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TPS548B22: Dynamically adjust VOUT

Aaron Hsu
Intellectual 565 points
Part Number: TPS548B22
Other Parts Discussed in Thread: TPS549B22, TPS546B24A

HI  All

Due to the equipment side, VOUT needs to be dynamically adjusted
The conditions are as follows
VIN=12V
IOUT=15A(max)
[000]=1V (initial state)
[001]=1V (default)
[010]=0.97V
[011]=0.95V
VOUT=1V(TYP) MIN=0.99V MAX=1.01V
VOUT=0.97V(TYP) MIN=0.96V MAX=0.98V
VOUT=0.95V(TYP) MIN=0.94V MAX=0.96V
Since the VOUT condition must be very precise, I want to use TPS548B22
VSEL Pin function, can I use MOSFET to switch the resistance to achieve (parallel resistance), 75K and 60.4k and 1.78k, to achieve dynamic adjustment of VOUT?

  • +1
    TI__Expert 5310 points

    Hello, 

    The VSEL pin is a pin strap pin, which cannot be dynamically adjusted while the device is operational. This part reads the VSEL pin voltage at startup and latches the value internally. You may power down the device, change the VSEL resistance, and then power up the device with the newly selected VSEL voltage. I do however realize this is not necessarily practical.

    If you would like to dynamically adjust the output voltage on the TPS548B22, you may switch in parallel resistors to modify a resistor divider between VOUT, RSP, and RSN. 

    We also have similar products with that offer dynamic voltage adjustment via PMBus. 

    The TPS549B22, is a very similar product with a PMBus interface that allows for dynamic output voltage adjustment via the VOUT command value

    https://www.ti.com/product/TPS549B22

    Alternatively, I may recommend the TPS546B24A, which has similar functionality and operating ranges to the TPS549B22:

    https://www.ti.com/product/TPS546B24A

    Regards,

    Alec Biesterfeld