CS1610/11/12/13

DS929F5

13

The ADC output code is filtered to suppress noise and

compared against a reference code that corresponds to

125/130°C. If the temperature exceeds this threshold, the

chip enters an external overtemperature state and shuts

down. This is not a latched protection state, and the ADC

keeps tracking the temperature in this state in order to clear

the fault state once the temperature drops below 110°C.

When exiting reset, the chip enters startup and the ADC

quickly (<5ms) tracks the external temperature to check if it is

below the 110°C reference code before the boost and second

stages are powered up. If this check fails, the chip will wait

until this condition becomes true before initializing the rest of

the system.

For external overtemperature protection, a second low-pass

filter with a time constant of two minutes filters the ADC output

and uses it to scale down the internal dim level of the system

95 °C (see Figure 15). The large time constant for this filter

ensures that the dim scaling does not happen spontaneously

tolerance, series resistor), which corresponds to a

temperature of 95°C for a 100k

 NTC (100k

(125°C). The CS1610/11/12/13 uses this calculated value to

Figure 15. LED Current vs. eOTP Temperature

Beyond this temperature, the IC shuts down using the

mechanism discussed above. If the external overtemperature

protection feature is not required, connect the eOTP pin to

GND using a 50k

-to-500k resistor to disable the eOTP

feature.

Temperature (

°C)

125

95

50%

100%

0

25