4 digit 7 segment display

The rating is 3 Amps and I want regulated DC power supply.Is there is any circuit

Of course, sir.

Needless to say, it is far more economical to purchase electronic subsystems to accomplish your task, rather than build from individual components, much less take the time to actually design a circuit. And since a busy yet frugal person such as yourself is always pressed for time (your longest missive to s.e.d. or s.e.b. on this subject being only twenty-one words in length -- you undoubtedly throw words around like manhole covers because time is money), I'm assuming you''ll want to go that route.

For the power supply, the you should purchase a Kepco BOP-36-5 operational power supply, which will provide up to +/-36V at up to 5 amps. You can easily remedy that by connecting an external pot to the external reference voltages available on the back terminals, then wire the device up as a non-inverting amplifier, and use feedback resistors to limit the maximum voltage excursion to +/-24V.

For the display, you may wish to go with an Omega LDP-146-F3-R-1, which in addition to totalizing, will display voltage in the range requested in lovely 4" LED numbers. Easy-to-follow instructions for hooking up the power supply and the display circuit are contained in the respective equipment manuals.

I hope this has been of service, and this response has provided you complete satisfaction, as was my exact and specific intent.

Have a nice day Chris