UCC25600: Inquiry whether the circuit's output specification is implemented

Eunseok Kang

Part Number: UCC25600

Hello, TI expert.

I am testing the LLC block by applying UCC25600, TL103WAIDR.

Spec is shown in the table below. (Max 360V / 3A output)

There is a situation where CC/CV control is not possible during LLC operation, so it is during debugging but cannot be resolved.

So, I want to check whether the current LLC circuit is suitable for satisfying the output specifications.

Please check if the attached LLC circuit diagram can implement the output specifications.

Please tell us if there is a part where you need to modify the inductance, resonance cap, and circuit diagram RC values to satisfy the corresponding output specifications.

The current LLC specifications are as follows:

1) Lp(1st inductance)

Trans(T302, T303) : 36uH (In the circuit diagram, two transformers are connected in series, Lp: 72uH)

2) Lr(Leakage inductance) :

Trans(T302, T303): 7uH (In the circuit diagram, two transformers are connected in series, Lr: 14uH)

Leakage Trans(T301) : 10uH

3) Number of turns

Trans(T302, T303) : 1st 11turns / 2nd 30turns (In the circuit diagram, the first is 22 turns in series and the second is 30 turns in parallel.)

4) Resonance cap : 94nF

Thank you.

(LLC)_Charger_SCH_REV01_210510.pdf

over 4 years ago

0 Yunsheng Qu over 4 years ago

TI__Genius 9790 points

Hi，Eunseok

You posted the same topic in below thread, and I provided comment to you. The power stage has no problem, the root cause should be related to feedback loop design, So I asked you to check the waveform of OC pin? The waveform is needed, so please help to get it.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/996870/ucc25600-adjustment-of-transformer-specifications-to-reduce-llc-output-current-ripple

Yunsheng

0 Eunseok Kang over 4 years ago in reply to Yunsheng Qu

Prodigy 60 points

Hello, Yunsheng

I attach the UCC25600 OC pin waveform.

During operation, the symptom is not CC/CV control, and the LLC FET bursts when a load is applied.

When the initial input is applied and when the load is applied, the OC PIN voltage rises and falls significantly, but the waveform could not be

measured due to the above-described FET death phenomenon.

The waveform below is the measured waveform with load applied when CC/CV control is not performed.

please check. Thank you.

0 Yunsheng Qu over 4 years ago in reply to Eunseok Kang

TI__Genius 9790 points

Hi，Eunseok

The OC waveform is quite normal without load. If the resonant current is oscillated with CV/CC load, you need to check the reference of CC loop and output voltage of CC loop and CV loop.

1. If the CC_Vref is oscillated, the issue is related to CC_Vref

2. if the CC_Vref is stable, the issue is related to compensator of CC loop or CV loop.

Yunsheng

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UCC25600: Inquiry whether the circuit's output specification is implemented