MP2790 Partial discharge fault

Battery Management
1

I’m attempting to put an MP2790 into discharge mode. A summary of the registers:

  • FET_SRC is set for register control
  • FET_CFG is simple, though I see the same behaviour in direct mode
  • I start with ACTIVE_CTRL having all FETs off, later attempting 3 (charge + discharge FETs on)
  • STBY_PFET_EN = 1
  • STBY_STATE_EN = 0 due to some current limitations on our board
  • PROTECT_IN_SAFE_CFG = 0
  • I do not use plugin detection
  • ALERT_POL = 1
  • DSG_SOFTON_EN = 1
  • INT_ALERT_CTRL = 1
  • Most interrupts and faults are enabled

There’s a lot more (that I can provide on request).

The current behaviour is that the I2C bus to the chip is functioning fine, xAlert is functioning basically fine; but after I set ACTIVE_CTRL to attempt to get both the charge and discharge FETs enabled, only one set enables and the other stays disabled. This is confirmed when I check the power status, where I’m only at NORMAL A, and the FET status where CHG_DRV is 1 but DSG_DRV is 0.

I assume I’m encountering this scenario:

If only one FET driver is off due to a fault, the state is maintained.

I’ve checked all of the following locations for fault bits:

  • 01 power status
  • 02 standby status
  • 0E watchdog status
  • 11 FET status
  • 20 OC status
  • 27 SC status
  • cell overvolt, cell undervolt, cell mismatch, cell dead
  • every bit in interrupt 0 and interrupt 1

The BM doesn’t tell me why it’s only half-enabled. How can I figure this out, and how can I fix it so that I get into Normal B?

2

Hello Greg,

Apologies for the delayed response. For this request, I have contacted the FAE and FSE contacts local to your region for more direct support. You should expect them to contact you soon regarding the MP2790 in discharge mode.

Best,

Krishan

3

That was 26 days ago. I’ve not heard anything, sales reps don’t pick up the phone or answer emails, the general phone line does not respond on the operator or support extensions.

Is MPS still in business? It seems not.

4

Hello again,

I’m glad you reached back. This is true, 26 days is certainly way too long to wait for a response here.

We’ve been going through a bit of a transitory period but are indeed still in business. I will push these contacts to email you.

Best,

Krishan

5

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