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Original question:

BQ76942EVM: How to Enabled The REG0 Config & REG12 Config Enable Register to Get The Voltage at REG1 & REG2 Pin on BQ76942EVM...

BQ76952: BQ76952, How to get REG0 and REG1&2 enabled?

Raimo Ikonen
Prodigy 10 points
Part Number: BQ76952
Other Parts Discussed in Thread: BQ76942EVM

Hello,

I do have similar configuration problem than BQ76942EVM -thread, but can't get the regulators activated even checksum and length are written.

The problem may relate on page making of technical documents, they are not easy to read because of one column instead of two - it makes big difference to read and find something.

Below is data captured from the buss, all seems to be there, and there is 500ms gap before sending checksum and length:

Any ideas to continue?

Raimo

  • 0
    TI__Guru* 80963 points

    Hi Raimo,

    Something doesn't look right in this sequence. For example, if you want to set REG1 to 3.3V, you should be writing this:

    10 3E 90 00  (Enter CONFIG_UPDATE mode)

    10 3E 37 92 01   (Write REG0 Config address 0x9237 with data of 0x01)

    10 60 35 05   (checksum and length)

    10 3E 36 92 0D  (Write REG1 Config address 0x9236 with data of 0xD)

    10 60 2A 05   (checksum and length)37 95

    10 3E 92 00 (Exit CONFIG_UPDATE mode)

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    Prodigy 10 points

    Hi Matt,

    And thank you for the kind support.

    In deed, the addresses were wrong and CONFIG_UPDATE mode is required. However, the need to be something more since voltages on BREG and REG1 does not appear even voltage at the BAT pin is 12.4V. Those are tested several times and captured data from I2C buss is same as in your example. There is several seconds delays between commands - all should be in place(?).

    Regulator circuitry is same as in the Figure 16-2., in the specification http://www.ti.com/product/BQ76952

    Best regards,

    Raimo

  • 0 in reply to Raimo Ikonen
    TI__Guru* 80963 points

    Hi Raimo,

    How is the voltage to the REGIN pin being supplied? REG1 and REG2 are supplied from REGIN?

    Regards,

    Matt

  • 0 in reply to Matt Sunna
    Prodigy 10 points

    Hi Matt,

    The REGIN pin is supplied via NPN BJT which is driven by BREG pin. Collector is feed from PACK+ voltage and it’s about 12 V during programming. It’s same circuit than in the product specification. My understanding is that primary problem is missing REG0 output, it may solve REG1&2 too.

    RST_SHUT is also checked, it’s pulled on low state. Wake by TS2 is tested too, no impact. Pinnouts, traces and solderings are checked - it’s hard to find reason in HW.

    Since REG18 is present (1,8 V) and the IC generates ACK signals, it should work. Timing may be last issue which is not checked yet.

    Best regards,
    Raimo

  • 0 in reply to Raimo Ikonen
    TI__Guru* 80963 points

    Hi Raimo,

    Yes, setting the REG0_EN should turn on the BREG pin which will result in REG1 turning on. Try waiting around 2ms between I2C commands when writing the registers. 

    Best regards,

    Matt