EUP9232
0V Battery Charge Inhibiting Function *2
Delay Circuits
The overcharge detection delay time (tCU1,2), the
overdischarge detection delay time (tDD1,2), and
the overcurrent detection delay time1 (tI0V1) change
with an external capacitor (C3). Since one
capacitor determine each delay time, delay times
are correlated by the following ratio:
Overcharge delay time: Overdischarge delay time :
Overcurrent delay time =100:10:1
This function is used for inhibiting charging when
either of the connected batteries goes 0V due to its
self-discharge. When the voltage of either of the
connected batteries goes below 0 V charge inhibit
voltage 1 and 2 (VOINH1,2), the charging FET gate
is fixed to "EB-" to inhibit charging. Charging is
possible only when the voltage of both connected
batteries goes 0V charge inhibit voltage 1 and
2 (VOINH1, 2) or more. Note that charging may be
possible when the total voltage of both connected
The delay times are calculated by the following
batteries is less than the minimum value (VDSOPmin
)
equations : (Ta=-40 to +85℃)
of the operating voltage between VCC and VSS
even if the voltage of either of the connected
batteries is 0 V charge inhibit voltage 1 and 2
(V0INH1, 2) or less. Charging is prohibited when the
total voltage of both connected batteries reaches
the minimum value (VDSOPmin) of the operating
voltage between VCC and VSS.
Min.
Typ.
Max.
Overcharge detection delay
time tCU [s] = Delay factor
9.364)×C3 [µF]
0.6409) ×C3 [µF]
0.06682) ×C3 [µF]
(2.5,
4.545,
Overdischarge detection delay
time tDD [s] = Delay factor
(0.3045, 0.4545,
(0.02864, 0.04545,
Overcurrent detection delay
time tIOV1 [s] = Delay factor
Remark The delay time for overcurrent detection 2
is fixed by an internal circuit. The delay time cannot
be changed via an external capacitor.
0V Battery Charging Function *2
*1. When initially connecting batteries, the IC may fail to
enter the normal condition (discharging ready state).If so,
once set the VM pin to VSS voltage (short pins VM and
VSS or connect a charger).
This function is used to recharge both of two
serially-connected batteries after they self-
discharge to 0V. When the 0V charging start
voltage (V0CHA) or higher is applied to between VM
and VCC by connecting the charger, the charging
FET gate is fixed to VCC potential.
*2.Some lithium ion batteries are not recommended
to be recharged after having been completely
discharged. Please contact the battery manufacturer
when you decide to select a 0V battery charging
function.
When the voltage between the gate and the source
of the charging FET becomes equal to or higher
than the turn-on voltage by the charger voltage, the
charging FET turns on to start charging. At this
time, the discharging FET turns off and the
charging current flows through the internal
parasitic diode in the discharging FET. If all the
battery voltages become equal to or higher than the
overdischarge release voltage (VDU1, 2), the normal
condition returns.
DS9232 Ver1.1 Feb. 2007
17
EUTECH [ EUTECH MICROELECTRONICS INC ]
