We’ve made a 150W (5V / 30A) design using the UCC2891 active clamp converter
An undervoltage test is to be performed by overloading the UCC2891 to over current limit and let the output voltage droop to 4.8V. Below 4.8V the op-amp – opto-coupler circuit pulls the SD pin of UCC2891 to ground shutting down the device
This protection mechanism works fine till -15 deg C and below this the UCC2891 fails to restart after removing the fault. It seems to be in hic-up mode
I need your advice on whether this type of testing is normal in telecom systems i.e. overloading the output to hit current limit and then droop the output voltage to trigger the protection circuit
The design works fine, if I do the undervoltage testing by just modifying the TL431 reference voltage to set output voltage below 4.8V at -35 deg C
ALL CONTENT AND MATERIALS ON THIS SITE ARE PROVIDED "AS IS". TI AND ITS RESPECTIVE SUPPLIERS MAKE NO REPRESENTATIONS ABOUT THE SUITABILITY OF THESE MATERIALS FOR ANY PURPOSE AND DISCLAIM ALL WARRANTIES AND CONDITIONS WITH REGARD TO THESE MATERIALS, INCLUDING BUT NOT LIMITED TO, ALL IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT OF ANY THIRD PARTY INTELLECTUAL PROPERTY RIGHT. NO LICENSE, EITHER EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, IS GRANTED BY TI. USE OF THE INFORMATION ON THIS SITE MAY REQUIRE A LICENSE FROM A THIRD PARTY, OR A LICENSE FROM TI.
Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI and its suppliers reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.