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BQ24870s ACOC Feature Problem

Moshe Ben gigi
Prodigy 60 points
Other Parts Discussed in Thread: BQ24780S

Hi,

Evalute BQ24780s-EVB trying to test ACOC latch off

We try to test the ACOC protection feature on the BQ24780S-EVB we’ve got a strange behavior  Please Advise ,

BQ24780s Initiated register

  • 0x12  =  0108

  • 0x3B =   C210

  • 0x38 =   0304

  • 0x37 =   1CC0 EN_ACOC, ACOC ICRIT 125%

  • 0x3C =   0254 ICIRIT Threshold  = 110% of Input  Current

  • 0x3D =  8130

  • 0x3A =  0000

  • 0x14 =   0200

  • 0x15 =   3010

  • 0x39 =   0100 (512ma) Discharge Current

  • 0x3F =   0200 (512ma) Input  Current

  • 0xFE =   0040

  • 0xFF =   0030

The PROCHOST indication work O.K, when the external electronic load is above 512ma the PROCHOST is set.

Rising the current load up to 4 Amp cause the ACOC event ACFET/RBFET Turn off and cut the external Power Adapter,

Lower the Current load to 3.5Amp cause ACFET/RBFET  to turn on again No Latch off .

 

Expected result : Input Current Limit (512ma)  * 110% = ICRIT * 125% = ACOC Event @ 700ma ==è ACFET/RBFET is latches off .

 

Please Advise :

 

 How to control the ICRIT  ACFET/RBFET Turn off point ? How to set ACOC protection lower than 4Amp?

Thanks,

Moshe

  • 0
    TI__Guru 56650 points

    ACOC Vacp-acn  range is from 50mV to 190mV. So, the lowest ACOC current could be 5A with 10mohm sense resister. Lower ICRIT may not set ACOC lower than 5A with 10mohm sense resister.

    To get a lower ACOC current, you can increase sense resister.

  • 0 in reply to Wang5577
    Prodigy 60 points
    O.K,
    Please clarify, How dynamically (by software) change ACOC latch off point.

    Let's say I am using sense register of 30mohem -> ACOC will be in the range off 1.6Amp - 6.333Amp.

    - Is ICRIT Threshold bits in register ProchotOption0 Register (0x3CH) can set ACOC latch off point?
    - Is The InputCurrent() register can set the can set ACOC latch ?
    Or it is only control by ACOC Limit bit (REG(0x37)[9] as 125% or 200%.

    Thnaks