Freeze and thaw functions in SQL server

Hi
I want to do the backup of SQL server. I want the backup to be consistent. So before starting the backup i want to freeze the DB and once i finish i want to thaw it.I read the Microsoft SQL server virtual backup specifications. It is concerned with taking backup of the DB using snapshot or without using snapshot.I dont want the sanpshot to be created. I just want to frreeze it and i will take the backup ( with ot without snapshot ) . After that i want to thaw it. Is it possilble using VDI or is there some other way to do that ?And how to use the Freeze and Thaw functions in SQL server.

Thanks in Advance