TPS2115: Using TPS2115 to switch Power between AC and USB

Mahesh Hooli

Part Number: TPS2115
Other Parts Discussed in Thread: TPS65217, ,

Hello,

In our power architecture we have TPS65217 and TPS2115 .

We use TPS65217 to switch between AC and USB but the load is only AM355x processor and DDR.

But for the peripherals ( as load current is higher) we use TPS2115 Power mux to switch between AC and USB. Is there any risk in this power scheme? . Can we get same real time switching from TPS2115 as we can get from TPS65217?

Thanks,

Mahesh

over 9 years ago

0 Darwin Fernandez over 9 years ago

TI__Mastermind 41800 points

Hi Mahesh,

What voltages are your AC and USB rails? Also, what is the expected load's output current?

0 Mahesh Hooli over 9 years ago in reply to Darwin Fernandez

Intellectual 740 points

Hi Darwin,

Both AC and USB voltages are 5V. Load current is approx 1A.

VDD_5V -> is from AC wall

USB_DC -> from USB connector

Either one or both of the power can be present and we would like to have preference given to VDD_5V. The schematics is shown below.

0 Darwin Fernandez over 9 years ago in reply to Mahesh Hooli

TI__Mastermind 41800 points

Hi Mahesh,

Under these conditions, I see no issues with using TPS2115A.
Note we recommend the A-version as it has less switchover droop as shown in Figure 6 of its datasheet.

0 Mahesh Hooli over 9 years ago in reply to Darwin Fernandez

Intellectual 740 points

Thank you Darwin for the review in quick time.

0 Mahesh Hooli over 9 years ago in reply to Mahesh Hooli

Intellectual 740 points

Hello,

We plan to use TPS2115A in auto switch mode and we need IN1 as a priority input.
Our schematics is similar to Figure 14 of datasheet.
Datasheet says "circuit will connect IN1 to OUT until the voltage at IN1 falls below a user-specified value" .
Wondering how to set "user-specified value" for IN1?

0 Darwin Fernandez over 9 years ago in reply to Mahesh Hooli

TI__Mastermind 41800 points

Hi Mahesh,

Per the truth table, OUT will be VIN1 as long as it is a higher voltage than VIN2.

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TPS2115: Using TPS2115 to switch Power between AC and USB