Teensy 4.1 drops the 5V supply voltage down to 3.3V, so I understand it can be driven from a 3.7V LiPo battery without any issues. However, if I connect a USB flash drive to the USB host port, I assume that the USB drive will also be supplied with 3.7V.
I am trying to find info about whether this is considered a reasonable risk to take. From what I can find, most USB flash drives internally use 3.3V logic. But I can't find information about whether they drop the usual USB supply voltage from 5V to 3.3V using a pair of resistors (which would then drop 3.7V down to 3.7V * 3.3V/5V = 2.442V), or whether they use a voltage regulator.
The best advice I could find is "Most USB flash drives should work fine on 3.7V, but some may simply not work."
I can test this with specific drives, but I need a sense of how commonly drives will work vs. fail. Does anybody have a sense for this?
If I'm supplying Teensy with power from a 3.7V battery, is there any simple way to step up the voltage to 5V for the USB host port?
I am trying to find info about whether this is considered a reasonable risk to take. From what I can find, most USB flash drives internally use 3.3V logic. But I can't find information about whether they drop the usual USB supply voltage from 5V to 3.3V using a pair of resistors (which would then drop 3.7V down to 3.7V * 3.3V/5V = 2.442V), or whether they use a voltage regulator.
The best advice I could find is "Most USB flash drives should work fine on 3.7V, but some may simply not work."
I can test this with specific drives, but I need a sense of how commonly drives will work vs. fail. Does anybody have a sense for this?
If I'm supplying Teensy with power from a 3.7V battery, is there any simple way to step up the voltage to 5V for the USB host port?