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Original question:

TPS62801: TPS62801 or TPS62802 Power Save/PWM mode switching circuit example

TPS62802: PWM Mode without GPIO Control

Shiv Agarwal
Prodigy 50 points
Part Number: TPS62802
Other Parts Discussed in Thread: TPS62824A, TPS628301

I am using the TPS62802 to output 1.8V. 
I have a 10K Pull down at the VSEL/MODE Pin. 

I want to run this IC in PWM mode only, however, I do not have a GPIO free on my controller. 
Could you please propose how do I go about this?
Please feel free to suggest an alternate IC (Buck only) for my application.

Thanks!

  • 0
    TI__Mastermind 22080 points

    Hello Shiv,

    I'm glad to see your interest in the TPS62802. Unfortunately there is no change to force the PWM mode without switching VSEL/MODE pin to high. Alternatively you could try the TPS62824A device if a QFN package, VINmin of 2.4V and an FB voltage divider is OK for your project. The TPS628301 could also be an option. Please let me know if there is a specific feature of the TPS62802, which can not be covered by the mentioned alternative devices.

    Best regards,

    Andreas.

  • 0 in reply to Andreas Mueller
    Prodigy 50 points

    The size of TPS62824A and TPS628301 are bigger for my application.


  • 0 in reply to Shiv Agarwal
    Prodigy 50 points

    Hi Andreas, I need to resolve this soon. Could we connect offline? I have sent you a DM. 

    I am thinking of using an OR gate at the VSEL/MODE Pin. 
    Please see the circuit image attached. Does this work to get the device in PWM mode?
    I also want to make sure that the OR Gate Output is not going to load the R2D and give a wrong VOUT. 
    Also, is there a Eval Kit for TPS62802 and the OR Gate? 

    OR GATE
    www.ti.com/.../sn74lvc1g32.pdf

  • 0
    TI__Mastermind 22080 points

    Hello Shiv,

    you could also connect the VSEL/MODE Pin to Vout.

    Vout will be 0V (actively discharged) before the device started.

    This will select the 1.8V Vout prior startup.

    Later Vout of 1.8V will enable PWM at the VSEL/MODE pin.

    In the simulation with the PSpice model this approach worked.

    There is a TPS62800EVM-892 available and enough in stock for ordering.

    Let me know if you have further questions.

    Best regards,

    Andreas.