ADE7762ARWZ Analog Devices Inc, ADE7762ARWZ Datasheet - Page 25

• Manufacturer Part Number: ADE7762ARWZ
• Description: IC, POLYPHASE ENERGY METERING, SOIC-28
• Manufacturer: Analog Devices Inc

Specifications of ADE7762ARWZ

• Ic Function: Polyphase Energy Metering IC With Phase Drop Indication
• Supply Voltage Range: 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SOIC
• No. Of Pins: 28
• Input Impedance: 140 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 8.5mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Meter Type: 3 Phase
• Brief Features: On-Chip Creep Protection, High Frequency Output
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADE7762EBZ - BOARD EVALUATION FOR ADE7762
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

SELECTING A FREQUENCY FOR AN ENERGY METER APPLICATION
As shown in Table 5, the user can select one of seven frequencies.
This frequency selection determines the maximum frequency on
F1 and F2. These outputs are intended to be used to drive the
energy register (electromechanical or other). Because seven
different output frequencies can be selected, the available
frequency selection has been optimized for a 3-phase, 4-wire
service with a meter constant of 100 imp/kWh and a maximum
current of between 10 A and 100 A. Table 8 shows the output
frequency for several maximum currents (I
voltage of 220 V (phase neutral). In all cases, the meter constant
is 100 imp/kWh.
Table 8. F1 and F2 Frequency at 100 imp/kWh
I
10
25
40
60
80
100
The f
output frequencies on F1 and F2. When designing an energy
meter, the nominal design voltage on the voltage channels
should be set to half scale to allow for calibration of the meter
constant. The current channel should also be no more than
half scale when the meter sees maximum load. This allows
overcurrent signals and signals with high crest factors to be
accommodated. Table 9 shows the output frequency on F1
and F2 when all six analog inputs are half scale.
Table 9. F1 and F2 Frequency with Half-Scale AC Inputs
SCF
0
1
0
1
0
1
0
1
MAX
(A)
1 to 7
S1
0
0
0
0
1
1
1
1
frequencies allow complete coverage of this range of
S0
0
0
1
1
0
0
1
1
f
2.24
4.49
1.12
4.49
5.09
1.12
0.56
0.56
1 to 7
(Hz)
F1 and F2 (Hz)
0.18
0.46
0.73
1.10
1.47
1.83
Frequency on F1 and F2
(Half-Scale AC Inputs) (Hz)
0.23
0.46
0.12
0.46
0.52
0.12
0.06
0.06
MAX
) with a line
Rev. 0 | Page 25 of 28
When selecting a suitable f
frequency output at I
meter constant should be compared with Column 5 of Table 9.
The frequency that is closest in Table 9 determines the best
choice of frequency (f
Wye meter with a 25 A maximum current is being designed,
the output frequency on F1 and F2 with a 100 imp/kWh meter
constant is 0.46 Hz at 25 A and 220 V (see Table 8). Looking at
Table 9, the closest frequency to 0.46 Hz in Column 5 is 0.46 Hz.
Therefore, f
FREQUENCY OUTPUTS
Figure 2 shows a timing diagram for the various frequency
outputs. The outputs F1 and F2 are the low frequency outputs
that can be used to directly drive a stepper motor or electro-
mechanical impulse counter. The F1 and F2 outputs provide
two alternating high going pulses. The pulse width (t
120 ms, and the time between the rising edges of F1 and F2 (t
is approximately half the period of F1 (t
period of F1 and F2 falls below 550 ms (1.81 Hz), the pulse
width of F1 and F2 is set to half of their period. The maximum
output frequencies for F1 and F2 are shown in Table 6.
The high frequency CF output is intended to be used for
communications and calibration purposes. CF produces a
90 ms-wide active high pulse (t
to active power. The CF output frequencies are given in Table 7.
As in the case of F1 and F2, if the period of CF (t
190 ms, the CF pulse width is set to half the period. For exam-
ple, if the CF frequency is 20 Hz, the CF pulse width is 25 ms.
1 to 7
= 4.49 Hz is selected for this design.
MAX
1 to 7
(maximum load) with a 100 imp/kWh
). For example, if a 3-phase, 4-wire
1 to 7
frequency for a meter design, the
4
) at a frequency proportional
2
). If, however, the
5
) falls below
ADE7762
1
) is set at
3
)