Boost/buck regulator with or without Teensy 3.2 linear regulator

[devison]

Hi,

I'm building a balancing robot based around a Teensy 3.2. It will be powered by one 18650 Lithium Ion battery (2.75-4.2V, 3400mAh, 2C).

Part of the robot will be running on 3.3V, including the Teensy, an 9-axis IMU, blue-tooth LE module, sd card, motor controller, quadrature encoders, microphone, etc.

I am using a polulu buck/boost regulator and am wondering whether to:

1. Have this regulator output 3.3V to power the Teensy 3.3V input and other components directly. (Pololu suggested the regulator would likely work fine like this).
2. Have this regulator output 3.6V and then use the Teensy 3.2 linear regulator to drop to 3.3V

The same battery will be powering a step-up regulator to 8V powering two motors, which will changing direction and speed frequently, so there is likely to be a bunch of noise.

The second option above would presumably give cleaner power but perhaps is unnecessary and wasteful having the losses of two regulators in series. I'm a beginner here, so would appreciate other opinions about whether this is an advisable extra step.

Thanks,
Dan

 

[Jp3141]

I don't think there will be any noticeable difference in Teensy performance or behaviour. The T3.2 regulator won't be particularly effective in further reducing the switching regulator noise.

Overall efficiency would be higher just setting the DC/DC to 3.3 V, but in fact most of your power is going to be consumed by the motors, so this is a negligible difference.

 

[devison]

Thanks very much for your reply.
Regards,
Dan