Adjusting Phases of Multiphase Ablation Generator to Detect Contact

A method of ablation, comprising the steps of:

• generating a plurality of replicas of an RF signal having a given frequency;
• setting phases and amplitudes of the plurality of replicas;
• amplifying the plurality of replicas of the RF signal, and driving a respective plurality of ablation electrodes in a patient body with the amplified replicas;
• receiving a return signal, comprising a superposition of the plurality of replicas sensed by the patch electrode;
• adjusting the phase of the amplified replicas to be in phase;
• determining from the return signal that a state of contact exists between the ablation electrodes and target tissue in the patient;
• and
• ablating the target tissue with the ablation electrodes in an ablation mode of operation wherein the phases of the amplified replicas differ from one another.

A method to ablate tissue in a system having a signal generator configured to generate an RF signal coupled to a control circuitry, the control circuitry configured to set phases and amplitudes of a plurality of replicas of the RF signal generated by the signal generator with a plurality of non-linear amplifiers to amplify the plurality of replicas of the RF signal and drive a respective plurality of n ablation electrodes in a patient body with the amplified replicas;

• and a processor, configured to receive a return signal comprising a superposition of the plurality of replicas sensed by a patch electrode attached to the patient body, the method comprising the steps of:
• switching the replicas of current injected to the n ablation electrodes to be in-phase while applying a voltage at increasing level and measuring the replicas of current with an analyzer,
• checking whether tissue is in contact when the in-phase replicas of current injected into each electrode requires a change in voltage greater than a zero base value, and
• changing the n electrodes to be out of-phase to continue ablation of the tissue.