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TPS546B24A: Survey -- 3.3V to 0.75V @ 18A use for TPS546B24A

Delun Kao
Intellectual 265 points
Part Number: TPS546B24A
Other Parts Discussed in Thread: TPS546D24A

Hi TI,

There is currently a case where the configuration is Vin=3.3V, Vout=0.75V, Iout=18A.  Does this material fit my configuration? Or have other suggestions?

(Need to monitoring the output voltage and output current.)

------------------------------

If this material meets my specifications, I want to confirm the following questions.

A. Can the output voltage & frequency be set by analogy? Or must it be set by digital?

B. How to read the output and edit the register? ( TPS546B24A > PMBus > Dongle > PC ? ,  If this is the path, what kind of dongle do I need? )

C. The accuracy of the output can be adjusted? Each scale is 0.1V?

  • 0
    TI__Mastermind 48180 points

     

    Yes, the TPS546B24A can support a 3.3V to 0.75V @ 18A power solution.  While the TPS546B24A requires a minimum 4.0V VDD5 voltage to provide sufficient voltage to drive the power FETs, there is an application note in its product folder under "Technical Documents" on how to build use the SYNC_OUT feature with a small discrete voltage doubler circuit to pump a 3.3V input into a 6V AVIN into, and use the internal VDD5 regulator to generate a 4.7V gate drive.

    https://www.ti.com/product/TPS546B24A#tech-docs

    or the direct link here: https://www.ti.com/lit/pdf/sluaa03

     

    If this material meets my specifications, I want to confirm the following questions.

     

    A. Can the output voltage & frequency be set by analogy? Or must it be set by digital?

    Both the Output Voltage and the Switching frequency are set digitally, however the initial digital output voltage and switching frequency can be selected by resistors on the VSEL and MSEL1 pins.

    With a single resistor from VSEL to AGND, an initial voltage of 0.5V - 1.25V in 0.05V steps, including 0.75V can be selected.  With 2 resistors, one from VSEL to AGND and one from VSEL to BP1V5 voltages from 0.6V to 1.2V in 0.010V steps can be selected.  Once the part is powered up, higher resolution is available (see below)

    Like the output voltage, the Switching Frequency is always digitally programmed, but the initial setting can be selected with resistors connected to MSEL1.  Switching Frequencies of 275kHz, 325kHz, 450kHz, 550kHz, 650kHz, 900kHz, 1.1MHz and 1.5MHz are available. 

     

    B. How to read the output and edit the register? ( TPS546B24A > PMBus > Dongle > PC ? ,  If this is the path, what kind of dongle do I need? )

    The TPS546B24A will respond to PMBus commands issued to it from any source.  To ease the development, TI offers a Graphical User Interface (GUI) the FUSION Digital Power Designer available for download.  FUSION uses the USB-to-GPIO interface dongle to interface between a computer, running the FUSION software, and the 10-pin header on our evaluation modules.

    While these solutions are available from TI, any I2C / SMBus or PMBus interface solution will work.

    https://www.ti.com/tool/USB-TO-GPIO

    https://www.ti.com/tool/FUSION_DIGITAL_POWER_DESIGNER

    The output voltage is read by the READ_VOUT command (Command Code 8Bh), using the same exponent as set by VOUT_MODE (discussed below)

    The output current is read by the READ_IOUT command (Command Code 8Ch), using the PMBus Standard Linear11 format.  The upper 5 bits (15:11) provide the exponent in signed 2s compliment format while the lower 11 bits provide a mantissa in signed 2s compliment format. 

    For more information, see their respective pages in the datasheet:

    READ_VOUT - Section 7.6.64

    READ_IOUT - Section 7.6.65

    C. The accuracy of the output can be adjusted? Each scale is 0.1V?

    Regardless of the method used to provide the initial value for VOUT, once the TPS546B24A is powered up, the output voltage can be adjusted.  The resolution available is based on the setting of the VOUT_MODE command (Command Code 20h).  At the default value of 97h, the Linear-16 format is set to -9 for 2^-9 Volts (1.95mV) per LSB.  If higher or lower resolution is required, VOUT_MODE can be adjusted when the output voltage is disabled to select higher or lower resolution.  The maximum resolution available is VOUT_MODE = 94h, which sets an exponent of -12 for 0.244mV / LSB

    For 0.75V output voltage, the accuracy of the output voltage regulation is provided in the datasheet:

    +/- 0.005V for 0-85C

    +/- 0.006V for 0-125C

    +/- 0.008V for -40 to +150C

  • 0 in reply to Peter James Miller
    Intellectual 265 points

    HI TI,

    How many times can EEPROM be written?
    If our host can communicate with VR through PMBus, can we use commands to read and write the registers inside? Or must we use a dongle?

    Thanks

  • 0 in reply to Delun Kao
    TI__Mastermind 48180 points

     

    [DK] How many times can EEPROM be written?

    [PJM] The User Store NVM used in the TPS546D24A is Electronic Erasable Programmable Read-Only Memory (EEPROM).  It is rated for a minimum endurance of 1,000 Erase/Write cycles at a die temperature of 150C.  The endurance improves as die temperature during the Erase/Write cycle decreases.

    The User Store NVM is only written to during a STORE_USE_ALL (Send Byte to Command Code 15h with no data bytes).


    [DK] If our host can communicate with VR through PMBus, can we use commands to read and write the registers inside? Or must we use a dongle?

    [PJM] Yes.  The TPS546D24A responds to any valid PMBus communication regardless of the source.  There is no special enable or handshake with the USB-to-GPIO.

  • 0 in reply to Peter James Miller
    Intellectual 265 points

    Hi Peter,

    If I want to fix the set parameters (such as output voltage or output rate), can he permanently record them in the controller? (I'm referring to the number of times in this circle)

    Thanks.

    BR,

    Delun

  • 0 in reply to Delun Kao
    TI__Mastermind 48180 points

     

    {DK] If I want to fix the set parameters (such as output voltage or output rate), can he permanently record them in the controller? (I'm referring to the number of times in this circle)

    Yes.  Many of the PMBus settings are supported with Non-Volatile Memory (NVM) so that they will retain those settings through power loss and restoration of power.  To store the current PMBus settings to NVM, you use the send byte protocol with command code 15h (STORE_USER_ALL).  This commits the current PMBus values to NVM. 

    The TPS546B24A can support this function a minimum of 1,000 times at a 150C die temperature and more at lower die temperatures.