ade7518 Analog Devices, Inc., ade7518 Datasheet - Page 28

• Manufacturer Part Number: ade7518
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc, And Lcd Driver
• Manufacturer: Analog Devices, Inc.

ADE7518
USING THE POWER SUPPLY FEATURES
In an energy meter application, the 3.3 V power supply (V
is typically generated from the ac line voltage and regulated to
3.3 V by a voltage regulator IC. The preregulated dc voltage,
typically 5 V to 12 V, can be connected to V
tor divider. A 3.6 V battery can be connected to V
shows how the ADE7518 power supply inputs are set up in this
application.
Figure 30 shows the sequence of events that occurs if the main
power supply generated by the PSU starts to fail in the power
meter application shown in Figure 29. The SAG detection can
provide the earliest warning of a potential problem on V
SAG LEVEL TRIP POINT
(240V, 220V, 110V TYPICAL)
SAGCYC = 1
AC INPUT
Figure 30. Power Supply Management Interrupts and Battery Switchover with Only V
V
P
2.75V
V
– V
1.2V
DCIN
V
DD
N
PSU
5V TO 12V DC
Figure 29. Power Supply Management for Energy Meter Application
REGULATOR
DCIN
3.3V
through a resis-
BAT
. Figure 29
V
BCTRL
DD
SWOUT
V
DD
V
.
SAG EVENT
BAT
(FSAG = 1)
DCIN
V
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)
V
V
DD
P
N
64
60
61
58
45
49
50
DETECTION
SAG
When a SAG event occurs, user code can be configured to back
up data and prepare for battery switchover if desired. The rela-
tive spacing of these interrupts depends on the design of the
power supply.
Figure 31 shows the sequence of events that occurs if the main
power supply starts to fail in the power meter application shown
in Figure 29, with battery switchover on low V
enabled.
Finally, the transition between V
power supply modes (see the Operating Modes section) are
represented in Figure 32 and Figure 33.
SUPERVISORY
SUPERVISORY
VOLTAGE
VOLTAGE
V
(FVDCIN = 1)
DCIN
EVENT
t
1
DD
POWER SUPPLY
MANAGEMENT
IF SWITCHOVER ON LOW V
Enabled for Battery Switchover
t
2
AUTOMATIC BATTERY SWITCHOVER
V
SWOUT
CONNECTED TO V
BSO EVENT
(FBSO = 1)
V
DD
SW
and V
(ADDR. 0xF8)
IPSMF SFR
DD
BAT
IS ENABLED,
BAT
and the different
DCIN
or low V
DD