This report focuses on designing the power stage for a SEPIC converter. The design procedure is generic on selecting suitable components of the SEPIC power stage for the given application specifications. The LM5155EVM-SEPIC evaluation module is used as the example to illustrate the design procedure, and the circuit performance results are also presented in the LM5155EVM-SEPIC User's Guide. For typical applications the LM5155 and LM5156 Quickstart Calculator for SEPIC Regulator Design (Rev. A) can also be used to efficiently complete the calculations described in this report.
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The typical design procedures and calculations to implement a non-synchronous SEPIC power stage operating in continuous conduction mode are presented in this report. The converter in this example is based on the LM5155EVM-SEPIC and can provide a regulated output of 12 V at 1 A from an input of 4 V to 32 V. When the input voltage is between 4 V to 6 V, the output power is derated down to 6 W.
The Figure 1-1 shows the basic configuration of a SEPIC power stage.