Sense voltage stuck at constant value

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Emb3_BP

Joined: 24 Jun 2009
Posts: 4

30 Jun 2009 7:04 Sense voltage stuck at constant value

I am using a combination of L297 and L298 for driving 0.5 amp stepper motor.
I have set the reference voltage at 1.1V, but the voltage observed across the SENSE1 is 1.76V and across is 2.8v on the scope. This means more motor current is being pumped into the motor.

I have also tried reducing the Vref to 0.5V, even then the voltage across SENSE1 and SENSE2 remain same.

Vref = 1.1V
Sense resistors = 2.2E
Motor Supply voltage = 15V
Motor current max = 0.5A
Resistance/phase of the motor = 16.48E

What could be the possible cause of this problem?

any suggestions could be of great help..
thanks in advance...