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LDO slew rate enhancer circuit.

Manjunath Inder
Prodigy 190 points

Hi,

Can anyone suggest some simple LDO slew rate enhancer(which is used to improve transient response in LDO's)

Regards

Manjunath I

 

  • 0
    TI__Expert 7140 points

    Hi Manjunath,


    What kind of slew rate enhancer do you mean? LDO internal bandwidth limits slew rate and response. LDO with external resistor divider can be modified to have feed-forward capacitor which can improve transient response. Please see link below for detailed explanation.

    http://www.ti.com/lit/an/sbva042/sbva042.pdf

    Do you have some specification for the slew rate and applications what it is used for? Also input and output voltages and load current would be are interesting?


    Best Regards,

    Jari Niemelä

  • 0 in reply to Jari Niemela13
    Prodigy 190 points

    Hi Jari,

    Thank you for replying.

    I'm Designing a high slew rate DC electronic load in which a voltage feedback operational amplifier is driving a power MOSFET (Varying its resistance in the saturation

    mode and dissipating heat) .The main objective of this work is to design a high slew rate load (current Sinking).

    I have two doubts Regarding the above.

    1.Will the Input Control Voltage Slew rate across Op-AMP determine the Output current slew rate through MOSFET

    2.Do we need a Saturation mode Gate driver to achieve the above  objective.  

    and is there any FET Drivers available(That operates MOSFET in Saturation region).

     

    Regards 

    Manjunath I

    What I believe is  Driving the MOSFET with just Op Amp will not yield the required high slew rate (since the input current of the FET is not sufficient to

    Charge the Input capacitance of the MOSFET .

    So i decided to look into the MOSFET Gate drivers which are used in LDOs.I thought it will give some insights about the operation of  MOSFET in

    saturation region(with good transient response)