R16AN0002EU0300 Rev.3.00
Page 7
Jan 6, 2022
ISL9241 Operation Modes Application Note
2. Transitioning Between Modes (NVDC/Bypass/RTB)
You can use firmware commands to configure the ISL9241 to transition between the different modes.
shows the major and minor states that the ISL9241 can operate in and the transitions between them. The
commands in this document are suggestions/recommendations. You can start with these commands for your first
implementation/evaluation, but you must test the commands on your system to see if the commands need to be
modified for your application in your final implementation.
Bypass State:
Set up the system with the Bypass gates ON to make VSYS = VADP and allow flow of current from
the adapter directly to the load. In this state, the adapter is connected directly to the system, but the ISL9241 is not
switching, so the charging and reverse turbo boost functions are disabled.
(BYPSG = on, NGATE = off, BGATE = off, MaxSysV = 0, RTB bit = 0, CC = 0, MinSysV= 0)
Charging State:
The adapter is connected directly to the system (Bypass) and charging is enabled, but
the turbo boost function is disabled. Use this state when the adapter can support the entire system load.
(BYPSG = on, NGATE = off, BGATE = on, MaxsysV = non-zero, RTB bit = 0, CC = non-zero, MinsysV = non-zero)
Reverse Turbo-Boost State (RTB):
The Bypass gates are ON and Reverse Turbo Boost is enabled and primed
to meet any load requirements. The battery can supplement the adapter to provide power in this mode. Charging
is disabled.
(BYPSG = on, NGATE = off, BGATE = on, MaxsysV = non-zero, RTB bit = 1, CC = 0, MinsysV = 0)
RTB + Charging State:
An extension of RTB with battery charging enabled.
(BYPSG = on, NGATE = off, BGATE = on, MaxsysV = non-zero, RTB bit = 1, CC = non-zero, MinsysV = non-zero)
Bat State:
Reached when the adapter is unplugged and ACOK goes low. The system load is supported by the
battery.
(BYPSG = off, NGATE = on, BGATE = on, MaxsysV = non-zero, RTB bit = 0, CC = 0, MinsysV = 0)
Figure 6. Transition State Diagram
6WDWH
.
,QVW
1XP
.
/HJHQG
6WDWH%XEEOH
,QVWUXFWLRQV
(YHQW'ULYHQ,QVWUXFWLRQV
19'&
%\SDVV
57%
%\SDVV
&KUJ
57%
&KUJ
$
&
'
(
)
,
+
*
-
%
19'&
&KUJ
.
/
%DW
0
0
0
0
1
,QVW
1XP
*Renesas recommends going to RTB
only if VBAT > MinSysVoltage
