Low energy implantable devices and methods of use

A method of delivering stimulation to a target tissue of a patient, the method comprising:

• coupling a first electrode of a lead comprising a plurality of electrodes to a first circuit of a stimulation circuitry an implantable pulse generator;
• coupling a second electrode of the lead to a second circuit of the stimulation circuitry of the implantable pulse generator;
• delivering a first phase of a stimulation pulse via implementing of a first switch configuration in the first circuit and in the second circuit of the stimulation circuitry, wherein the first circuit comprises:
• an adjustable resistance element comprising a first terminal and a second terminal;
• a first switch coupled to the first terminal of the adjustable resistance element, the first switch selectively coupleable with a stimulation-voltage node and a ground node;
• a second switch selectively coupling the a first one of the plurality of electrodes to one of:
• the second terminal of the adjustable resistance element;
• and the stimulation-voltage node;
• wherein the first switch configuration couples the first switch of the first circuit to a ground node and the second circuit to a stimulation voltage node,
• implementing a second switch configuration corresponding to an interphase delay in the first circuit and in the second circuit;
• delivering a second phase of the stimulation pulse via implementing of a third switch configuration, wherein the third switch configuration couples both the first circuit and the second circuit to a node;
• and
• adjusting a resistance of the adjustable resistance element in the first circuit to control a current of the second phase of the stimulation pulse.

A method of delivering stimulation to a target tissue of a patient with an implantable pulse generator, the method comprising:

• determining a desired value of a current of desired stimulation pulse;
• delivering a first stimulation pulse having a first current, wherein the first current of the first stimulation pulse has a value less than the desired value of the current of the desired stimulation pulse;
• measuring a first impedance of the target tissue of the patient at the first current of the first stimulation pulse;
• and
• delivering a second stimulation pulse having a second current set based on the first impedance.

A method of delivering stimulation to a target tissue of a patient with an implantable pulse generator, the method comprising:

• determining a desired value of a current of a desired stimulation pulse;
• iteratively:
• delivering a test stimulation pulse with stimulation circuitry having a setting to deliver a current less than the desired value of the current of the desired stimulation pulse;
• measuring an impedance of the target tissue of the patient during delivery of the test stimulation pulse;
• and
• until the current of the test stimulation pulse approximately matches the desired value of the current of the desired stimulation pulse, updating the setting of the stimulation circuitry to deliver an increased stimulation current.