LTC1729CMS8-4.2 Linear Technology, LTC1729CMS8-4.2 Datasheet - Page 9

• Manufacturer Part Number: LTC1729CMS8-4.2
• Description: IC CTRLR BATT CHRGR LI-ION 8MSOP
• Manufacturer: Linear Technology

Specifications of LTC1729CMS8-4.2

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
State Machine
The state machine is responsible for the following items:
1. When to start and stop the charger. The internal timer
2. When a battery is installed, the state machine must
3. When a deeply discharged battery is installed, trickle
The state machine diagram is shown in Figure 6. Note that
the Charge state includes the Precondition state, the
charger “ON” state and the Reset mode.
must be initialized every time a new battery is installed
or when the input supply is applied.
determine if it is a new battery or if the previous battery
has been reinstalled.
charge conditioning must take place before the full
charge current.
U
FOR MORE THAN 1SEC
U
STATUS = PULL-DOWN
V
BAT
FOR MORE THAN 1SEC
V
C
< V
= PULL-DOWN
I
PAUSE
BAT
MAX
STATUS = PULL-DOWN
= 0
V
W
V
BAT
PRECONDITION
C
I
= PULL-DOWN
t
BAT
MAX
> V
V
= 12mA
MAX
BAT
= 1HR
V
BAT
< V
V
V
MIN
NTC
NTC
> V
FOR MORE THAN 1SEC
U
STATUS = PULL-DOWN
MAX
V
> 2.79V OR
< 0.405V
STATUS = PREVIOUS STATUS
V
STATUS = OPEN
Figure 6. State Diagram
C
C
V
V
V
RESET MODE
= PULL-DOWN
CHARGE
BAT
BAT
BAT
= PULL-DOWN
I
NO BAT
BAT
V
I
BAT
C
> V
< V
< V
HOLD MODE
= PULL-DOWN
= 0
= 0
I
MIN
MIN
MAX
BAT
= 0
STATUS = PULL-DOWN
V
BAT
Reset and Hold are the two modes that will cause the
charger to stop charging (V
state machine. The Reset mode clears all the timers and
forces the state machine to begin in the Charge state
(STATUS pin pulled low). This mode is only activated
momentarily at power-up or when the NTC pin is below the
Reset threshold. The other interrupt condition is called the
Hold mode. When the voltage on the NTC pin is above
2.79V (cold) or below 0.405V (hot), the state machine is
locked in the present state until the NTC pin voltage returns
to the proper range. While in the Hold mode, the charging
is disabled and the timers are frozen.
The charger is enabled only during the charger “ON” state.
There are three ways that the state machine can exit the
charger “ON” state. The first is for a 3-hour time-out which
is denoted as the time > t
CHARGER “ON”
I
t
> V
BAT
V
MAX
C
MIN
= OPEN
= 1.3mA
V
FOR MORE THAN 1SEC
= 3HR
BAT
V
TIME > t
STATUS = OPEN
C
> V
= PULL-DOWN
MAX
I
BAT
DONE
MAX
= 0
V
V
NTC
NTC
NOTE: FOR STATUS
PULL-DOWN = HARD:
FOR CURRENT > C/10
PULL-DOWN = 50 A:
FOR CURRENT < C/10 FOR 3SEC
< 2.79V AND
> 0.405V
MAX
C
pin pulled low) and ignore the
LTC1729 Series
transition to the Done state.
1729 F06
9