Uploading file in PHP returns nothing when file size is big

Question

<?php
//max size of about 2 mb  
define('MAX_FILE_SIZE','2000000');//2 MB 
$allowed_file_types=array('image/jpg','image/png','image/jpeg');
//var_dump($_FILES['file_to_upload']);
if($_SERVER['REQUEST_METHOD']=='POST'){
    if(isset($_POST['action'])){
        if($_POST['action']=='upload_image'){
            //if($_FILES['file_to_upload']['error']){

            //}
            if(isset($_FILES['file_to_upload'])){
                $file_arr=$_FILES['file_to_upload'];
                $check=false;
                echo $file_arr['type'];
                //for allowing image type only 
                foreach($allowed_file_types as $type){
                    if($file_arr['type']==$type){
                        $check=true;
                    }
                }

                if($check){
                    //checking size limit
                    if($file_arr['size']>MAX_FILE_SIZE){
                        echo "<p class='warning'>The file size is above limit. Optimize the image and upload again.</br>Your File Size:".round(($file_arr['size']/1000000),2)."MB<br/>Allowed File Size: ".round((MAX_FILE_SIZE/1000000),2)."MB</p>";
                    }else{
                        upload_form($file_arr);
                    }
                }else{
                    echo "<p class='warning'>".$file_arr['type']." type of file is not allowed to upload</p>";
                }

            }
        }
    }
}

I am using this code to get information about file for uploading from a form. Basically what happens is when i select a file greater than 2.7/3 mb the var_dump i have used on the $_FILES return null. This is working on all other files less than that size. I get proper array from $_FILES. What may be causing this to happen? any suggestions?

BTW php.ini max_upload_size==65M