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UCC24612: UCC24612/UCC24610 in Forward Topo

Part Number: UCC24612
Other Parts Discussed in Thread: UCC24610,

Dear colleague,

My power module customer asked

1. Whether UCC24612/UCC24610 could be used in Forward? Please describe it in detail.

 I find a materials as below, why Control SR cannot control with UCC24612?

2. UCC24610 has SYNC PIN, which controls the secondary side by sampling the signal of the primary side. UCC24612 does not sample from the primary side. Is that a problem?

3. For UCC24612 reference design, I only found UCC24612 application in LLC and Flyback in Do we have related reference design?

4. If customer want to use SR, do we have better reference design?

Appreciate it for your powerful support!

Best Regards,

Rock Su

  • 1. On your statement "Control SR cannot control with UCC24612", do you mean UCC24612 cannot turn on SR MOSFET or cannot turn off SR MOSFET? We need to review your circuit of UCC24612 together with control SR MOSFET to see if your circuit is correct made.
    2. UCC24612 uses VD to VS voltage drop to make control so not need to sample the primary directly. What problem are you referring to?
    3. UCC24612 is created for LLC and flyback. If using it in forward, a rule of thumb is fsw < 100kHz.
    4. we do not have a reference design to use UCC24612 for a forward converter.
  • UCC24610 can be used in Forward when fsw>100kHz?
  • Yes, up to 600kHz based on the datasheet, on a proper external circuit designed for SYNC, i.e.,  a proper signal to SYNC to make GATE turn off.

    In applications, the power losses have to be evaluated carefully to make trade-offs between targeted efficiency and switching frequency.