RT1062 R5 won't power off of Vin

OpenMV Boards
1

Hello,

I’m having an issue powering my RT1062 board off of Vin. I have a 3.7V battery (measured voltage of 3.9V) but when I connect it to Vin nothing happens. The green LED does not turn on, and when I check the RAW pin voltage with a multimeter it is 0V. I’ve checked my connections between the battery and the board and they all seem to be good. Plugging into a USB still works.

I previously accidentally flipped the polarity from the battery so I’m afraid that this might have fried that power line, but there was no smoke and I was under the impression that there was reverse polarity protection so I’m unsure if this is the actual cause of the issue.

If this is the problem, is it possible to bypass whatever component would’ve been blown?

Thank you,

Robert Olomon

Update: If I connect to the JST connector, rather than the Vin pin, the board works and I get normal multimeter readings. I can connect to the webserver it’s hosting and see that I get normal camera data, so everything is working except the green light, which still isn’t coming on. The green light comes on when I connect over USB. Is this normal behavior?

2

Hi, yes, the green power light only turns on when you have VIN or USB power. This is on purpose as if you are running off a battery you don’t want the power LED killing your battery. The RT1062 is designed to run for years off a battery. So… the LED draw could reduce the battery life significantly when the system is in low power modes (e.g. drawing 30uA).

The minimum VIN voltage from the external headers is 4.7V. This is because of the battery charger, it just blocks outputting power until you hit that. If you want to power the system with a lower voltage. Apply that voltage via the RAW pin using a diode or ideal diode. The system can work then down to like 3.5V in this case (using an ideal diode, probably 3.7V with a Schottky diode).