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PMP4650 - Details

Atul Bhakay
Genius 3205 points
Other Parts Discussed in Thread: TPS40210

Hi,

In PMP4650 can somebody explain the function of the circuits related to transistor Q2 9 related circuit is R1, D6 and D5) and also function of transistor Q100 and related components - R101. R102 and R103

 

Regards

Atul Bhakay         8255.13v to 130v_12va750_TPS40210_sluk002.pdf

  • 0
    TI__Mastermind 25286 points

    well,

    as VIN increases from 0, at the staryt-up, D6 & Q2 provide the positive voltage on /EN, that keep the device "OFF"

    D7 locks any biasing to the winding 1-2 of T1

    D5 set a kind of threshold: as VIN is greater than 10V then Q100 is switched on, pulling /EN down, that enables the device.

    as the device starts working, the D7 bias the R101 divider, turning off the Q2 (on D5 cathode there is around 11V fix: as D7 cathode si 9-10V Q2 is off!): this saves the Q2 power consumption...

    viceversa at the turn-off stage (VIN falling down below 11V)...

    Vincenzo

  • 0 in reply to Vincenzo Pizzolante
    Genius 3205 points

    Hi,

    Thanks for the detailed answer. My queries have been answered comprehensively.

    Thanks once again

    Regards

    Atul Bhakay