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V2 testing results

A project log for Robot Power Distribution Board

Provides stable 5V and 3.3V rails, a direct power output, and I2C expansion.

kyle-isomKyle Isom 08/01/2019 at 04:530 Comments

I hooked up some power resistors (1-8R 10W) to the various outputs and ran it through its paces.

First up was supplying 8V @ 1A to an 8R resistor hooked up to the motor controller (8V / 8R should be roughly 1A). 

Next, I attached a 4.5R load to the 3.3V output (2x1R in parallel with a 4R in series). The LM111733V is limited to 800mA sources, so that should give 733mA that's around 2.5W. After about 30s, it starts to short circuit; I suspect this is due either to the traces not being able to supply the current or the resistors overheating and causing problems; at 10W, I wouldn't suspect that but they did feel pretty warm afterwards.

Finally, I tried supplying 8V @ 1.1A with 4.5R load on the 5V outputs (which should be about 1.1A). There's a 0.2V drop across the load, which I suspect is due to the load.

I did try switching the motor kill switch while the load was applied and it didn't fuse, which is a good sign.

The tests indicate that I should aim for improved thermal dissipation and widen up my traces.

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