Dear supporter, yesterday I opened a case: CS0677800. Mr. Ray Vincent Aranzaso of Texas Instruments Customer Support, suggest me to open a ticket here.
My trouble is with Webench design #210 using the LM5122.
In July, I built with Webench our design #197 (now erased) to get a boost with OUT=72Vdc@5A and IN=24Vdc. (I am not expert with power supply, so -usually- I use Webench with good results, till now). That projects had some "choices" and "idealities", we are not abled to cross over.
Retrying many times, yesterday I was able to detect a almost-fully-defined-solution (project #210): it has only Dbst component not defined. I opened a case with TI to demand if it is possible to parallelize a known diode to achieve the target or if the STPS30SM120S could be used. It has only 120V=VRRM, but I do not understand (in webwench project) why webench put VRRM=84V and VRRMmax=150V.
Below my case CS0677800.
Dear Supporter,
I am newbie with power boost converter, so I demand you a help.
I should realize inside an appliance, a boost converter with ABOUT 72V@3A of output. Similar in the past, I tried to use WEBENCH tool, but I got "unfeasible" solutions. Modifying my appliance I am able to decrease the required output power to 153W, using a Vout@Iout=68V@2.25A . I achieved this result in my webench design #210 I attached with this support require.
In the start this design doesn't fit with webench, but forcing fsw=600KHz, the tool answer me (putting the fsw@300KHz about) with the design attached.
With the configuration/topology reached in Design#210, I get only a problem: Dbst is named as "CUSTOM", and it is not identified.
The data for the Dbst are:
a) VRRM= 84V (but looking inside the component into webench there is a VRRMmax= 150V coupled with VRRM)
b) Iomin=1A (Iomax=2A)
c) Vf@Io=500mV
First question: I do not understand how is possible to have VRRMmax=150V. How is possible, please?
Basing my choice on MOUSER database (the preferred with WEBENCH), I found the power schottky diode STPS30SM120S, which has a 120V=VRRM, while it agree with required features (b and c above).
Second question: could you help me to find a right diode, please?
Third question: could I use several diode into parallel mode to solve the problem, please? Any suggestion(s), please?
Fourth question: Since the 24Vdc supply voltage could has a transitory (I must pick form the input about 165W), have you any suggest for this period, please?
Thank you in advance.
Best Regards, DB.WBDesign210_2.pdf
