TPS61220 - Vin > Vout: could damage the part?

Humberto Moreira

Other Parts Discussed in Thread: TPS61220, TPS63030

I'm usign TPS61220 on a 2-battery cell powered device. So, input voltage is 3.3V throug 1.8V. I need an output of 2.8V, 60mA.

Since the part will be working with Vin > Vout for a while (2.8V through 3.3V), I expect no regulation above the output. My question, is there any risk with the part being damaged during that period?

Is there any alternative part/solution to the above?

Hubert

over 12 years ago

0 Michael Green over 12 years ago

TI__Genius 16870 points

If your input voltage ranges between 1.8V and 3.3V while the desired output voltage is 2.8V and Iout = 60mA, then you will need a buck-boost converter. Take a look at the TPS63030. Its input voltage range is 1.8V to 5.5V and 2.8Vout the converter should easily be able to deliver the desired 60mA.

0 Humberto Moreira over 12 years ago in reply to Michael Green

Prodigy 20 points

Thanks Michael.

Let's assume I can not change the part, my question is about the behavior and/or risk I'm taking. Is my application totally wrong?

0 Paolo Reggio over 12 years ago in reply to Humberto Moreira

Intellectual 930 points

Hi Humberto.

In my opinion it depends only from which is the maximum allowable recharging voltage of your battery...

If it is 2.8V, yes, your application is completely wrong because you will not have recharging current control when your input voltage exceed 2.8V (neglecting diode losses).

I'd prefer to look for a buck-boost/flyback solution...

Bye

Paolo

0 Chris Glaser over 12 years ago

TI__Guru**** 150650 points

Please see this design note on the behavior when Vin > Vout: http://e2e.ti.com/support/power_management/non-isolated_dcdc/w/design_notes/tps61220-preformance-with-vin-near-vout.aspx

Operating the part that way won't normally damage it.

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TPS61220 - Vin > Vout: could damage the part?