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TPS65910 / BOOT MODE decision timing

Guru 20090 points
Other Parts Discussed in Thread: TPS65910A, TPS65910
Hello,
 
I would like to know about BOOT MODE decistion timing.
Please see the attached file as my questions.
 
 
Please let me know about timing of VCC7, VRTC and PWRHOLD.
We would like to operate BOOT MODE 10.
BOOT1 is connected to VRTC and BOOT0 is connected to GND.
PWRHOLD and VCC7 are asserted High at about the same time.
<Questions>
1: If PWRHOLD will be asserted High before VCC input or VRTC powered up, will be
     BOOT MODE 00 ?  Or will be BOOT MODE 10?
2: Please let me know the decision timing of BOOT mode.(Is it PWRHOLD rising edge ?)
3: Please let me know the time specification between VCC7 and VRTC  (above ① time)
4: If we should assert PWRHOLD after VRTC, please let me know the time specification
     between VRTC and PWRHOLD (above ② time).
 
Best Regards,
Ryuji Asaka
  • Hi Rayuji-san,

    This is not a normal use case for the device. PWRHOLD is not meant to pullup beore VRTC of VCC&. function of the PWRHOLD is to keep the device on. Which means after device turns on PWRHOLD must be pulled up within 1 sec of device turing on to keep device active.

     

  • Hello Puneet san,
     
    Thank you for the reply.
    I understood that we can't pull up PWRHOLD before VRTC.
    Please let me know below.
     
    -Q1: BOOT MODE decision timing
    Is it PWRHOLD rising edge ?
     
    -Q2: timimg characteristics of  VCC7 to VRTC
    Could you please let me know the time from VCC7 to VRTC ?
    I can't find any specification of its.
     
    -Q3: timing characteristics of VRTC to PWRHOLD "H"
    We use PWRHOLD as POWER ON enable event.
    Since we can't pull up PWRHOLD before VRTC and VCC, when can we pull up PWRHOLD for POWER ON enable ?
    Is it 1sec ?
     
     
    Best Regards,
    Ryuji Asaka
  • 1. Boot mode is decided as soon as device gets power.

    2. It is hard to specify that as board paracits will play big factor here.

    3. you cant pullup the PWRHOLD before VCC but before VRTC you can as long as you dont have any load on VRTC.

     

  • Hello Puneet san,
     
    Thank for the reply.
    Could you please let me know about below for understanging BOOT MODE timing ?
     
    (1)my understanding of BOOT MODE
    BOOT MODE is decided as soon as device gets power. (i.e. OFF STATE)
    And actual BOOT MODE is decided by conditions of BOOT1 pin and BOOT0 pin when the Power On Enabled occurred.
    Therefore, if we would like to use PWRHOLD as "POWER ON Enable"  and  boot the TPS65910A as BOOTMODE=10,
    We must assert PWRHOLD to "H" after deciding BOOT1="H and BOOT0="L".
    Is my understanding correct ?

    (2) PWRHOLD before deciding BOOTMODE=10
    When we input "H" to BOOT1 after having input "H" to PWRHOLD, the TPS65910 boot in BOOTMODE=00 continuously?
     
    (3) same timing of PWRHOLD and BOOT1
    Could you please let me know the BOOT MODE when we toggled "H" to BOOT1 and PWRHOLD at the same time ?
     
     
    Best Regards,
    Ryuji Asaka
  • Ryuji-san,

    Our local FAE will be in touch with you on this topic, we had internal discussion with him .

    Also, I would highly recommend to get one EVM from ti.com . It would be very helpful to get these queris clarified with EVM as it is a stand alone EVM of the device . This will help with much better understanding of device.

    Hope this helps!

  • Hello Puneet san,
     
    Thank you for your reply.
    Sorry for bothering you.
    I already request the EVM however I can't get yet.
    However our customer request those questions.
     
    Best Regards,
    Ryuji Asaka