LP3954 Datasheet, PDF (30/60 Pages) National Semiconductor (TI) – Advanced Lighting Management Unit

LP3954
SNVS340D – JUNE 2005 – REVISED MARCH 2013
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FF
E0
C0
A0
80
60
40
20
00
01234567
INPUT CURRENT (PA)
Figure 31. ADC Code vs Input Current in Light Measurement Mode
TEMPERATURE MEASUREMENT
The temperature measurement requires two external components: resistor and thermistor (resistor that has
known temperature vs resistance curve). The ADC reads the voltage level at ASE pin and converts the result in
digital word. User can read the ADC output from register. The known temperature allows for example to monitor
the temperature inside the display module and decrease the current level of the LEDs if temperature raises too
high. This function may increase lifetime of LEDs in some applications.
R
TEMPERATURE
SENSOR
V_DDA
AIN
S1
-
ADC
+
V_DDA
S2
Figure 32. Temperature Sensor Connection Example
30
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