Low Noise Fixed Dropout ±2.5 to ±12VOUT 3A Power Supply Reference Design for Ultrasonic CW Pulse Generators

This reference design allows a digitally programmable power supply to power a continuous wave (CW) mode ultrasound transmitter circuit via a 24V bus. There are two adjustable outputs (±2.5 to ±12V) under user software control. These outputs provide positive and negative regulator outputs up to 2A with very low ripple and noise. By adding more regulators in parallel, the power supply can be scaled to provide higher output currents up to 3A. The power supply can also be synchronized to an external clock.

characteristic

• ● Independent positive and negative voltage power supplies for CW mode in ultrasound
• ● To reduce output ripple, the high-performance, low-noise LDO operates as a power supply filter, resulting in the lowest ripple (less than 100µV at 1.6A load) with minimal LDO heat dissipation.
• ● Includes two high-performance buck regulators for creating adjustable outputs
• ● LDO has adaptive voltage drop, and a special circuit makes the LDO output always 1V lower than the LDO input.
• ● Able to achieve switching frequency synchronization with the ultrasonic master clock or system clock frequency