TUSB4041I: Device ports running at much reduced speed?!

Hi Karl,

If you disconnect and reconnect the cable between the hub and the host, does it always revert to USB full speed instead of high speed?  Have you tried disabling and re-enabling the driver? 

Regards,

JMMN

Hi,

Yes we have tried this and still we get the "this device can perform faster." We check the USB config and descriptors and indeed it states the speed of the Hub as full speed not high speed. Tired on 4 computers running Windows 7. Also tested cable and it is not that.

The IC seems to have had some failure internally that is causing this problem.

I dont have an EEProm attached to the device so it should be running default values, all the 4 ports work fine just all at FS not HS.

Hi Karl,

You said this problem occurred after the hub was working properly for awhile? It does sound like the device may have been damaged. An electrical overstress on the USB_DP/USB_DM lines on the upstream port could possibly be responsible, but you would need to return the unit to TI for failure analysis to confirm that.

Regards,
JMMN

Hi JMMN,

Thanks for your replies, yes it does seem something has damaged the port somehow, I did not add any protection external components to the upstream port traces, Maybe I should do this?

I can upload my schematics if it helps?

Thanks

Yes, please upload your schematics.

drive.google.com/.../view

This is the USB info on the hub.

Hi Karl,

Yes, you can add an ESD protection device like the TPD2E001 to protect the upstream USB_DP/USB_DM lines in future designs. Please note that without receiving the failing device for failure analysis, I can't determine if any pins have been damaged through ESD or not.

Where and how would be best to send it?

We have ordered a replacement unit now, was my schematics looking ok?

The system is an Astronomy Camera controller. Takes measurements of temp,humidity,rpm and controls the Peltier cooler. The usb hub is great feature to support the various other equipment used whilst imaging.

Many thanks

Hi Karl,

I'll contact you off the forum to provide information on the return.

Regards,
JMMN

I didnt get a message from you that I could see?

Were my schematics looking good to your expert eye?

One thing, If I revise the design I will add the protection diode array TPD2E001 to the design. Do I need to use the series resistor as stated in the application note?

Many Thanks,

Karl

Hi Karl,

I was out of office yesterday, you should get a message today.

So the series resistor in the TPD2E001 datasheet appears to be a throwback to USB 1.1 where series resistors in DP/DM path were much more common, it is not a required value. Also, there are newer ESD protection options like TPD2E1B06 or TPD2E2U06 available as well. Your schematic looks fine functionally. If you wanted to get an official USB logo, you would need to implement the overcurrent reporting, drop the capacitance on the upstream VBUS, and use an EEPROM to report the non-removable ports, but the hub should work as currently designed without those changes.

Regards,
JMMN

Thanks for your reply,

I will do another revision of the design and implement one of the protection devices among other small changes to the pub. This is not a production unit and I am a hobbyist with no formal qualifications in design but I'm pleased I did an good job of the design.

Thanks for your help