Tool/software: WEBENCH® Design Tools
I want to implement a design created by the WebBench Power Designer. But I would like to substitute parts to reduce the cost.
Primary question:
The Power Designer must be using a set of criteria to select parts - are those criteria available from the tool?
Explanatory/Secondary question:
I like that the Power Designer suggests specific parts; but, how can I tell when a part value was selected because the optimum part is not in its catalog?
Of course, I can go through all of the waveforms and datasheet equations to come up with my own values; but, it would boost my confidence if the Power Designer more directly supported my conclusions.
I found the "Operating Values" output; but this doesn't specifically address parameters for part selection.
The example that prompted this question:
In the design I am looking at, the Power Designer used two 3W, 3mOhm resistors in parallel for the sense resistor. Why two resistors in parallel? To get more power dissipation or just to get a smaller resistance? The "Operating Values" lists the power dissipation of these resistors as 300mW. The suggested part is 10x this value!
Hi Paul
1. To answer your primary question, yes Webench uses set of criterion such as cost and footprint to name a couple of them. We can always select the low cost or low footprint design from optimization option in Webench too.
Another way to select the different resistor would be through alternate parts selection where we can sort the available resistors for power rating , price, footprint etc.
2. Webench has a limited database as well. Currently it would be difficult to tell, the selected part is due to unavailability of optimum part. I will forward this as feedback to development team to consider for its future road map. But you can always select alternate parts for the components.
3. On the third query, this might have done to handle more input current. But I have forwarded this query to experts. Will get back on this.
Best Regards,
Bhushan
