University of California

Hariprasad Chandrakumar

Dejan Markovic

Neuromodulation systems in accordance with embodiments of the invention can use a feed-forward common-mode cancellation (CMC) path to attenuate common-mode (CM) artifacts appearing at a voltage input, thus allowing for the simultaneous recording of neural data and stimulation of neurons. In several embodiments of the invention, the feed-forward CMC path is utilized to attenuate the common-mode swings at V, which can restore the linear operation of the front-end for differential signals. In several embodiments, the neuromodulation system may utilize an anti-alias filter (AAF) that includes a duty-cycles resistor (DCR) switching at a first frequency f, followed by a DCR switching at a second frequency f. The AAF allows for a significantly reduced second frequency fthat enables the multi-rate DCR to increase the maximum realizable resistance, which is dependent upon the frequency ratio f/f.

High input impedance, high dynamic range, common-mode-interferer tolerant sensing front-end for neuromodulation systems

A high dynamic range sensing front-end for bio-signal recording systems in accordance with embodiments of the invention are disclosed. In one embodiment, a bio-signal amplifier includes an input signal, where the input signal is modulated to a predetermined chopping frequency, a first amplifier stage, a parallel-RC circuit connected to the first amplifier stage and configured to generate a parallel-RC circuit output by selectively blocking an offset current, a second amplifier stage connected to the parallel-RC circuit that includes a second input configured to receive the parallel-RC circuit output and generate a second output that is an amplified version of the input signal with ripple-rejection. Further, the bio-signal amplifier can also include an auxiliary path configured for boosting input impedance by pre-charging at least one input capacitor. In addition, the bio-signal amplifier can also include a DC-servo feedback loop that includes an integrator that utilizes a duty-cycled resistor.

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Los Angeles, CA, United States of America

Hariprasad Chandrakumar