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UCC28610: alternative w/o cascode and constant current mode?

Stefan Lintner
Expert 5165 points
Part Number: UCC28610
Other Parts Discussed in Thread: UCC28600, , UCC28780, UCC28700, UCC28730, UCC28750, LM5023, UCC28781

Hi Team,

We are looking for a suitable IC for flyback control. Do you have an IC similar to the UCC28610 (valley switching, secondary side regulation) that doesn't have a cascode and constant current mode? Alternatively, do you have an IC similar to the UCC2871X (valley switching, primary side regulation), but without constant current mode? IC's with QR mode (transition mode) like UCC28600 aren't suitable for us.

To give you some more info about our use case: 

For example the full load is 70 W and low input voltage 600 VDC, then transition mode (also known as quasi resonant mode QR) means that the MOSFET will always switch in the first valley with frequency e.g. 100 kHz. When the load starts to drop, MOSFET will still switching in the first valley, but the frequency will increase. After reaching max frequency (UCC28600 is 130 kHz) it goes to DCM. However we are mainly interested in load 85 to 100 % of full load, where dominates the main function – transition mode (UCC28600) or valley switching (UCC28610).

UCC28780 seems very interesting, but the it has a lot of components around.

Are there any other solutions which we are missing?

BR,
Stefan

  • +1
    TI__Mastermind 24375 points

    Hi Stefan,

    Thank you for reaching out.

    Unfortunately most offline flybacks (especially PSRs) like UCC2871x/ UCC28700/ UCC28730 etc. have constant current control. So there are no other options in this family of devices.

    On the SSR options, there is this new low cost UCC28750 which does not have CC mode but is fixed frequency controller with frequency foldback and burst modes.

    If looking for QR like one LM5023 might also be an option similar to UCC28600.

    Yes, UCC28780 could be used, but it has the extra switch to recycle the leakage energy and there is also UCC28781 which is ZVS flyback with controlling the secondary side SR to achieve zero voltage switching. So performance wise QR (UCC28600 family) < ZVSF (UCC28781) < ACF (UCC28780/2).

    Regards,

    Harish