power path transistor, single FET, diod

Stephane JUHEL

Other Parts Discussed in Thread: BQ24172, BQ24170

Hello,

For the bq24170/bq24172, there is differents appilcation circuit, which use 2 FET (power path transistor), single FET or Diod .

What are the conditions to use 2FET, single FET or Diod ?

Do you have application note which explain the better choice ?

Futhermore, what are the reasons to use or not a Zener diod between REGN and SW pin ? This diod is indicate optional.

Thanks and Best Regards,

Stéphane

over 13 years ago

0 Tahar Allag over 13 years ago

TI__Mastermind 32400 points

Hi Stephane,

In order to provide you with clear answer, which figures are you referring to in ht e first question. If you are referring to figure 1 to 4 in the datasheet, the title in the figures explains the difference between each application circuit.

The diode from REGN to BTST is to generate high-side driver bootstrap voltage .

-Tahar

0 Stephane JUHEL over 13 years ago in reply to Tahar Allag

Intellectual 320 points

Hi Tahar,

Yes I am referring to the figure 1 to 4. I understand the 2 NMOS are necessary when the battery are removable.

I will probably design according the figure 2 (bq24172), but with 5V input.

Thanks,Stéphane

0 Tahar Allag over 13 years ago in reply to Stephane JUHEL

TI__Mastermind 32400 points

Hi Stephane,

Figure 2 has battery learn function.

-Tahar

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power path transistor, single FET, diod