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BQ78350-R1: troubles getting into sleep mode via command

marc heinemann
Prodigy 70 points
Part Number: BQ78350-R1

Hi there fellow engineers, 

i'm currently working on the sleep mode via smbus command. I do not have any problems, to get into the shutdown mode, since I have to send the Shutdown command to the manufacturer access register once (or twice, depending on the sealing mode). However sending the device to sleep mode is not as simple as that. At first, let me explain, what i got from your technical reference guide. 

I send the following command to address 0x0B (without PEC):

0x44 (manufacturer access) 0x02 (bytes) 0x11 0x00 (sleep mode)

and if the condition (current is lower than the set sleep current) is fulfilled, the device will be set to sleep mode. It will only leave sleep mode, if alert flags are set and / or the current increases. 

I have the following questions.

1. to get into the sleep mode, do i have to fulfill all the conditions (mentioned in 8.3.1 of the technical reference document) or just the the current < sleep current condition

2. is it possible to leave the sleep mode via smbus command?

3. if I'm in sleep mode, what bits indicate the sleep mode? If I read these bits, do i leave the sleep mode since there is further SMBus communicaiton? If so, how can I recognize Sleep mode

Until now, i was not able to get into the sleep mode, although the current was always zero and therefore the current condition was met. Sending the 0x10 0x00 (shut down) command works pretty well.

Thanks in advance for answering my questions and best regards, 

Marc 

  • 0
    TI__Guru* 76230 points
    Hi Marc
    1. Yes, you still have to fufill all the conditions.
    2. yes it is possible. Communication address to the gauge will wake it up from sleep.
    3. You can't read a flag to know if you are in sleep mode. The communication would wake the gauge up.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 70 points
    Hi Onyx,
    Thanks for your answers.

    3. how do i recognize the sleep mode then? There is a pin 'PWRM - 15', which can indicate the power state mode, but I'm not sure how to configure it. As far as I know, the pin is an open drain output, which becomes low if the battery is in sleep mode and the GaugeConfiguration[PWRMSleep] = 0. How to I set it to zero and do I have to unseal it first?

    Thanks in advance and regards,
    Marc
  • 0 in reply to marc heinemann
    TI__Guru* 76230 points
    Hi Marc
    To make any modifications to data flash, the gauge needs to be unsealed.

    The most certain way to determine the gauge is in sleep mode is by measuring the current into the gauge. You can also check the pulses on the TS pin. It would pulse once every 20 s ( or what ever time you set the sleep time to be) while in sleep mode.
    thanks
    Onyx