SLVAE69 July 2019 TPS568215 , TPS56C215
3.1 Efficiency Comparison
With external VREG5 supplied, the internal LDO is disabled. The analog circuitry and driver power supply will come from the external VREG5 supply. While monitoring 12 V normal input rail efficiency, it could be observed that the external VREG5 supply efficiency is slightly higher than internal VREG5 supply. The comparison curve is shown in Figure 5.
Figure 5. Efficiency Comparison Between Internal and External VREG5 Power Supply