TIDA-00443: AC INPUT CURRENT DISTORTION

kalyanraj Durairaj

Part Number: TIDA-00443
Other Parts Discussed in Thread: UCC28180

Hi,

This is kalyan. we are currently working on the TIDA00443 PFC circuit for charger application.

In fixed boost mode we are facing some issues related to input AC current,

for the given AC input ,DC link voltage is maintained at 390V. boost part is working fine,but input current is not sinusoidal (distorted waveform- attached). initially say some 100V AC input ,current waveform looks sinusoidal. beyond that input voltage level current is distorted. herewith i have attached the input current and Isense waveforms for your reference. what could be the reason for this?

Isense and input AC current

Drain to source voltage and input current

Input AC current

Regards,

Kalyan

over 5 years ago

0 Teng Feng over 5 years ago

TI__Genius 13660 points

Hi Kalyan,

I have contacted one of my colleagues to answer your question. Thanks.

Regards,
Teng

0 Yunsheng Qu over 5 years ago

TI__Genius 9790 points

Hi, Kalyan

I found ISENSE has a lot of noise, do you have RC filter on ISENSE pin? Could you provide you schematic?

This issue would be related to layout, you can check ground plane of UCC28180, The ground plane should connect to negative terminal of PFC output capacitor.

regards,

Yunsheng

0 kalyanraj Durairaj over 5 years ago in reply to Yunsheng Qu

Intellectual 270 points

HI, Yunsheng,

Thanks for your interest in this.

we are using the RC filter on Isense also Ground plane is well connected with Output capacitors.

herewith i have attached the schematic diagram and layouts for your reference. pls give your suggestions.

SCHEMATIC DIAGRAM

LAYOUT

Isense

Regards,

Kalyan

0 Yunsheng Qu over 5 years ago in reply to kalyanraj Durairaj

TI__Genius 9790 points

Hi, Kalyan

Ground of UCC28180 can only be connected to negative terminal of PFC Capacitor, cannot be connected to Source of MOSFET.

Could you confirm, I saw the Ground of UCC28180 is connected to Source of MOSFET.

BR,

Yunsheng

0 kalyanraj Durairaj over 5 years ago in reply to Yunsheng Qu

Intellectual 270 points

hi, Yunsheng

yes, Ground of UCC28180 is connected to Source of MOSFET. As per the schematic ,capacitor negative,mosfet's source terminal and UCC28180 gnd are interconnected right?

controller ground is connected to single node with the power circuit (ie, source of mosfet).

Are you telling, there should be a two separate connection from output capacitor to controller ground and mosfet's source terminal?

Regards,

Kalyan

0 Yunsheng Qu over 5 years ago in reply to kalyanraj Durairaj

TI__Genius 9790 points

Hi, Kalyan

The total schematic looks fine to me. I still consider it as layout issue.

You can cut off all of the connection from Ground of UCC28180 and power Ground first. And connect Ground of UCC28180 to capacitor negative.

Regards,

Yunsheng

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TIDA-00443: AC INPUT CURRENT DISTORTION