Smart Power Selector
The smart power selector seamlessly distributes power
from the external CHGIN input to the battery (BAT) and
the system (SYS). With both an external adapter and
battery connected, the smart power selector basic
functions are:
●
When the system load requirements are less than the
input current limit, the battery is charged with residual
power from the input.
●
When the system load requirements exceed the
input current limit, the battery supplies supplemental
current to the load.
●
When the battery is connected and there is no
external power input, the system is powered from the
battery.
Thermal Current Regulation
In case the die temperature exceeds the normal limit, the
MAX20335 will attempt to limit the temperature increase
by reducing the input current from CHGIN. In this condi-
tion, the system load has priority over charger current, so
the input current is first reduced by lowering the charge
current. If the junction temperature continues to rise and
reaches the maximum operating limit, no input current
is drawn from CHGIN and the battery powers the entire
system load.
Figure 2b. Power-On Sequencing Without Battery
MAX20335
PMIC with Ultra-Low I
Q
Voltage Regulators and
Battery Chargers for Small Lithium Ion Systems
www.maximintegrated.com
Maxim Integrated
│
31
001
010
SYS
POR
RST
011
100
111
t
RST
BUCK CANNOT
BE ALWAYS ON
CHGIN
LDO_En
Buck_En*
_Seq
0%
25%
50%
100%
% of t
RST
ALWAYS
*After being enabled, the buck converters have an 8ms (typ) blanking time before the output voltage starts to rise.
-ON
15ms
30ms
15ms
ENABLE VIA
I
2
C/MPC
ENABLE VIA
I
2
C/MPC
