ADE7753ARS Analog Devices Inc, ADE7753ARS Datasheet - Page 10

• 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

ADE7753
Gain
Waveform register will give an indication of the offset in the
channel. This offset can be canceled by writing an equal and
opposite offset value to the relevant offset register. The offset
correction can be confirmed by performing another read.
Note when adjusting the offset of Channel 1, one should
disable the digital integrator and the HPF.
di/dt CURRENT SENSOR AND DIGITAL INTEGRATOR
di/dt sensor detects changes in magetic field caused by ac
current. Figure 5 shows the principle of a di/dt current
sensor.
The flux density of a magnetic field induced by a current is
directly proportional to the magnitude of the current. The
changes in the magnetic flux density passing through a
conductor loop generates an electromotive force (EMF)
between the two ends of the loop. The EMF is a voltage signal
which is proportional to the di/dt of the current. The voltage
output from the di/dt current sensor is determined by the
mutual inductance between the current carrying conductor
and the di/dt sensor.
1
2
4
8
16
Figure 4– Channel Offset Correction Range (Gain = 1)
Figure 5– Principle of a di/dt current sensor
Correctable Span
±50mV
±37mV
±30mV
±26mV
±24mV
-50mV
Offset Correction range
CH1OS[5:0]
1Fh
3Fh
00h
Magnetic field created by current
(directly propor tional to current)
Table II
0mV
PRELIMINARY TECHNICAL DATA
01, 1111b
11, 1111b
LSB Size
1.61mV/LSB
1.19mV/LSB
0.97mV/LSB
0.84mV/LSB
0.77mV/LSB
+50mV
+
-
Offset
Adjust
EMF (electromotive force)
induced by changes in
magnetic flux density (d/dt)
Sign + 5 Bits
Sign + 5 Bits
–10–
The current signal needs to be recovered from the di/dt signal
before it can be used. An integrator is therefore necessary to
restore the signal to its original form. The ADE7753 has a
built-in digital integrator to recover the current signal from
the di/dt sensor. The digital integrator on Channel 1 is
switched off by default when the ADE7753 is powered up.
Setting the MSB of CH1OS register will turn on the
integrator. Figures 6 to 9 show the magnitude and phase
response of the digital integrator.
Figure 6– Combined gain response of the digital integrator
Figure 8– Combined gain response of the digital integrator
Figure 7– Combined phase response of the digital integra-
-1.5
-2.5
-3.5
-4.5
-5.5
-1
-2
-3
-4
-5
-6
-10
-20
-30
-40
-50
10
40
0
and phase compensator (40Hz to 70Hz)
-88.5
-89.5
-90.5
-88
-89
-90
tor and phase compensator
45
and phase compensator
10
2
10
50
2
FREQUENCY-Hz
FREQUENCY-Hz
FREQUENCY-Hz
55
60
10
10
3
3
REV. PrF 10/02
65
70