ISL12027 Intersil Corporation, ISL12027 Datasheet - Page 15

• Manufacturer Part Number: ISL12027
• Manufacturer: Intersil Corporation

There are two options for setting the change-over conditions
from V
register controls this operation.
Note that the I
battery backup, that function is controlled by the SBIB bit.
That operation is covered after the power control section.
OPTION 1- STANDARD POWER CONTROL MODE
In the Standard mode, the supply will switch over to the
battery when
lower. In this mode, accidental operation from the battery is
prevented since the battery backup input will only be used
when the
To select Option 1, BSW bit in the Power Register must be
set to “BSW = 0”. A description of power switchover follows.
Standard Mode Power Switchover
• Normal Operating Mode (V
To transition from the V
following conditions must be met:
• Condition 1:
• Condition 2:
• Battery Backup Mode (V
The ISL12027 device will switch from the V
when one of the following conditions occurs:
• Condition 1:
• Condition 2:
There are two discrete situations that are possible when
using Standard Mode:
These two power control situations are illustrated in Figures
13 and 14.
- Option 1 - Standard Mode
- Option 2 - Legacy Mode (Default)
(V
V
where V
V
where V
V
where V
V
where V
FIGURE 13. BATTERY SWITCHOVER WHEN V
DD
DD
DD
DD
V
BAT
V
V
TRIP
BAT
DD
DD
V
< V
< V
> V
> V
BAT
)
V
to Battery back-up mode. The BSW bit in the PWR
BATHYS
TRIP
BATHYS
TRIPHYS
BAT
TRIP
BAT
TRIP
DD
- V
V
BATHYS
2
- V
+ V
DD
supply is shut off.
C bus may or may not be operational during
≈ 2.2V
+ V
BATHYS
BATHYS
drops below V
≈ 50mV
≈ 50mV
TRIPHYS
≈ 30mV
V
DD
BATTERY BACKUP
BAT
to V
BAT
<
15
DD
MODE
) to Normal Mode (V
V
BAT
) to Battery Backup Mode
TRIP
TRIP
mode, both of the
and
or V
BAT
V
BAT
BAT
V
BAT
, whichever is
BAT
to V
>
+ V
V
< V
DD
DD
BATHYS
TRIP
2.2V
1.8V
)
TRIP
mode
.
ISL12027
OPTION 2 -LEGACY POWER CONTROL MODE
(DEFAULT)
The Legacy Mode follows conditions set in X1226 products.
In this mode, switching from V
comparing the voltages and the device operates from
whichever is the higher voltage.
To select the Option 2, BSW bit in the Power Register must
be set to “BSW = 1”.
• Normal Mode (V
To transition from the V
conditions must be met:
V
• Battery Backup Mode (V
The device will switch from the V
following condition occurs:
V
The Legacy Mode power control conditions are illustrated in
Figure 15 below.
DD
DD
V
FIGURE 14. BATTERY SWITCHOVER WHEN V
FIGURE 15. BATTERY SWITCHOVER IN LEGACY MODE
BAT
V
V
V
< V
> V
TRIP
BAT
DD
BAT
BAT
+V
- V
V
TRIP
BATHYS
BATHYS
OFF
DD
) to Battery Backup Mode (V
BATTERY BACKUP
DD
V
DD
to V
BAT
MODE
DD
) to Normal Mode (V
BAT
BAT
to V
mode, the following
BAT
VOLTAGE
to V
is simply done by
DD
V
TRIP
mode when the
BAT
+ V
ON
TRIPHYS
BAT
> V
DD
April 17, 2006
3.0V
2.2V
)
)
FN8232.3
TRIP
IN