Relative ultrasound energy measurement circuit

A relative ultrasound energy estimation circuit has been designed in a standard 0.35-μm CMOS process, to be a part of a thumb size Internet connected wireless ultrasound measurement system. This circuit measures the relative energy between received ultrasound pulses, and presents an output signal that is linear to the received energy. Post-layout simulations indicate 7 bit linearity for 500 mV input signals, 5 μsec startup and stop times, 2.6 mW power consumption during active state. The active area measures 0.6 mm₂ including digital logic, bias generation, and an on-chip oscillator. The circuit has been sent for manufacturing in the Austrian Microsystems C35B4 process via Europractice MPW.