LC05111CMT
www.onsemi.com
9
Description of Operation
(1) Normal mode
•LC05111CMT 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. 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 0.95 mA (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.
b. VCC level rise more than Over−discharge
release voltage2(Vuvr2) without charger.(Auto
wake−up function)
•If CS pin voltage will get lower than charger detecting
voltage (Vchg) by connecting charger under the
condition that cell voltage is lower than over−discharge
detection voltage, internal power MOS FET as
DCHG_SW is turned on and power dissipation in
power MOS FETs is suppressed.
*In case that charging current is low enough, ripple current
will be appeared at S2 terminal when CS pin voltage is near
by the threshold of charger detecting voltage (Vchg).
It is caused that the two modes, charger detected and charger
not detected (charging through parasitic diodes of
DCHG_SW, is alternately appeared.
•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).
(4) Discharging over−current detection mode 1
•Internal power MOS FET as DCHG_SW will be turned
off and discharging current will be shut off if CS pin
voltage will get equal to or higher than discharging
over−current detection current (Ioc) over the delay time
of discharging over−current (Toc1).
This is the discharging over−current detection mode 1.
In discharging over−current detection mode 1, CS pin
will be pulled down to Vss with internal resistor Rcsd.
•The recovery from discharging over−current detection
mode will be made after the following two conditions
are satisfied.