This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
i want to design dual power supply with high current rating ,i am not familiar with lm2576.
can anybody tell me how to use lm2576 negative (-5 volt) generation. please reply me i am waiting .
In reply to Luke Pan:
Also I saw LM7905 is a negative output LDO for max 1.5A output. So for the -5V/5A negative output, I'm afraid you need an negative output controller.
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
Perhaps I can provide some help here. First, if you are using a center-tapped transformer secondary then you need to tie the center tap of the transformer to the center of two output capacitors. This provides separate positive and negative dc sources for the two regulators in your application. Without this connection there isn't a midpoint ground reference for either regulator to act upon and it will not function predictably, if at all. Once that correction has been made there is a second issue that often causes issues with heavy loads connected across symmetrical supply regulators.; that of a startup issue where one or the other supply regulator fails to start up. This can be resolved by placing reverse biased Schottky diodes across each of the two supply outputs. I have illustrated both suggestions in the attached schematic. Thank you. Lets us know your progress. AlanYogesh.pdf
Alan Martin - Wide Vin Applications Wrangler (retired)
In reply to Alan Martin:
thanks for your response,
i will try this on my circuit and let you know the result.and i have one doubt , i used 1000uf cap as a filter capacitor is there any effect of this. should i switch to 2200uf .
In reply to yogesh nandurkar:
The following schematic might not have attached to my earlier response. (Can't tell from my browser.)
This schematic using an AC input via a bridge rectifier will need a center tapped transformer to generate the independent raw +and - voltages into each rail regulator.
A better approach is to use two buck regulators, one in conventional buck configuration to create +5VDC. The second one in inverting buck-boost for the -5V rail as shown in Ap Note SNVA722B by Anston Lobo.
Each of these regulators will need a reverse biased Schottky diode placed across it's output to insure correct start-up since the end application can pull current from one rail to the opposite without conduction through the common ground.
Consider the following approach. Refer to SNVA722B
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content 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. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. 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.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.