UCD3138: UCD3138 LLC firmware Burst Mode

metin

Part Number: UCD3138

Hello everyone,

I'm developing my application using LLC Firmware. I faced an unknown “on” condition on DPWM2A signal while burst mode is active. This condition is occured inside my hiccup mode which has transition to idle state, wait a while and go to regulated state.

If I disable burst mode on DPWM3A, this unknown on situation disappeared. I believe that this is because DPWM2A falling edge is derived from DPWM3A falling edge wih EDGEGEN feature but if DPWM3A signal is not valid (because of BURST Mode) DPWM2A is not falling to 0.

Is that comment true? what will be the side effects if I changed DPWM3 burst enable bit to disable. (DPWM3 burst mode is enabled by default on original firmware)

Best,

over 6 years ago

0 Yitzhak Bolurian over 6 years ago

TI__Mastermind 18370 points

On some versions of UCD the signals generated by EDGEGEN do not go down when bust or fault condition occur.
Which exact part number are you working with?

0 metin over 6 years ago in reply to Yitzhak Bolurian

Prodigy 90 points

Hi Yitzhak,

I have UCD3138CC64EVM-030 with UCD3138RGC

Best,

Metin

0 Yitzhak Bolurian over 6 years ago in reply to metin

TI__Mastermind 18370 points

Hi Metin,

The behavior you observed is expected in UCD3138RGC.
Most applications can tolerate this kind of behavior.
I hope that is your case as well.

Regards,

0 metin over 6 years ago in reply to Yitzhak Bolurian

Prodigy 90 points

Hi Yitzhak

Thanks for your reply.

For TI's LLC application, this kind of behaviour can be fixed with disabling DPWM3 Burst mode off. Because this causes DPWM2A to go up for a time while burst condition is active. Is that make sense to you? But they implemented not to disable burst mode. I wonder why - because I'm a little bit new to this controller and I don't want to change anything without understanding the underlying reason.

metin

0 Yitzhak Bolurian over 6 years ago in reply to metin

TI__Mastermind 18370 points

Are you working on full bridge LLC? Because I do not remember that half bridge LLC uses EDGEGEN.
In any case, you do may change the code. I am not sure why this was not implemented.
We might have used a UCD3138A that does not have this issue with EDGEGEN.

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UCD3138: UCD3138 LLC firmware Burst Mode