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LM5160 REFERENCE DESIGN 3.3V OUTPUT

vipin mishra
Intellectual 270 points
Other Parts Discussed in Thread: LM5160, LM5022, TPS54060, LM5017

Hi all,

I want to design a Flyback topology based 12V-60V input with 3.3V output  DC-DC power supply so i have chosen LM5160.But in its datasheet there is no 

information about the 3.3V output.

Could anybody please share the Reference design of LM5160 with 3.3V OUTPUT.

regards,

vipin

  • 0
    Intellectual 390 points

    Vipin mishra,

         Yes you can design for the specifications mentioned below Vin=12V-60V with Vout=3.3V & Iout = 1.5A (maximum).

    Please find the below attachment for reference diagram. Another suggestion is just use TI webbench for designing.

    webench_design_3531082_14_651495761.pdf

  • 0 in reply to ATHIESHKUMAR T
    Intellectual 270 points
    Hi ATHIESHKUMAR T,

    Thanks for quick reply sir.But it is in synchronous Mode not in flyback i think.If i am right then please share the Flyback mode 3.3V output reference design also.

    Regards,
    Vipin
  • 0 in reply to vipin mishra
    TI__Genius 9130 points
    Vipin,

    You did not specify how much power or output load current you need?

    You can use the TI Design Power Parametric Search to find existing designs to meet required specs. You can find the tool here (on ti.com, click on "Applications & Designs", then click on "TI Designs". Then click the grey button "Search power reference design parameters" on the left:
    www.ti.com/.../refdesignsearchresults.tsp

    The page can be slow to load (many possible designs to choose from). You can refine the list by entering required input voltage range, output range, output current, isolated/non-isolated, DC or aC input, etc. You can also specify keywords (e.g. a particular IC part number, or topology, etc).

    The page refreshes the list of matching designs after every input, so it can take a while to refresh - you need to have patience with it - if it looks like it has hung, don't worry it will come back eventually!

    Using this tool, I just searched for deisgns that meet 12-60 V input range with 3.3 V output. 3 possible designs were found:

    1. http://www.ti.com/tool/PMP6938
    Non-isolated buck with 3V3 @ 50 mA - very low power.

    2. http://www.ti.com/tool/PMP9282
    Isolated flyback using LM5022 - output 3.3 V @ 4.5 A, 15 W.

    3. http://www.ti.com/tool/PMP4986
    Isolated flyback with wide input range using TPS54060, output 3.3 V @ 300 mA, 1 W.


    There may be other suitable designs for different output voltage that can be adapted to 3.3 V, it really depends on your load current.


    If you want to specifically use LM5160, you can search the power designs library using "LM5160" as keyword - this returns 10 possible designs, but none are 3.3 V output, closest is 5 V, and none are rated up to 60 V.

    E.g. www.ti.com/.../PMP10571

    But bear in mind that LM5160 is a "Fly-buck" controller, not Flyback - it is basically a buck converter with integrated FET's that allows a second isolated output to be generated from a second winding on the buck inductor, but this second output is not directly regulated.


    I hope this helps answer your question, if so, please click the "verify answer" button.


    Thanks,
    Bernard
  • 0 in reply to Bernard Keogh
    Intellectual 270 points
    Hi Bernard,

    Thanks for your quick reply and suggestion also.

    Requirement:

    Input = 8 V-60 V
    Output = 3.3 V
    Load current =>800 MA
    Need isolation from input to output

    so Flyback and Flybuck both are OK for me,as they are having isolation.

    Could you suggest any part number with proven reference design to use for my application.


    Regards,
    Vipin
  • 0 in reply to vipin mishra
    TI__Genius 9130 points
    Vipin,

    The original spec above was 12 V min, now you say it's 8 V min. That actually makes a big difference, since it limits the choice of control IC's to ones with a lower VCC startup voltage.

    For 12-60 V input range, there are 3 designs for 3.3 V output, as listed above:

    1. http://www.ti.com/tool/PMP6938
    Non-isolated buck with 3V3 @ 50 mA - very low power.

    2. http://www.ti.com/tool/PMP9282
    Isolated flyback using LM5022 - output 3.3 V @ 4.5 A, 15 W.

    3. http://www.ti.com/tool/PMP4986
    Isolated flyback with wide input range using TPS54060, output 3.3 V @ 300 mA, 1 W.

    PMP9282 is probably the closest fit, and you could start with this and redesign it for lower power. This is actually rated to go down to 9V minimum Vin, so close to your 8-V spec. If you adjust the resistor divider on the UVLO pin, you can change it to start at <8 V (currently it starts at 8.8 V typ). The LM5022 can operate down to 6 V input.


    Thanks,
    Bernard
  • 0 in reply to Bernard Keogh
    Intellectual 270 points
    Dear sir,

    I need the isolated output buck converter output but the parts suggested does not have isolation .For input 12V-60V is okay but output cannot go less than 1 A.

