TPS61221: ORing circuit (LTC4412) with two inputs 3.3V (battery) and 5V (from USB input) followed by TPS61221.

venkatesh sujanimuk

Prodigy 110 points

Part Number: TPS61221
Other Parts Discussed in Thread: TPS63031, TPS61220

Hi,

am using diode ORing circuit before TPS61221.

so TPS61221 has input either 3.3V (battery) or 5V(USB).

is it ok to operate TPS61221 with USB voltage? do you see any potential risk in the circuit below?

any recommendations? or reference design when operated with USB voltage? o/p needed is constant 3.3V

over 4 years ago

0 venkatesh sujanimuk over 4 years ago

Prodigy 110 points

0 Brigitte over 4 years ago in reply to venkatesh sujanimuk

TI__Guru 59825 points

Hello venkatesh,

It seems that there were problems with the attachment. Please attach again.

In general the device is able to handle up to 5.5V, so I do not expect issues with a USB supply as long as it fulfills the USB spec.

0 venkatesh sujanimuk over 4 years ago in reply to Brigitte

Prodigy 110 points

Hi,

i need output of 3.3V. and WEBENCH POWER DESIGNER does not allow me to give input as 5V.

but the datasheet says that input range is 0.7 to 5.5V. please clarify.

Regards,

Venkatesh

0 venkatesh sujanimuk over 4 years ago in reply to venkatesh sujanimuk

Prodigy 110 points

Hi,

can you please resolve the issue faster, so that we can quickly find the alternate solution as we are in final phase of our project release.

0 Jasper Li over 4 years ago

TI__Mastermind 46905 points

Hello venkatesh,

as the input voltage could be lower or higher than VOUT, you need to a buck-boost converter. the TLV61221 can't work.

what is the output current from 3.3V output? I would suggest a device.

0 venkatesh sujanimuk over 4 years ago in reply to Jasper Li

Prodigy 110 points

I need 50mA (max). please suggest the device

0 Jasper Li over 4 years ago in reply to venkatesh sujanimuk

TI__Mastermind 46905 points

Hi,

you could have a look at TPS63031.

0 venkatesh sujanimuk over 4 years ago in reply to Jasper Li

Prodigy 110 points

Hi,

this is VSON package. is there any package with similar features?

note that am operating with 2AA cell batteries.

0 Jasper Li over 4 years ago in reply to venkatesh sujanimuk

TI__Mastermind 46905 points

Hi,

what is the issue with this package? this device support downs to 1.8V input voltage, which is good enough for 2AA battery

0 venkatesh sujanimuk over 4 years ago in reply to venkatesh sujanimuk

Prodigy 110 points

Hi,

VSON package will increase the cost of PCB. that is the problem.

Regards,
Venkatesh

0 Jasper Li over 4 years ago in reply to venkatesh sujanimuk

TI__Mastermind 46905 points

unfortunately, the kind of device only have SON, QFN and BGA package. i'm the first time to know that such a package increasing the PCB cost.

we can change the power structure.

1. remove the LTC device

2. find a buck converter to generate 3.4V

3. use TPS61220 to generate 3.2V.

4. connect buck converter and TPS61220 output together.

if the 3.4V output presents, the TPS61220 would stop switching. if the 3.4V remove, the TPS61220 switches and regulate the output to 3.2V.

Power management

Power management forum

TPS61221: ORing circuit (LTC4412) with two inputs 3.3V (battery) and 5V (from USB input) followed by TPS61221.