L298N Motor Driver Circuit Problem
April 27, 2011
For some reason I am really struggling with implementing a simple L298N motor driver. I have a simple breadboard robot and I am trying to run a Timya dual gearbox off the driver. I made a recommended circuit from the data-sheet but for some reason when I pull one of the inputs high (by connecting it to 5V power rail) the motor driver does not activate the motor outputs. I used an oscilloscope to measure all the voltages and everything is as it should be but for some reason the outputs always remain grounded. I could appreciate some help as I do not know what I am doing wrong. I have read forums related to this on LMR and have not found a solution. Bellow are pictures of the connections and the circuit. I have also attached the data sheet.
PS I have tried changing the L298N driver and I get the same result so it is not a case of the driver being fried.
My setup worked when I used this schematic: http://www.solarbotics.com/assets/schematics/solarbotics-l298_schematic_complete.jpg
The original setup was wrong because Vss of 5v is needed for logic and Vs for motor power must be at least Vss + 2.5V. I was trying to use 5V for both. From my understanding this difference is necessary to bias the internal transistors of the driver.
Thanks to everyone who helped!