TPS54260 Low Dropout improvement and internal Boot Charge function

Kenneth Du

Genius 14295 points

Other Parts Discussed in Thread: TPS54260

Hi,

I have noticed that I could improve TPS54260 low dropout improvement by the following solutions:

Solution a. Diode tied from input to BOOT

Solution b. External voltage at BOOT

My questions are:

1. What is the function of internal "Boot Charge"? Is it a LDO? What's the difference between "Boot Charge" and solution a?

2. Is there a maximum external voltage limit when using solution b?

Looking forward to your reply!

Thanks!

Kenneth Du

0 JohnTucker over 9 years ago

The absolute maximum BOOT voltage is 8 V above the PH pin voltage. For a detailed discussiion of drop out see this document:

0 Kenneth Du over 9 years ago in reply to JohnTucker

Hi, John,

Thank you very much!

Can I think like this: a higher BOOT voltage than 8 V above PH will break down the internal MOSFET driver circuit?

0 JohnTucker over 9 years ago in reply to Kenneth Du

Yes it will most likely damage the IC.

0 Kenneth Du over 9 years ago in reply to JohnTucker

Hi, John,

I have another question with TPS54260.

According to the datasheet, if RT=200kohm,fSW=450kHz~720kHz, and comparing with 581kHz, the tolerance is about 22.5%.

So if I use RT=412kohm, what is the tolerance? Is it still 22.5%?

Thanks.

Kenneth

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