L293D vs L9110 DC motor drivers

I'm using L293D motor driver to drive my DC motors (small yellow DC motor), I have wired everything correctly and even the motors were rotating correctly. Then i noticed that sometimes the motor does not rotate but when i grab it i can feel a beat and when i measured the voltage across its terminals it was 4.4v which is enough to drive DC motor. Worthy to mention that i rotate one motor at a time and i put only one motor on the L293D IC (even though it can drive two motors). example of what happens: in first iteration the motor rotates forward and backward correctly, second iteration it moves forward and doesn't move backward and so on in a random way.

what can the problem be ? and if i replaced L293D with L9110 will it behave correctly and not cause such problems ?

Please read the "How to use this forum" post and follow the directions.

There are many possible reasons for your problem: battery too small, wiring wrong, motor current too high for the driver, driver chip overheating, wrong code, etc.

First iteration, second iteration? What iterations are these? You need to describe/show how the setup is powered and connected.

jremington: Please read the "How to use this forum" post and follow the directions.

There are many possible reasons for your problem: battery too small, wiring wrong, motor current too high for the driver, driver chip overheating, wrong code, etc.

I'm using a power supply not a battery so i know for sure that it supplies sufficient voltage and current, also the wiring is correct because at first few iterations it worked quite well. Iteration is iterating on every motor and for each motor i move it forward stop backward stop. So the code can't be wrong too. What i have in mind is that it can be chip overheating problem even though i'm connecting the overheat sink to ground.

And my more important question is: is L9110 driver better than L293D driver ?

MarkT: First iteration, second iteration? What iterations are these? You need to describe/show how the setup is powered and connected.

Iteration is iterating on every motor and for each motor i move it forward stop backward stop. It's quite a big circuit but i'll try to describe it. I use a power supply and i use a voltage regulator (from 12v to 5v). The driver itself is connected quite correctly 4 gnd's are connected, its enables come from the arduino and the two pins for powering the IC and providing the motor with power are connected to 5v (voltage regulator output not arduino).

Please read the "How to use this forum" post and follow the directions.