SLOA284A january   2020  – may 2023 AFE5832 , AFE5832LP , ISO7741 , ISOW7841 , LM25037 , LM25180 , LM5180 , LM5181 , LM5181-Q1 , TX7316 , TX7332

 

  1.   1
  2.   Designing Bipolar High Voltage SEPIC Supply for Ultrasound Smart Probe
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Key Design Challenges
    2. 1.2 Potential Topologies for Generating High Voltage Supply
  5. 2Design of high voltage circuit using SEPIC topology
    1. 2.1 TI HV Supply Architecture Using SEPIC Topology
  6. 3Test Results
    1. 3.1 Efficiency and Load Regulation
    2. 3.2 Output Ripple Measurement
    3. 3.3 Load Transient Test
    4. 3.4 Noise Measurement
    5. 3.5 Thermal Performance
  7. 4Possible Variants of the Design
    1. 4.1 Option 1: Programmable Output Voltage
    2. 4.2 Option 2: Support Input From 1S Li-Ion Battery
    3. 4.3 Option 3: Output Voltage Up to ±100 V
  8. 5Layout Guidelines
  9. 6Clock Synchronization
  10. 7Summary
  11. 8References
  12. 9Revision History

1.1 Key Design Challenges

The quality of the final ultrasound image is directly dependent on the quality of the power supply, since the noise from the supply can distort the image. The key design challenges are as follows:

  • Dual rail HV (±80 V @ 25 mA) generation from USB supply with single stage implementation and transformer-less approach to achieve height <5 mm with HV Rail symmetry <1 % and load regulation within 2%
  • Efficient layout and placement to achieve high signal to noise ratio (SNR) with noise floor below -90dB and data integrity, by minimizing conducted and radiated emissions
  • Overall system efficiency > 80% and thermal performance (temperature rise <15° C above ambient)