5 ms·
The limits on the input voltage are a little frustrating. Not being able to go over 5.5v means you can't just strap it to a 2S li-po and drive servos off the pw
by regularfry 6y ago
The limits on the input voltage are a little frustrating. Not being able to go over 5.5v means you can't just strap it to a 2S li-po and drive servos off the pwm outputs. Anyone know how strict that 5.5v limit is, and what's likely to go pop if you gave it 7.4v?
- amelius 6y agoIf you configure the PWM outputs as open-drain, then you might be able to run the servos from a higher voltage than the MCU, depending on how much current the ports can sink.
- regularfry 6y agoYeah, that's at least another part though, even if it is just a regulator to get the 7.4v down to 5v. Just seems like a bit of a miss.
- guenthert 6y agoWith batteries you'll want a buck/boost regulator (DC-DC converter) in any case. At a $4 retail price, that would be a significant share of BOM for a specialized use case. For professional use, nobody stops you from creating such a board, amateurs are better of using a commercial USB power cell (likely more expensive than the Pi Pico though).
- regularfry 6y agoThere's already a buck/boost on the board. It's just limited to 5.5v max. It's also not that specialised, given that we've got people like adafruit advertising that the pwm is for servos, and lithium polymers are a hugely common power source.
- guenthert 6y agoIndeed. The schematic shows a Richtek rt6150b-33gqw, which is a buck-boost converted [1]. I fully would have expected a buck converter or LDO there. Well, pity then. Take it up with the RPi foundation ;-} On the plus side, this should allow you to run the Pi Pico from a single lithium cell on Vbus. [1]https://www.richtek.com/assets/product_file/RT6150A=RT6150B/DS6150AB-05.pdf https://www.richtek.com/assets/product_file/RT6150A=RT6150B/...