Power efficiency with Boost vs Buck-Boost using same regulator

Question

I'm doing a few tests and figuring out what will be the best option for what will eventually be part of a battery powered circuit. I have both a boost and buck-boost converter, both using the XLSEMI XL6009 regulator. I have both set to 12V output and connected to an 8ohm power resistor to simulate a 1.5A load.

Using a lab bench power supply to simulate different voltages, I noticed with sub 12V inputs, the power consumption stays very close to 20W using the boost converter. But with the buck-boost, I'm seeing 24W starting at 12V with increasing power consumption as voltage decreases.

Is it normal for buck-boost converters to be less efficient? I imagined it would have been roughly the same power efficiency, since it uses the same regulator.

I included a link to the XL6009 datasheet here

Answer 1

The buck-boost circuit in the data sheet that you may be using is this one: -

Note that it uses a transformer to transfer power to the output (in red). Transformers will be about twice the inefficiency of a single inductor used in a boost circuit: -

And, in any type of power converter like this, it will be the wound components that are likely to be the most wasteful of power hence, the buck-boost circuit shown above will be significantly less efficient than the boost converter.