SA9108F

sames

5/12

PIN DESCRIPTION (Continued)

Pin

Pin

PLCC-44 DIP-40

12

NC

Not connected

24

NC

34

NC

44

NC

FUNCTIONAL DESCRIPTION

The SAMES SA9108F is a CMOS mixed signal Analog/Digital integrated circuit, which

performs two phase power/energy calculations over a dynamic range of greater than

1000:1, to an overall accuracy of better than Class 1.

The integrated circuit includes all the required functions for 2-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 SA9108F generates pulses, the frequency of which is proportional to the power

consumption. The pulse rate follows the instantenous power measured. Direction

information is also provided.

1.

Power Calculation

In the Application Circuit (Figure 1), the mains voltages from Line 1 and Line 2, are

converted to currents and applied to the voltage sense inputs IVP1 and IVP2. The

mains voltage (2 x 115 V) is divided down through voltage dividers to 14V. The

resulting input currents into the A/D converters are 14

µA

and R

For the current sense inputs the voltage drop across the current transformers'

terminating resistors are converted to currents of 16

µA

means of resistors R

The signals providing the current information are applied to the current sensor inputs

IIN1, IIP1 and IIN2, IIP2.

In this configuration, with the mains voltage of 2 x 115 VAC and rated currents of

80A, the output frequency of the SA9108F energy metering integrated circuit at

FOUT1 is 64Hz. In this case 1 pulse will correspond to an energy consumption of

2 x 9.2 kW/64Hz = 287.5 Ws.

Designation

Description