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BQ24392: USB2.0 and BG1.2 certification/test

Nariaki Ogasawara
Intellectual 1215 points
Part Number: BQ24392

Hi team,
 
 The customer is trying USB2.0 certification and BG1.2 compliance test.  
 But D+/- Eye pattern (High Speed) is NG and BG1.2 compliance test is some items was failed.
 He checked signal quality by simulation, it had no issue.
 The impedance of D+/- is 90+/-9 ohm. 

 What should I check?
 If I send the schematic, pattern and BC1.2 test result, can you check these? 

  

Regards,
Ogasawara

  • 0
    TI__Guru 60870 points
    Hello Ogasawara-san,

    The BC1.2 failures are expected:

    BQ24392 can detect more than just BCv1.2 compliant chargers but achieving this extra functionality requires a proprietary algorithm other than what is defined in the BCv1.2 specification
    •The BQ24392 proprietary detection algorithm fails the BC1.2 compliance test at the following steps:
    –7.3 step 6 requires a 14.25 kΩ - 24.8 kΩ pull down resistor from DM to GND
    •The voltage divider created by the BQ24392’s internal resistance from DM to GND and the BCv1.2 tester creates a voltage outside what the BC1.2 tester is expecting
    –7.5 step 16 requires a voltage source 0.5 V to 0.7 V on DP after a DCP has been detected by a PD
    •BQ24392 algorithm doesn’t apply this minimum 0.5 V voltage source for the duration of a DCP attachment
    –7.6 step 19 requires a voltage source 0.5 V to 0.7 V on DM and a current sink on DP
    •BQ24392 doesn’t implement this architecture
    –7.15 requires the PD to apply a 0.6 V Source on DP to indicate the SDP is detected as a dead battery
    •BQ24392 algorithm doesn’t apply the 0.6 V source on DP if a SDP is detected with a dead battery

    The eye diagram failure is not expected, it looks like there is a lot of jitter in the signal. The BQ24392 is not a redriver, retimer so it will not improve the signa lapplied to it. How close is the signal source to the BQ24392?

    Regards,
    JMMN
  • 0 in reply to JMMN
    TI__Intellectual 1215 points
    Hi JMMN,

    Thank you for your response.
    The customer has concern about layout and line impedance.
    When I send to Schismatic, layout and BG1.2 test result, can you check them?

    Regards
    Ogasawara
  • 0 in reply to Nariaki Ogasawara
    TI__Guru 60870 points
    Sure, accept my friend request and send to me privately if your customer does not wish to post on a public forum.

    Regards,
    JMMN
  • 0 in reply to JMMN
    TI__Intellectual 1215 points

    Hi JMMN,

     Thank you for your advice. Eye Pattern issue will be fixed.
     I understand BQ29392 does not pass the BG1.2, could you tell me the number that the test does not pass?

    S/N

    Test Parameter

    BQ24392

    1

    BC 1.2 Implement Check

    Supported or Not support

    2

    Bypass Capacitance Test

     

    3

    B-UUT Initial Power-up Test

     

    4

    Data Contact Detect Test_ With Current Source

     

    5

    Data Contact Detect Test_No Current Source

     

    6

    DCP Detection Test

     

    7

    CDP Detection Test

     

    8

    SDP Detection Test

     

    9

    Dead Battery Provision Test

     

    10

    Common Mode Test- High Speed

     

     Regards,
    Ogasawara

  • 0 in reply to Nariaki Ogasawara
    TI__Intellectual 1215 points

    Hi JMMN,

     I have one more question.
     Is BQ24392 compliant with BC 1. 2?

    Regards,
    Ogasawara

  • 0 in reply to Nariaki Ogasawara
    TI__Guru 60870 points
    Hello Ogasawara-san,

    The BQ24392 is compatible with the BC 1.2 specification, but it cannot pass the USB BC 1.2 compliance testing:

    TI uses a proprietary algorithm that is different from the BC1.2 specified test procedure you list above which gives our part an advantage to be able to detect additional chargers other than the BC1.2 compliant chargers. Our part can correctly detect BC1.2 chargers as well as chargers that are not BC1.2 compliant so we can use this device for additional applications.


    Regards,
    JMMN