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TPS62097-Q1: 2MHz Forced PWM Mode

Casey McCrea
Guru** 102585 points
Part Number: TPS62097-Q1

Hey Team,

For section 7.4.2 in the datasheet I'm a little confused. Is it possible to operate TPS62097-Q1 at 2MHz with forced PWM? If so, what is the method?

Best Regards,

Casey 

  • 0
    TI__Genius 14870 points
    Hi Casey,

    The table 1 in datasheet is explaining how you will get the 2MHz in forced PWM mode. Could you explain where you are getting confused?

    Best regards,
    Tanvee
  • 0 in reply to Tanvee
    TI__Guru** 102585 points
    Tanvee,

    For the 2MHz option in the table, the operating mode is listed as PWM/PSM and Forced PWM. There's also a note about toggling the MODE pin after detection but it's unclear what the process is. Are you supposed to GND the pin before raising EN, and then bring it high after the part has booted? Or are you supposed to keep it low after boot? Or bring it high then low again after boot?

    Best Regards,
    Casey
  • 0 in reply to Casey McCrea
    TI__Genius 14870 points
    Hi Casey,

    MODE pin is used for Switching frequency and Operating mode setup. First MODE pin should be connected to the AGND to set 2MHz during the MODE detection time period. After that set the MODE pin logic high and than device will be in forced PWM mode.

    Best regards,
    Tanvee
  • 0 in reply to Tanvee
    TI__Guru** 102585 points

    Hey Tanvee,

    Thanks you! I understand now. 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    Prodigy 10 points
    Hi Tanvee,

    I'm the customer who asked the original question. Toggling MODE pin is not practical for us since that will need 2 GPIOs to control this part (one for enable and the other MODE). I'm curious if the frequency setting in Table 1 is discrete or continuous. For example, a 18kOhm resistor between MODE to AGND sets 1.75MHz in forced PWM, and a 39kOhm sets 2.25MHz. What happens if I use a resistor in between, for example, 28kOhm?

    Another question is, under Table 1, it states "leaving the MODE pin open forces the device into PWM mode". So if I leave it open all the time, at what frequency will it operate?

    Thanks!
    Yiyong
  • 0 in reply to Yiyong Li
    TI__Genius 14870 points
    Hi Yiyong,

    I would not suggest to use the 28kOhm because device mode outside datasheet is not characterized. If you need 2 MHz frequency I would recommended to use TPS62810q1 which has more features like small package, better performance with adjustable switching frequency.

    The statement "Connecting the MODE pin to AGND with a resistor or leaving the MODE pin open forces the device into PWM
    mode for the whole load range" applies to the mode where AGND pin connected with resistor. For 2MHz forced PWM mode have to follow the procedure I explained.


    Best regards,
    Tanvee