4.4 VDD

The MIC26400 requires an external VDD supply to bias the internal reference and control circuitry. This supply can be provided either through the on-board regulator circuit on the evaluation board or from an independent external power supply. The regulator derives the VDD rail from the input voltage. At higher input voltages, the power dissipated in this regulator increases proportionally, reducing the converter efficiency. In such conditions, the regulator can be disabled, allowing VDD to be supplied directly from an external source. Bypassing the regulator reduces bias-related power losses and improves the overall efficiency of the converter.