The below images show the efficiency measured using the TPS54J061EVM-067. The TPS54J061EVM-067 will have slightly improved efficiency at very light loads with its higher resistance FB divider. Figure 2-1 through Figure 2-3 shows the efficiency in FCCM mode for different input voltages when using internal VCC and external 3.3-V VCC. Figure 2-4 through Figure 2-6 shows the improved light load efficiency in DCM mode with internal VCC and external 3.3-V VCC. Lastly, Figure 2-7 and Figure 2-8 shows the improved efficiency with the switching frequency reduced to 600 kHz with internal VCC in FCCM and DCM mode, respectively.

Figure 2-1 Efficiency – FCCM, Internal VCC, f_SW = 1100 kHz

Figure 2-3 Efficiency – FCCM, External 3.3-V VCC, f_SW = 1100 kHz, R13 = 0 Ω

Figure 2-5 Efficiency – DCM, External 3.3-V VCC, f_SW = 1100 kHz, R13 = 4.7 Ω

Figure 2-7 Efficiency – FCCM, Internal VCC, f_SW = 600 kHz

Figure 2-2 Efficiency – FCCM, External 3.3-V VCC, f_SW = 1100 kHz, R13 = 4.7 Ω

Figure 2-4 Efficiency – DCM, Internal VCC, f_SW = 1100 kHz

Figure 2-6 Efficiency – DCM, External 3.3-V VCC, f_SW = 1100 kHz, R13 = 0 Ω

Figure 2-8 Efficiency – DCM, Internal VCC, f_SW = 600 kHz