An Integrated Programmable High-Voltage Bipolar Pulser with Embedded Transmit/Receive Switch for Miniature Ultrasound Probes

This letter presents a compact programmable high-voltage (HV) pulser for ultrasound imaging, designed for driving capacitive micromachined ultrasonic transducers (CMUTs) in miniature ultrasound probes. To enable bipolar return-to-zero (RZ) pulsing and embedded transmit/receive switching, a compact back-to-back isolating HV switch is proposed that employs HV floating-gate drivers with only one HV MOS transistor each. The pulser can be digitally programmed to generate bipolar pulses with and without RZ, with a peak-to-peak swing up to 60 V, as well as negative and positive unipolar pulses. It can generate bursts of up to 63 pulses, with a maximum pulse frequency of 9 MHz for an 18-pF transducer capacitance. Realized in TSMC 0.18-μm HV BCD technology, the pulser occupies only 0.167 mm ². Electrical characterization results of the pulser, as well as acoustic results obtained in the combination with a 7.5-MHz CMUT transducer, are presented.