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TPS92633-Q1: external NTC resistor application

Hazel Sun
Expert 6535 points
Part Number: TPS92633-Q1

Hi team,

Customer want to use TPS92633-Q1. In design, each PCB requires a 2pcs chip, for the ICTR pins, can I connect the two chip pins together to share the thermal derating circuit? There are no corresponding application examples in the data table. The left and right IC sets the same LED current, same input voltage, same the number of LED strings.

my concern is that if two NTC's are separated, the temperature inconsistency will cause the LED current of the two chips to be inconsistent.

thanks 

  • 0
    TI__Genius 17245 points

    There will be a delay in the response because the support engineer is not in today.  

    I can speak to you about this problem in general.  You usually have a separate thermistor because there can be differences in the temperature of the device or LEDs (depends on what you are trying to monitor) based on a variety of reason.  It could be next to a hot object?  It could be close to a heat sink.  Maybe there is no airflow on one device and the other does have air flow.   They can share the ICTRL input and tie both of the devices together if they are trying to save on components, but it depends on what they are trying to achieve.  Maybe they want to the LEDs to be protected and put the thermistor next to the LEDs such that it will derate the current once the LEDs get to hot.  This is a system level design decision they must make using their best engineering judgement.  All we can do is tell them how the part works and express concerns or ask for clarification on what they are trying to achieve to let them know if it will work as they intended.   

    Pedro might have more to add on this based on his experience with this part, but I would get clarification on what they are trying to achieve and why.

    -fhoude