SA9103C

sames

5/16

1.

Power calculation

In the Application Circuit (Figure 1), the voltage drop across the shunt will be

between 0 and 16mV (0 to 80A through a shunt resistor of 200µ

Ω). This voltage is

converted to a current of between 0 and 16µA, by means of resistors R

The current sense input saturates at an input current of ±25µA peak.

For the voltage sensor input, the mains voltage (230V AC) is divided down through

a divider to 14V. The resulting current into the A/D converter input is 14µA at

nominal voltage, via resistor R4 (1M

Ω).

In this configuration, with a mains voltage of 230V and a current of 80A, the

SA9103C functions at its optimum conditions, having a margin of 3dB for overload

available.

2.

Analog Input Configuration

The input circuitry of the current and voltage sensor inputs are illustrated below.

These inputs are protected against electrostatic discharge through clamping

diodes.

The feedback loops from the outputs of the amplifiers A

shorts on the signal inputs. Exact duplications of the input currents are generated

for the analog signal processing circuitry.

VOLTAGE

SENSOR

INPUT

DR-00831

IVP

SS

V

CURRENT

SENSOR

INPUTS

IIP

IIN

SS

V

DD

V

SS

V

DD

V

DD

V

GND