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UCC28180: UCC28180 Design Calculator

Hirotaka Matsumoto
Guru 27585 points
Part Number: UCC28180


Hi all

Would you mind if we ask UCC28180?

<Question1>
On UCC28180 Design Calculator, there is the description "Reverse Recovery Charge".
We have never seen this parameter at diode's Electrical Characteristics.
Does it depend on diode which we use?
If you have some infromation, could you give us?

<Question2>
We can't understand "Desired Number of Line Cycles For Output Hold up Time（typ one line cycle)".
So, could you let us know detailed information?

Kind regards,

Hirotaka Matsumoto

  • 0
    TI__Mastermind 34465 points
    Hello Hirotaka Matsumoto
    1. The UCC28180EVM uses for example the C3D04060A diode. According to the datasheet it has a reverse recovery charge (or total capacitive charge) of 10nC. You need to check the datasheet for whichever part you use
    2. The holdup time can be specified in mS or in terms of line cycles. If the input line frequency is 50Hz then one line cycle is equivalent to 20mS, two line cycles would be 40mS and so on.

    Regards
    John
  • 0 in reply to John Griffin1
    Guru 27585 points

    John san

    Thank you for your reply!

    We have an additional question about "Required Minimum Output Voltage".

    How much of this value should we configure?
    For example; Minimum voltage(85V) × √2

    Kind regards,

    Hirotaka Matsumoto

  • 0 in reply to Hirotaka Matsumoto
    TI__Mastermind 34465 points
    Hello Matsumoto-san,
    The terms used in the calculator are confusing and could do with some explanation.
    The "required minimum output voltage" is a voltage that needs to be specified in your design requirements.
    For example if the high voltage output is 400V and the input AC is removed for 20mS, the output voltage starts to decay.
    The "required minimum output voltage" is the minimum acceptable output voltage for the pfc output that your system can support.
    For example the 400V output could decay to 325V before the regulators on the high voltage DC begin to shutdown.
    This voltage and the interrupt time set the value of output capacitance
    Regards
    John