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TWL6032: TWL6032

Venkat Dronamraju
Prodigy 200 points
Part Number: TWL6032
Other Parts Discussed in Thread: TPS80032

Hi,

We are working on an legacy product that uses OMAP 4470 and PMIC TWL 6032 (A2B4). The battery charging is cutting off at 45 Deg C instead of 40 Deg C. We are trying to analyze code and circuit to make changes and have following questions.

Questions:

  1. How is register GPADC_TRIM 17 and GPADC_TRIM18 are configured. Looking at the data sheet (SWCU095B_TWL6032_ES1v1_ES1v2 page 266), it seems is a read register and configured based on VREF voltage. But not able to figure out how to modify the threshold.
  2. Are GPADC_TRIM17 and 18 Pre-programmed or OEM can modify?
  3. While measuring VREF in circuit, it seems to be 1.25V. So is GPADC_VREF (B11), internally supplied by PMIC or user configurable?  Can you please share details around it.
  4. Can you please share Internal mechanism of PMIC around Battery Charging control via temperature.

Thanks in advance!

  • 0
    TI__Genius 17380 points

    Hello,

    I want to confirm you have the full datasheet? It was under NDA so the version online seems to just be short version. 

    If not, I'll try to get you a copy through the sales team. For short term, the TPS80032 datasheet is the same part and I will reference that: https://www.ti.com/lit/gpn/tps80032 

    With that, I'll jump in:

    1. How is register GPADC_TRIM 17 and GPADC_TRIM18 are configured. Looking at the data sheet (SWCU095B_TWL6032_ES1v1_ES1v2 page 266), it seems is a read register and configured based on VREF voltage. But not able to figure out how to modify the threshold. 
      1. [KL] These values are read out by your software and used to calibrate how it interprets the voltages read from the GPADC. There are equations in the datasheet for how to use them
    2. Are GPADC_TRIM17 and 18 Pre-programmed or OEM can modify?
      1. [KL] Hopefully above clarifies that these are values provided to the user from the testing of the unit to allow you to calibrate your system
    3. While measuring VREF in circuit, it seems to be 1.25V. So is GPADC_VREF (B11), internally supplied by PMIC or user configurable?  Can you please share details around it.
      1. [KL] PMIC generates GPADC_VREF for use with the GPADC, it does not have any user settings. It can support up to 200 uA.
    4. Can you please share Internal mechanism of PMIC around Battery Charging control via temperature.
      1. [KL] It is in section 4.9.5 Battery Temperature Monitoring of TWL6032 DM, section 5.9.5 in the TPS80032 datasheet

  • 0 in reply to Kevin LaRosa
    Prodigy 200 points

    Hi Kevin,

    Thanks so much for responding. I will review and respond.

    Can you please share TWL6032 full datasheet under NDA?

    Regards,
    Venkat

  • 0 in reply to Venkat Dronamraju
    TI__Genius 17380 points

    Hi Venkat, 

    It should be sent over now, let me know if the information is not sufficient. There is not much support left for these old OMAP PMICs but we will do our best to help.

  • 0 in reply to Venkat Dronamraju
    Prodigy 200 points

    Hi Kevin,

    Rob (Robert Eschbach) shared TWL6032 full datasheet with us. Thanks again!

    Above you referenced about equations to use TRIM 17 and TRIM 18. I apologize for some reason, I am not able to see equations. In the below diagram, we have not populated Rx and Ry in the circuit. So basically based on TRIM 17 and TRIM 18 setting, we are cutting off Battery at 45 Deg C. We are trying to cut off Battery at 40 Deg C now, however not able to make changes to TRIM 17 or 18 since they are read register. Please advice if we are missing something.

  • 0 in reply to Venkat Dronamraju
    Prodigy 200 points

    Hi Kevin,

    Further reviewing TWL6032 datasheet Table 4.3, Page 116 (GPADC Calibration parameters), it shows calibration other than TRIM 17 and 18. We follow the same procedure in code. So it seems there is no calibration procedure stated.

    Page 39 (Table 3-11 Battery Charger electrical characteristic), shows Low and High threshold voltages ranging (OTP bits under Battery Temperature measurements) from 0.25v (0.2*Vref(1.25v)) to 1.125v (0.9*Vref(1.25)). So if we have to cut off temperature at 40 Deg C. What should be the values entered in this registers and how to write them. (since these are read registers)

    Regards,

    Venkat

  • 0 in reply to Venkat Dronamraju
    TI__Genius 17380 points

    Hi Venkat,

    My apologies, it's been a long time since a TWL6032 question came up. I was mixing up RATIO_TLO / RATIO_THI with the generic GPADC trim (section 4.12.4 Calibration).

