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TPS54340: Please suggest if it is right part as per the requirement

VIVEK ROY
Prodigy 20 points
Part Number: TPS54340
Other Parts Discussed in Thread: LM26003, LMR23630

Dear TI Technical Support Team,

We are going to design a non-isolated Buck converter to drive a transient load (current during off time 200mA and on time 2A) with frequency 200Hz and D=12% and max acceptable ripple on Vout is 100mV (Vout=8V, Vin= 9 - 32V).

We choose TPS54340. Please suggest if it is the right part to handle this transient load. If not, please sugest the right part no, as the design is initial stage we can change the part no. 

If you have any technical write up, explaining design issues and best way to handle this kind of load behaviour, please share.

Regards

Vivek

  • 0
    TI__Expert 4100 points
    Hello,
    For high efficiency solution we are also suggesting to evaluate following devices LM26003 and LMR23630.
    Both of these devices can meet your specifications and deliver possibly higher efficiency and cost effective solution for your operating conditions.

    The device you have chosen can certainly handle your application requirements.
    Depending on your application requirements (solution size, efficiency, cost) there are multiple devices that can meet your operating parameters.

    As far as design recommendations are concerned, please use device datasheet as your primary source. If further help is needed there are also number of application notes available among other resources.

    Bets regards
    Brani
  • 0
    TI__Expert 5745 points

    Hi

    what's the slew rate of the current transient? If it's lmore than 100mA/us, the overshoot and undershoot are really hard to be less than 100mV in the wide Vin. The value of the overshoot and undershoot in output (it also can be called ripple) are related with the slew rated, Cout, Vin, Vout, loop respond and so on. 

    For the wide Vin, the main control are current control mode and voltage control mode, and the cross frequency of them are not wide enough for fast load step.

    Or you can try to add a feed-forward cap to improve the loop respond.(See the detail in the attachoptimize the loop respond with the feedforward capacitor.pdf)

    Thank you!

  • 0 in reply to Vental Mao
    Prodigy 20 points
    Hi,

    Thanks for your support. Yes the slew rate is at higher side. We are going to use a GPRS modem in our product which will offer this kind of transient load.

    Now there is a little change in the design parameter, now maximum Vin can be 48V. Please suggest the part no of Buck converter which can accept 48V as input (it may go upto 54V) and can drive the GPRS modem, which needs 2A while transmitting and accepts max 200mV ripple.

    Regards
    Vivek