Part Number:DRV8881
Hi all
Would you mind if we ask DRV8881E?
There is formula (1) for the chopping current on the datasheet P16.
At the our customer's circuit, they configured as follows;
-Vref=0.49V
-TRQ=00(100%)
-RISENSE=0.2ohm±1%
Actually(result), current limit was 250mA～310mA.ISENSE pin voltage was 0.05V～0.06V.
Using formula(1), calculation value is 370mA.
There is some difference between calculation value and result data.
So, using Figure 9. xISEN Trip Voltage over VREF Input on the datasheet P9,
in case of VREF=0.49V, trip voltage is 0.05V.
It seems that the customer's result is correct in case of Figure 9.
We would like to confirm formula(1).
Is this formula(1) for current limit in case of Vref=3.3V only?
In case of Vref=0.49V, formula(1) is not suitable, right?
And then, AV(gain amplifier) is not linearity, right?
As the background of this question, our customer would like to calculate limit current in case of VREF=0.5V.
Kind regards,
Hirotaka Matsumoto