Datasheet

LTC3677-3
35
36773f
operaTion
tions indicates that the condition is true. For example, 1
read back from bit A3 indicate that LDO1 is enabled and
regulating correctly. A status read from the LTC3677-3
captures the status information when the LTC3677-3
acknowledge its read address.
Table 6. I
2
C READ Register
STATUS REGISTER
ADDRESS: 00010011
SUB-ADDRESS: None
BIT NAME FUNCTION
A0 CHARGE Charge Status (1 = Charging)
A1 STAT[0] STAT[1:0]; 00 = No Fault
01 = TOO COLD/HOT
10 = BATTERY OVERTEMP
11 = BATTERY FAULT
A2 STAT[1]
A3 PGLDO[1] LDO1 Power Good
A4 PGLDO[2] LDO2 Power Good
A5 PGBCK[1] Buck1 Power Good
A6 PGBCK[2] Buck2 Power Good
A7 PGBCK[3] Buck3 Power Good
Bit A7 shows the power good status of Buck3. A 1 indicates
that Buck3 is enabled and is regulating correctly. A 0 indi-
cates that either Buck3 is not enabled, or that the Buck3 is
enabled, but is out of regulation by more than 8%.
Bit A6 shows the power good status of Buck2. A 1 indicates
that Buck2 is enabled and is regulating correctly. A 0 indi-
cates that either Buck2 is not enabled, or that the Buck2 is
enabled, but is out of regulation by more than 8%.
Bit A5 shows the power good status of Buck1. A 1 indicates
that Buck1 is enabled and is regulating correctly. A 0 indi-
cates that either Buck1 is not enabled, or that the Buck1 is
enabled, but is out of regulation by more than 8%.
Bit A4 shows the power good status of LDO2. A 1 indicates
that LDO2 is enabled and is regulating correctly. A 0 indi-
cates that either LDO2 is not enabled, or that the LDO2 is
enabled, but is out of regulation by more than 8%.
Bit A3 shows the power good status of LDO1. A 1 indicates
that LDO1 is enabled and is regulating correctly. A 0 indi-
cates that either LDO1 is not enabled, or that the LDO1 is
enabled, but is out of regulation by more than 8%.
Bits A2 and A1 indicate the fault status of the charger
measurement circuit and are decoded in Table 6. The too
cold/hot state indicates that the thermistor temperature is
out of the valid charging range (either below 0°C or above
40°C for a curve 1 thermistor) and that charging has paused
until the battery returns to valid charging temperature. The
battery overtemperature state indicates that the battery’s
thermistor has reached a critical temperature (about
50°C for a curve 1 thermistor) and that long-term battery
capacity may be seriously compromised if the condition
persists. The battery fault state indicates that an attempt
was made to charge a low battery (typically < 2.85V) but
that the low voltage condition persisted for more than 1/2
hour. In this case charging has terminated.
Bit A0 indicates the status of the battery charger. A 1
indicates that the charger is enabled and is in the con-
stant-current charge state. In this case the battery is
being charged unless the NTC thermistor is outside its
valid charge range in which case charging is temporarily
suspended but not complete. Charging will continue once
the battery has returned to a valid charging temperature.
A 0 in bit A0 indicates that charger has reached end-of-
charge (h
C/10
) and is near V
FLOAT
or that charging has been
terminated. Charging can be terminated by reaching the
end of the charge timer or by a battery fault as described
previously.