SNVA406C May   2010  – January 2022 LM27402

 

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9 Evaluation Board Component Selection

This section describes the design process for the LM27402 evaluation board. Unless otherwise indicated, all formulae assume units of the following:

  • Amps (A) for current
  • Farads (F) for capacitance
  • Henries (H) for inductance
  • Volts (V) for voltage

The first equation to calculate for any buck converter is duty ratio:

Equation 1. GUID-D75027DC-5C33-42C2-804D-61A01807AAF6-low.gif

Due to the resistive powertrain losses, the duty ratio will increase based on the overall efficiency, η. Setting η = 1 yields an approximate result for D.