And my implementation, my be help you;

<?php

//pdf classes

require_once('lib_path/fpdf/fpdf.php');

require_once('lib_path/pdf/pdf.php');

require_once('lib_path/tfpdf/tfpdf.php');

require_once('lib_path/pdf/pdf5.php');

$pdf = new PDF5();

$pdf->AliasNbPages();

$pdf->AddPage();

$pdf->AddFont('DejaVu','','DejaVuSansCondensed.ttf',true);

.......

There: pdf5:

"class PDF5 extends tFPDF
{

    function Footer() {....."

tfpdf.php:

"class tFPDF extends FPDF".....

Work fine :)

Big Thanks to tFPDF Devs