BQ24620: Abnormal HIDRV and LODRV Outputs

Alex K16

Part Number: BQ24620

Hi,

I am trying to troubleshoot a charger board designed to replicate the BQ24620EVM with nearly 100% commonality in components.

The board seems to be engaging but we are getting some strange signal problems on the HIDRV and LODRV pins.

I am attaching the captured data for two similar configurations.

The configuration A is using 0.05Ohm sense resistor, 100K-84K VISET divider and 700K-100K VFB divider.

The configuration A is using 0.05Ohm sense resistor, 100K-98K VISET divider and 700K-100K VFB divider.

We expected 1.5A current from the configuration A, but we are getting only 1.25A.

We expected 1.65A current from the configuration B, but we are getting only 1.10A.

Thanks a lot for your help,

AlexCaptured Data.zip

over 5 years ago

0 Kedar Manishankar over 5 years ago

TI__Mastermind 24075 points

Hi Alex,

This is very useful information. Can you also share your schematic so I can analyze?

0 Alex K16 over 5 years ago in reply to Kedar Manishankar

Intellectual 300 points

Hi Kedar,

I appreciate you getting back to me very much.

Here is the schematic. Please keep in mind that we changed the sense resistor during our latest testing from the original 0.01 Ohms to 0.05 Ohms and reconfigured the voltage dividers accordingly.

Thanks,

Alex

0 Alex K16 over 5 years ago in reply to Alex K16

Intellectual 300 points

One part that is present on the EVM board but not on ours the 4.7 Ohm resistor between the BTST and D1.

I am not sure if this can cause the types of problems that we are observing.

Alex

0 Kedar Manishankar over 5 years ago in reply to Alex K16

TI__Mastermind 24075 points

Hi Alex,

the 4.7ohm resistor limits the current, when REGN charged the BTST cap through the REGN diode, whenever the LSFET is on. This would not cause the issues we are seeing. Since the other post contains lots of waveforms, let us consolidate this thread with that one, and continue the discussion there.

0 Alex K16 over 5 years ago in reply to Kedar Manishankar

Intellectual 300 points

Hi Carlo,

Thanks for clarification.

Since this issue is now discussed offline, I am going to mark it solved.

Thanks again,

Alex

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BQ24620: Abnormal HIDRV and LODRV Outputs