AUIPS7125R Datasheet, PDF (7/16 Pages) International Rectifier – CURRENT SENSE HIGH SIDE SWITCH

Current sensing accuracy
Ifb
Ifb2
AUIPS7125R
Ifb1
Ifb leakage
I offset
Iout1
Iout2
Iout
The current sensing is specified by measuring 3 points :
- Ifb1 for Iout1
- Ifb2 for Iout2
- Ifb leakage for Iout=0
The parameters in the datasheet are computed with the following formula :
Ratio = ( Iout2 – Iout1 )/( Ifb2 – Ifb1)
I offset = Ifb1 x Ratio – Iout1
This allows the designer to evaluate the Ifb for any Iout value using :
Ifb = ( Iout + I offset ) / Ratio if Ifb > Ifb leakage
For some applications, a calibration is required. In that case, the accuracy of the system will depends on the variation of
the I offset and the ratio over the temperature range. The ratio variation is given by Ratio_TC specified in page 4.
The Ioffset variation depends directly on the Rdson :
I offset@-40°C= I offset@25°C / 0.8
I offset@150°C= I offset@25°C / 1.9
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