variable output buck converter

Andrew Xiang36

Other Parts Discussed in Thread: TPS62147, TPS54628, TPS62135, TPS62180, TPS54824

I want to design a variable output buck converter with a DAC, voltage 1-5V, current 2A max. Input voltage is 12Vdc.

Since the output will be PI controlled to drive a TEC, Vout needs to respond rather quickly to the desired point. I am worried about the stability when I am driving different dc voltage into the FB pin.

Which buck converter is most suited for such appliction? Please recommend a buck converter.

over 7 years ago

0 Chris Glaser over 7 years ago

TI__Guru**** 150870 points

Hi Andrew,

You can use TPS62147/8 for this, operating the device in forced PWM mode so that it can sink current and transition Vout most quickly.

0 Andrew Xiang36 over 7 years ago in reply to Chris Glaser

Prodigy 60 points

Do you have a version for 5.5A output? For larger current ?

0 Andrew Xiang36 over 7 years ago in reply to Chris Glaser

Prodigy 60 points

I need to run it at continously 2A, is that a good fit? How about TPS54628 ?

0 Chris Glaser over 7 years ago in reply to Andrew Xiang36

TI__Guru**** 150870 points

Hi Andrew,

Do you need 2A or 5.5A? There is the 4A TPS62135/6 which are pin to pin with TPS62147/8.

For 6A, we have TPS62180.

What is your maximum ambient temperature?

0 Andrew Xiang36 over 7 years ago in reply to Chris Glaser

Prodigy 60 points

How about 6A , voltage 9V. Input Voltage is 12V.
It is for ambient temperature.

0 Andrew Xiang36 over 7 years ago in reply to Andrew Xiang36

Prodigy 60 points

Can you please take a look at TPS54628 ? I like the packaging with bigger heat dissipation.

0 Chris Glaser over 7 years ago in reply to Andrew Xiang36

TI__Guru**** 150870 points

Hi Andrew,

A colleague supports that device, so I will let him comment.

Your ambient temp range is still unknown to me. Is it 25 C (room temperature)?

And what did you mean with 9V?

0 Andrew Xiang36 over 7 years ago in reply to Chris Glaser

Prodigy 60 points

It is for room temp.

Supply is 12Vdc, I have several TEC so I wan to use one buck converter that will work for all. Some are 4V, some are 9V, some are in the middle.

I will use a current sensing resistor to monitor the current. It would be nice if I could set a max current on those buck.

0 Neal Zhang over 7 years ago in reply to Andrew Xiang36

TI__Expert 4720 points

Hi Andrew,
The Output Voltage Range of TPS54628 is 0.76 V to 5.5 V. To get more clear, please list your spec as this: Vin=?, Vout=?, Iout=5.5A

0 Chris Glaser over 7 years ago in reply to Andrew Xiang36

TI__Guru**** 150870 points

Hi Andrew,

TPS62135/6 can output up to 4A to up to 12Vout.

If you need higher current, a device like TPS54824 might work.

Here's a simple reference design that shows how to adjust the output voltage of any DC/DC to drive a TEC: http://www.ti.com/tool/PMP9759

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variable output buck converter