• State Resolved
  • Locked Locked
  • Replies 10 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 4445 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.

BQ24800: About ACOK

Norimichi Hosogai
Prodigy 230 points

Part Number: BQ24800

[About chapter 8.3.1.2]

About the following description,

>An external resistor divider attenuates the adapter voltage before it goes to ACDET. If the battery boost mode is
>not used, the adapter detect threshold must be programmed to a value greater than the maximum battery
>voltage, but lower than the minimum allowed adapter voltage.

(1). Why should be set the voltage before it goes to ACDET threshold is greater than the maximum battery voltage when battery boost mode is not used? 

　　Does above note  mean that the voltage goes around as shown below at remove the Adapter?　Please teach the reason.

(2). And also, Why should be set the voltage before it goes to ACDET threshold is greater than the system regulation voltage when the battery only boost mode is used? 

>If the battery only boost mode is used, the adapter
>detect threshold must instead be programmed to a value that is higher than the system regulation voltage
>programmed in REG0x38[5] and REG0x3E.

(3). During ACOK deglitch time 150 ms, chatting is ignore , is it right?
      And ACOK will be output when ACOK condition(VACDET>2.4V, VUVLO<VCC<VACOC, VCC-CSRN>VSLEEP) is continued 150ms or more, is it right?

     We would like to confirm for just to make sure.

[About Electrical charactrisc]

(4). Please teach the spec of Satuation Voltage @drain current  and spec of leakage current like a below PROCHOT spec.

We must be check the above for design around A COM port.

Best regards,

  • 0
    Prodigy 230 points

    I'm sorry again, I added question and modified comment.

    [About chapter 8.3.1.2]

    About the following description,

    >An external resistor divider attenuates the adapter voltage before it goes to ACDET. If the battery boost mode is
    >not used, the adapter detect threshold must be programmed to a value greater than the maximum battery
    >voltage, but lower than the minimum allowed adapter voltage.

    (1). Why should be set the adapter detect threshold must be programmed to a value greater than the maximum battery voltage?Please teach the reason.

    Does above note mean that the voltage goes around as below diagram at remove the Adapter?　
    (For example, if condition of adapter detect threshold is 16V, and Battery voltage is 17V, even if remove the adapter, ACOK is still keeped by battery voltage?)

    (2). About the description "the adapter detect threshold must be programmed to a value greater than the maximum battery voltage",  this threshold is Falling(H->L) Threshold mean? or Rising (L->H) Threshold?

    (3). And also,  Why should be set the adapter detect threshold must be programmed to a value greater than the system regulation voltage when the battery only boost mode is used? 

    >If the battery only boost mode is used, the adapter
    >detect threshold must instead be programmed to a value that is higher than the system regulation voltage
    >programmed in REG0x38[5] and REG0x3E.

    (4). During ACOK deglitch time 150 ms, chatting is ignore , is it right?
          And ACOK will be output when ACOK condition(VACDET>2.4V, VUVLO<VCC<VACOC, VCC-CSRN>VSLEEP) is continued 150ms or more, is it right?

         We would like to confirm for just to make sure.

    [About Electrical charactrisc]

    (5). Please teach the ACOK spec of Satuation Voltage @drain current  and ACOK spec of leakage current like a below PROCHOT spec.

    We must be check the above for design around ACOK port.

    Best regards

  • 0 in reply to Norimichi Hosogai
    TI__Mastermind 41226 points

    1. The voltage goes around the charger like you drew. This is because when Q3 switches on ACDET is exposed to the battery voltage.

    2. This means that that the adapter must be between the maximum battery voltage and the minimum system voltage. Let's say you have max battery voltage of 12 volts and a minimum adapter voltage of 19 volts. Then, ACDET should trigger somewhere in the range of 12 volts to 19 volts.

    3. Because SYS connects to the ACDET voltage divider, the ACOK must be programmed greater than SYS so it doesn't trigger when battery only boost mode is enabled. By doing this, ACOK won't give off a wrong signal.

    4. The device can still communicate over I2C while in deglitch time. The deglitch timer makes sure that ACOK does not trigger multiple times in a period of time. ACOK is only outputted as long as the charger thinks an adapter is detected.

    5. The output Saturation Voltage is the max voltage from PROCHOT when PROCHOT is pulled low. Leakage current is the current that leaks from PROCHOT to GND.

    Regards,
    Ethan Galloway

  • 0 in reply to Ethan Galloway
    Prodigy 230 points

    Thank you for your help.

    >The device can still communicate over I2C while in deglitch time. The deglitch timer makes sure that ACOK does not trigger multiple times in a period of time. >ACOK is only outputted as long as the charger thinks an adapter is detected

    Which is the  ACOK decision point A or B?

    (At deglitch time 150ms)

    Best reagards,

  • 0 in reply to Norimichi Hosogai
    TI__Mastermind 41226 points

    It's A. This can adjusted in the register settings.

  • 0 in reply to Ethan Galloway
    Prodigy 230 points

    Thank you for your reply.

    We would like to confirm some behabior of ACOK and ACDET.

    (1). Is below Figure 1 behabior correct? (Chatting->High)

    ・Is ACOK Low to High and High to Low timing correct? 

     

    (2). Is below Figure 2 behabior correct? (Chatting->Low)

    Is ACOK Low to High and High to Low timing correct?  

    (Even if ACDET level is Low at 150ms from ACDET High trigged , ACOK goes to High little moment as below Figure2? Or ACOK keeps Low?)

    (3). Is below Figure 3 behabior correct? (Chatting continues)

    (Repeat judge, When ACDET High, ACOK to High after 150ms, then when ACDET Low, ACOK to Low immediatry…?　as Figure 3)  

    Best regards,

  • 0 in reply to Norimichi Hosogai
    TI__Mastermind 41226 points

    1. Yes, that is correct.

    2. No, that is not correct. ACOK goes low when the adapter goes low. ACOK will not go high at the end of the deglitch time if it sees the adapter is low.

    3. ACOK will not go high for the first pulse, but it will go high for all the following pulses.

    Keep in mind that the deglitch time provided by a very simple clock. The parts have a wide variation for the clock and we do provide a specification for the deglitch timer.

    Also, generating a signal like question 3 will be difficult in real life because of the high capacitance on the adapter input.

    Also, ACOK will go to a 1.3 second deglitch time by default after the first plug in.

  • 0 in reply to Ethan Galloway
    Prodigy 230 points

    Thank you for your help. I understood almost  of your explanations.

    I would like to confirm the below for just to make sure.

    (1). At below condition, even if ACDET L triggeredd just a very very little moment,
    Does ACOK go Low until next deglitch time?

    (2). Is below diagram behavior correct? 

    Best regards,

  • +1 in reply to Norimichi Hosogai
    TI__Mastermind 41226 points

    1. That behavior is correct.

    2. That is also correct.

  • 0 in reply to Ethan Galloway
    Prodigy 230 points

    I'm sorry. ACOK goes low condition is below?
    Is it correct?

    If invalid any one of following, ACOK goes to low.

    For example,  even if only the above last condition(VCC-VSRN>VSLEEP) is invalid and others are valid, ACOK will be low?

    Best regards,

  • +1 in reply to Norimichi Hosogai
    TI__Mastermind 41226 points

    Norimichi,

    Yes, that is correct.

    Ethan Galloway