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TPS8804EVM: Possiblity of LED Pulse width configuration below 1milli seconds (like in micro seconds) through TPS GUI

Selvam Krishnan
Prodigy 140 points
Part Number: TPS8804EVM
Other Parts Discussed in Thread: TPS8804, USB2ANY

Tool/software:

Good day TI Team,

Summary :

Please guide us for setting TPSEVM LED pulse width below 1 milli second ( like in micro seconds) through TPS GUI

Details:

In TPS GUI,

It looks the TPS GUI software allows minimum LED pulse width as 1ms.

Reference snap : From “Configure LED Enable PWM Settings” - present in enclosed file - LED_Pulse_Setting_Below1MilliSeconds.png

In TPS8804 datasheet ,

We can set the LED pulse width in usec(microseconds)also.

Reference Snap:  (From section 8.2.2.3 LED Voltage Supply Selection – Page 41)   - present in enclosed file - LED_Pulse_Setting_Below1MilliSeconds.png

 Also, datasheet suggested LED pulse width remains below 1ms 

Reference Snap:  ( From section 7.3.4.1 LED Current Sink – Page 23) - present in enclosed file - LED_Pulse_Setting_Below1MilliSeconds.png

 

Please guide us about possibilities for configuring LED pulse width in usec(microseconds)

Advance Thanks for guidance.

 

Regards

Selvam

  • 0
    TI__Prodigy 230 points

    Hi Selvam,

    Sorry this question was missed during the US holidays. The GUI does not accept a setting below 1ms for the PWM signal on LEDEN, so the setup will need a workaround.

    LEDEN would normally be controlled by the application's microcontroller, so it can be disconnected from the USB2ANY and GUI control.  You can provide your own PWM signal on LEDEN by removing jumper J9 on the TPS8804 EVM (disconnecting the USB2Any pin) and connecting your own PWM signal (from a signal generator or preferably an MCU) to LEDEN test point TP34.

    The related app note provides additional information on optimizing the supply current of the system:  Achieving 10-Year Battery Life with Smoke Alarm TPS8802.

    Thanks & Regards,

    Jesse

  • 0 in reply to Jesse Gronowski
    Prodigy 140 points

    Hi Jesse,

    Sorry for late reply due to festival holidays in India. 

    Thanks for the update regarding usage of external PWM and App note details.

    We will try external PWM through MCU and revert back, if any clarification needs. 

    Thanks

    Selvam