TPS2546: different device with different discharge operation from S0 to S5

Ann_Lien

Part Number: TPS2546

Hi expert,

My customer has a question about discharge operation for TPS2546.

They tested 3 conditions and result is shown as below. Mode change = CDP to DCP_auto (CTL1= H->L, CTL2/CTL3/ILIM_SEL/EN= H)

no device on connector -> VBUS drop for 2.X seconds
connect keyboard or mouse -> VBUS will keep 5V, no drop.
connect cell phone -> VBUS drop for 2.X seconds.

May we know why is there different operation with the same setting? Thanks a lot!!

Best regards,

Ann Lien

over 7 years ago

0 Chuck Branch over 7 years ago

TI__Mastermind 34131 points

In case 1, no load is detected, so the device will discharge the bus. ~2 seconds is able the time it should take to discharge the bus.
In case 2, there is a load present and the Sleep-Mode Charging detects the mouse this and keeps the bus alive
In case 3, the data lines are disconnected and the phone must be disconnecting the load based the cable disconnect from the data lines being disconnected by the TPS2546. The behavior here is based on the Phone, not the TPS2546.

0 Kenneth Lu over 7 years ago in reply to Chuck Branch

Prodigy 20 points

Hi expert,

This is PEGA EE Kenneth, Could you help to tell more detail about case 2?
Is mouse trigger TPS2546 into the Sleep-Mode Charging ?
What conditions will make TPS2546 into Sleep-Mode ?

What's the behavior of VBUS If we connect with usb flash?

Thanks
Kenneth

0 Kenneth Lu over 7 years ago

Prodigy 20 points

Hi expert,

This is PEGA EE Kenneth, Could you help to tell more detail for case 2?
Is mouse trigger TPS2546 into the Sleep-Mode Charging?
What conditions will make TPS2546 into the Sleep-Mode?

What's the behavior of VBUS discharge if we connect with USB flash?
Mode change = CDP to DCP_auto (CTL1= H->L, CTL2/CTL3/ILIM_SEL/EN= H)

Thanks
Kenneth

0 Chuck Branch over 7 years ago in reply to Kenneth Lu

TI__Mastermind 34131 points

Case 2 is very well described in section 8.3.6.1 of the datasheet.

The VBUS output will be discharged on a mode change from 1111 to 0111

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TPS2546: different device with different discharge operation from S0 to S5