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BQ25601: bq25601 Vsys volatege at NVDC , from NVDC to DPM to Supplement

Katsuhiro Kanao
Intellectual 1710 points
Part Number: BQ25601

HI

 

Would you please let me know the VSYS voltage at DPM mode, when Mode is changing NVDC -> DPM -> Supplement

Is my undersangdin corect ? Would you plese let me know VSYS at DPM mode ?

 

1. Battery voltage < VSYS_MIN

At charging ( NVDC)   VSYS= VSYS_MIN + 180mV

( page 22 of data sheet, “system is typically 180 mV above the minimum system voltage setting” )

At DPM mode         VSYS = VBAT+ VDPM_BAT_TRACK  

                       ( page 38, Sets VINDPM to track BAT voltage. Actual VINDPM is higher of register value and VBAT + VDPM_BAT_TRACK

At Supplement         VSYS = VBAT (by BAT FET=ON)

2. Battery voltage <>VSYS_MIN

At charging(NVDC)   VSYS= VBAT (At oage 22, "As the battery voltage rises above the minimum system voltage, BATFET is fully on")

At DPM mode         VSYS = ? 

At Supplement       VSYS = VBAT (by BAT FET=ON)

 

 

 3. Fig16 of page 23

*Is this condition Battery voltage < VSYS_MIN?

*What is 3.6V ?

*Is VSYS_MIN 3.4V ?

* What is 3.18V ?

best regards K.Kanao

  • 0
    TI__Expert 5590 points
    Please see my response below:

    Would you please let me know the VSYS voltage at DPM mode, when Mode is changing NVDC -> DPM -> Supplement

    Is my undersangdin corect ? Would you plese let me know VSYS at DPM mode ?



    1. Battery voltage < VSYS_MIN

    At charging ( NVDC) VSYS = VSYS_MIN + 180mV

    A: Yes, correct.

    At DPM mode VSYS = VBAT+ VDPM_BAT_TRACK

    ( page 38, Sets VINDPM to track BAT voltage. Actual VINDPM is higher of register value and VBAT + VDPM_BAT_TRACK

    A: In VINDPM, the input voltage is regulated. But VSYS is still 3.68V.

    At Supplement VSYS = VBAT (by BAT FET=ON)

    A: Yes

    2. Battery voltage >VSYS_MIN

    At charging(NVDC) VSYS= VBAT (At oage 22, "As the battery voltage rises above the minimum system voltage, BATFET is fully on")

    A: Yes

    At DPM mode VSYS = ?

    A: same as above. VINDPM has no impact to VSYS

    At Supplement VSYS = VBAT (by BAT FET=ON)

    A: YES


    3. Fig16 of page 23

    *Is this condition Battery voltage < VSYS_MIN?

    *What is 3.6V ?

    A: VSYS_MIN

    *Is VSYS_MIN 3.4V ?

    A: Should be VSYS_MIN = 3.6V

    * What is 3.18V ?
    A: When battery is discharging, VSYS is lower than VBAT
  • 0 in reply to Hong Mao
    TI__Intellectual 1710 points
    Thnak you for reply.

    Here is another question.
    Supplement Mode is described as ( data sheet 8.3.7.10, Page 2) "When the system voltage falls 180 mV (VBAT > VSYSMin) .........below the battery voltage,the BATFET turns on ......"

    Accoding to page 22, "As the battery voltage rises above the minimum system voltage, BATFET is fully on").

    So BAT FET is already turn before supplement mode.
    Is Supplement Mode description wrong ?

    best regards K.Kanao
  • 0 in reply to Katsuhiro Kanao
    TI__Intellectual 1710 points
    Would you please reply for my question ?

    best regards K.Kanao
  • 0 in reply to Katsuhiro Kanao
    TI__Expert 5590 points
    Sorry to get back to you late. In charge mode, BATFET is fully on, which is correct. When supplement condition is met, the BATFET is controlled in supplement mode. BATFET control is handed over to supplement mode. During the transition, BATFET keeps on.
  • 0 in reply to Hong Mao
    TI__Intellectual 1710 points
    Hi
    Thank you for your support.
    1. At Supplement, system voltage falls 180mv(VBAT>VSYSMIN) below the battery votlage.
    Is this condtion that the Battery is full charged (BAT FET is off afeter charge termination ) only ?
    2. BATFETenable ( Exit Shipping Mode), P27, 8.3.10.43
    I coudl not finde BATFET Enalbe register, is this measn BATFET_DIS register ?
    3. OVPFET
    In data sheet,OVPFET is typo.
    But there is a OVP register in EVM soft at Reg 05 bit 6 . This is posisible to set 0 or 1.
    Is this should be set as default ( 0) ?

    best regards K.Kanao
  • 0 in reply to Katsuhiro Kanao
    TI__Expert 5590 points
    1. At Supplement, system voltage falls 180mv(VBAT>VSYSMIN) below the battery votlage.
    Is this condtion that the Battery is full charged (BAT FET is off afeter charge termination ) only ?

    The condition is not just for BATFET off. BATFET is bidirectional even it is not in supplement mode.

    2. BATFETenable ( Exit Shipping Mode), P27, 8.3.10.43
    I coudl not finde BATFET Enalbe register, is this measn BATFET_DIS register ?

    Yes

    3. OVPFET
    In data sheet,OVPFET is typo.
    But there is a OVP register in EVM soft at Reg 05 bit 6 . This is posisible to set 0 or 1.
    Is this should be set as default ( 0) ?

    Keep as default.