Tool/software: WEBENCH® Design Tools
At low output currents the WEBENCH tool sometimes rounds both efficiency and input current to zero. For example using the shared design webench.ti.com/.../SDP.cgi , specified for output current up to 120mA, this happens if you set the output current to 10% of this i.e. 12mA and the input voltage to the maximum design value of 5.25V. At the minimum input voltage of 4.38V it works OK, giving Efficiency 63.4% and Iin Avg 25.2mA.
There is also a problem with the resolution of the cursor readout in the chart display. If you hover the cursor over the left-hand end of the red trace on the Efficiency chart it reads out values of Output Current 0.01A and Efficiency 63.44 (presumably %), which is the value for 12mA, not 10mA output. Similarly, the next point available for readout claims to be at 0.02A but is actually at 24mA, and so on at every 10% increment of the design maximum output current. This is much clearer in the old Flash tool, which correctly reports the points at 12mA steps.
