LC05112CMT
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10
Description of operation
(1) Normal mode
LC05112CMT controls charging and discharging by detecting cell voltage (VCC) and controls S2-S1
current. In case that cell voltage is between over-discharge detection voltage (Vuv) and over-charge
detection voltage (Vov), and S2-S1 current is between charge over-current detection current (Ioch) and
discharge over-current detection current (Ioc), internal power MOS FETs as CHG_SW, DCHG_SW are all
turned ON.
This is the normal mode, and it is possible to be charged and discharged.
(2) Over-charging mode
Internal power MOS FET as CHG_SW will be turned off if cell voltage will get equal to or higher than
over-charge detection voltage (Vov) over the delay time of over-charging (Tov).
This is the over-charging detection mode.
The recovery from over-charging will be made after the following three conditions are all satisfied.
a. Charger is removed from IC.
b. CS pin voltage will get equal to or higher than discharge over-current detection current (Ioc) due to load
connected
c. Cell voltage will get lower than over-charge release voltage (Vovr) over the delay time of over-charging
release (Tovr) due to discharging through load.
Consequently, internal power MOS FET as CHG_SW will be turned on and normal mode will be resumed.
In over-charging mode, discharging over-current detection is made only when CS pin will get higher than
discharging over-current detection current 2(Ioc2), because discharge current flows through parasitic
diode of CHG_SW FET.
If CS pin voltage will get higher than discharging over-current detection current 2 (Ioc2) over the delay time
of discharging over-current 2 (Toc2), discharging will be shut off, because internal power FETs as
DCHG_SW is turned off.(short-circuit detection mode)
After detecting short-circuit, CS pin will be pulled down to Vss by internal resistor Rcsd.
The recovery from short circuit detection in over-charging mode will be made after the following two
conditions are satisfied.
a. Load is removed from IC.
b. CS pin voltage will get equal to or lower than discharging over-current detection current 2 (Ioc2) due to
CS pin pulled down through Rcsd.
Consequently, internal power MOS FET as DCHG_SW will be turned on, and over-charging detection
mode will be resumed.
(3) Over-discharging mode
If cell voltage will get lower than over-discharge detection voltage (Vuv) over the delay time of
over-discharging (Tuv), discharging will be shut off, because internal power FETs as DCHG_SW is turned
off.
This is the over-discharging mode.
After detecting over-discharging, CS pin will be pulled up to Vcc by internal resistor Rcsu and the bias of
internal circuits will be shut off. (Stand-by mode)
In stand-by mode, operating current is suppressed under 0.95uA (max).
The recovery from stand-by mode will be made by internal circuits biased after the following two conditions
are satisfied.
a. Charger is connected.
By continuing to be charged, if cell voltage will get higher than over-discharge detection voltage (Vuvr) over
the delay time of over-discharging (Tuvr), internal power MOS FETs as DCHG_SW is turned on and normal
mode will be resumed.
In over-discharge detection mode, charging over-current detection does not operate.
By continuing to be charged, charging over-current detection starts to operate after cell voltage goes up
more than over-discharge release voltage (Vuvr).
