This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS51604 powerup state

Other Parts Discussed in Thread: TPS51604

We're using a TPS51604 in an application where it is controlled by a MCU. The MCU powers up with all its pins configured as inputs which puts both PWM and \SKIP pins into Tri-state mode on TPS51604. There is a note in the datasheet (see p.10) which states that \SKIP pin should not be in Tri-state mode when the driver starts and indeed we verified that it causes the driver not to work properly.

In order to fix the problem we have installed a 4.7K pull down resistor on the \SKIP line (but not PWM) to make sure TPS51604 powers up with the \SKIP pin low. This does work most of the time but occasionally the driver will power up and appear dead/disabled, ie the PWM signal does not command the DRVH/DRVL outputs.

Did we properly address the note regarding not starting up the driver in very low power mode? What might be causing the occasional glitch? We would also appreciate any other ideas regarding troubleshooting this issue.

Thanks for your help, TI!


  • Hi Leonard,

    This was posted a year ago. Are you still looking for a response?
    It appears the post should reside in the non-isolated dc/dc forum.
  • Yes, I believe the answer will assist others who may have the same question or who would like to see a definitive solution.


  • Hi Leonard,

    The thread has been moved back to the Non-isolated DC/DC forum where the device is supported.
  • The below informaiton from another post (link is provided as below) might help to solve the latch issue.

    For the driver IC TPS51604to un-latch prior to start-up, proper input PWM sequence needs to be  supplied.

    We recommend a 10..22kOhm pull-down resistor from CSD87335 Switch-Node pin to Ground.

    This resistor would not affect the System power Loss and Efficiency, but will provide a path for the Bootstrap Cap charging during the initial PWM pulse.

    Charging the Bootstrap Cap is a condition necessary to happen prior to the first tri-state to High PWM transition so the Internal TPS51604 Bootstrap FET is enhanced. In this way we can obtain the first pulse on PWM HS output. As a result, the CSD87355 will start switching thus obtaining correct PWM pulse outputs.