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MAX1771 equivalent?

Jan Rychter
Intellectual 305 points
Other Parts Discussed in Thread: LM3478, TPS40210

I'm looking for a chip similar to the MAX1771. It's an adjustable step-up DC-DC controller with an external MOSFET switch, popular with people designing tube circuits, nixie clocks, etc, where voltages of 150V-450V are needed. The MAX1771 has drawbacks: it's expensive, and very sensitive to feedback noise.

Is there a similar, more modern solution from TI? I tried looking for one, but could not find it. Looking for advice.

  • 0
    TI__Mastermind 25296 points

    please have a look at LM3478 and/or TPS40210 at the links

    http://www.ti.com/product/lm3478

    http://www.ti.com/product/tps40210

    Vincenzo

  • 0 in reply to Vincenzo Pizzolante
    Intellectual 305 points

    Thanks for your reply — I looked at both, but... the TPS40210 is quite difficult to use because of its versatility. The LM3478 is much closer to what I was looking for, but (at least on paper) it isn't as efficient as the MAX1771.

  • 0 in reply to Jan Rychter
    TI__Mastermind 25296 points

    yep, what you saw is the differce in device power consumption (at high IOUT the efficiency are the same)...

    if you look for high efficiency parts then an embedded fet solution would be the right choice, but I need to know the specification of the boost you are going to implemente...

    I suggested you the TPS40210 because the one with the wider options...

    Vincenzo

  • 0 in reply to Vincenzo Pizzolante
    Intellectual 305 points

    Vincenzo,

    Oh -- I didn't notice that. I actually don't really care that much about Iq (at least it isn't critical). I'd like to have efficiency under load, stability (also when transitioning from a full load to no load), low cost and low component count.

    What I need is to boost 12V to 150-250V (adjusted with a pot). In most cases about 25mA of current is required, but I also need a version which can produce 80mA at 150V. There should be a shutdown pin. A simple boost configuration is fine, so that no transformers are required.

    This type of supply is used in hundreds of hobby tube-based projects built by people around the world. You can see http://www.desmith.net/NMdS/Electronics/NixiePSU.html for an example based on the MAX1771, with excellent comments.

    Any advice is much appreciated.

    --J.

  • 0 in reply to Jan Rychter
    TI__Mastermind 25296 points

    Hi,

    attached you can find two example of reference designs, the closest one to your needs.

    Based on this you can apply little changes in order to obtain the performance you wish: indeed, you can simply keep the power parts used on MAX board (at the link you sent to me) and replace the MAX with TPS for the control one (tuning then the compensation network, in according to the changes).

    Please keep in mind that TPS40210 is a very well supported device (simulation models, even the license-free TI-Tina, application notes, refrerence designs, design tools like Webench, and so on,...)

    Have a look at the part page http://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=tps40210&linkId=1 

    Furthermore, the High Temperature version, the Automotive one and EVM are available as well...

     

    The attachements:

    1513.PMP2739.pdf

    0207.PMP3876.pdf

     

  • 0 in reply to Vincenzo Pizzolante
    Intellectual 305 points

    Thank you. You've convinced me to at least try the TPS40210 :-) I'll get samples and design something, following what SwitcherPro tells me (Webench doesn't really work for me). Perhaps we can get a HV supply for tubes design that isn't based on the MAX after all.

    As for the attachments -- those are interesting designs. I don't understand the transformer/diode setup in PMP2739, though.