• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 853 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ24195: VSYSTEM of BQ24195

michael YANG
Prodigy 195 points
Part Number: BQ24195

Hi Team ,

Regarding the datasheet of BQ24195 , when the battery is lower than 3.5V , the Vsys will be 3.5V+150mv .

I guess the 150mv is used to ensuer there is enough Dropout  in LDO mode .

but ,  in fact ,the Vsys is 3.5V while not 3.5+0.15=3.65V ,could you please help to clarify it ? thanks! 

  • 0
    TI__Intellectual 960 points
    Michael,

    Under the conditions of VBAT < 3.5 volts, the VSYS is at the level of 3.5 volts + 150mV.

    Could you provide some more specifics so I can try to reproduce your issue?

    1. Is this on the bq24195 EVM?
    2. What are the current register settings for your device? Specifically, I'm interested in the REG01. If the min system voltage is set lower here that could explain why your voltage is lower than you expect.
    3. What is the VBUS voltage?
    4. What is the System load?
    5. What is VBAT?
    6. What is ILIM (lower of register setting and resistor setting)

    Regards,

    Parker
  • 0 in reply to ParkerHolloway
    Prodigy 195 points
    Hi Parker,
    thanks for your reply . please refer follows for your information.

    1. Is this on the bq24195 EVM?
    R. No, it is base on our PCB.

    2. What are the current register settings for your device? Specifically, I'm interested in the REG01. If the min system voltage is set lower here that could explain why your voltage is lower than you expect.

    R. the current (CC setting) is 2 A in current setting registor.

    3. What is the VBUS voltage?
    R. Vbus is 5V during test .

    4. What is the System load?
    R. No system load is connected .

    5. What is VBAT?
    R.Vbat=4.2V

    6. What is ILIM (lower of register setting and resistor setting)
    R. it is 3A.


    After changing the CC current to 1A , the Vsystem rising up to 3.5+0.15=3.65V .
    And the BQ24195 will always work well even the CC current back to 2A.
    Great thanks for your support in advance.


    BR
    Michael.Yang
  • 0 in reply to michael YANG
    TI__Intellectual 960 points
    Hi Michael,

    Can you post the contents of registers 0, 1, 8, and 9? I want to see if there is a fault condition, or if you are in VINDPM or IINDPM at this state.

    Do you have a current sink or battery connected at the BAT pin?

    Is charge enabled on the device?

    Is BATFET turned off?

    When you say that the bq24195 will always work well after changing the current to 1A and back to 2A, do you mean that the VSYS is at the correct 3.5+0.15 as expected?

    Parker
  • 0 in reply to ParkerHolloway
    Prodigy 195 points

    Hi Parker,
    Great thanks for your reply .
    after check with our guys , this issue is caused by wrong max input current setting , the real max input current is 2A while not 3A .
    The max input current limit should be more than CC and the max system load .
    After change it , it work well .