Other Parts Discussed in Thread: UCC256404
Tool/software: WEBENCH® Design Tools
Hi Forum Members,
I am new to the WEBENCH forum and wish to seek some help. I design power supplies and have done so for awhile. My recent designs are LLC topology and I have so far done an excellent job. I have 500K units in the field with very small failure rate. My last design was using SSL4120 from NXP. NXP is no longer in the power supply device market anymore and I have turned all my attention towards TI. I did use the NXP tool when they were in the business but its gone now. I only use NXP because nine years ago they were the only semi manufacture to offer a totally inclusive LLC Controller device; PFC, HBC and FET drivers all in one device.
NXP was then, this is now, I am aware that TI has WEBENCH and I want to learn to use it.I am also very aware that TI has a great LLC solution as well.
Here is where I would need a little help. The most difficult step in designing power supplies is in the LOOP analysis for the design. Many compensation loops can be modeled. I would like to know if I could model a OTA Transconductance Feedback loop in WEBENCH. I am aware of how to do this when the OPAMP is external to the device. Simply calculate the voltage to current ratio for the feedback resistor and add the feedback capacitor via calculation for the bandwidth of interest.
I see some controllers where the OTA is internal to the SMPS controller allowing OTA an output pin only. This type of OTA will need to have the additional compensation feedback components to be attached on the output PIN of the internal OTA. These additional compensation components are attached externally to the internal OTA output, the components in the loop are typically a resistor in series with a cap to ground along with a single cap to ground which is in parallel with the series branch.
I would like to model this INTERNAL OTA within WEBENCH and see the BODE plot. Is there a reference example I could review. Any input is appreciated.
Next, I am looking at the TI UCC256304 device. This device device is also an LLC Controller. I found document SLUSD60. The design procedure starts on page 49. It starts with WEBENCH and I do understand all of these equations. At the end of this design doc there is a Design Spreadsheet on page 65 called "UCC256304 Desgin Calculator, UCC634." I cannot locate this spreadsheet.
Has it been removed as WEBENCH should be the dominate tool, or is it still good to have. If so where can I find this spreadsheet?
Thanks for the help.