AOZ9004B
When a battery is in the normal status, and the discharge
current becomes abnormally higher (EB+ pin and EB- pin
shorted), and thus the VM pin voltage is equal or higher
Battery Charging Function “Unavailable”
This function inhibits recharging when a battery that is
internally short-circuited (0V battery) is connected. When
the battery voltage is the 0V battery charge inhibition
than load short-circuiting detection voltage (V
) for
SHORT
load short-circuiting detection delay time (t
), the IC
SHORT
battery voltage (V
) or lower, the charging control
0INH
turns off the discharge control MOSFET and stops
discharging. This status is the load shorting-circuiting
status. In the load shorting-circuiting status, the VM pin
and VSS pin are shorted by the resistor between VM pin
MOSFET gate is fixed to the EB- pin voltage to inhibit
charging. When the battery voltage is the 0V battery
charge inhibition battery voltage (V
charging can be performed.
) or higher,
0INH
and VSS pin (R
) in the IC. When the short-circuiting
VMS
condition is released, the VM pin returns to the VSS
potential. The resistance (R ) between the VM pin and
Calculation of Current Limit
VMD
VDD pin is not connected in the load shorting-
circuiting status.
The charge and discharge current limit is determined by
the charge and discharge over-current threshold voltages
(V
and V
), and the total resistance of the internal
DIOV
CIOV
Charge Over-Current Status
MOSFET (R ). Use the following equations to deter-
SS
When a battery in the normal status, and the charge cur-
rent is higher than the specified value and the status lasts
mine the maximum and minimum current limits:
for the charge over-current detection delay time (t
),
CIOV
the charge control MOSFET is turned off and charging is
stopped. This status is the charge over-current status.
This IC will be restored to the normal status from the
charge over-current status when, the voltage at the VM
pin returns to charge over-current detection voltage
VDIOV _ MAX
VDIOV _ MIN
IDIOV _ MAX
ICIOV _ MAX
=
=
; IDIOV _ MIN =
RSS _ MIN
VCIOV _ MAX
RSS _ MAX
VCIOV _ MIN
; ICIOV _ MIN
=
RSS _ MIN
RSS _ MAX
(V
) or higher by removing the charger. The charge
CIOV
over-current detection function does not work in the over-
discharge status. The resistance (R ) between the VM
VMD
pin and VDD pin, and the resistance (R
) between the
VMS
VM pin and VSS pin are not connected in the charge
over-current status.
0V Battery Charging Function “Available”
This function is used to recharge a connected battery
whose voltage is 0V due to self-discharge. When the 0V
battery charge starting charger voltage (V
) or a
0CHA
higher voltage is applied between the EB+ and EB- pins
by connecting a charger, the charging control MOSFET
gate is fixed to the VDD pin voltage.
When the voltage between the gate and source of the
charging control MOSFET becomes equal to or higher
than the turn-on voltage due to the charger voltage, the
charging control MOSFET is turned on to start charging.
At this time, the discharging control MOSFET is off and
the charging current flows through the internal parasitic
diode in the discharging control MOSFET. When the
battery voltage becomes equal to or higher than over-
discharge release voltage (V ), the AOZ9004B enters
DU
the normal status.
Rev. 1.2 August 2008
www.aosmd.com
Page 10 of 17
AOS [ ALPHA & OMEGA SEMICONDUCTORS ]
