$my_string = "Lorem Ipsum is simply dummy text of the printing and typesetting industry."
Expected result :
"Lorem Ipsum <br/> is simply<br/> dummy text<br/>of the printing<br/> and typesetting<br/> industry."
Tag should be added after every 12th character and not like this :
There are ma<br/>ny variations
Give it a try with wordwrap. I think it should solve your problem.