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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

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

enter image description here

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: -

enter image description here

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.

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    \$\begingroup\$ that makes a lot of sense now! Thank you Andy! \$\endgroup\$ – allen Jan 20 at 15:15

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