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BQ24773: BQ24773 ACDRV not going to trigger ACFET & RBFET

Rahul Surawase48
Expert 2395 points
Part Number: BQ24773

Hello TI, 
               ACDRV is not going to trigger ACFET and RBFET, which i already explain in this thread https://e2e.ti.com/support/power-management/f/196/p/844044/3122867#3122867

We are looking to clarify some doubts of BQ24773 which I mention below,

1. as share image1, BQ24773 of CMSRC+5.9V meaning ..? what is required voltage on 5 volts input adapter across the CMSRC ..?

Image1


2. Requirement of ACDRV Charge Pump, this affect the ACDRV 
3.as share image2, ACDET require more than 2.4 V ..?
4.what is the require condition and voltage of ACOVP I/P's..? 

Image2

5. What is the minimum voltage and current require to BQ24773 ..?
6.There is any standard connector require to identify the I/P supply source ..?
7. why not ACDRV change the voltage level and drive the ACFET & RBFET, how to findout the root-cause of this issue ..?
8. as per the other forum discussion, we observe everyone is suffering from this problem and not find any resolve thread of this issues ...? 
9. There is any defect in this part ...?
 

I need to figure out the issue as early as possible because we already spend too much time to resolve the issues, thanks for your valuable responses

Thanks and Regards,
Rahul Surawase 

  • 0
    Expert 2395 points

    Hello TI, 
                 Also check ACDET > 2.4 but there is no change in ACDRV Voltage 
    we replace R1=390K & R2=470K for ACDET= 2.7V
    If ACDET is rquired to set >2.4 volts as per the datasheet 
    In the TI BQ24773 Evaluation reference design there is ACDET set to 0.65V...??

    Thanks & Regards,
    Rahul Surawase  

  • 0 in reply to Rahul Surawase48
    TI__Mastermind 25800 points

    Hey Rahul,

    1. That is the reference voltage for the ACDRV voltage. ACDRV is meant to be 5.9-6V above the CMSRC voltage.

    2. The charge pump is referenced to the CMSRC voltage. You need to meet the ACOK conditions in order for the charge pump to be active.

    3. Yes, ACDET requires more than 2.4V to operate the converter. It must be >0.6V in order to have the IC active.

    4. The voltage of the ACOVP protection is found in the EC table, section INPUT OVERVOLTAGE COMPARATOR (ACOVP).

    5. The important voltage thresholds for the BQ24773 to operate are found in the EC table, under sections: ACOK COMPARATOR, UNDER VOLTAGE LOCKOUT COMPARATOR (UVLO), SLEEP COMPARATOR (VCC_BAT), OPERATING CONDITIONS and the section 7.3 Recommended Operating Conditions

    6. No standard connector. Just something to get the input voltage to VCC and ACDET, and the rest of the charger, and obviously ground. 

    7. I would confirm you are following the description as mentioned in section 8.3.3 System Power Selection regarding the ACFET's Cgs and Cgd.

    8. I think we need to look at a startup waveform showing the ACDRV voltage and CMSRC voltage, the VCC voltage, and the SRN voltage. You should overlap the ACDRV voltage and the CMSRC voltage ground point. I would also capture the ACDET voltage with 500mV/div at least to capture the change in the input. 

    9. We can't say that yet. I would also recommend testing using an EVM to verify whether you see this on an EVM as well.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    TI__Mastermind 25800 points

    Hey Rahul,

    I will close this thread and we will communicate about this issue in your other thread about the same issue here:

    https://e2e.ti.com/support/power-management/f/196/t/845274

    Regards,

    Joel H