    RATIO_TLO and RATIO_THI are fixed by OTP. I checked and it looks like all released TWL6032 variants have TLO = 0.6 and THI = 0.2.

    So, the goal is to create a resistor divider network with your chosen NTC resistor to get the right settings.

    I searched my computer and found the attached spreadsheet. I think PMIC and resistors are pretty consistent, I'd be more concerned as to whether the characteristics of the NTC have drifted or changed. If you changed NTC, you may have to adjust the resistor divider.

    Let me know if this helps!

    TWL6032_Thermistor_CalculationExample.xlsx

  • 0 in reply to Kevin LaRosa
    Prodigy 200 points

    Dear Kevin,

    Thanks a Million !! Your response is spot to understand the current issue. This is 7 year old product so was trying to reverse engineer the design and your spreadsheet and response kind of explains everything.

    I just a few questions. Promise this will be mostly likely last questions :)

    We are using NTC  NCP15XH103F03RC (R (25DegC)= 10000, B=3380)

    1. In the current design (0 to 45 Deg C cut off), we are not using Rx and Ry. Based on spreadsheet, when i plug Thermistor numbers. It won't give Rx and Ry numbers and probably makes sense for not using resistors.  Do you agree?

    2. Now when i plug (0 to 40 DegC) in the spreadsheet , still it does not give Rx/Ry numbers. So does that mean we don't have a combination resistors for 0 to 40Deg C with this NTC ? Let me know your thoughts.  

    3. So if i need to cut off at 40 Deg C. The only option is to change thermistor. Let me know your thoughts.

    Again thanks so much for your time.

    Regards,
    Venkat 

  • 0 in reply to Venkat Dronamraju
    TI__Genius 17380 points

    Hi Venkat,

    1. I don't understand what you mean here. There must be some form of resistor divider to get GPADC_IN1 to be a value related to the NTC resistance. If Rx is a short and Ry is floating, then that would be connecting VREF to GPADC_IN1. Can you help clarify?

    2. Correct, the particular NTC cannot be linearized in the desired range. You could shift it up or down, but not make it any tighter.

    3. Correct

  • 0 in reply to Kevin LaRosa
    Prodigy 200 points

    Hi Kevin,

    Thanks so much for responding.

    Clarification about Point 1:

    We did not use Rx and Ry. We have provision but not populated. Please find details of schematic in the word file attached.  Let me know if my understanding is correct.

    Again really appreciate your time :)

    Regards,

    VenkatPortion of the Circuit pertaining to Battery Temperature.docx

  • 0 in reply to Kevin LaRosa
    Prodigy 200 points

    Hi Kevin,

    Thanks so much for responding.

    Clarification about Point 1:

    We did not use Rx and Ry. We have provision but not populated. Please find details of schematic in the word file attached.  Let me know if my understanding is correct.

    Again really appreciate your time :)

    Regards,

    Venkat6518.Portion of the Circuit pertaining to Battery Temperature.docx

  • 0 in reply to Venkat Dronamraju
    TI__Genius 17380 points

    HI Venkat,

    Thank you for the clarification.

    Looking at the schematic, R147 is your Rx. It connects VREF to ADCIN1. Using Rx  = 19.1kΩ and Ry = 10000000000 (open circuit), the calculator comes up with -0.33 C to 45.80 C, so perfectly aligned with your expectation.

    From there, your previous analysis is still correct - there isn't an Rx / Ry combo that provides 0 to 40 with that thermistor.

  • 0 in reply to Venkat Dronamraju
    Prodigy 200 points

    Hi Kevin,

    Hope you are doing well!

    When you get chance, please review my document. If all makes sense, we can close the case.

    Again thanks so much for all your responses and sharing spreadsheet.

    Regards,
    Venkat

  • 0 in reply to Venkat Dronamraju
    Prodigy 200 points

    Hi Kevin,

    Thanks so much for responding. Somehow over looked your previous  response.

    Again thanks so much :)

    Regards,

    Venkat

  • 0 in reply to Venkat Dronamraju
    TI__Genius 17380 points

    It's confusing when the response ends up on the next "page" of E2E, I've had it happen to me several times.

    No problem, good luck with your project!