TPS40303: Powering an Altera/Intel FPGA for efficiency purpose - is it safe

Pascale Crouzillat

Part Number: TPS40303

Hello,

I need to generate a 0.9V from a 12V input (17A max) and the design is highly constraint in efficiency.

I did look at the recommended TI parts for Altera/Intel but I need an efficiency above 90%. Which I achieved with a TPS40303 part in WeBench, selecting efficiency as the main criteria.

At start-up, the overshoot is around 0.950V where the input is between 0.87V and 0.93V. And there is a similar issue with the load transient response.

Is there anything I could do to lessen the overshoot ?

over 4 years ago

0 Pascale Crouzillat over 4 years ago

Prodigy 30 points

Pascale Crouzillat said:

Pascale Crouzillat said:
At start-up, the overshoot is around 0.950V where the input is between 0.87V and 0.93V.

I meant : The FPGA specifies its power input between 0.87V an 0.93V

0 Gerold Dhanabalan - Online Design Tools over 4 years ago

TI__Genius 14455 points

Hi Pascale,

Are you referring to simulation results in WEBENCH? I see it going all the way to 0.98V in simulation. It should be possible to minimize the overshoot by increasing the output capacitance and also tuning the compensation.

Regards,

Gerold

0 David_Daniels over 4 years ago in reply to Pascale Crouzillat

TI__Genius 16670 points

Pascale,

Do you have schematic and wave forms you can share? For the startup, you may be able to extend the soft start time by adding a larger value capacitor on the EN/SS pin to reduce the overshoot at start up For the load transient, add output capacitors and/or changing the frequency compensation to increase the bandwidth as Gerold is suggesting.

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TPS40303: Powering an Altera/Intel FPGA for efficiency purpose - is it safe