ADE7753ARSZ Analog Devices Inc, ADE7753ARSZ Datasheet - Page 41

• Manufacturer Part Number: ADE7753ARSZ
• Description: IC ENERGY METERING 1PHASE 20SSOP
• Manufacturer: Analog Devices Inc

Specifications of ADE7753ARSZ

• Input Impedance: 390 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 3mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.200", 5.30mm Width)
• Meter Type: Single Phase
• Ic Function: Single-Phase Multifunction Metering IC
• Supply Voltage Range: 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADE7753ZEB - BOARD EVALUATION AD7753
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

With WDIV and CFNUM set to 0, LAENERGY can be
expressed as
LAENERGY
The calculated Wh/LSB ratio for the active energy register, using
Equation 39 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 calibration
frequency or line cycle accumulation measurements can be
used to determine the energy offset. Gain calibration should be
performed prior to offset calibration.
Offset calibration is performed by determining the active
energy error rate. Once the active energy error rate has been
determined, the value to write to the APOS register to correct
the offset is calculated.
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 register represents 2
of the AENERGY[23:0] active energy register.
The steps involved in determining the active energy error rate
for both line accumulation and reference meter calibration
options are shown in the following sections.
Calibrating Watt Offset Using a Reference Meter Example
Figure 82 shows the steps involved in calibrating watt offset
with a reference meter.
INT
(
CF
APOS = −
Wh
IB
Figure 82. Calibrating Watt Offset Using a Reference Meter
(
LSB
expected
IB(expected)
=
)
CF OUTPUT AND THE REFERENCE METER
. 3
MEASURE THE % ERROR BETWEEN THE
×
AENERGY
CALCULATE APOS. SEE EQUATION 49.
SET I
LINECYC
200
OUTPUT, AND THE LOAD IN WATTS
WRITE APOS VALUE TO THE APOS
(
489
=
imp/Wh
TEST
1
REGISTER: ADDR. 0x11
+
) 1
−
= I
4
CLKIN
IB
:
MIN
Error
2 /
, V
=
×
TEST
PERIOD
. 6
378
Rate
= V
×
NOM
×
10
×
2
, PF = 1
/ 8
35
−
4
CLKIN
02875-A-008
×
(
CFDEN
b
and
+
(49)
Rev. A | Page 41 of 60
1
−
))
33
For this example:
Meter Constant:
Minimum Current:
Load at Minimum Current:
CF Error at Minimum Current:
CF Numerator:
CF Denominator:
Clock Frequency:
Using Equation 49, APOS is calculated to be −522 for this example.
Then,
Using Equation 49, APOS is −522.
APOS can be represented as follows with CFNUM and WDIV
set at 0:
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 = −
APOS =
−
⎛
⎜
⎝
1
(%
100
3 .
ERROR
%
⎞
⎟
⎠
×
CF
9
CF(IMIN)
6 .
. 3
(
. 0
IMIN
579545
×
05436
. 3
3600
)
490
)
) × W
200
×
1
W
IMIN
×
=
×
CFNUM
=
CFDEN
2
10
IMIN
. 0
35
. 0
IMIN(nominal)
×
05436
6
MeterConst
000110933
×
=
CLKIN
−
MeterConst
MeterConstant(imp/Wh) = 3.2
I
W
%ERROR
CFNUM = 0
CFDEN = 489
CLKIN = 3.579545 MHz
522
+
+
MIN
1
1
IMIN
3600
− CF
ant
= 40 mA
(imp/Wh)
= 9.6 W
Hz
IMIN(expected)
3600
CF(IMIN)
ant
×
(imp/Wh)
(
CFDEN
= 1.3%
ADE7753
+
) 1
×
(50)
(51)
(52)
2
35