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TPS22965: Why TPS22965 has two power inputs

user5953335
Prodigy 220 points
Part Number: TPS22965
Other Parts Discussed in Thread: TPS22918, TPS22990, TPS22976, TPS22975

Hi,

we are planning to use TPS22965 in our projects, but i found it has two power inputs, VBIAS and VIN. it makes our design complicated.

We are using other load switches which has only one power input.

so my question is why TPS22965 has two power inputs ? my understanding is it has change pump inside so only one input is enough. what's the reason behind this ?

Thank you for your help!

  • 0
    TI__Mastermind 32650 points

    Hi User,

    The device requires the use of both VIN and VBIAS.

    VBIAS is the voltage rail that is used to power and bias the internals of the device. VIN is the voltage rail that the device will pass to VOUT when turned on.

    It is possible to connect VBIAS and VIN in parallel by using the same voltage rail if the voltage level is in the recommended range for both pins.

  • 0 in reply to Shreyas Dmello
    Prodigy 220 points

    Hi ,

    Thank you for your answer.  We are also using another load switch TPS22918 which is only one input to bias  internals of the device and also to OUT.

    two questions:

    1.  i am still wondering why TPS22965 doesn't use VIN to  to power and bias the internals of the device like most other load switch does.

    2.  VBIAS is connected to change pump in TPS22965. but in TPS22918 Vin is connected to change pump.  why TPS22965 used an additional pin connected to change pump?

  • 0 in reply to user5953335
    TI__Mastermind 32650 points

    Hi User,

    TPS22918 and TPS22965 are different devices with different capabilities and for different load purposes. TPS22965 is a 6A, 0.8V to 5.7V device while TPS22918 is a 2A, 1V to 5.5V device.

    For TPS22965, both VIN and VBIAS are critical pins to correctly power and use the device. This is not unique as many of our offerings like TPS22976, TPS22975, TPS22990, etc all have BIAS pins. As mentioned before, the BIAS pin and the VIN pin can be connected to the same voltage rail.

  • 0 in reply to Shreyas Dmello
    Prodigy 220 points

    Hi,

    I think you don't answer my question.

    i am a hardware engineer, so i need to understand this part because it will be used in our project and i wonder if there is any bugs that makes you use two inputs.

    Now that BIAS pin and the VIN pin can be connected to the same voltage rail, then why you separate them ?

  • 0 in reply to user5953335
    TI__Mastermind 32650 points

    Hi User,

    Different device have different IP. Some devices require a BIAS voltage to correctly set internal voltages and power the device. This is beneficial in situations where the VIN voltage is insufficient (eg: Vin=0.8V) to correctly bias the device. The VIN voltage is the voltage that you mean to switch between the input and output on your system. There is no connection between VBIAS and VOUT.

    VBIAS and VIN are not connected internally and need to be supplied external to the device. If the voltage rail is an acceptable level from VBIAS and VIN, both pins can be supplied from the same external voltage rail.

    Please refer to the datasheet for more information.