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TPS65070 power up/down methods and sequencing for L138

clliu
Prodigy 160 points
Other Parts Discussed in Thread: TPS65070

Hi,

Will use TPS65070 to power L138, have read its datasheet and a few related docs s few times, but still have couples of questions not clear:

1, SYS voltage should ramp up as soon as AC or USB is applied, regardless of the state of or actions on PB_IN or POWER_ON . is this correct?

2, After applying AC or USB voltage, SYS ramps up, DCDCx and LDOx are in disabled state, turning on them happens only after setting POWER_ON high(PB_IN is idle, high by default)?

3, When a battery is the only power source(its voltage is higher enough to power the system),  to turn on the system, PB_IN should be low and set POWER_ON high while PB_IN is low. So the power-up triggering mechanism is different when system is power by a battery only and by either AC or USB. is this correct?

4, How to put the TPS65070 in OFF state, i.e. to turn off all the DCDCx and LDOx? Just by making POWER_ON low, regardless of the power sources(AC, or USB, or battery)?

5, In article, Powering Freon with TPS65070(slva371s), EN_DCDC2 and EN_DCDC3 are tied to GND, according to the tables in TPS65070 datasheet on page 54, if the pins are tied to "0", the relevant DCDCx will be permanently disabled. Do i still miss something?

6, What it the DCDC_SQx and LDO_SQx  settings for the article in question 5?

7, In TPS65070 datasheet, some EEPROM bits are mentioned,  how many of them are in the chip and more importantly how many of the registers settings are non-volatile?

Thanks,

clliu

 

  • 0
    TI__Expert 6060 points

    Please find asnwers embedded below.

     

    1, SYS voltage should ramp up as soon as AC or USB is applied, regardless of the state of or actions on PB_IN or POWER_ON . is this correct?

    Yes this is correct, SYS will ranp up as soon as voltage at AC or USB is applied.

    2, After applying AC or USB voltage, SYS ramps up, DCDCx and LDOx are in disabled state, turning on them happens only after setting POWER_ON high(PB_IN is idle, high by default)?

    Correct, to start the DC/DC converters either pull POWR_ON high or /PB_IN low. To keep converters enabled POWER_ON needs to be pulled high beofre /PB_IN is released high again.

    3, When a battery is the only power source(its voltage is higher enough to power the system),  to turn on the system, PB_IN should be low and set POWER_ON high while PB_IN is low. So the power-up triggering mechanism is different when system is power by a battery only and by either AC or USB. is this correct?

    Yes you are 100% correct.

    4, How to put the TPS65070 in OFF state, i.e. to turn off all the DCDCx and LDOx? Just by making POWER_ON low, regardless of the power sources(AC, or USB, or battery)?

    Yes pulling POWER_ON low from ON state will disable the DC/DC converters. DC/DC converers and LDOs will ranmp down in reveresed power up seuqence.

    5, In article, Powering Freon with TPS65070(slva371s), EN_DCDC2 and EN_DCDC3 are tied to GND, according to the tables in TPS65070 datasheet on page 54, if the pins are tied to "0", the relevant DCDCx will be permanently disabled. Do i still miss something?

    It is recommended to terminate enable pins of DC/DC converters and LDOs that are part of the internal power up sequence.

    6, What it the DCDC_SQx and LDO_SQx settings for the article in question 5?

    The DCDC_SQx  = 011 and LDO_SQx = 001  is device unique setting. It is the standard setting of the TPS65070.

    7, In TPS65070 datasheet, some EEPROM bits are mentioned,  how many of them are in the chip and more importantly how many of the registers settings are non-volatile?

    All of the User Register data is valoatile, this mean you will lose all information you have written to the User Regsiter once you remove power.

    At Power up the device loads default date from internal EEPROM, EEPROM is not accessable by the customer.