I'm trying simulation of Power Designer.
Following is my setting. (input voltage:5.24V/5.35V/5.47V, output voltage:5.1A, output current:1.5A)
But it is appeared error below.
Could you tell me this reason?
Error message
Design cannot be created!
Your preferred device does not work with the inputs you selected.
Please change your inputs or select another device.
Hi Yosuhiro,
Thanks for coming to us with your queries.
There is some limitation on the Vin & Vout combinations that Power Designer (Webench) can support to ensure the device will operate properly. For your application, with 5.24V input voltage, the output voltage will regulate at 5.1V with 1.5A of load current. See calculation for 100% duty cycle operation below.
VIN(min) = 5.1V + 1.5A * (100mohm + 38.7mohm) = 5.308V
* Inductor: XAL4020-222MEC
The calculation above requires a minimum input voltage of 5.3V to have a Vout of 5.1V. Please be reminded that the Rdson of the high-side FET considered was the typical value only and not yet the worst case. Hence, even with a 5.35V input supply, the device may not regulate at 5.1V/1.5A if the device has a higher RDSon (at high temp).
By the way, you might want to consider using a different device (ex. TPS628512 or mid-VIN) that can support up to => 6V input.
Let me know if you need additional information.
Best regards,
Excel
