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TPS65023: TPS65023 Application Question

Kuo John
Expert 1075 points
Part Number: TPS65023

Hi Sir,

According to effective use of battery capacity.
Case  when VBAT is 3.3VDC-3.6VDC can work output 3.3VDC for DC/DC,
but LDO maybe VBAT 3.3VDC-3.4VDC not work output 3.3VDC since LDO need meet drop voltage, right?

if right, could you help advise other PMIC support 3 DC/DC and 1 LDO (lower than 50mV drop voltage)? thanks.  



  • 0
    TI__Genius 16410 points
    Hi,

    I've assigned this post to the appropriate applications engineer, he will respond to your question.

    Regards,
    Karl
  • 0 in reply to Karl Wallinger
    Expert 1075 points
    Hi Sir,

    Thank you. I'll wait your good news.

    Regards,
    John
  • 0 in reply to Kuo John
    TI__Mastermind 30280 points
    Kuo,

    What is the load on your LDOx rail that will be set to 3.3V?

    If you look on the Electrical Characteristics table on page 9, it says the voltage drop across LDOx has a typical value of 65 mV with VINLDO = 1.5V at 50mA output current. This is quite close to your expectation of a 50mV drop.

    And yes, the DC-DC use P-channel high-side FETs with 100% duty cycle operation, so essentially VOUT=VIN, but there will always be a voltage drop across the FET, so that VOUT = VIN - ILoad*Rds,on

    If you cannot use the TPS65023 because your battery voltage is expected to drop below 3.4V when 3.3V output rails are needed, there may not be a PMIC that meets all of these strict requirements.

    What type of battery chemistry and battery charger are you using?
  • 0 in reply to Brian Berner
    Expert 1075 points
    Dear Brain,

    Battery type is Li battery.

    Regards,
    John
  • 0 in reply to Kuo John
    TI__Mastermind 30280 points
    John,

    There are multiple battery chemistries that use Lithium (Li). See en.wikipedia.org/.../Lithium_battery for more details.

    In order to determine the best PMIC to suit your design, we would need to know the minimum, nominal, and maximum voltages that will be applied as the input voltage (VIN) to the PMIC.

    It could also help to know all of the output voltages and current required by each rail. This is sometimes referred to as a power tree. Can you provide this info?