We present an area- and power-efficient applicationspecific
integrated circuit (ASIC) for a miniaturized 3-D ultrasound
system. The ASIC is designed to transmit pulse and receive
echo through a 36-channel 2-D piezoelectric Micromachined
Ultrasound Transducer (pMUT) array. The 36-channel ASIC
integrates a transmitter (TX), a receiver (RX), and an analog-todigital
converter (ADC) within the 250-μm pitch channel while
consuming low-power and supporting calibration to compensate
for the process variation of the pMUT. The charge-recycling
high-voltage TX (CRHV-TX) in standard CMOS generates up
to 13.2-VPP pulse while reducing 42.2% peak TX power consumption.
Also, each CRHV-TX automatically calibrates excitation
voltage according to acoustic pressure of pMUT. The
dynamic-bit-shared ADC (DBS-ADC) shares the most significant
bits (MSBs) among four channels based on the signal similarity
between adjacent channels. The analog front end (AFE) with
a received signal sensitivity indicator (RSSI) changes its gain
adaptively in real time depending on input signal strength. The
ASIC consumes 1.14-mW/channel average power with 1-kHz
pulse repetition frequency (PRF) and three TX pulses per cycle.
The ASIC in 0.18-μm 1P6M Standard CMOS has been verified
with both electrical and acoustic experiments with a 6×6 pMUT
array.
Researcher/Author: Jihee Lee, Kyoung-Rog Lee, Benjamin E. Eovino, Jeong Hoan Park, Luna Yue Liang, Liwei Lin, Hoi-Jun Yoo and Jerald Yoo