The efficiency test for a 250kHz switching frequency utilized the same arrangement as the 50kHz frequency test but incorporated a smaller newly designed transformer. Solid lines represent the results for design 2, while dashed lines correspond to the design 3. Figure 1-9 shows the efficiency plotted against the output current for both designs, and Figure 1-10 displays the output voltage as a function of the output current.

The tests were performed at input voltages of 1.8V, 2.4V, and 3.6V. The increasing in switching frequency to 250kHz resulted in a higher power dissipation for MSPM0L1306 generating PWM signals, as evidenced by a comparison of data from Figure 1-5. This increase in power consumption contributed to a decrease in the efficiency of design 3 comparing with design 2. Nonetheless, at an input voltage of 3.6V, design 3 also can achieve an efficiency of up to 77%.