SLVAFC5 March   2022 TPS629210 , TPS629210-Q1

 

  1.   Trademarks
  2. 1Inverting Buck – Boost Topology
    1. 1.1 Concept
    2. 1.2 Output Current Calculations
    3. 1.3 VIN and VOUT Range
  3. 2Digital Pin Configurations
    1. 2.1 Enable Pin
    2. 2.2 MODE/S-CONF Pin
    3. 2.3 Power Good Pin
  4. 3Design Considerations
    1. 3.1 Input Capacitor Selection
    2. 3.2 Output Inductor Selection
    3. 3.3 Stability Limits and Output Capacitor Selection
  5. 4Layout Considerations
  6. 5How to Modify a Buck to Inverting Buck-Boost?
  7. 6Typical Performance and Waveforms
  8. 7Conclusion
  9. 8References

3.2 Output Inductor Selection

When selecting the inductor value for the inverting buck - boost topology, the equations provided in the Output Current Calculations section should be used instead of the ones provided in the data sheet. These equations help to select the right inductance by designing for a maximum inductor current (IL(max)) for a given inductance. IL(max) should be kept below the minimum current limit value of TPS629210-Q1 (1.3 A) for a reliable design. The recommended output inductor for TPS629210-Q1 is in the range of 2.2uH to 3.3uH. See Selecting L and Cout for Stability for the stability impact of the inductor selection.