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UCC28180 driver no output

JI RO
Prodigy 30 points
Other Parts Discussed in Thread: UCC28180

I used UCC28180 in PFC circuit for DC fan PSU.

Desired output = 360 V 80W

Inductor = 1 mH,R shunt = 0.2 ohm, R divider for Vsense 990 kohm and 14 ohm.

Rfreq = 22kohm

When I supply 14 Volt to Vcc.  The PWM never started. No signal at Pin 8.

I changed the IC ,Nothing changed.

Here are all voltage across all pin.

Vcc pin = 14.61

VComp = 5 volt.

VSense  = 4 volt.

IComp = 0.5

Tomorrow I will capture the signal and post it if it is necessory. 

  • 0
    Prodigy 30 points
    Edited****
    R divider for Vsense 990 kohm and 14 kohm.
  • 0 in reply to JI RO
    TI__Mastermind 31580 points
    Hi JI,

    Whats the voltage level on the ICOMP pin?

    Regards

    Peter
  • 0 in reply to Peter Meaney
    Prodigy 30 points

    Hi Peter,

    Now the driver is working properly.

    I wonder it works after I changed Mosfet from FCPF400D60 to 2sk3114 .

    It can switch only 2-3 times, then IC driver is damaged at pin 8 (gate drive).

    So I decide to remove turn-off diode at Mosfet  then now it works well.

    I have 2 question about this.

    1.Why driver does not switch when I use FCPF400D60 despite higher Id.

    2.Why driver is not damaged when I removed turn-off diode.

    Note .Diode turn off is SKN9

    Ji RO

  • 0 in reply to JI RO
    TI__Mastermind 31580 points
    Hi JI,

    The FET change should make no difference unless the first FET was damaged. Did you check the impedance of the gate to source on the FCPF400D60?

    The Driver pin should not be damaged when the diode is removed. Can you send a scope plot of the gate drive waveform? You could also order the UCC28180 EVM board, www.ti.com/.../ucc28180evm-573 to give you a reference for the waveforms and operational performance.

    Regards

    Peter