ADE7757EB AD [Analog Devices], ADE7757EB Datasheet - Page 3

• Manufacturer Part Number: ADE7757EB
• Description: Evaluation Board Documentation ADE7757 Energy Metering IC
• Manufacturer: AD [Analog Devices]

LOGIC OUTPUTS
ADE7757 provides the active power information in the
form of an output frequency. The three frequency outputs
are F1, F2 and CF. Consult the datasheet for more infor-
mation on these outputs. The logic outputs F1 and F2 are
intended to be used to drive an impulse counter or stepper
motor. The outputs are buffered and available at the con-
nector SK6. A stepper motor may be directly connected
here. The power supply for the buffer is +5V (SK4A) and
may be connected to the ADE7757 supply using jumper
JP15, or to its own supply.
The logic output CF can be directly connected to an LED
using JP14 (Position B) or to an optically isolated output (Posi-
tion A). By closing Positions A and B, both options are se-
lected. The optically isolated output is available at connector
SK5. This isolated output is useful when the evaluation board
is connected directly to a high voltage (e.g., 220 V residential). A
typical connection diagram for this isolated output is shown in
Figure 5.
All logic outputs can be monitored via test points 6 to 8
(TP6 to TP8). These test points provide easy access for
scope probes and meter probes.
REV. PrF
A
50Hz
50Hz
30mV
220V
JP14
R12
Figure 4. Typical Connection for Analog Inputs
Figure 5. Typical Connection for Opto Output
B
R11
H11L1
SK1A
SK2A
SK1B
SK1C
SK2B
U4
CFOUT
VPLUS
VMINUS
AGND
JP6
JP5
R19
R20
JP8
R4
JP7
C18
R18
R5
PRELIMINARY TECHNICAL DATA
JP4
JP2
JP1
R16
R17
JP3
R21
JP18
R15
R22
SK5B
SK5C
SK5A
JP17
C19
A
B
C16
C17
JP9
+
N
JP16
P
5V to 12V
TP1
TP2
P
N
TP4
TP5
V1N
V1P
COUNTER
V2N
V2P
–3–
EVALUATION BOARD SET UP AS AN ENERGY
METER
Figure 6 shows a wiring diagram that allows a simple
energy meter to be implemented using the ADE7757
evaluation board. The current transducer used in this ex-
ample is a 400 µ
with a line voltage of 220 V and a maximum current of
25 A. The frequency outputs F1 and F2 can be used to
drive a mechanical counter. These outputs will be cali-
brated to provide 100 imp/kWhr. The logic output CF
has an output frequency that can be up to 2048 times higher
OUTPUT FREQUENCY SELECTION
ADE7757 provides up to four different output frequencies
on F1 and F2. The output frequency selection is made via
the logic inputs S0 and S1—see ADE7757 datasheet. On
the evaluation board these inputs are set by using jumpers
JP12 and JP13. The logic input SCF is set via jumper 11
(JP11). For a full explanation of the ADE7757 output
frequency selection see the datasheet.
INTERNAL CLOCK
The ADE7757’s integrated oscillator serves as the clock
source to the chip. A precise 6.2 k
tolerance and low drift is used to drive the internal oscilla-
tor.
NEUTRAL PHASE
Figure 6. ADE7757 Evaluation Board as an Energy Meter
SHUNT
LOAD
JP1 = OPEN
JP2 = OPEN
JP3 = OPEN
JP4 = OPEN
JP5 = OPEN
JP6 = OPEN
JP7 = OPEN
JP8 = CLOSED
JP9 = N
220V
5A
5.000V
SK2A
SK2B
SK1C
SK1A
SK1B
2mV
JP11 = 1
JP12 = 1
JP13 = 0
JP14 = A,B
JP16 = P
JP17 = A
JP18 = CLOSED
R21 = REMOVED
AGND
shunt. The meter is intended to be used
V1N
V1P
SK3A
JP6
AGND VDD
R19
R20
JP5
C18
SK3B
R21
EVAL-ADE7757EB
JP18
R15
R22
5.000V
JP17
FREQUENCY DISPLAY
B
A
resistor with low
SK5A
SK5B
SK5C
0.9776 Hz
TP4
V2
54.5mV
imp/kWhr
100