ade7762 Analog Devices, Inc., ade7762 Datasheet - Page 24

• Manufacturer Part Number: ade7762
• Description: Polyphase Energy Metering Ic With Phase Drop Indication
• Manufacturer: Analog Devices, Inc.

ADE7762
For simplification, assume that Φ
V
P then becomes
where:
As the LPF on each channel eliminates the 2ω
the equation, the active power measured by the ADE7762 is
If a full-scale ac voltage of ±500 mV peak is applied to the
voltage channels and current channels, the expected output
frequency is calculated as follows:
Note that if the on-chip reference is used, actual output
frequencies can vary from device to device due to a reference
tolerance of ±8%.
A
= V
V
V
V
V
V
Freq
P
P
P
f
AN
BN
1
CN
AN
REF
B
=
=
=
to
V
2
= V
7
= V × sin(π/3)
= V × sin(2π/3)
V
V
2
×
BN
=
=
=
=
=
×
0
AN
AN
V
C
V
I
5 .
V
. 0
2
2
2
×
C
×
= V. The preceding equation becomes
BN
4 .
×
×
56
×
×
I
V
=
I
I
B
. 6
I
V
I
B
A
rms
=
0
Hz
×
A
A
313
×
nominal
×
I
×
⎛
⎜
⎝
×
sin
,
A
sin
⎛
⎜
⎝
sin
2
SCF
×
sin
2
=
⎛ π
⎜
⎝
×
3
0
⎛ π
⎜
⎝
⎛ π
⎜
⎝
3
I
5 .
⎛ π
⎜
⎝
3
+
2
B
3
⎞
× ⎟
⎠
2
=
2
×
⎞
⎟
⎠
V
3
reference
=
×
+
S0
0
⎞
⎟
⎠
BN
sin
⎞
⎟
⎠
5 .
I
2
×
sin
+
C
4 .
=
×
sin
×
(
sin
ω
=
⎛
⎜
⎝
2
. 0
S1
A
I
2
l
⎛
⎜
⎝
B
500
= Φ
56
⎛
⎜
⎝
ω
t
ω
=
2
×
+
l
value
ω
l
t
1
×
t
π
m
B
+
2
l
+
t
3
)
= Φ
V
2
×
π
3
+
3
2
3
cos
π
peak
⎞
⎟
⎠
2
=
3
⎞
⎟
⎠
C
π
⎞
× ⎟
⎠
. 0
= 0 and that
⎛
⎜
⎝
l
⎞
⎟
⎠
component of
ω
133
cos
⎞
⎟
⎠
ac
l
+
t
+
( )
=
Hz
ω
2
l
3
t
π
⎞
⎟
⎠
+
(21)
(17)
(18)
(19)
(20)
Rev. 0 | Page 24 of 28
Table 6 shows a complete listing of all maximum output
frequencies when using all three channel inputs.
Table 6. Maximum Output Frequency on F1 and F2
SCF
0
1
0
1
0
1
0
1
FREQUENCY OUTPUT CF
The pulse output calibration frequency (CF) is intended for use
during calibration. The output pulse rate on CF can be up to
64× the pulse rate on F1 and F2. Table 7 shows how the two
frequencies are related, depending on the states of the logic
inputs S0, S1, and SCF. Because of its relatively high pulse rate,
the frequency at this logic output is proportional to the instantane-
ous active power. As is the case with F1 and F2, the frequency is
derived from the output of the low-pass filter after multiplication.
However, because the output frequency is high, this active
power information is accumulated over a much shorter time.
Thus, less averaging is carried out in the digital-to-frequency
conversion. The CF output is much more responsive to power
fluctuations with much less averaging of the active power signal
(see Figure 12).
Table 7. Maximum Output Frequency on CF
SCF
0
1
0
1
0
1
0
1
S1
0
0
0
0
1
1
1
1
S1
0
0
0
0
1
1
1
1
S0
0
0
1
1
0
0
1
1
S0
0
1
1
1
0
0
1
1
f
2.24
4.49
1.12
4.49
5.09
1.12
0.56
0.56
Maximum Frequency for AC Inputs (Hz)
0.92
1.84
0.46
1.84
2.09
0.46
0.23
0.23
1 to 7
(Hz)
CF Maximum for AC Signals (Hz)
16 × F1, F2 = 14.76
8 × F1, F2 = 14.76
32 × F1, F2 = 14.76
16 × F1, F2 = 29.51
160 × F1, F2 = 334
16 × F1, F2 = 7.38
32 × F1, F2 = 7.38
16 × F1, F2 = 3.69