BQ29707 MRK F5 does not set DOUT LOW at 0.1V on V-, but oscilates at 35.6 Hz = NOK.

Peter Kristensen

BQ29707 MRK F5 does not set DOUT LOW at 0.1V on V-, but oscilates at 35.6 Hz = NOK.

Thus current limit is above 2Amps at 0.05+0.02 Ohms, Rsense + RFET. FET is CSD85302L.

COUT is LOW at -0.1V on V- =OK.

Over/Under voltage 2.8 to 4.28V is OK.

Please investigate and return to me asap, thanks.

Vish Nadarajah over 7 years ago

you need a resistance of ~ 2.2K from V- to PACK- as per the d/s

Peter Kristensen over 7 years ago in reply to Vish Nadarajah

Hi Vish Nadarajah.

I replied to this one some days ago, but now it is lost:
I do have 2K on the V- pin:

Vish Nadarajah over 7 years ago in reply to Peter Kristensen

Hi Peter,

After reviewing the schematics, the in-ability to pull-down the gate ( on-->Off) may be attributing to the gate oscillating. Hence, recommend

using ~5M from Gate to Source for the DSG and GHG FET. There is mention of the on pp21 section 10.2.2, but not drawn on the schematics.

Peter Kristensen over 7 years ago in reply to Vish Nadarajah

Hi Vish. The 5 MOhm on the gates does the trick. I wish that I had known this sooner. Thanks. BR. Peter

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