Want to understand 50mv offset referenced in data sheet. Watching an ammeter, I see a reading of approx 20mv with 800ma on the ammeter. Where does the 50mv offset come into play?
Could you tell me how you are measuring the voltage and the current? Could you also tell me what you measure on the CS pin when you have zero current?
Measuring the current via an ammeter on the 12v power supply going to the driver for the motor. With motor stopped, the current is 15ma and the voltage - measured with multimeter - on the CS pin is 60mv. With motor running at 730ma the voltage on the CS pin is 77mv. I think I’m now seeing the answer to my question. The 50mv offset is acturally 60mv in my case. and the 77-60 = 17mv corresponds to the 730ma which is roughly 20mv per A. Agree ?
Yeah, it sounds like you have it figured out. By the way, the supply current will only equal the motor current if you are not using PWM (i.e. the PWM pin is held high); otherwise, they will be different and the current reading will also not be meaningful during the off portion of the PWM cycle.