I want to drive a DC motor using an L298N H-Bridge Driver IC. I'm using the schematic from this website:
The motor is 24 V with about 7.5 ohm impedance (thus, it draws about 3.2 A). I'm using a 24V power supply, rated 10A max.
If the motor is not connected, the voltage (measured either at Vin or motor terminal) is 24V, but once the load (motor) is connected, the voltage drops to 3V.
I've tried the logic input when load is disconnected, they work well as expected (measured as 24V or -24V at motor terminals according to logic input being fed).
Can you enlighten me about what's happening with this circuit?
P.S.: I'm using 2N3906 2N3904 for transistors, 1N5822 for flyback diodes. From schematic above I've also added a 10uF / 25V decoupling capacitor between Vin and GND.
Best Answer
Now I found why it's not working... Well, actually it works if and only if it start with logic 00 (undriven state) in it's input pins. Any input pin can only be pulled high after some brief period of time.
It is suggested in L298N datasheet (in Application Information section, 2nd point, last paragraph -- page 7 of 14) that "Before to Turn-ON the Supply Voltage and before to Turn it OFF, the Enable input must be driven to the Low state."
Since the enable line is boolean OR product of the logic inputs, both of them must be set to zero (low) before supply applied to Vs (power supply).