Low-voltage, low-noise power supply reference design for ultrasound front-ends

This reference design is a power supply optimized specifically for powering eight 16-channel receive AFE ICs in ultrasound imaging systems. This design uses a single-chip DC/DC converter + LDO combo regulator to set each LDO input just above the dropout voltage while fully utilizing the LDO PSRR, thereby reducing parts count while maximizing efficiency. In addition, ultra-low noise LDOs help achieve the highest possible analog-to-digital conversion resolution, resulting in higher image quality. The design's ability to synchronize the switching frequency with the master clock frequency and the system clock frequency allows system designers to apply simple filtering techniques to eliminate power switching noise on ground loops or use spread spectrum clocking to reduce EMI. Additionally, the design implements an electronic fuse device, providing a simple and flexible method of overcurrent protection.

characteristic

• ● Suitable for 12V input ultrasonic system front-end
• ● Electronic fuse with input current limit 4.2A
• ● Can power eight AFEs, with up to 128 channels (number of channels can be expanded), and supports 36W power output
• ● Combination DC/DC converter + LDO IC maximizes LDO efficiency by setting the LDO input just above the dropout voltage
• ● Use high PSRR and ultra-low noise (4.4μVRMS) LDOs to achieve the highest possible analog-to-digital conversion resolution
• ● Provide a common synchronous power supply for all AFEs on the same T/R board, thereby reducing the layout space and helping to reduce noise and eliminate EMI.