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TIDA-00701: how can TIDA-00701 increase efficiency?

yang-lun chien
Prodigy 80 points

Part Number: TIDA-00701
Other Parts Discussed in Thread: PMP20612

Tool/software:

Hi
I am working on a 100W flyback power supply design,
and i found TIDA-00701 reference design on the TI website,
However, EVK’s specifications mention that the average efficiency is about 88%~89%,
Are there any suggested modifications that can increase efficiency?
Thanks

Attach details:
www.ti.com/.../TIDA-00701

  • 0
    TI__Expert 6005 points

    Hello Yang-lun,

    I don't suggest to change the topology for the DC/DC stage of this charger, since 100W is a bit low to consider LLC or half-bridge.

    Now, by keeping the architecture of TIDA-00701, it should be possible to increase the DC/DC efficiency by removing the passive clamp (or snubber) network D8, D7 and C18, and replace it with the active network of a 2-Switch Flyback used in PMP20612, see documentation under following link:

    https://www.ti.com/tool/PMP20612

    In this reference design (according to the schematic) a high side FET Q200 (therefore 2-SW Flyback)  is driven by means of a gate drive transformer T200 and small-signal FET Q201. So my suggestion is to use the power stage from TIDA-00701 but adding the extra high-side FET and gate driver according to PMP20612.

    I also see that the Flyback transformer in TIDA-00701 is pretty hot, reaching 81.7°C at 26°C ambient. Bu improving the performance of this transformer, it should be possible to increase the efficiency even further.

  • 0 in reply to Roberto S.
    Prodigy 80 points

    hi roberto
    i'II try to modify schematic,
    many thanks.

  • 0 in reply to yang-lun chien
    TI__Expert 6005 points

    OK, sure. Just let me know by reopening this thread if you need further support.

  • 0 in reply to Roberto S.
    Prodigy 80 points

    hi Roberto

    here is the schematic below，and should you have any suggestions, please advise.
    thanks alot.

    sch_ucc28740_double100w.pdf

    p1、PFC converter
    p2、flyback converter
    p3、Dual-Port PD

  • 0 in reply to yang-lun chien
    TI__Expert 6005 points

    Hi Yang-lun,

    I had a look to your schematic and most sections seem good to me. I have just few notes about the following point:

    - I see you used the voltage divider on U202 R208 and R219 from PMP20612, but you employed the same transformer like in TIDA-00701: these two designs have different transformers, so I suggest to take these two resistors from TIDA and not from PMP20612 (otherwise it will result into different brown-in threshold and output OVP).

    - I cannot find how you supply VCC of the PFC controller. I mean, in TIDA-00701 we have two diodes, and the first internal diode D9 supplies VCC of PFC. If that was a typo, please add another diode or use dual one.

    - Regarding the compensation network R227 and C214, its' connected between REF pin of U204 and pin 1 of the optocoupler. Normally this network is connected to pin 1 of U204, and I am not sure whether your connection impacts the loop; I suggest therefore to move R227 from pin 1 of U203 to pin 1 of U204. In addition, please add also a 100 pF between pin 1 and 2 of U204: it will give you more flexibility during stability analysis.

    Thansk,

    Roberto