Sens A resistor for L6206?

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I wonder if sombody could tell me what is the best value of resistor
for SensA and SensB pins for L6206? And what voltage/current levels
should I expect back?
I don't see any suggestions in their data sheet and I need feedback.
Thanks everyone,
Walter.

Re: Sens A resistor for L6206?
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Unless you are using external current control, 0 ohms is the right value.

- Sauli



Re: Sens A resistor for L6206?
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I would like to measure the current consumption, for this reason I
think I have to connect sensing resistors to those two pins. Is that
what you mean by external current control?

Walter.

Re: Sens A resistor for L6206?

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value.

Current sense resistors are needed if you use external circuit for PWM
regulation of the load current.  You have an inductive load like a motor or
solenoid?  The overcurrent detection circuit can also be used for current
regulation, but as the datasheet says it is not very precise, especially at
higher load currents.

With an inductive load and PWM control, using the sense resistor for
measuring the (average) load current is not quite straightforward.  The
current through the sense resistor is not constant and, depending on the
decay method, it could be zero (slow decay) or flow into the sense pin (fast
decay) during the PWM off time.  The document at
http://www.st.com/stonline/books/pdf/docs/8700.pdf  shows the current paths
with the two decay modes.  If you don't use PWM, the situation is simpler.

In any case the resistance of the sense resistor should be as low as
possible to minimize the power dissipation, typically below 1 ohm.

-Sauli



Re: Sens A resistor for L6206?
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Look at application note AN1315 from www.st.com
It uses a different chip, but the sense resistor is actually made up
of two .22 ohm resistors in parallel that are 1W rated.

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