SLUAAX9 June   2025 BQ25756

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2MOSFET Power Losses in Buck and Boost Chargers
    1. 2.1 Buck Mode Losses
    2. 2.2 Boost Mode Losses
    3. 2.3 Closing Thoughts for FET Losses
  6. 3Evaluating MOSFETs Using the Design Calculator
    1. 3.1 Correlating MOSFET Data Sheet Parameters With the Design Calculator Parameters
    2. 3.2 Design Calculator MOSFET Comparison Example
  7. 4BOM Evaluation
  8. 5Summary
  9. 6References

2 MOSFET Power Losses in Buck and Boost Chargers

In a switch-mode converter, the total losses come from the MOSFET losses and the parasitic resistances of the reactive and inductive components. For the energy storage elements, the losses come from the equivalent series resistance of each component. This application note focuses on the MOSFET losses and which parameters contribute to these losses. For ease of reference, Figure 2-1 is a MOSFET parasitic model.

MOSFET Parasitic Model Figure 2-1 MOSFET Parasitic Model