ADE7753ARSZ Analog Devices Inc, ADE7753ARSZ Datasheet - Page 43

• 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

Phase Calibration
The PHCAL register is provided to remove small phase errors.
The ADE7753 compensates for phase error by inserting a small
time delay or advance on the voltage channel input. Phase leads
up to 1.84° and phase lags up to 0.72° at 50 Hz can be corrected.
The error is determined by measuring the active energy at I
and two power factors, PF = 1 and PF =0.5 inductive.
Some CTs may introduce large phase errors that are beyond the
range of the phase calibration register. In this case, coarse phase
compensation has to be done externally with an analog filter.
The phase error can be obtained from either CF or LAENERGY
measurements:
If watt gain and offset calibration have been performed, there
should be 0% error in CF at unity power factor and then:
The phase error is
The relationship between phase error and the PHCAL phase
correction register is
The expression for PHCAL can be simplified using the
assumption that at small x:
The delay introduced in the voltage channel by PHCAL is
The delay associated with the PHCAL register is a time delay if
(PHCAL − 0x0D) is positive but represents a time advance if
this quantity is negative. There is no time delay if PHCAL =
0x0D.
The phase correction is in the opposite direction of the phase
error.
Error =
Error = %ERROR
Phase Error (°) = −Arcsin
PHCAL=
INT
Arcsin(x) ≈ x
Delay = (PHCAL − 0x0D) × 8/CLKIN
Phase Correction (°) = −(PHCAL − 0x0D)
⎛
⎜
⎝
Phase
LAENERGY
Error
CF(IB,PF = .5)
( )
°
LAENERGY
IB
×
,
PERIOD
PF
360
=
5 .
⎛
⎜
⎜
⎝
/100
Error
−
°
LAENERGY
IB
3
⎞
⎟
⎠
(
+
expected
⎞
⎟
⎟
⎠
0x0D
)
IB
2
×
(
expected
PERIOD
360
)
°
2
B
(56)
(58)
(60)
(61)
(57)
(59)
Rev. A | Page 43 of 60
Calibrating Phase Using a Reference Meter Example
A power factor of 0.5 inductive can be assumed if the pulse
output rate of the reference meter is half of its PF = 1 rate. Then
the %ERROR between CF and the pulse output of the reference
meter can be used to perform the preceding calculations.
For this example:
CF % Error at PF = .5 Inductive: %ERROR
PERIOD Register Reading:
Then PHCAL is 11 using Equations 57 through 59:
PHCAL can be expressed as follows:
Note that PHCAL is a signed twos complement register.
Setting the PHCAL register to 11 provides a phase correction
of 0.08° to correct the phase lead:
Error = 0.215% / 100 = 0.00215
Phase Error (°) = −Arcsin
PHCAL = INT
PHCAL =
INT
Phase Correction (°) =
Phase Correction (°) =
⎛
⎜
⎜
⎝
Figure 84. Calibrating Phase Using a Reference Meter
−
Arcsin
CALCULATE PHCAL. SEE EQUATION 59.
WRITE PHCAL VALUE TO THE PHCAL
SET I
MEASURE THE % ERROR BETWEEN
⎛
⎜
⎜
⎝
⎛
⎜
⎝
REFERENCE METER OUTPUT
Error
−
TEST
THE CF OUTPUT AND THE
. 0
REGISTER: ADDR. 0x10
3
07
= I
°
⎞
⎟
⎟
⎠
b
−
−
×
×
, V
(
(
8959
360
PERIOD
11
TEST
PHCAL
⎛
⎜
⎜
⎝
. 0
−
2
°
00215
= V
PERIOD = 8959
π
0x0D
⎞
⎟
⎠
3
NOM
+0x0D = −2 + 13 = 11
−
⎞
⎟
⎟
⎠
, PF = 0.5
)
0x0D
⎞
⎟
⎟
⎠
+ 0x0D
×
=
8960
360
02875-A-010
−
CF(IB,PF = .5)
. 0
)
×
°
07
=
PERIOD
°
. 0
360
ADE7753
08
= 0.215%
°
°
(62)