Variable-output radiofrequency ablation power supply
A medical system is provided, including an ablation system having at least one ablation element and a sensor, a generator operable to deliver radiofrequency ablation energy to the ablation element. A power supply defines a duty cycle and provides a voltage to the generator, and the power supply has a duty cycle modulator and an amplitude modulator. A processor is connected to the power supply, the generator, and the sensor. The processor obtains a feedback signal from the sensor, and adjusts the duty cycle modulator and the amplitude modulator according to the feedback signal.
1. A method of treating a patient with an ablation system having a generator, an ablation element, a sensor, and a power supply comprising a variable resistance operatively coupled between the sensor and a processor, the method comprising:
selecting an energy delivery mode for treatment from at least one of monopolar ablation energy and bipolar ablation energy;
selecting a desired value of an operating parameter;
placing the ablation element and sensor proximate to a treatment site;
delivering an electrical output from the power supply to the generator;
delivering ablation energy from the generator to the ablation element;
measuring a value of the operating parameter with the sensor;
comparing the measured value of the operating parameter to the desired value of the operating parameter to determine a comparison value; and
modulating the amplitude of the electrical output from the power supply by the processor altering the variable resistance based on the comparison value.
2. The method of claim 1 , wherein the operating parameter is temperature.
3. The method of claim 1 , wherein the variable resistance comprises a field-effect transistor (FET).
4. The method of claim 3 , wherein the variable resistance further comprises a resistor coupled with the FET.
5. The method of claim 4 , wherein the FET comprises the features of a diode and a transistor, and wherein altering the variable resistance comprises the processor activating the transistor to allow current to flow through the resistor.