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BQ21061: Volatile Memory Concerns

Part Number: BQ21061
Other Parts Discussed in Thread: BQ25120A

Hello,

Our company is interested in using the BQ21061 for our design, however, we are concerned about this device not having non-volatile memory for the charging configurations. For our application, we typically only charge our device after the battery is fully depleted. Due to the protection circuitry already included with our battery, when the battery is fully depleted, we see 0 volts from the battery output, hence the charging IC will be unpowered and it's configurations will be reset. When we are charging the device from depletion, we keep the MCU powered off, so it's unable to re-program the charging IC until our device is powered back on.

Are there any suggestions for working around these constraints, and if not, are there any alternative IC's available that include non-volatile memory?

Thank you,

-Ricardo

  • Hi Ricardo,

    Our chargers typically do not include non-volatile memory aside from the default settings of the device. Are there any particular register values that you are hoping to preserve after a discharge event?

    Best Regards,

    Juan Ospina

  • Hello Juan,

    Yes, we were hoping to preserve the register values of the charge current (register 0x13), the LDO output voltage setting (0x1D). However, there may be some other registers we are interested in preserving. I saw in a previous question, it was mentioned that there exists a one-time programmable non-volatile memory that sets the defaults of the registers, which is done at the factory. Is it possible for us to customize these parameters?

    -Ricardo

  • Hi Ricardo,

    Unfortunately, there isn't really a way to customize these parameters. What are the default values for these register values? There may be other chargers that provide default values to match your charge current and LDO output voltage.

    Best Regards,

    Juan Ospina

  • Hi Ricardo, 

    Let us know which registers you would like to preserve, we will take a look to see if we have something close to your specifications. 

    We also have BQ25120A family of devices which is similar (has a DC-DC) which use resistor settings for the ILIM/ ISET values and goes into the register settings when the MCU is powered up and communicating on I2C. 

    Regards,

    Gautham 

  • Hello Gautham,

    Thank you for following up with me! I will look into the suggested chip, it looks very interesting for our application! We'd need a cell charge voltage of 4.2V, and a minimum charge current of 200mA. Ideally the LDO will be set to 3.3V by default, but 1.8V is something we might be able to work with.

    I'll follow up with you if the IC you suggested will work for us!

    Thank you,

    -Ricardo