• State
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 58 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

TPS61288: When enable pin is low, the output is the same as the input

Santo Prattico'
Prodigy 30 points
Part Number: TPS61288
Other Parts Discussed in Thread: TPS61178, TPS61046, TPS61378-Q1

Tool/software:

Hi. I am using the TPS61288 in my design which has a rechargeable battery. When the enable pin is low, I expect to see no output, but instead, I see the same voltage as that on the input pin. I am controlling the enable pin with a 3.3V signal from a microprocessor. Am I doing something wrong?

Thanks

Santo

  • 0
    TI__Genius 12935 points

    Hi Santo,

    You are doing everything right.

    TPS61288 is not true load disconnect due to the body diode of its upper mos.

    If you'd like 0V at output side when the device is disabled, you need to choose device with true load disconnect function.

    Like TPS61378-Q1,TPS61046 or TPS61178.

    Best Regards,

    Fergus

  • 0 in reply to Fergus He
    Prodigy 30 points

    Hi Fergus. Many thanks for the reply. I didn't notice this issue before, but now the PCB is ready for mass production so I can't change to the other devices unless they are pin-to-pin compatible.  Anyway, many thanks for the clarification.

    Just while we are on the topic, the TPS61288 is powering an audio power amplifier IC which requires substantial bulk capacitance. Can the TPS61288 bear approximately 1500 uF distributed along the power line?

    BR

    Santo

  • 0 in reply to Santo Prattico'
    TI__Genius 12935 points

    Hi Santo,

    Sorry to hear that we can do nothing about the situation. One of the workarounds is to add a load switch to the output side.

    Yes, TPS61288 is capable of such large output capacitors as the input current will be limited when starting up.

    Best Regards,

    Fergus