Crazyflie with 2-3S

[Slaxx]

Hi
I plan to use the Crazyflie electronics with a 2 or 3S lipo battery and brushless motors. If I saw it correctly, one problem is the NCP702SN30, which can run only on up to 5.5V (the charging management is left completely away). I am looking around for a replacement and try to use also an LDO that is for low power application. However it seems very hard to find any that can deliver up to 550mA output current as the NCP does. Is this output current limit necessary or can it also be set lower? Do you have some values for maximum currents that occur?

Thx

[tobias]

Have you checked last monday post? I'm not totally sure what you want to do but you don't have to change the regulators as you can power the CF2 from 5V on VUSB (which you can get from the brushless controllers with BEC).

[Slaxx]

I just checked it and this is quite interesting. However, it is not quite what I am looking for.
I'm currently redesigning the board to make it run for a brushless quad with 2-3S battery. Therefore I have to remove the battery management chip and replace the NCP702SSN30 since this one can only support up to 5.5V supply voltage. I'm currently looking for a replacement of this LDO and was wondering what the specifications were that it has to fulfill, such that I can choose an optimal replacment.

[tobias]

Ahh that explains what you want to do. The NCP702 is chosen mainly because of the ultra low quasient current, pretty good SNR and good peak load. As it is used to power the always on domain the quasient current is important. I guess it would not be your case so you could go with a more standard regulator which has descent SNR and peak load capabilities. The peak load is because the RF-amp consumes current in bursts when packets are sent out which the regulator should handle well.

[Slaxx]

I talked with an electrical engineer and he told me that LDOs are not suitable for conversion of such high voltage differences or the currents get quite small in order not to reach the termal limits. For this reason I use a DC/DC converter instead that transforms the 7.4 or 11.1V down to 3.3V and then I can use the same LDOs as on the Crazyflie again.
Thank you for your remarks