ADE7763ARS Analog Devices Inc, ADE7763ARS Datasheet - Page 41

• Manufacturer Part Number: ADE7763ARS
• Description: IC ENERGY METER 1PHASE 20SSOP
• Manufacturer: Analog Devices Inc

Specifications of ADE7763ARS

• 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
• For Use With: EVAL-ADE7763ZEB - BOARD EVALUATION FOR ADE7763
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Calibrating Phase w
With an accurate source, line cycle accumulation is a good
method of calibrating phase error. The value of LAENERGY
must be obtained at two power factors, PF = 1 and PF = 0.5
inductive.
For this example:
Meter Constant:
Line Voltage:
Line Frequency:
CF Numerator:
CF Denomina
Base Current:
Half
PERI D Register:
Expected Line Accumulation at Unity Power Factor (from Watt
Gain ection):
Acti
ve
Line Cycles Used at Base Current:
O
s
Energy Reading at PF = 0.5 inductive:
Figure 76. Calibrating Phase with an Accurate Source
SET HALF LINE CYCLES FOR ACCUMULATION
tor:
CALCULATE PHCAL. SEE EQUATION 55.
ACCUMULATION ADDR. 0x09 = 0x0080
ENABLE LINE CYCLE ACCUMULATION
READ LINE ACCUMULATION ENERGY
WRITE PHCAL VALUE TO THE PHCAL
SET I
IN LINECYC REGISTER ADDR. 0x1C
RESET THE INTERRUPT STATUS
RESET THE INTERRUPT STATUS
INTERRUPT ADDR. 0x0A = 0x04
READ REGISTER ADDR. 0x0C
READ REGISTER ADDR. 0x0C
SET MODE FOR LINE CYCLE
TEST
REGISTER: ADDR. 0x10
ith an Accurate Source Example
= I
INTERRUPT?
INTERRUPT?
b
ADDR. 0x04
YES
YES
, V
TEST
MeterConstant(imp/Wh) = 3.2
V
f = 50 Hz
CFNUM = 0
CFDEN = 489
I
LINECYC
PERIOD = 8959
LAENERGY
LAENERGY
L
b
nominal
= 10 A
= V
NOM
= 220 V
, PF = 0.5
IB
NO
NO
= 2000
IB(expected)
IB, PF = 0.5
= 9613
= 19186
Rev. A | Page 41 of 56
The error using Equation 52 is
Using Equation 55, PHCAL is 11.
Note that PHCAL is a signed, twos complement register.
The phase lead is corrected by 0.08 degrees when the PHCAL
register is set to 11:
VRMS and IRMS Calibration
VRMS and IRMS are calculated by squaring the input in a
digital multiplier.
The s
filter
the rms value. An offset correction is provided to cancel noise
and offset contributions from the inpu
Ther
filter does not completely attenuate the signal. This noise can be
min
zero crossing of the voltage signal. The IRQ
configured to indicate the zero crossing of the voltage sign
This flowchart demonstrates how VRMS and IRMS readings
are synchronized to the zero crossi
imized
. The square roo
Error =
Phase Er
PHCAL = INT
Phase Correctio
Phase Correction (°) = −
e is ripple n
v
quare of the rm
2
) (
t
=
by synchronizing the rms register readi
9613
ror (°) = −Arcsin
2
V
oise from the 2ω term because the low-pass
19186
sin(
−
⎛
⎜
⎝
n (°) = −
19186
−
s value is extract
t of the output o
ω
. 0
t
2
)
07
×
2
°
×
2
(
(
=
11
PHCAL
V
8959
360
⎛
⎜ ⎜
⎝
. 0
. 0
sin(
−
0021
0021
°
0x0D
ngs of the voltage input.
3
⎞
⎟
⎠
ω
f this low-pass filter give
+
ed from v (t) by a low-p
t
−
)
t.
⎞
⎟ ⎟
⎠
0x0D
)
=
0x0D
=
×
V
−
360
8960
2
output can be
. 0
=
−
)
07
×
2
°
−
V
°
2
=
PERIOD
2
ADE7763
+
ngs with the
. 0
×
360
13
08
cos(
°
°
=
2
11
ω
al.
t
(59)
)
ass
s