如何在我的控制器动作中包含dompfg ..现在它显示空白页面

i am using dompdf to convert html content to pdf.. this is my basic code

$path_pdf = BASE_PATH.'/public/dompdf/dompdf_config.inc.php'; 
require_once($path_pdf); 
$html = '<p>Hello PHP</p>';         
$dompdf = new DOMPDF();
$dompdf->load_html($html);
$dompdf->render();
$dompdf->stream("sample.pdf");

but at second line where i have included dompdf ... after doing it all when i run this page it shows me blank screen..and after doing some debugging i found dompdf_config.inc.php is not including... i have checked my files path, it is correct. Any idea.. Thank in advance.