SA9602E

sames

5/14

FUNCTIONAL DESCRIPTION

The SA9602E is a CMOS mixed signal Analog/Digital integrated circuit, which performs

power/energy calculations across a power range of 1000:1, to an overall accurancy of

better than Class 1.

The SA9602E in both DIP-20 and SOIC-20 package options is a direct replacement for

the SA9102E with the advantage of no external loop capacitors.

The integrated circuit includes all the required functions for 1-phase power and energy

measurement such as two 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 SA9602E generates pulses, the frequency of

which is proportional to the power consumption. Two frequency outputs (FOUT1 and

FOUT2) are available, with a third frequency option available on request. The pulse rate

follows the instataneous power consumption measured.

1.

Power Calculation

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

0 and 16mV

This voltage is

converted to a current of between 0 and 16µA

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

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

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

mains voltage, via resistor R4 (1M

Ω).

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

frequency of the SA9602E power meter chip at FOUT1 (Pin 12) is 1.16kHz. In this

case 1 pulse will correspond to an energy consumption of 18.4kW/1160Hz =

15.9Ws.

The output frequency at FOUT2 is FOUT1 /290 (i.e. The frequency ouput at FOUT1

divided by 290).

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.