Relative vs fullpath when executing file

When executing cmd/batch/exe file from the powershell command line (or within .ps1 script file), I see the following behavior:

1. Using relative path:

   ./bin/<file to execute> -> executes in same shell windows

2. Using full path:

   d:/fullpath/bin/&l开发者_JS百科t;file to execute> -> executes in new shell (window)

Can anybody shed some light on this behavior and how to influence this (with other words let the fullpath execute in same shell window)