A compact bipolar high-voltage pulser with a novel transistor gate-source protection scheme for ultrasound imaging applications

In this article, a compact integrated high-voltage (HV) pulser is presented, which can serve as an actuator in area-limited medical ultrasound imaging applications. The proposed HV pulser is capable of producing bipolar return-to-zero (RTZ) HV pulses with a maximum peak-to-peak amplitude of 60 V. A novel RTZ stage including a new transistor gate-source protection scheme is used in this work, resulting in a reduced die area by enabling the use of an embedded transmit/receive (T/R) switch and obviating the need for a separate T/R switch. The proposed HV pulser also incorporates programmable delay elements by which the RTZ time can be controlled. By selecting the minimum allowed value of delay, the pulser is able to generate square-wave HV pulses as well. Designed and implemented in a 0.18-mu m HV Bipolar-CMOS-DMOS (BCD) technology, the pulser occupies a layout area of 0.455 mm2. The function of the proposed design has been verified using post-layout simulations when driving a 220-pF capacitor in parallel with a 1-k omega resistor load. The simulation results indicate that the pulser consumes an average power of 14.85 mW when producing 2-MHz, three-cycle HV pulses with a pulse repetition frequency (PRF) of 5 kHz. A bipolar high-voltage ultrasound pulser with a compact implementation is presented in this article. A novel return-to-zero stage with an embedded transmit/receive switch makes this pulser suitable for being used as an ultrasound transmitter in area-limited ultrasound imaging applications.image