- Custom Development
Failure to follow the instruction on Testing with Real Hardware: Important Safety Warnings can lead to motor current flowing in the USB connector. When that happens, the TPS2111 blows. To prevent this, always use an isolated USB adapter. If it happened, the solution is to replace the chip.
Patch: the ATP304's gate resistor has to be replaced. It was 0 ohm, it needs to be 510k.
Why? Slowing down the MOSFET's transition lowers the in-rush current. This lowers the stress on the fuse, and on the PCB. This stress was sometimes leading to the fuse blowing shortly after an experiment is started.
Patch: Add 10nF between the gate and source of the ATP304 MOSFET. There is no footprint, solder a ceramic axial cap across the component's legs.
Why? the ATP304's can self-turn-on when the battery voltage is above 30V. The physical manifestation is a spark when you connect the battery. This lead to a high current, and this current has the same effects as the in-rush current.