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bq29209: Need resistor value for calculate leakage current

Beginner
Intellectual 2381 points
Part Number: BQ29209

Here is functional block diagram for bq29209. Please help to confirm the following questions.

 

  1. The internal resistor of FET
  2. The resistor from VDD to CB_EN
  3. If internal FET is open, there is a leakage current from VDD to CB_EN

 

  • 0
    TI__Expert 6085 points

    1. The internal resistance can be derived from the  ICB1 = V1/ (Rcb +  Rint).

    2. Yes there is a pull-up resistor, but can be a linear or switched in.

    3. There will be leakage current on CB_EN and is specification is Icb_en = 200nA(max).

  • 0 in reply to Vish Nadarajah
    TI__Expert 6085 points
    as to the "pullup" on CB_EN pin---> its a 50nA current source into an LDO. There is a reverse blocking diode in series with the current source.
    the linear resistor-symbol needs to be modified.

    If CB_EN is held to GND, there will be a current path ( upto 200nA) from VDD to CB_EN.

    The internal FET resistance ~ 100 ohm from the equation given earlier.