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BQ76940EVM: uv_trip calculatıon

ZEL?HA KAYGUN
Prodigy 210 points
Part Number: BQ76940EVM
Other Parts Discussed in Thread: BQ76940

Hi;

ı am confiusing about determining uv_trip in bq76940 evm software; in datasheet there is a calculation an example of referance design like above:

 UV_TRIP_FULL = (UV – ADCOFFSET) ÷ ADCGAIN  Remove the upper 2 MSB and lower 4 LSB from the full 14-bit value, retaining only the remaining middle 8 bits. This can be done by shifting the OV_TRIP_FULL and UV_TRIP_FULL binary values 4 bits to the right and removing the upper 2 MSB

from referance design:

The selected UV Threshold is 2.5 V. – Therefore, UV_TRIP should be programmed with 0x1A.

but for 2.5v it seems like 0x96 right?

PS: ADCGAIN = 377 uV/LSB ,ADCOFFSET=44mV

Regards..

  • 0
    TI__Expert 7455 points

    Hi,

    Apologies, it seems there is a miscalculation in the datasheet. The value you stated is correct. We are currently working on updating the datasheet. 

  • 0 in reply to Shawn Hinkle
    Prodigy 210 points

    hi;

    thanks for your reply.I have another question about fets.

    as you see in pic; the fets combined each other like dual connection ı think it is suppose  to increasing the capacity of carrying current.But when charging begins they are not working at the same time.I removed one of them then the second one was on . how they work together at the same time ?

    additionally;The charge current must be 15A or smaller according to referance design but when charge begins the current limited around 6A .Could it be related to the condition of the fet sutiation?Or should it change  the sense resistor ?

    Thanks in advance.

  • 0 in reply to ZEL?HA KAYGUN
    TI__Expert 7455 points

    Hi,

    Could you please start a new thread for this new topic?