SA9603C
1. Power Calculation
In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 16mVRMS (0 to 80A through a shunt resistor of 200µΩ). This voltage
is converted to a current of between 0 and 16µARMS, by means of resistors R1 and
R2.
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 14VRMS. The resulting current into the A/D converter input is 14µARMS
at nominal voltage, via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the
SA9603C 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 AI and AV generate virtual
shorts on the signal inputs. Exact duplications of the input currents are generated
for the analog signal processing circuitry.
V
D D
IIP
V
V
S S
D D
C U R R E N T
S E N S O R
IN P U TS
A I
IIN
V
S S
V
D D
IV P
V O LTA G E
S E N S O R
IN P U T
V
S S
A V
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G N D
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sa m e s
SAMES [ SAMES ]