    Any part will be OK but that should have isolation from input to output.

    regards,
    Vipin
  • 0 in reply to vipin mishra
    TI__Genius 9130 points
    PMP9282 above is an isolated Flyback design that runs from 9-60 V input, and provides 3.3 V output at up to 4.5 A. It can easily be modifed to run down to 8 V input.

    It could further be redesigned for less output current.

    The isolation is achieved through the Flyback transformer, not the choice of IC.
  • 0 in reply to Bernard Keogh
    Intellectual 270 points

    Dear sir,

    Thanks for your quick reply.I will use the same circuit suggested.

    regards,

    Vipin 

  • 0 in reply to vipin mishra
    Intellectual 270 points

    Hi sir,

    I am using the same circuit PMP9282 but the graphs for 500 MA Load is not convincing or very poor.so how can i reduce the output current without effecting the

    IC performance.

    Regards,

    Vipin

  • 0 in reply to vipin mishra
    TI__Genius 9130 points
    Vipin,

    Can you explain your question?

    If I look at the PMP9282 test report, I do not see any performance graphs at 500-mA load, so I do not know what you are referring to.


    Thanks,
    Bernard
  • 0 in reply to Bernard Keogh
    Intellectual 270 points

    Dear sir,

    I want to reduce the output of the circuit used in PMP9282 to Max of 800 ma .Could you suggest how i can reduce the PMP9282 output without effecting the 

    PMP9282  performance.

    Regards,

    Vipin

  • 0 in reply to Bernard Keogh
    Intellectual 270 points

    Dear sir,

    PMP9282 has a very high output current  and its test result at 450 ma is very bad but i will be using it maximum at 450 ma so please suggest me how can reduce the Output current of the PMP9282 for my application.

    Please suggest some method to reduce it without effecting the board (PMP9282) performance.

    Regards,

    Vipin

  • 0 in reply to vipin mishra
    TI__Mastermind 30120 points

    Hello,

    You will need to look at the Switching losses to increase the lower output current efficiency.  Losses are dominated by switching losses at low output currents and conduction losses at higher output currents.  I therefore suggest looking at MOSFETs with similar VDS ratings but with Low Gate charge to increase transition times when turning the FET on and off, you may need to increase the RDSon of the selected mosfet to achieve your goal here?  I would also look at using a Diode with a similar in VRRM rating, but with perhaps a higher forward voltage drop, but with a much lower reverse recovery time.  The above methods are the easiest approaches to increasing lighter load efficiencies.  You may also want to look into the transformer design and may the operation looking into a DCM flyback?  But at this point you may need to consider a completely new design, and design from “ground” up at this point?

  • 0 in reply to David Baba
    TI__Genius 9130 points
    Vipin,

    As David mentioned above, the PMP9282 design would need to be redesigned using a more appropriate smaller power stage for the lower output power. But it was the closest existing TI reference design for your requirement. The 8-V minimum input voltage is probably the most limiting spec.

    If redesign of the PMP9282 design is less favoured, then using a Flybuck with LM5160 is another possibility. While there is no reference design or EVM for 3.3-V output, the datasheet and app notes contain all the required design equations and instructions needed.

    This is the datasheet, it shows the detailed design of a dual 8/12-V output design, that could be adapted to generate 3.3 V instead of 12 V:
    www.ti.com/.../lm5160

    If the isolated output regulation is not good enough (quite possible since the isolated output is so low, only 3.3 V), this app note shows how opto feedback can be added to improve the regulation of the isolated output:
    www.ti.com/.../snva727

    Again, this deals with 12-V outputs, but can be adapted for 3.3 V using the same design equations.

    There are design calculator tools available to help you design for your exact/custom requirements:
    www.ti.com/.../lm5160dntfbk-calc

    Finally, the Webench tool can be used to assist you with your design, this can be accessed from the LM5160 product page:
    www.ti.com/.../toolssoftware

    However, this tool maybe only supports non-isolated designs at present.


    If you would like TI Power Design Services (PDS) to generate a custom reference design for your application, you should contact your local TI FAE/support team, who can make the request for you. The PDS managers will evaluate the opportunity and may be able to assign an engineer to your project, depending on the size of the opportunity and their workload.


    Thanks,
    Bernard
  • 0 in reply to Bernard Keogh
    Intellectual 270 points

    Dear sir,

    We are using the LM5017 reference design for isolating the input and output .But output current  present at the secondary of Transformer is very less and it is only 200 MA but i need to update the secondary side of transformer up to 400-500 MA .

    Can you please suggest is there any way how can i variate the current flowing between Primary and Secondary.

     

    I want to make 9.5V output of 400 ma atleast.

     

    i

    Regards,

    Vipin

  • 0 in reply to vipin mishra
    TI__Genius 9130 points
    Vipin,

    Is this a new request/question? Is this related in any way to the previous discussion in this thread? I think it looks like a new discussion.

    If this is a new question, please start a new post/discussion thread to keep it separate, then the appropriate person will be able to respond to your question.


    Thanks,
    Bernard