UCC29002: Load sharing controller

sathyapal reddy

Part Number: UCC29002

Tool/software:

Hello Team,

I am using UCC29002 LOAD share IC for my converter,the output load current is 8.33A,The problem is when change the load current from full load to lower load that is till 1A the load sharing is proper in terms of DC rms current but when observed the load current waveform ,it is DC current which is proper till 5A but when i reduce the load current below the 5A the current pattern is noisy but the DC rms current measured is equally shared among the two converters,the gain set is 100,and sense resistor is 3mohm,even when i increased the sense resistor value or the gain there is no change in the behaviour.could you help me to fix the issue i have attached the current waveforms captured at different load currents for your reference12V Variant paralleing current waveforms.docx

4 months ago

0 Ning Tan 4 months ago

TI__Genius 12795 points

Can you share the schematic here?

0 sathyapal reddy 4 months ago in reply to Ning Tan

Prodigy 30 points

Hi Ning Tan

Please find attached screen shot of my schematic

Parallel circuit.docx

The gain is 100 and sense resistor used is 3 milli ohm,my full load current is 8.33A and output voltage is 12V nominal.

0 Ulrich Goerke 4 months ago in reply to sathyapal reddy

TI__Mastermind 40580 points

Hello Sathyapal,

I believe that the instability in load-sharing seen for current < 5A may be due to a few different factors.

1. LS bus filter cap C60 maybe introducing time delay. A cap on the LS signal is not recommended. Please remove C60.
2. The GND return for U5 and components associated with U5 should connect to -OUTPUT at the output connector, not to VOUT-.
3. The 3.3kR value of R24 to VOUT+ will drop ~10V with Ivdd current of 3mA, which is typical, so U5 will not function.
Reduce R24 value to 1kR or 470R to provide U5 with enough voltage and current to function.
4. Value for C33 and C50 on EAO output (5.7uF total) seems rather low for load share. Ceao is typically higher.
Use the Excel design tool (if you have not already done so) to determine the correct design:
https://www.ti.com/tool/download/SLUC684

Regards,
Ulrich

0 sathyapal reddy 4 months ago in reply to Ulrich Goerke

Prodigy 30 points

Hi Ulrich,

Thank you for the response, we have many queries regarding this load share controller IC functionality, Last year we had teams call regarding the same.

we would like to connect with you through short teams meet at your convenient time. I can share the meeting invite.

Please propose your convenient date and time.

Regards

Sathyapal

Eaton

0 Ning Tan 4 months ago in reply to sathyapal reddy

TI__Genius 12795 points

Can you please connect with our local FAE to arrange a meeting?

Thanks

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UCC29002: Load sharing controller