ADE7753ARS Analog Devices Inc, ADE7753ARS Datasheet - Page 31

• Manufacturer Part Number: ADE7753ARS
• Description: IC ENERGY METERING DETEC 20-SSOP
• Manufacturer: Analog Devices Inc

Specifications of ADE7753ARS

• Rohs Status: RoHS non-compliant
• 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-ADE7753ZEB - BOARD EVALUATION AD7753

The active power signal (output of LPF2) can be rewritten as
where f
From Equation 13,
From Equation 19 it can be seen that there is a small ripple in
the energy calculation due to a sin(2 ωt) component. This is
shown graphically in Figure 68. The active energy calculation is
shown by the dashed straight line and is equal to V × I × t. The
sinusoidal ripple in the active energy calculation is also shown.
p(t) = VI −
E(t) = VIt −
L
is the line frequency, for example, 60 Hz.
⎡
⎢
⎢
⎢
⎢
⎢
⎢
⎣
⎡
⎢
⎢
⎢
⎢
⎢
⎢
⎣
CHANNEL 2
1
4
π
+
OUTPUT
⎛
⎜
⎝
VI
f
FROM
FROM
L
2f
8
LPF2
ADC
9 .
L
1
VI
⎞
⎟
⎠
+
2
APOS[15:0]
⎛
⎜
⎝
⎤
⎥
⎥
⎥
⎥
⎥
⎥
⎦
2f
8
× cos(4πf
9 .
LPF1
L
⎞
⎟
⎠
2
⎤
⎥
⎥
⎥
⎥
⎥
⎥
⎦
WGAIN[11:0]
× sin(4πf
Figure 69. Energy Calculation Line Cycle Energy Accumulation Mode
L
t)
ZERO CROSS
DETECTION
L
t)
WDIV[7:0]
%
LINECYC [15:0]
CALIBRATION
Rev. A | Page 31 of 60
CONTROL
(18)
(19)
+
+
Since the average value of a sinusoid is 0, this ripple does not
contribute to the energy calculation over time. However, the
ripple can be observed in the frequency output, especially at
higher output frequencies. The ripple gets larger as a percentage
of the frequency at larger loads and higher output frequencies.
The reason is simply that at higher output frequencies the
integration or averaging time in the energy-to-frequency
conversion process is shorter. As a consequence, some of the
sinusoidal ripple is observable in the frequency output. Choosing
a lower output frequency at CF for calibration can significantly
reduce the ripple. Also, averaging the output frequency by using
a longer gate time for the counter achieves the same results.
48
23
LAENERGY [23:0]
E(t)
Figure 68. Output Frequency Ripple
–
0
4×π×f
ACCUMULATE ACTIVE
ENERGY IN INTERNAL
REGISTER AND UPDATE
THE LAENERGY REGISTER
AT THE END OF LINECYC
LINE CYCLES
L
Vlt
t
(1+2×f
VI
L
/8. 9Hz )
0
02875-0-067
02875-0-068
sin(4×π×f
L
×t)
ADE7753