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UCC14240-Q1: COM-VEE voltage regulation

Patrick Ruf
Genius 4810 points
Part Number: UCC14240-Q1
Other Parts Discussed in Thread: UCC25800, UCC14140-Q1, UCC25800-Q1

Hi,

The UCC14240-Q1 device uses a two switch "balancer-like" topology to regulate the COM-VEE voltage (Figure 7-2 in the UCC14240-Q1 datasheet).

Does TI have a device that has just this kind of regulator integrated to use as standalone voltage regulator for split-rail supply (higher power capability than UCC14240-Q1 output)?

A use case could be as a secondary side regulator for a bias-supply in conjunction with the UCC25800 (for higher power applications).

Regards,
Patrick

  • 0
    TI__Mastermind 25355 points

    Patrick,

    The RLIM functionality of UCC14240-Q1 acts like you describe as a "balancer-like" topology. However, it's important to recognize there are two feedback loops each working to regulate the output voltage. The RLIM helps to maintain charge balance between the split capacitor output and this works successfully based on the RLIM knowing when the output voltages (FBVDD, FBVEE) have deviated from their set regulation points. The RLIM responds by sourcing of sinking current in/out of the capacitive divider midpoint to compensate for the imbalance.

    To add this function to UCC25800 is not possible, in it's present architecture, since this device is operating open loop. An equivalent RLIM function would need to have a reference by having knowledge of the set regulation point. For UCC25800 we select the transformer turns ratio to provide enough voltage margin above whatever post-regulation is being applied. If using a split capacitor output, we select the capacitor values such that C1*V1=C2*V2.

    Regards,

    Steve

  • 0 in reply to Steven Mappus1
    Genius 4810 points

    Hi Steve,

    My meaning was more of a separate compagnion device that sits on the secondary side after an additional regulator (e.g. LDO).

    Regards,
    Patrick

  • +1 in reply to Patrick Ruf
    TI__Mastermind 25355 points

    Hi Patrick,

    Understood - the same previous comments/concerns apply even for a stand alone device as you describe. A stand-alone device needs to have knowledge of where the output voltage rails ought to be and this would be independent of whether the voltage rails were regulated (like UCC14140-Q1) or unregulated (like UCC25800-Q1).

    TI does not currently have a device like this in our portfolio. Next time we gather to discuss new product ideas, I will mention your suggestion. Thanks for your contribution to the TI E2E forum.

    Regards,

    Steve