TSC1031 datasheet(20/26 Pages) STMICROELECTRONICS

20 / 26 page

Application information

TSC1031

20/26

Doc ID 16875 Rev 2

The current multiplier gain K2 can be set to 2.5 or 5 depending on the voltage applied on the

SEL pin.

Since they define the full-scale output range of the application, the Rsense resistor and the

amplification gain Av are important parameters and must therefore be selected carefully.

The TSC1031’s dedicated schematic eases the implementation of EMI filtering in harsh

environments. A simple filter is described in Figure 22, where the input filtering is performed

by Rf1, Rf2 and Cf.

The values of Rf1 and Rf2 should be equal so as to balance the contribution on both

amplifier inputs. The value of the Cf capacitor should be selected so that the cut-off

frequency of the first-order low-pass filter provides enough attenuation to the high frequency

interferences.

To balance the contribution of Rf1 and Rf2 in the current sense amplifier gain, an output

resistor Rf3 should be connected between pin A1 and Gnd. The value of Rf3 should be

chosen according to the following formula.

K1 = 10 = Rg3/Rg1= Rf3/Rf1 = Rf3/Rf2

If these precautions having been taken, the TSC1031’s gain is unaffected by the

implementation of the input filtering resistors.

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