LTC3210 Datasheet, PDF (11/16 Pages) Linear Technology – MAIN/CAM LED Controller in 3mm × 3mm QFN

U
OPERATIO
Thermal Protection
The LTC3210 has built-in overtemperature protection.
At internal die temperatures of around 150°C thermal
shutdown will occur. This will disable all of the current
sources and charge pump until the die has cooled by
about 15°C. This thermal cycling will continue until the
fault has been corrected.
Mode Switching
The LTC3210 will automatically switch from 1x mode
to 1.5x mode and subsequently to 2x mode whenever
LTC3210
a dropout condition is detected at an LED pin. Dropout
occurs when a current source voltage becomes too low
for the programmed current to be supplied. The time
from drop-out detection to mode switching is typically
0.4ms.
The part is reset back to 1x mode when the part is shut
down (ENM = ENC = Low) or on the falling edge of ENC.
An internal comparator will not allow the main switches to
connect V_BAT and CPO in 1x mode until the voltage at the
CPO pin has decayed to less than or equal to the voltage
at the V_BAT pin.
3.8
V_BAT = 3V
3.6
V_CPO = 4.2V
C2 = C3 = C4 = 2.2µF
3.4
3.2
3.0
2.8
2.6
2.4
–40
–15 10
35
60
TEMPERATURE (˚C)
85
3210 F03
Figure 3. Typical 1.5x R_OL vs Temperature
4.6
V_BAT = 3V
4.4
V_CPO = 4.8V
C2 = C3 = C4 = 2.2µF
4.2
4.0
3.8
3.6
3.4
3.2
–40
–15 10
35
60
85
TEMPERATURE (˚C)
3210 F04
Figure 4. Typical 2x R_OL vs Temperature
3210f
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