I'm reviewing a single component DC converter for the TI SWIFT This article is a review of the efficiency of switching device.
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Efficiency According to Specs and Fellow RoadTesters
The datasheet of the TPSM84A21TPSM84A21 says shows the efficiency graph.
As in the image below, I've also measured with VG open.
Feeding a stable 5V to VG improves the efficiency with a few (2 - 4) %.
Road Tester fmilburn has measured efficiency on his kit, and posted that on his Road Test Review.
I'm reproducing his results without permission 
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My Measurements
The datasheet and Frank's measurements show the switcher operating in the middle of it's input range, at 12 V*.
I've measured at the lower and upper range, 8 V and 14 V.
I've increased the current draw for 4 combinations, from 0 A to 7.75 A.
- top left: 8 V in, 0.6 V out
- top right 14 V in, 0.6 V out
- bottom left: 8 V in, 1.2 V out
- bottom right: 14 V in, 1.2 V out.
spreadsheet attached to this blog
Ignore the first few low range measurements. Too close to 0 to calculate a reliable efficiency.
The yellow coloured measurements are done with a non-calibrated current meter. Don't pin me down on those.
This is because the internal resistance of my DMMs limits what I can draw from the EVM at 0.6 and 1.2 V.
* Frank also tested at 9 V, see the referenced image and his review.
| Related blog |
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TI SWIFT Power Module EVM RoadTest: Module Review and Test Setup |
| TI SWIFT Power Module EVM RoadTest: Noise Measurements |
| TI SWIFT Power Module EVM RoadTest: Efficiency |
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