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BQ25601: Programmable system reset

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Replies: 4

Views: 75

Part Number: BQ25601

Hi,

Have some quick questions on the BQ25601.

1. Is tQON_RST (min 8s) programmable? This was programmable on BQ25120s.
2. Is it possible to initiate a system reset through software by writing to a register?  
3. Is the tBATFET_RST value (250ms) programmable?
4. Is the tSHIPMODE (1.1s) value programmable?
Thanks.
Hrishi
  • Hello,

    1) This is not programmable on this charger.

    2) What do you mean a system reset? Do you mean to disconnect the BAT rail from the SYS rail as well as the adapter? There is a register bit to disable the BATFET. This can create a reset condition in the battery only mode. When an adapter is present, you can set both the BATFET disable bit I just mentioned AND the HIZ enable bit to disable the converter. 

    3) This is not programmable on this charger.

    4) This is not programmable on this charger.

    Regards,

    Joel H

  • In reply to Joel Hernandez II:

    Hi Joel,

    2) What do you mean a system reset? Do you mean to disconnect the BAT rail from the SYS rail as well as the adapter? There is a register bit to disable the BATFET. This can create a reset condition in the battery only mode. When an adapter is present, you can set both the BATFET disable bit I just mentioned AND the HIZ enable bit to disable the converter. 

    I mean to get the same behavior as a BATFET_RST i.e. BATFET disabled for ~250ms and then re-enabled to perform a full system power reset. This is possible by holding QON low for >8s. Is it also possible by writing to a register? 

    Also, what is the expected behavior if QON is held low much longer say 20s? Do you expect the system to be held in reset till QON is pulled up or will BATFET be re-enabled 250ms after the 8s?

    Hrishi

  • In reply to 6000315:

    Hey Hrishi,

    It is not possible by register. However, there is a register bit to disable the BATFET. In this scenario, you would have to control when to flip the bit to re-enable the BATFET. 

    One problem in most customer systems is that the system rail powers the host controller; so you may not have a pull-up rail for your I2C bus when the BATFET is disabled. That would make the alternative I suggested improbable.

    And if the BATFET is held longer than 20s, it should not be held in reset. It would be reset for each 8s + 250ms pulse that passes. 

    Regards,

    Joel H

  • In reply to Joel Hernandez II:

    Ahh too bad! Thanks this is clear.

    Hrishi

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