Motor controller for tiny robot
Normally I could use L293D, but it requires 5V inputs for the trigger
  pins as well, but my project will be using only 3.7v


The L293D has input logic levels of 2.3V for logic 1 so that shouldn't be a problem.


  I want to build a tiny obstacle avoiding robot using a 3v coreless DC
  motor


The L293D is such an awful device that running it from 5V will probably only produce 3V at the motor terminals on light mechanical loads. If you read section 6.5 of the data sheet it tells you that with a motor current of 0.6 amps, the high voltage from the bridge will be Vcc2 - 1.4 V (3.6 volts typically) and the low output from the bridge will be +1.2 volts (typically) meaning that the voltage across the motor will be about 2.4 volts.

So if you want to use the L293D running from 5V (via a boost regulator from 3V to 5V) then you should be OK. Further information about L293D here

Or, use the DRV8836: -



DRV8834 runs at 2.5 volts and can supply over 2 amps, whereas the 35 and 36 are limited to 1.5 amps.