BQ25570: Polarity of PFET between VSTOR and System load

Christian Grau28

Part Number: BQ25570
Other Parts Discussed in Thread: BQ25505,

Dear All

The datasheet reccomend to add an external PFET between VSTOR and the System load (Chapter 7.2.4). Could you please let me know, what side the source of the PFET is supposed to be?

The Signal nVB_SEC_ON could be used... do I Need to generate it by inverting VBAT_OK or is it available from somewhere?

Thank you for your Support

Chris

over 6 years ago

0 Raheem over 6 years ago

TI__Mastermind 21590 points

Hello,

I'm going to assume you mean the BQ25505 since that is the device that has VBAT_SEC. The drain of the first PFET should be connected to VSTOR and the drain of the second PFET should be connected to the load. The source of both PFET are connected together. The signal /VB_SEC_ON should be connected to the gate as shown in the datasheet.

Regards,

Raheem

0 Christian Grau28 over 6 years ago in reply to Raheem

Intellectual 375 points

Dear Raheem

Thank you for your reply. I guess the datasheet for BQ22570 was copied from BQ25505... If you search for VBAT_SEC in BQ25570 datasheet you'll find it three times. But there is no Explanation, what this Signal is.

I will have to check if the PMOS Thing also applies to BQ22570 or if that's just Information that went astray.

Kind regards

Chris

0 Raheem over 6 years ago in reply to Christian Grau28

TI__Mastermind 21590 points

Hello,

The datasheet will be fixed.

Regards,

Raheem

Power management

Power management forum

BQ25570: Polarity of PFET between VSTOR and System load