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TPS7H4010-SEP: Output voltage clarifications

Part Number: TPS7H4010-SEP

Hello Guys,

Good day.

Our customer have a few questions on TPS7H4010-SEP, which we are hoping you could help.

1) Can this device provide a -3.3V output with a Vin of +12V? In other words can it provide a negative voltage with respect to the input voltage?

2) Also please check if it can output -3.3V when the input voltage is +28V.

The idea is to connect the Vout pin to system ground (0V) and then the return pin becomes the negative output voltage.

Thanks in advance!

Art

  • HI Art,

    I believe this was tested without success but we'll confirm and get back to you soon.

    Christian

  • Hi Art,

    We have not specifically tested or characterized these configurations so it will be important for them to thoroughly review their design. The TPS7H4010-SEP should theoretically be suitable for use in an inverting buck-boost configuration like you described, but there are special considerations that will apply. Some of the main ones are:

    • Verify that the input-output differential does not exceed the recommended differential between the PVIN and PGND pins (Using the values you provided, this condition is met: 12V + 3.3V < 32V, 28V + 3.3V < 32V)
    • The amount of current that can be supplied to the load is somewhat lower in this configuration. For Buck converters, the average inductor current and the load current are the same. But when a Buck is used in Inverting Buck-Boost configuration they are no longer equal - the average inductor current is larger than the load current. This means you need to make sure the average inductor current remains below the load current rating of the device (6A), which will mean the actual amount of current that can be supplied to the load will be lower than the load current rating.

     

    I recommend referencing this application report, which contains equations, examples, and other considerations for converting a Buck into an Inverting Buck-Boost (Working with Inverting Buck-Boost Converters).

    Hope this helps!

    Thanks,

    Sarah