LTC4099 Linear Technology Corporation, LTC4099 Datasheet - Page 25

• Manufacturer Part Number: LTC4099
• Description: I2C Controlled USB Power Manager/Charger
• Manufacturer: Linear Technology Corporation

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OPERATION
(BAT at 4.1V or 4.2V), but that the charge current is still
above the C/x detection level programmed. The CONSTANT
V, I
has dropped below the C/x detection level programmed,
and that charging is virtually complete. Note that if the
current limited USB compliant switching regulator is in
input current regulation, then the actual battery charge
current may be less than C/x due to insuffi cient available
power. If the LTC4099 is in input current limit, the charge
status bits will lock out (disallow) the state 1-1, indicating
that charging is complete. This feature prevents false full
capacity charge indications due to insuffi cient power to
the battery charger.
The status read from the LTC4099 is captured in one of
two ways. If an interrupt is currently pending, then the
available data represents the state of the LTC4099 at the
time the interrupt was generated. If no interrupt is pending,
then the data is captured when the LTC4099 acknowledges
Table 5. Safety Timer Decode
*Default Setting
Table 6. LTC4099 Status Data Bytes
BAT
TIMER2
0
0
0
0
1
1
1
1
<C/x bit indicates that the battery charge current
Bit 7 (MSB)
READ BYTE
Bit 0 (LSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
TIMER1
SAFETY TIMER SETTINGS
0
0
1
1
0
0
1
1
TIMER0
0
1
0
1
0
1
0
1
CHRGR1
CHRGR0
NTC1
NTC0
STATUS REGISTER
THERMAL REG
WALLGOOD
USBGOOD
BADCELL
TIMEOUT
4 Hours*
5 Hours
6 Hours
7 Hours
8 Hours
2 Hours
3 Hours
1 Hour
See Table 7
See Table 8
its read address. In the case of a pending interrupt, fresh
data can be assured by taking two consecutive readings
of the status information and discarding the fi rst set.
Shutdown Mode
The USB switching regulator is enabled whenever V
is above V
LTC4099 is not in one of the two USB suspend modes
(500μA or 2.5mA). When power is available from both
the USB (V
input is prioritized and the USB switching regulator is
disabled.
The battery charger will always start a charge cycle when
power is detected at V
down via a command from the I
termination after a charge cycle.
The ideal diode is enabled at all times and cannot be
disabled.
Table 7. NTC1, NTC0 Decode
Table 8. CHRGR1, CHRGR0 Decode
CHRGR1
NTC1
0
0
1
1
0
0
1
1
UVLO
BUS
CHRGR0
BATTERY CHARGER STATUS BIT DECODE
NTC0
) and WALL inputs, the auxiliary (WALL)
THERMISTOR STATUS BIT DECODE
0
1
0
1
0
1
0
1
, greater than V
BUS
BATTERY OVERTEMPERATURE
or WALL. It can only be shut
CONSTANT V, I
CONSTANT V, I
THERMISTOR STATUS
CONSTANT-CURRENT
DUVLO
BATTERY TOO COLD
BATTERY TOO HOT
CHARGER STATUS
NO NTC FAULT
CHARGER OFF
2
C port or by normal
above BAT and the
LTC4099
BAT
BAT
> C/x
< C/x
25
BUS
4099f