UCC28180: UCC28180

Hi M.Prathap 

at no load condition, there UCC28180 will works at burst mode due to loop calculation, so there should be a little fluctuation, but it should be very small.

Please add the waveform for further analysis.

Dear David,

Please check below images for reference, after checking of PFC voltage varies input volatges(85V, 150V, 230V) at 230VAC input after few seconds unit got failed. kindly give me the solution.

At 85VAC

At 230VAC

At 150VAC

Regards,

M.Prathap

Prethap,

The waveforms shows OUTPUT VOLTAGE PROTECTION(OVP_H) is triggered. And then driver of UCC28180 is stopped and recover when output voltage drop to 102% of regulated output voltage. 

Could you try to speed up voltage loop response?

Yunsheng

Dear sir,

Good Day!

Please help us to resolve issue.

Here the design details below.

• We are designed PFC for 2.4KW 
• Input voltage range :150V-275VAC(50Hz)
• Output:400V@6A
• Operating frequency:100KHz
• Input UVLO:85V
• Power factor:0.99
• Peak efficiency:98%
• Operation temperature:Room Temperature 25°C(With air flow)
• Auxiliary Voltage:12V

Design output details

• L:117uH
• Cin:1.5uF
• Cout:680uFx2
• Mosfet:STW33N60M2
• Diode:STPSC20H065CW
• Isense C:1nF
• Isense R:0.005E
• Icomp:2.2nF
• Vcomp:C2:4.7uF, C1:470nF, R1:18K
• Vsense:1nF

Schematic

Facing issues

• Initial we are faced with output voltage fluctuation at input voltage 85V, 150V, 230V. at 230V DUT was got failed(Mosfets)
• at above condition we placed 0.05E instated of 0.005E mistakenly.
• Again DUT was failed after right shunt value placed, at AC 50V(we are increasing AC voltage from 0V to 230VAC)
• we test with changing of Vcomp also but not solved.
• And We are also tested with 3.5KW reference design values but DUT was failing continuously.

Please resolve issue.

Regards,

Senatla IN

Hi, 

after using correct 0.005E, is the issue of output voltage fluctuation fixed?

Regarding to the 

• Again DUT was failed after right shunt value placed, at AC 50V(we are increasing AC voltage from 0V to 230VAC)

what is the output load at this condition? 

Here is my suggestion, startup with no load fristly. And apply load when the output voltage is ready. Since there is no brown-out function with UCC28180.

Yunsheng

Hello Yunsheng,

After pacing correct 0.005E shunt we are not able to observe voltage due to DUT fail.

Regards,

Senatla IN

Hi, Senatla IN

I think you need to fix the board first. 

PFC is the front end stage, there is second DCDC stage following PFC. So to PFC, during startup of PFC, there is no load to PFC. It is kind of no load startup.

what is result, if you startup PFC with no load? Can you observe output voltage?

Yunsheng

Hello Yunsheng,

We are startup PFC with no load only, voltage reaching to set voltage but once reaching voltage DUT fails.

*For the same we are found issue in PCB layout and it fixed. Now PFC working fine.

Thank you for your best support.

Regards,

 Senatla IN