ade7518 Analog Devices, Inc., ade7518 Datasheet - Page 25

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

POWER SUPPLY ARCHITECTURE
The ADE7518 has two power supply inputs, V
requires only a single 3.3 V power supply at V
A battery backup, or secondary power supply, with a maximum
of 3.7 V, can be connected to the V
ADE7518 connects V
power for the ADE7518 circuitry. The V
the voltage at the internal power supply (V
maximum output current of 6 mA. This pin can also be used
to power a limited number of peripheral components. The 2.5 V
analog supply (V
(V
Figure 27 shows the power supply architecture of ADE7518.
The ADE7518 provides automatic battery switchover between
V
Additionally, the BCTRL input can be used to trigger a battery
switchover. The conditions for switching V
V
section. V
3.3 V dc signal. This input is intended for power supply super-
visory purposes and does not provide power to the ADE7518
circuitry (see the Battery Switchover section).
BATTERY SWITCHOVER
The ADE7518 monitors V
switchover from V
status of the V
enabled by default. Setting Bit 1 in the Battery Switchover Configu-
ration SFR (BATPR, 0xF5) disables battery switchover so that
V
V
(PERIPH, 0xF4), which is described in Table 18. Bit 6 is set
when V
connected to V
BCTRL
DD
BAT
DD
SWOUT
INTD
and V
is always connected to V
and back to V
) are derived by on-chip linear regulators from V
is indicated by Bit 6 in the Peripheral Configuration SFR
SWOUT
V
BAT
DCIN
DCIN
POWER SUPPLY
MANAGEMENT
SCRATCHPAD
based on the voltage level detected at V
is connected to V
is an input pin that can be connected to a 0 V to
DD
V
BAT
DD
INTA
, V
Figure 27. Power Supply Architecture
.
DD
DD
) and the 2.5 V supply for the core logic
V
DCIN
BAT
DD
to V
are described in the Battery Switchover
, or BCTRL pin. Battery switchover is
or V
DD
BAT
V
SW
, V
BAT
LCD
can be configured based on the
V
SWOUT
BAT
SWOUT
to V
DD
, and V
and cleared when V
BAT
SWOUT
(see Table 17). The source of
LDO
LDO
RTC
input. Internally, the
SWOUT
DCIN
, which is used to derive
SWOUT
SWOUT
. Automatic battery
V
V
DD
3.3V
INTD
output pin reflects
INTA
DD
for full operation.
and V
) and has a
from V
DD
2.5V
SPI/I
UART
SWOUT
MCU
ADE
or V
SWOUT
BAT
2
DD
C
, and
.
DCIN
to
is
Rev. 0 | Page 25 of 128
.
The battery switchover functionality provided by the ADE7518
allows a seamless transition from V
battery switchover option ensures a stable power supply to the
ADE7518, as long as the external battery voltage is above 2.75 V.
It allows continuous code execution even while the internal
power supply is switching from V
the energy metering ADCs are not available when V
used for V
Power supply management (PSM) interrupts can be enabled to
indicate when battery switchover occurs and when the V
power supply is restored (see the Power Supply Management
(PSM) Interrupt section).
V
The following three events switch the internal power supply
(V
•
•
•
Switching from V
To switch V
that are enabled to force battery switchover must be false:
•
•
•
DD
SWOUT
to V
V
from V
BATPRG[1:0] bits in the Battery Switchover Configuration
SFR (BATPR, 0xF5) = 0b01. Setting these bits disables
switchover based on V
V
V
from V
the BATPR SRF are cleared.
Falling edge on BCTRL. When the battery control pin,
BCTRL, goes low, V
external switchover signal can trigger a switchover to V
at any time. Setting the bits INT1PRG[2:0] to 0bx01 in the
Interrupt Pins Configuration SFR (INTPR, 0xFF) enables
the battery control pin (see Table 15).
V
condition is enabled, V
remains above 1.2 V and V
V
V
BCTRL enabled. V
is high, and the first or second bullet point is satisfied.
DCIN
DCIN
DD
DCIN
DD
DD
) from V
BAT
< 2.75 V. When V
< 2.75 V enabled. V
remains above 2.75 V.
SWOUT
< 1.2 V. When V
is disabled by default.
< 1.2 V and V
DD
SWOUT
DD
to V
to V
.
DD
from V
BAT
to V
BAT
BAT
. This event is enabled when BATPRG[1:0] in
. This event is enabled when the
to V
BAT
SWOUT
DD
SWOUT
BAT
:
DCIN
DD
DD
DCIN
< 2.75 V enabled. If the low V
SWOUT
to V
SWOUT
switches back to V
falls below 2.75 V, V
falls below 1.2 V, V
switches from V
. Battery switchover on low
DD
DD
DD
switches to V
remains above 2.75 V.
, all of the following events
switches back to V
DD
to V
to V
BAT
BAT
and back. Note that
. An automatic
DD
DD
DD
SWOUT
to V
after V
SWOUT
ADE7518
after BCTRL
BAT
DD
switches
BAT
is being
switches
after
. This
DCIN
DD
DCIN
BAT