A Bipolar 3-Level High-Voltage Pulser for Highly Integrated Ultrasound Imaging Systems

The brief presents a design solution for a bipolar return to zero (RZ) 3-level high-voltage TX pulser for high performance portable ultrasound medical imaging systems. Designed to be integrated in the front end of a PMUT probe composed by a 64-channel array working in the 1-10 MHz frequency range, the pulser is compact and power efficient as it employs minimum number of power transistors while ensuring high transmitting linearity because of the implementation of the RZ state. The circuit presents programmable features such as variable delays and rise/fall times to be controlled independently through a digital interface and it dissipates only 4.5 mW to bias the PMUT in RX state while achieving a small R-eq (2.24 ohm). Transistor level and post-layout simulations performed in a BCD-SOI 0.16-mu m technology are reported to demonstrate the effectiveness of the approach.