Fully integrated high-voltage front-end interface for ultrasonic sensing applications

This paper concerns the design and implementation of a fully integrated high-voltage (HV) front-end transducer for ultrasonic sensing applications. This includes a programmable HV dc-dc converter (HVDC), a drive amplifier, and a tuneable pulse generator. The HVDC is based on a multistage two-phase voltage doubler and static level up shifters. The drive amplifier is composed of a static level-up stage and a Class-D switching output stage. Post-layout simulation and experimental silicon results are reported for two HVDC stages and a drive amplifier, which were fabricated using a 0.8-mu m CMOS/DMOS process and having a supply voltage of 5 V/400 V. The measurement results confirm the validation of the HV circuit implementation and its design optimization. An output voltage of up to 200 V was obtained from the HVDC. Also, the drive amplifier generates spikes up to 148 V, with rise and fall times of 69 and 58 ns, respectively. The peak current flowing through the transducer element can be as high as 200 mA.