EVAL-ADE7763ZEB Analog Devices Inc, EVAL-ADE7763ZEB Datasheet - Page 38

• Manufacturer Part Number: EVAL-ADE7763ZEB
• Description: BOARD EVALUATION FOR ADE7763
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADE7763ZEB

• Main Purpose: Power Management, Energy/Power Meter
• Utilized Ic / Part: ADE7763
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

ADE7763
WGAI
Note that WGAIN is a signed, twos complement register
With WDIV an
expr
The calculated Wh/LSB ratio for the active energy register,
using Equation 35 is 6.378 × 10
Watt Offset
Offset calibration allows outstanding performance over a wide
dynamic range, for example, 1000:1. To do this calibration two
measurements are needed at unity power factor, one at I
the other at the lowest current to be corrected. Either calibra-
tion frequency or line cycle accumulation measurements can be
used to determine the energy offset. G
performed prior to offset calibration.
Offset calibration is performed by determining the active energy
error rate. After determining the active energy error rate, calcu-
late the value to write to the APOS register to correct the offset.
The AENERGY registers update at a rate of CLKIN/4. The twos
complement APOS register provides a fine adjustment to the
active power calculation. It represents a fixed amount of power
offset to be adjusted every CLKIN/4. The 8 LSBs of the APOS
register are fractional such that one LSB of APOS represents
1/256 of the least significant bit of the internal active energy
register. Therefore, one LSB of the APOS registe
of the AENERGY[23:0] active energy register.
See the following sections for steps to determine the active
energy error rate for both li
meter calibration options.
Calibrating Watt Offset Using a Reference Meter Examp
Figure 73 shows the step
with a reference meter.
essed as
WGAIN = INT
LAENERGY
APOS = −
INT
Wh
N is calculate
(
LSB
CF
IB
(
expected
=
d CFNUM set to 0, LAENERGY can be
AENERGY
. 3
IB(expected)
200
)
(
×
489
d to be 480 using Equation
⎛
⎜
⎝
⎛
⎜
⎝
LINECYC
imp/Wh
19186
17174
1
+
s involved in calibrating watt offset
=
) 1
CLKIN
ne accumulation and reference
Error
−
IB
−4
1
=
2 /
⎞
⎟
⎠
is
. 6
Rate
×
×
378
2
PERIOD
12
ain calibration should be
×
×
⎞
⎟
⎠
2
=
10
35
480
−
×
4
/ 8
43.
r represents 2
CLKIN
×
b
.
(
CFDEN
and
(45)
Rev. B | Page 38 of 56
−33
le
+
1
))
For this example:
Meter Constant:
Minimum Current:
Load at Minimum Current:
CF Error at Minimum Current: %ERROR
CF Numerator:
CF Denominator:
Clock Frequency:
Using Equation 45, APOS is −522 for this example.
Then,
Using Equation 45, APOS is −522.
APOS can be represented as follows with CFNUM and WDIV
set at 0:
APOS =
−
CF Absolute Error = CF
CF Absolute Error =
(%ERROR
CF Absolute Error =
AENERGY Error Rate (LSB/s) =
CF Absolute Error ×
AENERGY Error Rate (LSB/s) =
0.000110933 ×
APOS = −
⎛
⎜
⎝
(%
1
100
3 .
Figure 73. Calibrating Watt Offset Using a Reference Meter
ERROR
%
⎞
⎟
⎠
×
CF OUTPUT AND THE REFERENCE METER
CF
MEASURE THE % ERROR BETWEEN THE
9
CF(IMIN)
CALCULATE APOS. SEE EQUATION 45.
(
SET I
. 3
IMIN
6 .
. 0
OUTPUT, AND THE LOAD IN WATTS
WRITE APOS VALUE TO THE APOS
579545
×
05436
)
)
TEST
. 3
×
490
3600
) × W
REGISTER: ADDR. 0x11
1
W
200
IMIN
= I
=
×
×
CFNUM
MIN
CFDEN
=
2
×
IMIN
. 0
10
IMIN(nominal)
, V
35
MeterConst
. 0
05436
6
TEST
000110933
×
=
CLKIN
MeterConstant(imp/Wh) = 3.2
I
W
CFNUM = 0
CDEN = 489
CKIN = 3.579545 MHz
MeterConst
−
= V
MIN
+
+
522
IMIN
3600
NOM
1
1
ant
= 40 mA
− CF
, PF = 1
= 9.6 W
(imp/Wh)
Hz
IMIN(expected)
CF(IMIN)
3600
ant
(imp/Wh)
×
= 1.3%
(
CFDEN
+
) 1
×
(46)
(47)
(48)
2
35