LTC4060 Linear Integrated, LTC4060 Datasheet - Page 8

• Manufacturer Part Number: LTC4060
• Description: Standalone Linear NiMH/NiCd Fast Battery Charger
• Manufacturer: Linear Integrated

OPERATIO
LTC4060
The LTC4060 is a complete linear fast charging system for
NiMH or NiCd batteries. Operation can be understood by
referring to the Block Diagram, State Diagram (Figure 1)
and application circuit (Figure 2). While in the unpowered
sleep mode, the battery is disconnected from any internal
loading. The sleep mode is exited and the shutdown mode
is entered when V
Lock Out) exit threshold. The UVLO thresholds are depen-
dent upon the number of series cells programmed by the
SEL0 and SEL1 pins. When shutdown occurs the ACP pin
goes from a high to low impedance state. The shutdown
mode is exited and the charge qualification mode entered
8
U
CC
LOW OR NO
rises above the UVLO (Undervoltage
SUPPLY
V
CELL
< AUTORECHARGE
THRESHOLD
SLEEP
AUTOMATIC
Figure 1. LTC4060 Basic State Diagram
RECHARGE
–∆V TERMINATION
(ACP = 0)
SUPPLY
GOOD
QUALIFICATION
FAST CHARGE
when all of the following conditions are met: 1) there is no
manual shutdown command from SHDN, 2) the battery
overvoltage detector does not detect a battery overvolt-
age, 3) the battery removal detector detects a battery in
place, 4) pause is inactive and 5) the IC’s junction tempera-
ture is normal. Once in the charge qualification mode the
thermistor interface monitors an optional thermistor net-
work to determine if the battery temperature is within
charging limits. If the temperature is found within limits
charging can begin. While charging, the CHRG pin pulls to
GND which can drive an LED.
PRECHARGE
SHUTDOWN
SHUTDOWN
(SHDN = 0)
MANUAL
CHARGE
(I
(I
MAX
MAX
/5)
ADEQUATE SUPPLY
AND CHARGER ENABLED
BATTERY PRESENT AND
TEMPERATURE GOOD
(OPTIONAL)
ADEQUATE V
TEMPERATURE GOOD
(OPTIONAL)
)
4060 F01
CELL
AND
BATTERY REMOVED,
BATTERY OVERVOLTAGE,
CHARGE PERIOD TIMED
OUT OR IC TOO HOT
4060f