UCC28950 Isink Isource temperature charactaristics

Kuramochi Tadahiko

Guru 28715 points

Other Parts Discussed in Thread: UCC28950

Hi,

The problem is occurred on my customer's circuit of UCC28950.

The problems seems to depend on the temperature characteristics of Isink/Isource.

So my customer requests the data of Isink/Isource temperature charactaristics on -20℃~80℃.

Could you give me these data?

Please let me know if you have any questions.

Regards,

Kuramochi

over 9 years ago

0 Peter Meaney over 9 years ago

TI__Mastermind 31580 points

Hi Tadahiko-san,

Can you explain more about the problem and can you tell me what pin of the IC you need the data for?

Regards

Peter

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

Hi, Meaney-san,

Thank you for your response.

>Can you explain more about the problem?
I'm making sure.

>Can you tell me what pin of the IC you need the data for?
My customer would like to know the sink/source current by the error amplifier.
So I guess that it's the compensation-pin.

Regards,
Kuramochi

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

Hi Meaney-san,

I confirmed the detail of problem.

Please refer the attached file.

4370.UCC28950 problem.xls

Regards,

Kuramochi

0 Peter Meaney over 9 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 31580 points

Hi Kuramochi-san,

I need to get some feedback from the design team, hopefully I will get a response by tomorrow.

Regards

Peter

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

Hi Meaney-san,
Thank you for your quick response!
I wait for your contact.

Regards,
Kuramochi

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

Hi Meaney-san,

How about this situation?

Regards,

Kuramochi

0 Peter Meaney over 9 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 31580 points

Hi Kuramochi-san,

I may need to clarify the question to the IC designer, however we have three days of internal training this week so sorry for the delay.

But the current capability on the pin should be within the values on the datasheet. I need to clarify if there is no risk of damage to the COMP pin with this control arrangement.

Regards

Peter

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

How about this situation?

0 Kuramochi Tadahiko over 9 years ago in reply to Kuramochi Tadahiko

Guru 28715 points

How about this situation?

0 Peter Meaney over 9 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 31580 points

Hi Tadahiko-san,

I aologise for not answering your question, the sink and source capability of the comp pin is specified in the data sheet as 5.75mA and -8mA respectively.

At high temperature the CTR of the opto-coupler will drop and it will also drop over the lifetime of the device as it ages. I suggest that the customer design with 100% margin in the design to account for the aging with additional margin for operation at high temperature.

Regards

Peter

0 Kuramochi Tadahiko over 9 years ago in reply to Peter Meaney

Guru 28715 points

Peter-san,

Thank you for your advise.
I inform my customer.

Could you show me the plot of temperature characteristics on -20℃~80℃ such as following?

Regards,
Kuramochi

Power management

Power management forum

UCC28950 Isink Isource temperature charactaristics