AOZ9004DI-00 AOSMD [Alpha & Omega Semiconductors], AOZ9004DI-00 Datasheet - Page 8

• Manufacturer Part Number: AOZ9004DI-00
• Description: Single-Cell Battery Protection IC
• Manufacturer: AOSMD [Alpha & Omega Semiconductors]

Theory of Operation
Please refer to the Timing Diagrams for more informa-
tion.
Normal Status
The AOZ9004D monitors the voltage between the V
pin and V
V
Since the device only draws a few microamperes of
current during operation and the voltage drop across the
low-pass filter R1 is negligible, the voltage between V
and V
voltage is in the range between over-discharge detection
voltage (V
and the VM pin voltage is in the range between the
charge over-current detection voltage (V
discharge over-current detection voltage (V
turns both the charging and discharging control FETs on.
In this normal status, charging and discharging can be
carried out freely.
Caution: Products with “Shut-down Function Available”
feature may not enable discharging when the battery is
connected for the first time. Connect the charger or short
V
Overcharge Status
When the battery voltage rises higher than overcharge
detection voltage (V
delay time (t
AOZ9004D turns off the charging control MOSFET to
stop charging. This condition is the overcharge status.
The resistance (R
and the resistance (R
pin are not connected. The overcharge status is released
in the following two cases:
1. When the battery voltage falls below overcharge
2. When a load is connected and battery voltage is
Caution: When both charger and load are connected
after overcharge detection, charging control FET still
remains off and a portion of the load current may flow
through body diode of charging control FET if the charger
can not supply the full load current. This condition may
overheat the charging control FET. Please refer to the
Typical Characteristics for more information.
M
M
Rev. 1.1 August 2008
pin and V
pin to V
release voltage (V
than -0.7V (Typ.) (charger is removed), the
AOZ9004D turns on the charging control MOSFET
and returns to the normal status.
below overcharge detection voltage (V
AOZ9004D turns on the charging control MOSFET
and returns to the normal status.
SS
is equal to the battery voltage. When the battery
SS
DL
SS
CU
) and overcharge detection voltage (V
pin and the voltage difference between the
SS
can restore the normal status.
) or longer in the normal status, the
pin to control charging and discharging.
VMD
CU
VMS
) between the V
CL
) for the overcharge detection
) and V
) between the V
M
pin voltage is higher
M
pin and V
CIOV
M
CU
DIOV
pin and V
) and
), the
), the IC
DD
CU
www.aosmd.com
DD
pin,
),
SS
DD
Over-Discharge Status
When the battery voltage falls below over-discharge
detection voltage (V
delay time (t
control MOSFET to stop discharging. This condition is
the over-discharge status. Under the over-discharge
status, the V
between the V
resistance (R
connected in the over-discharge status. When voltage
difference between the V
or lower, the productions with “Shut-down Function
Available” feature can enter the shut-down status to save
power. At this status, the current consumption is reduced
to the shut-down current consumption (I
down status is released when a charger is connected and
the voltage difference between the V
becomes 1.3V (Typ.) or higher.
When a battery in the over-discharge status is connected
to a charger and provides that the VM pin voltage is lower
than -0.7V (Typ.), the AOZ9004D releases the over-
discharge status and turns on the discharging MOSFET
when the battery voltage reaches over-discharge
detection voltage (V
not lower than -0.7 V (Typ.), the AOZ9004D releases the
over-discharge status and turns on the discharging
MOSFET when the battery voltage reaches over-
discharge detection voltage (V
Discharge Over-current Status
(Discharge Over-current, Load Short-circuiting)
When a battery is in the normal status, and the discharge
current becomes higher than specified value and the
status lasts for the discharge over-current detection delay
time (t
MOSFET and stops discharging. This status is the
discharge over-current status. In the discharge over-
current status, the V
resistor between V
When the load is disconnected, the V
V
and EB- pin (Refer to Figure 1) increases and is equal to
the impedance that enables automatic restoration and
the voltage at the V
current detection voltage (V
over-current status is restored to the normal status. Even
if the connected impedance is smaller than automatic
restoration level, the AOZ9004D will be restored to the
normal status from discharge over-current detection
status when the voltage at the V
discharge over-current detection voltage (V
SS
potential. When the impedance between the EB+ pin
DIOV
), the IC turns off the discharge control
DL
M
VMS
) or longer, the IC turns off the discharging
M
pin voltage is pulled up by the resistor
pin and V
) between the V
M
M
DL
DL
M
pin and V
pin returns to discharge over-
) for the over-discharge detection
) or higher. If VM pin voltage is
pin and V
M
DD
pin and V
DIOV
pin in the IC (R
DU
SS
SS
) or lower, the discharge
M
M
) or higher.
pin (R
pin becomes the
pin are shorted by the
pin and V
DD
M
M
pin and V
VMS
pin returns to the
pin is 1.3V (Typ.)
PON
AOZ9004D
DIOV
) in the IC.
). The shut-
VMD
SS
Page 8 of 16
) or lower
pin is not
DD
). The
pin