Ultrasound transmitters require a stable programmable DC power source to drive high current into piezo transducers during the transmission. The TIDA-01371 reference design demonstrates a positive and negative linear regulator that can provide output voltages varying from ±2.5 to ±100V. The programmability (meant to come from a DAC) is implemented using external control voltages. The low-noise performance helps in replacing passive and active noise filters with off-the-shelf low-noise positive and negative LDO regulators and a circuit to float the ground of the regulators. In addition, it uses external power MOSFETs to scale the current capability of regulators to support special imaging modes such as shear wave, or elastography, mode. In order to provide extremely high currents to the transducers, large input capacitors can provide high energy for 1ms of duration keeping the average current drawn from this power supply very low.
Features:
- Floating and tracking regulator, replaces passive and active noise filters with off-the-shelf LDO regulators with better than ±1.5% load regulation
- Innovative current sharing scheme uses TI's best-in-class low RDS(ON) CSD series power MOSFETs and low impedance driver circuits to improve the transient response
- Programmable output voltage from ±2.5V to ±100V using control signals coming from DAC
- Scalable in terms of output current for 1ms pulses (tested up to ±20A) to support special imaging modes
- Separate and independent positive and negative voltage power supplies enables flexibility in powering the ultrasound transmit circuit
Parts include:
CSD19533KCS 100V, 8.7mOhm, TO-220 N-Channel NexFET™ Power MOSFET
TLV171 36V Low-Power RRO General-Purpose Operational Amplifier
TLV2171 36V, Low Power, RRO, General Purpose Operational Amplifier
TPS7A33 Vin -3V to -36V, -1A, Ultra-Low Noise, High PSRR, Low-Dropout Linear Regulator
TPS7A47 36V, 1A, 4.17μVRMS, RF Low-Dropout (LDO) Voltage Regulator
Learn more by downloading the reference design below
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