bq25896 OTG and Register Setting Question?

Jerry Chu

Genius 4915 points

Other Parts Discussed in Thread: BQ25896

Hi,

I have some question about bq25896. Would you help it? Thanks!

1. What's bq25896 REG03 bit7 function?

2. Why bq25896 start the OTG function, it shows two steps?

over 11 years ago

0 SamW2000 over 11 years ago

TI__Intellectual 1910 points

1. Please see the attachment for BATLOAD_EN function

2. The OTG startup consists of two stages. During the first stage, Q1 is enabled is power by battery. The next stage, the converter starts switching and boost starts.

0 SamW2000 over 11 years ago in reply to SamW2000

TI__Intellectual 1910 points

1856.BATLOAD_EN.pdf

0 Jerry Chu over 11 years ago in reply to SamW2000

Genius 4915 points

Hi Sam,

It seems a function for battery detection. But why bq2589x needs it? And for the document, ther are only detect Vbat>4V? Thanks!

0 SamW2000 over 11 years ago in reply to Jerry Chu

TI__Intellectual 1910 points

The BOATLOAD_EN purpose is for host driven battery detection. Some customer prefer to disable charge which improve transient performance when battery is not detected.
When attached battery < full, it will start to charge autonomously and not detection is needed. When battery is not attached, the charger can report charge done due to parasitic capacitance and can be misinterpreted as fully charged.

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bq25896 OTG and Register Setting Question?