The efficiency test was conducted with input voltages set to 1.8V, 2.4V and 3.6V. Presented on Figure 1-7 are the efficiency curves versus the output current for both design 1 in solid lines and design 3 in dashed lines. In this test, design 3 runs with 50kHz switching frequency using a same transformer as design 1. At an input voltage of 3.6V, it is observed that both designs attain an efficiency more than 80%.

Figure 1-8 depicts the output voltage as a function of the output current for the two designs, where both demonstrating good linearity throughout the current range tested.