TPS65132S: About operation of disable status

Hi Teritama,

Our expert is currently out of office. He will reply to you later when back to office. Thanks for your understanding.

Best Regards,

Steven

Hi Teritama,

No worry about the reverse current, a synchronous boost converter is integrated in this IC which will prevent the reverse current when IC is off.

BR

Patrick

Hi Patrik-san, Steven-san,

Thank you for reply. I understand that no worry about reverce currrent.

The customer is concerned OUTN voltage increased when 1.8V start-up. I think it is no worry too for this device operation because there no protection about low voltage on OUTN side.

Is my understanding no problem?

Best regards,

teritama

Hi Teritama,

Yes, I don't think it will cause impact. But may I have a look at the schematic? I am trying to understand how the 1.8V IO voltage raises up the +/-5V rail.

BR

Patrick

Hi Patrik-san,

I overlooked that +0.8V is over the absolute rating on OUTN pin. It is required that prevent to not increase over 0.3V by diodes or etc.

I would suggested to use some extertnal protection. 

> But may I have a look at the schematic? I am trying to understand how the 1.8V IO voltage raises up the +/-5V rail.
⇒The customer guesses this is caused by power roop on internal circuit of OLED. And they said that it is difficult that prevent this power roop.
　I think it is required to prevent by external protection on OUTN line.

　Please your opinion.

Best regrds,

teritama

Hi Teritama,

When the IC is enabled, will the +0.8V disappear? If so, it has no impact.

BR

Patrick

Hi Patrick-san,

Yes, +0.8V on OUTN line start to decrease after the device enable.

In my understanding, we should avoid over absolute rating always. In this case is this no problem?

Best regards,

teritama

Hi Teritama,

Understood the situation, I will check this spec internally and turn back to you later.

BR

Patrick

Hi Patrick-san,

Thank you for your supporting. Are there any update about above?

Best regards,

teritama

Hi Teritama,

It is recommended not to have this overvoltage. So could you please check if it is able to isolate the IO voltage before EN the IC? If you could send me the schematic, I can help to provide if there is a workaround.

BR

Patrick

Hi Patrick-san,

Thank you for check. I would answer to the customer that it is need to impriment some measure to prevent VOUTN increase over +0.3V.

>So could you please check if it is able to isolate the IO voltage before EN the IC? 
⇒Does this means isorate between VOUTN line and OLED supply?

Best regards,

teritama

Hi Patrick-san,

I see. I would suggest to disconnect the load before power up TPS65132S to the customer.

When I recieve additional question from he customer. Please disscus about this with us.

Best regards,

teritama