Hi:
The L298N, capable of delivering continuous 2 A for each motor, has basically the same pins layout than the L293D. Plus it includes a current sensing pin for each motor. What is this?
Are those pins necessary? May I ignore them in my project?
Thanks
That depends. Do you want to limit the current to your motors ?
See pages 3, 6, 7, & 8 of the datasheet.
- SUGGESTIONS
A non inductive capacitor, usually of 100 nF, must
be foreseen between both Vs and Vss, to ground,
as near as possible to GND pin. When the large capacitor
of the power supply is too far from the IC, a
second smaller one must be foreseen near the
L298.
The sense resistor, not of a wire wound type, must
be grounded near the negative pole of Vs that must
be near the GND pin of the I.C.
The sense output voltage can be used to control the
current amplitude by chopping the inputs, or to provide
overcurrent protection by switching low the enable
input.
The brake function (Fast motor stop) requires that
the Absolute Maximum Rating of 2 Amps must
never be overcome.
RS1 = RS2 = 0.5 ohm, 2W
As you can see from the attached schematic of an L298 breakout board, they didn't ignore them.
You have to ask yourself, is it really smart to ask the question "Can I ignore the CURRENT SENSE resistors ?"
I wouldn't if I were you. I'll forget that you asked.
Since the current in question is DC and the resistor is connected to ground at one end , then we can say with reasonable certainty that the voltage drop across the resistor represents the current through both the device and the motors.
Thus E = I x R = 2A x 0.5 ohms = 1Vdc @ 2A /per motor. Connecting Sense-A and Sense-B pins to your arduino Analog input pins allows you to measure your motor current in REAL TIME and program current thresholds to abort operation if the motor tries to drive something against a wall or whatever. So if the maximum value you should measure is 1V (at 2A) if you don't think you will be drawing 2A you might consider using the INTERNAL 1.1V analog reference which would give you full scale (1023) at 2A.
If you don't use the internal reference you should consider adding a gain of 5 non-inverting op amp amplifier.
The L298N, capable of delivering continuous 2 A for each motor,
The data sheet makes this claim but don't believe it. You will be lucky to get 1 ampere/channel continuously. See this (but note that they want to sell you their driver) The Motor Driver Myth — Rugged CircuitsRugged Industrial Arduino Microcontrollers