LLTC4100EG View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LLTC4100EG' PDF : 30 Pages View PDF
LTC4100
Operation
The ILIM Decoder Block
The value of an external resistor connected from this pin
to GND determines one of four current limits that are
used for maximum charging current value. These limits
provide a measure of safety with a hardware restriction on
charging current which cannot be overridden by software.
Table 6. ILIM Trip Points and Ranges
EXTERNAL
RESISTOR
(RILIM)
ILIM VOLTAGE
CONTROLLED
CHARGING
CURRENT RANGE
Short to GND VILIM < 0.09VDD 0 < I < 1023mA
10k ±1%
0.17VVDD <
0 < I < 2046mA
VILIM < 0.34VVDD
33k ±1%
0.42VVDD <
VILIM < 0.59V
0 < I < 3068mA
Open (>250k,
0.66VVDD <
or Short to VDD)
VILIM
0 < I < 4092mA
GRANULARITY
1mA
2mA
4mA
4mA
The Voltage DAC Block
Note that the charger output voltage is offset by VREF.
Therefore, the value of VREF is subtracted from the
SMBus ChargingVoltage() value in order for the output
voltage to be programmed properly (without offset). If the
ChargingVoltage() value is below the nominal reference
voltage of the charger, nominally 1.184V, the charger
output voltage is programmed to zero. In addition, if the
ChargingVoltage() value is above the limit set by the VLIM
pin, then the charger output voltage is set to the value
determined by the VLIM resistor and the VOLTAGE_OR bit
is set. These limits are demonstrated in Figure 6.
25
RVLIM = 33k
20
The VLIM Decoder Block
The value of an external resistor connected from this pin
to GND determines one of five voltage limits that are ap-
plied to the charger output value. These limits provide a
measure of safety with a hardware restriction on charging
voltage which cannot be overridden by software.
Table 7. VLIM Trip Points and Ranges (See Figure 5)
EXTERNAL
RESISTOR
(RVLIM)
VLIM VOLTAGE
CONTROLLED
CHARGING VOLTAGE
(VOUT) RANGE GRANULARITY
Short to
GND
VVLIM < 0.09VVCCP
2900mV < VOUT
< 8800mV
16mV
10k ±1%
33k ±1%
100k ±1%
Open or
Tied to VDD
0.17VVDD < VVLIM
< 0.34VVDD
0.42VVCCP < VVLIM
< 0.59VVDD
0.66VVDD < VVLIM
< 0.84VVDD
0.91VVDD < VVLIM
2900mV < VOUT
< 13104mV
2900mV < VOUT
< 17408mV
2900mV < VOUT
< 21712mV
2900mV < VOUT
< 28000mV
16mV
16mV
16mV
16mV
15
10
5
0
0 5 10 15 20 25 30 35
PROGRAMMED VALUE (V)
4100 F06
NOTE: THE LTC4100 CAN BE PROGRAMMED WITH ChargingVoltage() FUNCTION VALUES
BETWEEN 1.184V AND 2.9V, HOWEVER, THE BATTERY CHARGER CONTROLLER OUTPUT
VOLTAGE MAY BE ZERO WITH PROGRAMMED VALUES BELOW 2.9V.
Figure 6. Transfer Function of Charger
For more information www.linear.com/LTC4100
4100fc
19
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