Datasheet

LTC4155
40
4155fc
Table 34. Input Undervoltage Current Limit (Brownout
Detection) Interrupt Mask
INPUT UNDERVOLTAGE CURRENT LIMIT (BROWNOUT
DETECTION) INTERRUPT MASK REG6
SUB ADDRESS 0x06 ENABLE_INPUT_UVCL_INT
DIRECTION Write and Readback
INTERRUPT ENABLE
STATUS D7 D6 D5 D4 D3 D2 D1 D0
Input Undervoltage
Current Limit
Interrupts Disabled*
0
Input Undervoltage
Current Limit
Interrupts Enabled
1
*Default.
Interrupt triggered by any change in INPUT_UVCL_ACTIVE. Any data
written to sub address 0x06 has side effect of clearing any pending
interrupt request.
APPLICATIONS INFORMATION
Figure 9. Alternate NTC Bias Network
Alternate NTC Thermistors and Biasing
The LTC4155 provides temperature qualified charging if a
grounded thermistor and a bias resistor are connected to the
NTC pin. Charging is paused if the temperature rises above
an NTC_TOO_HOT limit or falls below an NTC_TOO_COLD
limit. By using a Vishay curve 2 thermistor and a bias resis-
tor whose value is equal to the room temperature resistance
of the thermistor (r
25
), the upper and lower tempera-
tures are preprogrammed to approximately 40°C and
0°C, respectively. The NTC_HOT_FAULT threshold which
optionally generates an interrupt and/or enables the
overtemperature battery conditioner is preprogrammed
to approximately 60°C.
With minor modifications to the thermistor bias network
as shown in Figure 9, it is possible to adjust either one or
two of the three temperature thresholds with the constraint
that it is usually not possible to move the temperature
thresholds closer together. Intuitively, this would require
increased temperature sensitivity from the thermistor.
OPERATION
In the explanation below, the following notation is used.
r
25
NTC thermistor value at 25°C.
R
BIAS
Low drift bias resistor, connected between the
NTCBIAS and NTC pins.
Table 35. USB On-The-Go Step-Up Voltage Converter
Manual Activation
USB On-The-Go STEP-UP VOLTAGE CONVERTER MANUAL
ACTIVATION REG6
SUB ADDRESS 0x06 REQUEST_OTG
DIRECTION Write and Readback
STEP-UP
REGULATOR
ACTIVATION D7 D6 D5 D4 D3 D2 D1 D0
Step-Up Regulator
Activation Auto-
matic or Disabled*
0
Enable Step-Up
Voltage Regulator
1
*Default.
Regulator cannot be activated if voltage is applied to either the USB or
WALL inputs. Automatic activation controlled by LOCKOUT_ID_PIN. Any
data written to sub address 0x06 has side effect of clearing any pending
interrupt request.
R
NTC
R
BIAS
LTC4155
4155 F09
NTC
NTCBIAS
T
R
TEMP_RANGE