TIDT434 February   2025

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5. 1Test Prerequisites
    1. 1.1 Voltage and Current Requirements
    2. 1.2 Required Equipment
    3. 1.3 Dimensions
    4. 1.4 Test Setup
  6. 2Testing and Results
    1. 2.1 Efficiency Graphs
    2. 2.2 Efficiency Data
    3. 2.3 Thermal Images
    4. 2.4 Bode Plots
  7. 3Waveforms
    1. 3.1 Switching
    2. 3.2 Output Voltage Ripple
    3. 3.3 Short-Circuit Protection
    4. 3.4 Load Transients
    5. 3.5 Start-up Sequence

Description

This reference design is a 28V output, 12A synchronous buck converter for space missions operating from a 50V to 150V input range. Primary applications include stepping down voltages from solar panels and 120VDC power distribution buses. The TPS7H5006-SEP pulse width modulation (PWM) controller controls the power stage using voltage-mode control. The OPA4H199-SEP senses the sense resistor voltage which enables the output short-circuit protection. The adjustable dead time of the TPS7H6005-SEP allows the timing of the switching MOSFETs to be optimized and results in over 95% efficiency with a 100V input and over 96% efficiency with a 50V input. A 12V self-biasing circuit is included to power the control circuits directly from the output. If an external 12V bias is provided, the self-biasing circuit can be removed, and results in higher efficiency.