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TPS73801: TPS73801

samraj j
Prodigy 90 points
Part Number: TPS73801

Hi Team,

We are using LDO (TPS73801DCQ) in battery charging circuit. Please find below attached picture for yur reference. We have designed this circuit for charging the battery at 11.5V @ 1A. But when the battery is connected for charging, LDO is sourcing at 10.8V@1.5A beyond its rated current.Temperature goes very high if temperature crosses maximum limit IC and board may gets damage. But we require it to be charged @1A.  Please let us know why LDO is sourcing beyond its limit. Also please let us know how to limit the output current.
  • 0
    TI__Guru 50050 points

    HI Samraj,

    LDO's don't typically have a precise current limit. The TPS738 in particular only shows a minimum of 1.6A a typical of 2A:

    Out newer device the TLV767 has a much tighter current limit and has foldback current limit:

    Since you are monitoring the current. If you could use that to modulate the FB pin to lower the LDO voltage to keep the charging current in the desired range you might be able to achieve the desired functionality. 

    One other concern I have is thermal if the battery range is 7.2 to 11.5V (What is the chemistry for the battery?) from 12V to 7.2 at 1A, this is 4.8W. We will be thermally oscillating at these power levels. 

    I hope this helps.