ADE7761ARS-REF Analog Devices Inc, ADE7761ARS-REF Datasheet - Page 13

• Manufacturer Part Number: ADE7761ARS-REF
• Description: IC ENERGY METERING 20-SSOP
• Manufacturer: Analog Devices Inc

Specifications of ADE7761ARS-REF

• Rohs Status: RoHS non-compliant

OPERATION
POWER SUPPLY MONITOR
The ADE7761 contains an on-chip power supply monitor. The
power supply (V
If the supply is less than 4 V ± 5%, the ADE7761 goes into an
inactive state, that is, no energy is accumulated and the CF, F1,
and F2 outputs are disabled. This is useful to ensure correct
device operation at power-up and during power-down. The
power supply monitor has built-in hysteresis and filtering. This
gives a high degree of immunity to false triggering due to noisy
supplies.
The power supply and decoupling for the part should be such
that the ripple at V
normal operation.
ANALOG INPUTS
Channel V1 (Current Channel)
The voltage outputs from the current transducers are connected
to the ADE7761 here. Channel V1 has two voltage inputs, V
and V
However, at any one time, only one is selected to perform the
power calculation (see the Fault Detection section).
The maximum peak differential signal on V
is ±660 mV.
Figure 10 shows the maximum signal levels on V
The differential voltage signal on the inputs must be referenced
to a common mode (usually AGND).
+660mV + V
REVP - FAULT - CF -
–660mV + V
F1 - F2 OUTPUTS
ADE7761
1B
. These inputs are fully differential with respect to V
V
V
CM
CM
CM
V
1A
DD
, V
5V
4V
0V
Figure 10. Maximum Signal Levels, Channel 1
Figure 9. On-Chip Power Supply Monitoring
1B
INACTIVE
DD
) is continuously monitored by the ADE7761.
DD
COMMON MODE
does not exceed 5 V ± 5% as specified for
±100mV MAX
DIFFERENTIAL INPUT A
DIFFERENTIAL INPUT B
±660mV MAX PEAK
±660mV MAX PEAK
ACTIVE
TIME
AGND
V
CM
INACTIVE
1A
–V
V1
V1
V
V
V
1N
1A
1A
1N
1B
, V
and V
1B
, and V
1B
–V
1A
1N
Rev. A | Page 13 of 28
.
1N
1N
.
Channel V2 (Voltage Channel)
The output of the line voltage transducer is connected to the
ADE7761 at this analog input. Channel V2 is a single-ended
voltage input. The maximum peak differential signal on
Channel 2 is ±660 mV with respect to V
maximum signal levels that can be connected to Channel 2.
The differential voltage V
common mode (usually AGND). The analog inputs of the
ADE7761 can be driven with common-mode voltages of up to
100 mV with respect to AGND. However, the best results are
achieved using a common mode equal to AGND.
MISCAL Input
The input for the power calibration in missing neutral mode is
connected to the ADE7761 at this analog input. MISCAL is a
single-ended voltage input. It is recommended to use a dc signal
derived from the voltage reference to drive this pin. The maxi-
mum peak differential signal on MISCAL is +660 mV with
respect to V
can be connected to the MISCAL pin.
The differential voltage MISCAL–V
common mode (usually AGND). The analog inputs of the
ADE7761 can be driven with common-mode voltages of up to
100 mV with respect to AGND. However, best results are
achieved using a common mode equal to AGND.
Typical Connection Diagrams
Figure 13 shows a typical connection diagram for Channel V1.
The analog inputs are being used to monitor both the phase
and neutral currents. Because of the large potential difference
between the phase and neutral, two current transformers (CTs)
must be used to provide the isolation. Note that both CTs are
referenced to analog ground (AGND); the common-mode
+660mV + V
–660mV + V
+660mV + V
V
V
CM
CM
MISCAL
CM
CM
CM
V2
2N
Figure 11. Maximum Signal Levels, Channel 2
. Figure 12 shows the maximum signal levels that
Figure 12. Maximum Signal Levels, MISCAL
2P
DIFFERENTIAL INPUT
DIFFERENTIAL INPUT
±660mV MAX PEAK
–V
±660mV MAX PEAK
COMMON MODE
COMMON MODE
2N
±100mV MAX
±100mV MAX
must be referenced to a
2N
must be referenced to a
2N
. Figure 11 shows the
AGND
V2
V
MISCAL
V
CM
MISCAL
CM
V
V
V
2P
2N
2N
ADE7761