BIOELECTRONICS Rahul Sarpeshkar

Associate Professor

Research Lab of Electronics

Electrical Engineering and Computer Science

Bio-inspired Electronics: Electronics inspired by biology.

Biomedical Electronics: Ultra-low-power electronics for medical applications

CBA NSF talk. 10/12/06

Dynamic Range 120 dB at inputPower Dissipation ~14W (Estimated)

Power Supply Voltage ~150 mVVolume ~35mm x 1cm x 1 cmDet. Thr. At 3 kHz 0.05 Angstroms at eardrumFrequency Range 20 Hz – 20 kHz (in babies?)Outlet Taps ~35,000Filter Computations >1 GFLOPSPhase locking threshold ~5 kHzInformation is reported with enough fidelity so that the auditory system has thresholds forITD discrimination at ~10 sFreq. discrimination at 2 Hz (at 1kHz)Loudness discrimination ~1 dB

BIOLOGICAL COCHLEAR NUMBERSBIOLOGICAL COCHLEAR NUMBERS

Transmission Line Analogy: Fluid is an Inductor, Membrane Stiffness is a CapacitorTransmission Line Analogy: Fluid is an Inductor, Membrane Stiffness is a Capacitor

ANALOG VLSI AND BIOLOGICAL SYSTEMS LAB

The RF cochlea

UMC 0.13µm CMOS process

HF (5GHz)

LF (250MHz)

Transformer

Single stage Bias & programming

Spiking-Neuron-Inspired Analog-to-Digital ConverterSpiking-Neuron-Inspired Analog-to-Digital Converter

At 0.12pJ/quantization level, a version of this A-to-D may be the most energy-efficient A-to-D ever reported thus far. It is the first time-based A-to-D converter whose conversion time scales linearly with bit precision.

An Ultra-Low-Power Analog Bionic Ear Processor

The Bionic Ear (Cochlear Implant)

The 251W 16-channel Programmable Processor Performance Summary

1. 20x power improvement over best design today2. Better or comparable performance in 1.5m

technology today than A-D-then-DSP solution at the end of Moore’s law in an advanced nanometer technology.

3. First test with a deaf patient was successful, and she understood speech with it.

Block Diagram of Processor

1. Microphone2. Cable3. Speech Processor4. Coil5. Implanted Receiver6. Electrodes7. Auditory Nerve

CURING PARALYSIS: ELECTRONICS THAT DECODES THOUGHT

Electrode Array

Neural Amplifier

Array

Decoding Array

A/D and Wireless

Transceiver

Implanted in Brain

Wireless Receiver,

Programmer, and Recharger

To Prosthetic / Natural Arm

An Analog Architecture for Neural Recording, Decoding, and LearningAn Analog Architecture for Neural Recording, Decoding, and Learning

Adaptive 7W neural amplifier SPICE simulation of performance with real monkey data

Allows 1kbs-1 instead of 24Mbs-1 data bandwidth across the skull

PRINCIPLES FOR ENERGY-EFFICIENT DESIGN IN BIOLOGY AND ELECTRONICS

1. Special-Purpose Architectures2. Exploit analog basis functions for

efficient preprocessing before digitization or signal-to-symbol conversion

3. Slow-and-Parallel4. Exponential computing primitives

(high gm/I ratio in transistor)5. Balance Computation and

Communication Costs6. Adaptive Architectures with Learning