SA9105E
PIN DESCRIPTION (Continued)
Pin
PLCC
12
24
34
44
Pin
DIP
Designation
Description
NC
NC
NC
NC
Not connected
FUNCTIONAL DESCRIPTION
The SAMES SA9105E is a CMOS mixed signal Analog/Digital integrated circuit, which
performs three phase power/energy calculations over a range of 1000:1, to an overall
accuracy of better than Class 1.
The integrated circuit includes all the required functions for 3-phase power and energy
measurement such as oversampling A/D converters for the voltage and current sense
inputs, power calculation and energy integration. Internal offsets are eliminated through
the use of cancellation procedures.
The SA9105E generates pulses, the frequency of which is proportional to the power
consumption. Threefrequencyoutputs(FOUT1, FOUT2andFOUT3)areavailable. The
pulse rate follows the instantaneous power measured.
1. Power Calculation
In the Application Circuit (Figure 1), the mains voltages from Line 1, Line 2 and Line
3, are converted to currents and applied to the voltage sense inputs IVP1, IVP2 and
IVP3.
The current levels on the voltage sense inputs are derived from the mains voltage
(3 x 230 VAC) being divided down through voltage dividers to 14V. The resulting
input currents into the A/D converters are 14µA through the resistors R15, R16 and
R17.
For the current sense inputs the voltage drop across the current transformers
terminating resistors are converted to currents of 16µA for rated conditions, by
means of resistors R8, R9 (Phase 1); R10, R11 (Phase 2) and R12, R13 (Phase 3).
Thesignalsprovidingthecurrentinformationareappliedtothecurrentsensorinputs
IIN1, IIP1; IIN2, IIP2 and IIN3, IIP3.
In this configuration, with the mains voltage of 3 x 230 V and rated currents of 80A,
the output frequency of the SA9105E energy metering integrated circuit at FOUT1
is1.16kHz. Inthiscase1pulsewillcorrespondtoanenergyconsumptionof3x18.4
kW/1160Hz = 47.6 Ws.
The output frequency at FOUT2 is FOUT1/4. At FOUT3 the output frequency is
FOUT1/290.
41/12
sames
SAMES [ SAMES ]
