TUSB2077

Krishnamoorthy Baskaran

Other Parts Discussed in Thread: TPS2546, TPS2511, TUSB2077A, TUSB8040A1, TUSB8040A, TUSB8040, LM339

Our design is to required to support 2 modes of operations
1) SYNC mobile devices with the connected computer.
2) Provide high current charging function 2.1A to mobile devices when not connected to computer.

The main points of our circuit

USB HUB - TUSB2077

nBUSPWR, nGANGED connected to VCC3
MODE connected to Ground
XTL1, XTL2 = 6 MHz Crystal
nPWRON inverted using transistor and connected to TPS2546(EN pin)

Charging Port Controller and Power - TPS2546

Power by external 5DC power source.

Problem : TUSB2077 is disabled when DM0,DP0 not connected to Computer. The nPWRON is not asserted. Due to this TPS2546 disabled and not able to provide the charging current to connected devices.

Will this problem be solved if we change the Crystal to an Oscillator ? (Refer page 2 of datasheet " osc cannot be stopped while power is on, their use prohibits low-power suspend)

If not, advice how to solve this problem

over 11 years ago

0 Elias Villegas M. over 11 years ago

TI__Guru* 76130 points

Hello,

No, the nPWRON signals does not function as a "chip select", the nPWRON are controlled by the Hub upon an instruction sent by the USB Host, the hub itself cannot assert and de-assert the nPWRON without the USB Host intervention.

There are power switches designed to stand alone USB charging applications like the TPS2511

Regards.

0 Karuna over 11 years ago in reply to Elias Villegas M.

Prodigy 30 points

Hi Elias

We can not use the TPS2511 since it does not support USB communication.

This is the reason we have used TPS2546, as it support both HIGH-Current charging and USB communication.

As explained above, the product require to be able to SYNC and provide HIGH-Current for charging. [Note - do not need to support charging when SYNC in progress.]

Do you have any advice on how to use.

0 Elias Villegas M. over 11 years ago in reply to Karuna

TI__Guru* 76130 points

Hello,

The TUSB2077A can't assert/deassert its nPWRON terminals without USB Host connection.

You will need a USB Hub with Battery Charge support, like the TUSB8040A1

http://www.ti.com/product/TUSB8040A1?keyMatch=tusb8040a&tisearch=Search-EN

Regards.

0 Karuna over 11 years ago in reply to Elias Villegas M.

Prodigy 30 points

Hi Elias

Thanks for the feedback. Will review TUSB8040 and get back.

Karuna

0 Krishnamoorthy Baskaran over 10 years ago

Intellectual 270 points

Hi Elias

Need to provide the Charge status LEDs for all 7 ports..Pls advice the solution

If i do status monitor using simple Quad Comparator LM339 will work out. or any other solution

0 Elias Villegas M. over 10 years ago in reply to Krishnamoorthy Baskaran

TI__Guru* 76130 points

Hello,
Sorry, I don't understand the question, the TUSB2077A does not have output for status LEDs.
There should be several ways to implement a status LED, the first thing that I can think of is using the output from the Power management switch that controls VBUS for the downstream ports.
Regards.

Interface

Interface forum

TUSB2077