LTC3577-4_15 Datasheet, PDF (41/52 Pages) Linear Technology – Highly Integrated Portable Product PMIC

LTC3577-3/LTC3577-4
OPERATION
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 12. 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.
I²C Write Register Map (see the “I²C Input Data” section
for more details, all registers default to 0 when reset)
BUCK CONTOL
REGISTER
BIT NAME
B0 N/A
B1 N/A
B2 BK1BRST
B3 BK2BRST
B4 BK3BRST
B5 SLEWCTL1
B6 SLEWCTL2
B7 N/A
ADDRESS: 00010010
SUB-ADDRESS: 00000000
FUNCTION
Not Used—No Effect On Operation
Not Used—No Effect On Operation
Buck1 Burst Mode Enable
Buck2 Burst Mode Enable
Buck2 Burst Mode Enable
Buck SW Slew Rate: 00 = 1ns,
01 = 2ns, 10 = 4ns, 11 = 8ns
Not Used—No Effect On Operation
LED CONTROL
REGISTER
BIT NAME
B0 EN
B1 GR2
B2 GR1
B3 MD1
B4 MD2
B5 PWMC1
B6 PWMC2
B7 SLEWLED
ADDRESS: 00010010
SUB-ADDRESS: 00000001
FUNCTION
Enable: 1= Enable 0 = Off
Gradation GR[2:1]: 00 = 15ms, 01 = 460ms,
10 = 930ms, 11 = 1.85 Seconds
Mode MD[2:1]: 00 = CC Boost,
10 = PWM Boost, 01 = HV Boost
PWM CLK PWMC[2:1]: 00 = 8.77kHz,
01 = 4.39kHz, 10 = 2.92kHz, 11 = 2.19kHz
LED SW Slew Rate: 0/1 = Fast/Slow
LED DAC REGISTER
BIT NAME
B0 DAC[0]
B1 DAC[1]
B2 DAC[2]
B3 DAC[3]
B4 DAC[4]
B5 DAC[5]
B6 N/A
B7 N/A
ADDRESS: 00010010
SUB-ADDRESS: 00000010
FUNCTION
6-Bit Log DAC Code
Not Used—No Effect On 0peration
Not Used—No Effect On 0peration
LED PWM REGISTER
BIT NAME
B0 PWMDEN[0]
B1 PWMDEN[1]
B2 PWMDEN[2]
B3 PWMDEN[3]
B4 PWMNUM[0]
B5 PWMNUM[1]
B6 PWMNUM[2]
B7 PWMNUM[3]
ADDRESS: 00010010
SUB-ADDRESS: 00000011
FUNCTION
PWM DENOMINATOR
PWM NUMERATOR
357734fb
41