mc33348d ON Semiconductor, mc33348d Datasheet - Page 5

• Manufacturer Part Number: mc33348d
• Description: Lithium Battery Protection Circuit For One Cell Smart Battery Packs
• Manufacturer: ON Semiconductor

CELL CHARGING/DISCHARGING
CELL CHARGING FAULT/RESET
CELL DISCHARGING FAULT/RESET
FAULTY CELL
MOTOROLA ANALOG IC DEVICE DATA
Storage or Nominal Operation:
Charge Voltage Limit Fault:
Charge Voltage Limit Reset:
Discharge Current Limit Fault:
Discharge Current Limit Reset:
Discharge Voltage Limit Fault:
Discharge Voltage Limit Reset:
Discharge Voltage Limit Fault:
No current or voltage faults
V Pin 1
V Pin 1 < (V th(OV) – V H )
for 1.0 s
V Pin 5
for 3.0 ms and
V Pin 1 < (V th(OV) – V H )
for 1.0 ms
V Pin 5 – V Pin 3 < V th(dschg)
V Pin 1
consecutive 1.0 s samples
V Pin 3 > (V Pin 5 + 0.6 V)
V Pin 1
Input Conditions
Cell Status
(V Pin 3 + V th(dschg) )
V th(OV) for 1.0 s
V th(UV) for three
1.5 V
Both Charge MOSFET Q1 and Discharge MOSFET Q2 are on.
The battery pack is available for charging or discharging.
Charge MOSFET Q1 is latched off and the cell is disconnected
from the charging source. An internal current source pull–up is
applied to divider resistors R1 and R2 creating a hysteresis
voltage of V H . The battery pack is available for discharging.
Discharge current limit protection is disabled.
Charge MOSFET Q1 will turn on when the voltage across the cell
falls sufficiently to overcome hysteresis voltage V H . This can be
accomplished by applying a load to the battery pack. Discharge
current limit protection is enabled.
Discharge MOSFET Q2 is latched off and the cell is
disconnected from the load. Q2 will remain in the off state as long
as V Pin 5 exceeds V Pin 3 by
available for charging.
The Sense Enable circuit will reset and turn on discharge
MOSFET Q2 when V Pin 3 no longer exceeds V Pin 5 by
the load from the battery pack, or by connecting the battery pack
to the charger.
Discharge MOSFET Q2 is latched off, the cells are disconnected
from the load, and the protection circuit enters a low current
sleepmode state. The battery pack is available for charging.
The Sense Enable circuit will reset and turn on discharge
MOSFET Q2 when V Pin 3 exceeds V Pin 5 by 0.6 V. This can be
accomplished by connecting the battery pack to the charger.
This condition can happen if the cell is defective (<1.5 V). The
protection circuit logic will not function and the battery pack
cannot be charged.
V th(dschg) . This can be accomplished by either disconnecting
PROTECTION CIRCUIT OPERATING MODE TABLE
Battery Pack Status
Circuit Operation
MC33348
V th(dschg) . The battery pack is
On to Off
Off to On
Disabled
Charge
MOSFET Switches
Q1
On
On
On
On
On
Discharge
Outputs
On to Off
Off to On
On to Off
Off to On
Disabled
Q2
On
On
On
Function
Disabled
Disabled
Charge
Pump
Active
Active
Active
Active
Active
Active
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