Measuring load impedance with active stimulation pulses in an implanted pulse generator

A method, comprising:

• delivering electrical pulses to a patient;
• receiving a plurality of voltage signals from a selected body region of the patient in response to the delivering;
• generating amplitude-attenuated voltage signals by attenuating a voltage amplitude of at least some of the voltage signals;
• amplifying a subset of the amplitude-attenuated voltage signals differentially, thereby producing a differential output;
• and
• calculating an impedance associated with the selected body region based on the differential output.

A method, comprising:

• applying electrical stimulation therapy to a patient;
• obtaining a plurality of voltage signals from a selected body region of the patient based on the applied electrical stimulation therapy;
• generating amplitude-attenuated voltage signals by attenuating, via a plurality of individually-controllable voltage attenuators, a voltage amplitude of at least some of the voltage signals;
• routing a subset of the amplitude-attenuated voltage signals through one or more multiplexors for voltage amplification;
• amplifying the subset of the amplitude-attenuated voltage signals differentially to generate a differential output;
• and
• determining an impedance associated with the selected body region based on the differential output, wherein the determining comprises sampling the differential output at a plurality of predetermined points in time, and calculating the impedance in response to the sampling.