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TPS92520-Q1: External PWM operation

Part Number: TPS92520-Q1


I would like to know if using the external PWM can only be done if the device is in standalone mode.

Does it mean that the PWM switches ON/OFF the device based on the by changing the UDIM input and act as enable signal of the TPS92520.

Or We can use the external PWM in RUN mode of operation where the PWM signal controls the time for which switching is ON?


Suraj Kurde

  • Hello Suraj,

    You can use the UDIMx pin to control the output of the channel for both standalone and run mode.  In standalone, that is the only way you can do PWM dimming.  In run or limp-home mode you have the option to use either the UDIMx pin to do PWM dimming OR register settings.  Note, but default it is setup as external PWM dimming using UDIMx pins and there is a bit that needs to be set if you want to user internal PWM dimming by using internal registers settings.  This is all covered in the datasheet.  

    -Francis Houde

  • So, My question here is, incase if we are using external PWM in run mode on the UDIM input, During the low period of the PWM, Is the device still enabled due to UDIM input voltage( such that UDIM pin is not pulled below threshold of 1.21Volts approx)? As per my understanding the device is still in  enabled state using UDIM input, it's only the switching operation that is disabled during the off period of PWM.

  • Hello Suraj,

    We are working on this request, and will get back to you by the end of the day.

    Best Regards,


  • Hello Suraj,

    If the voltage does not fall below VUDIMx(EN) falling voltage then the channel will be enabled unless you are using the internal PWM register settings and have CHxINTPWM bit set to 1.  In ether case, internal PWM dimming or external PWM dimming using UDIM pin, if the voltage on UDIM falls below VUDIMx(EN) falling then the channel will be turned OFF.  Lets not confuse RUN state with channel enabled.