<?php
class Database
{
private $_connection;
private static $_instance;
private $_host = "IP";
private $_username = "USERNAME";
private $_password = "PASS!";
private $_database = "DATABASENAME";

public static function getInstance()
{
    if(!self::$_instance)
    {
        self::$_instance = new self();
    }
    return self::$_instance;
}

private function __construct()
{
    $this->_connection = new mysqli($this->_host, $this->_username, $this->_password, $this->_database);

    if(mysqli_connect_error())
    {
        trigger_error("Failed to connect to MySQL: " . mysql_connect_error(), E_USER_ERROR);
    }
}

private function __clone() { }


public function getConnection()
{
    $this->_connection->query('SET CHARACTER SET utf8');
    return $this->_connection;
}
}

<?php
require_once('database.php');

$db = Database::getInstance();
$db = $db->getConnection();