by lm317 » Thu Dec 16, 2010 5:53 pm
Hello -
Did anyone have any probs with this mod??
The voltage regulator (78L05) on the TH9x has a dropout voltage of
1.7V (Datasheet) - using a 2s Lipo and discharging to the min (3V/cell)
would leave you with 4.3V on the uC instead of 5V.
So of course it might work - but depending on the crystal frequency the
uC needs more or less voltage to operate safely.
Maybe Bruce can answer this - are we relaying on the uC to work with
less voltage than the design engineers supposed it to work with?
If u have a 2.4Ghz Modul working with 5V (don´t know if there are any -
FrSky internally converts to 3.3V) you wont provide it with the desired voltage either -
since it will use voltage regulator too. Hopefully a low voltage drop regulator....