UCC28950: comp over 2.8 v What will the gate pulse look like?

NWTkoji

Prodigy 110 points

Part Number: UCC28950

What kind of motion does the IC take when the COMP pin exceeds 2.8 V?

Although it is not using the CS pin, it will be like hiccup mode.

over 6 years ago

0 Colin Gillmor over 6 years ago

TI__Mastermind 25570 points

Hello

If COMP exceeds 2.8V and providing that the CS pin is at less than 2V the controller will run at Dmax.

Regards
Colin

0 NWTkoji over 6 years ago in reply to Colin Gillmor

Prodigy 110 points

I check while watching the waveform. The CS pin was 0V.

What is the cause of repeating the reboot?

0 Colin Gillmor over 6 years ago in reply to NWTkoji

TI__Mastermind 25570 points

Hello

Several things could be responsible and I really could not say without more information.

Can you post your schematic and some 'scope plots. The SS/EN, VCC, COMP, CS, OUTA pins to begin with.

Regards

Colin

0 Colin Gillmor over 6 years ago in reply to Colin Gillmor

TI__Mastermind 25570 points

Hello

Can you post an update with the information I requested above please ?

Regards
Colin

0 NWTkoji over 6 years ago in reply to Colin Gillmor

Prodigy 110 points

I am busy and I do not acquire the waveform, but when I pull up the SS pin through VCC to the resistance, I started driving with maximum duty.

The cs pin is unused and is GND.

0 Colin Gillmor over 6 years ago in reply to NWTkoji

TI__Mastermind 25570 points

Hello

I would expect the controller to run at Dmax when SS is tied high and the CS pin is at 0V.

Please note that the Abs Max rating on the SS/EN pin is Vref+0.4V. If you tie SS/EN to VCC then you may be exceeding this rating - it would depend on the resistance.

I'm going to close this thread - please re-open it or open a new thread if you need any further help.

Regards

Colin

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UCC28950: comp over 2.8 v What will the gate pulse look like?