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TWL6030 battery charging from USB questions

GregoireGentil
Expert 2330 points
Other Parts Discussed in Thread: TWL6030, TWL6032

Hello,

I would like to have a TWL6030 charging a 1-cell battery through USB. The three following cases should be supported:
* system working with battery alone present
* system working with USB alone plugged
* system working and battery charging if needed with battery present and USB plugged.

The following schematics would be used. I have a couple of questions:

Q1. Temperature is not a problem in this device. Which values for R25 and R26 should I use to have a voltage divider around GPADC_IN1 so that TWL6030 considers that it's in the valid temperature range to charge the battery in hardware more. The datasheet says "read the application note" but the application doesn't provide values or formula to calculate such values.

I'm confused by the circuitry around GPADC_IN0 in order to have the battery detected correctly with the three cases mentioned above. The TWL6030 datasheet and battery application note are a little bit confusing and there is no clear example (or I didn't understand the provided example...).

Many thanks in advance for any reply.

  • 0
    TI__Intellectual 2190 points

    Hi Gregoire,

    I'll take a look into this.

    For your first question, I see that it is possible to prevent the gating of charging with an EPROM bit. Is this a possibility for your particular application?

    Regards,

    Ben

  • 0 in reply to Benjamin Mak
    Expert 2330 points

    Benjamin,

    Yes, I would appreciate if I can get some feed-back. A few additional comments:

    - the TWL6030 datasheet SWCS045B.pdf has a table "external components" at the end, but the components are not referenced explicitly. The thermistor is referenced but I don't want to use this and it's hard to understand which other resistors the table is referencing to.

    - the Blaze-tablet schematics has so much circuitry with so many ESD, power, protection, over-protection components that it's difficult to read the divider values, if any. I'm not complaining here against those schematics, just saying that it's difficult to read.

    - The eprom would be an option (I see that 20V is needed) but I really want to do something simple, "working out of the box". From my understanding, if I have the right divider, I should be good to go.

    Grégoire

  • 0 in reply to GregoireGentil
    TI__Intellectual 2190 points

    Hi Gregoire,

    I just wanted to reach out to give you an update on the situation.

    I'm trying to get a hold of a calculation sheet that you can use to determine the resistor values in the divider network. I will let you know as soon as I get it.

     

    Thanks!

    Ben

  • 0 in reply to Benjamin Mak
    TI__Intellectual 2190 points

    Hi Gregoire,

    The TWL6030 does not actually support the situation where the USB is plugged in alone. The TWL6030 is designed for software control charging without a power path.

    The device you will want to look at is the TWL6032 if you want it to support all 3 situations.

    What is the EPROM configuration that you currently have set up? The EPROM is inherent in the device, so there will be no overhead on your part if it is used. Depending on your configuration, the battery temp detection can be disabled. We also need to know what is programmed into the EPROM to determine the values for those external resistors.

    Under the section "Battery Presence Detector" in the datasheet, it mentions that the presence of the battery can be detected with GPADC_IN0. This pin will require a pulldown resistor to ground. If the battery pack is removed , the GPADC_IN0 line will rise above the threshold and the TWL6030 will recognize that the battery has been removed.

    Thanks,

    Ben

  • 0 in reply to Benjamin Mak
    TI__Intellectual 2190 points

    I solved this offline, but I wanted to add a little bit to this discussion for anyone that might come across it.

    The TWL6030B107CMRR has charge gating based on battery temperatures disabled per this table.

    Thanks,

    Ben