• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 64 subscribers
  • Views 181 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

LM2766: max. capacitance for output capacitor (in-rush current limit?)

LM2766: Charging high output capacitance

Exequiel Quinto
Prodigy 20 points
Part Number: LM2766

Can this part be capable of charging an output cap of 4700uF? Charging time is not an issue as long as it is below 1 minute or so. During the charging time, output cap will not be subjected to any external load except the capacitor's DC leakage.

  • 0
    TI__Guru 51531 points

    Hi Exequiel,

    sorry for the late response.

    Can you share some more details:

    • input voltage
    • output voltage
    • leakage of the Capacitor to be used

    Best regards,

     Stefan

  • 0 in reply to Stefan Schauer
    Prodigy 20 points

    Hi Stefan,

    Thanks for the reply. Please see more details of the requirement below:

    Vin = 2V to 3V

    Vout = 2xVin or 4V to 6V

    Output Cap DC Leakage Current = <50uA

    For some additional information, the charge pump will only charge the capacitor for back up power. The charge pump will be disabled once the capacitor is fully charged so its not going to be charging the cap and supplying load at the same time.

    There's a separate question I have regarding the Abs Max Rating for the shutdown pin, screenshot shown below. The question is: If Vin is 3V, can the Shutdown pin be connected to 5V? 

    Best Regards,

    Exequiel

  • +1 in reply to Exequiel Quinto
    TI__Guru 51531 points

    Hi Exequiel,

    I do not expect issues with that configuration.

    The shutdown pin can not be connected to 5V if V+  (Vin)  is 3V - the internal ESD protection circuit will get conducting therefore the limit if V+  + 0.3V is given

    Best regards,

     Stefan