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UCC28630: UCC28630 v. UCC28631 for HV Battery Input

Part Number: UCC28630
Other Parts Discussed in Thread: UCC28631, UCC28704

Hi team,

My customer are currently designing with the UCC28630, but their input supply is going to be coming from a high voltage, DC battery. Due to the input, and lack of AC, do they need to be designing with the UCC28631 instead?

Thanks,

Jacob

  • Hello,

    The UCC28630 is a flyback controller for DC to DC applications.  Generally the AC input is rectified and filtered with a buck capacitor.  The High Voltage (HV) is rated for 700V.  As long as your input voltage is below 500 V this device will work for your application.

    If however the voltage is higher than 700 V you might consider using the UCC28704 instead that uses a resistor for trickle charge startup.

    Regards,

  • Hi Mike,

    I should have been more clear in my original question. Sorry about that! 

    Specifically looking at Figure 15 from Section 8.3.1. The UCC28630 says the HV pin must be connected to AC, but there is no AC present in the customer's system. Because of this, should we move to the UCC28631 or are we okay to connect UCC28630 HV pin to the DC?

    Thanks,

    Jacob

  • Hello,

    That note states to support X-capacitor discharge the UCC28630/3 devices.  

    If a DC is observed the UCC28630/3 devices believe that the X-Cap needs to be discharge.  You are correct that you need to switch to one of the other devices in this family if a DC input is used (UCC28631/2/4).

    Regards,