TPS61162D Vin is separated from power stage

tateo yamashiro

Other Parts Discussed in Thread: TPS61162, TPS61163A

Hi,

My customer has question about TPS61162D.
Could you tell me about questoin?

[Question]
My customer want to use TPS61162D for Dual Li-ion application.
So my customer consider the design separating Vin from power stage.
Can the TPS61162D be used with higher input voltage as long as the control circuitry is kept separate from the power stage?
Please see figure below.

Best Regards,
tateo

over 8 years ago

0 Angelos Tsiros over 8 years ago

TI__Intellectual 2140 points

I believe you can do this. In some architectures, the output voltage (VSW in this case) and VIN are used to control the switching loop. I don't believe this is the case here, since the TPS61162 employees a traditional current mode control. You can try it and verify that he switching frequency remains at 1.2MHz.

0 Angelos Tsiros over 8 years ago in reply to Angelos Tsiros

TI__Intellectual 2140 points

Hi,

I have verified that this will work fine for this device. At high Vbat, the boost may enter PFM operation but that's normal. The switching frequency and LED current accuracy are not affected.

0 tateo yamashiro over 8 years ago in reply to Angelos Tsiros

Guru 10890 points

Hi,

My customer also want to use TPS61163A.
Can the device be used in same circuit?

Best Regards,
tateo

0 Angelos Tsiros over 8 years ago in reply to tateo yamashiro

TI__Intellectual 2140 points

Yes, the TPS61163A will behave the same as the TPS61162D.

Regards,

Angelos

0 tateo yamashiro over 8 years ago in reply to Angelos Tsiros

Guru 10890 points

I appreciate for your kind support.
My customer has one more question about TPS61163A.

Q: Is there any start up and shutdown sequence requirement in this case?

Best Regards,
tateo

0 Angelos Tsiros over 8 years ago in reply to tateo yamashiro

TI__Intellectual 2140 points

The recommended startup sequence is: Apply VIN first, then VBAT, then enable the device.

The recommended shutdown sequence is: Disable the device, remove VBAT, then VIN.

Regards,

Angelos Tsiros

0 tateo yamashiro over 8 years ago in reply to Angelos Tsiros

Guru 10890 points

Thank you for your help.

My customer want to input VIN and VBAT at the same time.
Because he want to reduce the bom count.
If VIN and VBAT is inputted at the same time, what is concern?

Best Regards,
tateo

0 Angelos Tsiros over 8 years ago in reply to tateo yamashiro

TI__Intellectual 2140 points

There is no problem applying or removing VIN and VBAT at the same time. The concern would be if VBAT is applied while VIN is not. There is a chance that damage will occur to the device in this case because the control circuits are powered from VIN and if VIN is not present the state of some internal circuits may be random.

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TPS61162D Vin is separated from power stage