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.

  • Resolved

TPS40303 - Can Vdd != Vin?

Prodigy 180 points

Replies: 3

Views: 932

Hello,

We would like to use the TPS40303 with Vin tied to a 3.3V rail, can we power Vdd with a dedicated 5.0V supply (e.g. REG711)?

My intent is to increase the BP voltage from approx. 3.3V to 5.0V and thus obtain higher power efficiency (lower MOSFET RDSon).

[High side MOSFET is the IRF7821/ Low side is the IRF7832.]

Thank you,

Chris

  • Hi Christopher,

    I don't think you can have 5V Vdd and 3.3V Vin for this device. The high-side OC protection is based on the high-side Rds,on sensing, basically detecting the voltage difference of Vdd-SW, instead of Vin-SW.

    What I can think of is connecting 5V supply to BOOT through a diode, so that at least the high-side gate drive voltage is high.

    Regards,

    Na

    Na Kong
     
    Applications
    DC Solutions
    Power Management
    Texas Instruments
  • In reply to Na Kong:

    Hi Na,

    This information really helps, as it means we must find another TI SMPS that supports separate PVIN / VIN rails.  Our power source is super capacitor based, so we want to use as much of the available voltage range (3V-10V) as possible...

    I really like the TPS56921.  Any idea when it will be supported in WEBENCH?

    Thank you,

    Chris

  • In reply to Christopher George:

    Hi Chris,

    I would suggest you post your request of TPS56921 in a seperate thread. WEBENCH related question can be posted to WEBENCH forum:

    http://e2e.ti.com/support/development_tools/webench_design_center/f/235.aspx

    Regards,

    Na

    Na Kong
     
    Applications
    DC Solutions
    Power Management
    Texas Instruments

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.