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UCC28950: Settings etc. when used asynchronously

Kaji@PAN
Mastermind 7025 points
Part Number: UCC28950

Hi,

I would like to ask you about the UCC28950 device.
I am creating a circuit asynchronously.
(question 1)
DCM mode begins when the voltage on the CS pin falls below a user-set threshold and OUTE and OUTF go low in the data sheet.
However, since I am creating the circuit asynchronously, what is the behavior in this case?
(Question 2)
I don't think the DELEF and ADELEF settings are required for asynchronous circuits. In this case, what kind of settings should these pins have?
Can these pins be open?
(Question 3)
The sink and source currents of OUTA, OUTB, OUTC, and OUTD are specified as electrical characteristics of 0.2 A (TYP).
Is there a maximum rating for these sink and source currents?

Best regards,

  • 0
    TI__Mastermind 25570 points

    Hello Kaji-san

    A1/ If you are using dode rectification then the DCM mode has no effect and should be disabled (see A2).

    A2/ DCM mode should be disabled by tying the DCM pin to VREF. This disables OUTE and OUTF. OUTE, OUTF should be left open circuit, ADELEF tied to GND and DELAB should be tied to GND through a resistor in the range 13k to 90k (value is not important).

    A3/ The OUTx signals are intended to be used as the inputs to a MOSFET gate driver. The current required in this case is very low  (<<200mA). The data sheet gives values for the min and max output resistances. In general these outputs may be used to drive a gate driver IC without any concerns about their drive capability.

    Regards

    Colin

  • 0 in reply to Colin Gillmor
    Mastermind 7025 points
    Thank you for your reply.
    What should I do with the DELEF pin?
    Can I connect it to GND?
    Also, is the DELAB pin also involved?
    Best regards,
  • 0 in reply to Kaji@PAN
    TI__Mastermind 25570 points

    Hello Kaji-san

    There is a Typo in my earlier reply, I wrote DELAB instead of DELEF

    DELAB should be tied to GND through a resistor in the range 13k to 90k. The resistor value should be chosen to give the optimum delay for ZVS operation - there are details in the Data Sheet.

    DELEF should be tied to GND through a resistor in the range 13k to 90k (value is not important).

    Thanks for spotting this.

    Regards

    Colin