BQ24392: Fail the BC1.2 Test

Hi Wu,

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


Regards,
JMMN