STPMS2 datasheet(13/36 Pages) STMICROELECTRONICS

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STPMS2

Applications

DocID16525 Rev 5

13/36

Applications

The choice of external components is a crucial point in the application design, affecting the

precision and the resolution of the entire system. Among the several considerations, a

compromise should be found among the following requirements:

Maximize the signal-to-noise ratio in the voltage and current channel.

Choose the current-to-voltage conversion ratio kS and the voltage divider ratio so that

calibration can be achieved.

Choose kS to take advantage of the whole current dynamic range in accordance with

the desired maximum current and resolution.

To maximize the signal-to-noise ratio of the current channel, the voltage divider resistor

ratio should be as close as possible to those shown in Table 6. Figure 4 below provides a

reference application schematic diagram:



P = 64000 imp/kWh



INOM = 5 A



IMAX = 60 A

Typical sensitivity values for the current sensors are indicated in Table 6: "Recommended

external components in metering applications".

Figure 4: Detailed application schematic

STPMS2 Datasheet(PDF) 13 Page - STMicroelectronics