one of a sensed tissue property and a sensed power delivery property;
generating an error signal based on a comparison between the at least one control signal and the energy stored in the output;
discharging the stored energy to an inductive load in parallel with the output of the power supply based upon the comparison between the energy stored in the output and the control at least one signal;
activating a first switching component to discharge the stored energy to the inductive load;
activating a second switching component based on the discharge of the stored energy to control the activation of the first switching component;
providing a resistive element connected in series between the first switching component and ground; and
controlling a second switching component based on a voltage across the resistive element generated by the discharge of stored energy to selectively activate the first switching component.
2. A method according to claim 1 , including directing current from the inductive load to at least one diode.
3. A method according to claim 1 , including utilizing an output filter including an inductor and a capacitor at the output of the power supply.
4. A method according to claim 1 , including utilizing a comparator to switch the first switching component based on the comparison between the at least one control signal and the energy stored in the output.
5. A method according to claim 1 , including utilizing a transistor for the first and second switching components.
6. A method according to claim 5 , including selecting the transistor from the group consisting of a field-effect transistor (FET), a metal-oxide semiconductor field-effect transistor (MOSFET), and an insulated gate bipolar transistor (IGBT).
7. A method according to claim 1 , including utilizing at least one diode to direct current from the inductive load.
8. A method according to claim 1 , wherein the comparison is performed by an operational amplifier.