Controller dan Model untuk mPDF

//yang ini controllernya
public function unduh_data_tenaga_ahli(){
        $param          = $this->uri->segment(3);
        $data['result'] = $this->Crud_m->get_t_ahli_all();
        $data['param']  = $param;
        $this->load->view('cetak_laporan_tenaga_ahli',$data);
    }

//Yang ini modelnya
  public function get_t_ahli_all(){
     $query="select a.* from tenaga_ahli a   ";
      $sql=$this->db->query($query);
      if($sql->num_rows() >0 ){
          return $sql->result();
      }else{
        return 0;
          }
   }

//untuk tombol downloadnya
<div class="actions">
            <a href="javascript:;" class="btn  btn-danger content-refresh" onclick="unduh_data_tenaga_ahli(1)" ><i class="fa fa-file-pdf-o"></i> Cetak Pdf</a>
            <a href="javascript:;" class="btn  btn-success content-refresh" onclick="unduh_data_tenaga_ahli(2)" ><i class="fa fa-file-excel-o"></i> Cetak Xls</a>
        </div>
          </div>
        </div>
    </div>
</div>
<script>
   function unduh_data_tenaga_ahli(v){
      url = "<?php echo site_url()?>crud/unduh_data_tenaga_ahli/"+v;
      window.open(url,'_blank');

   }
</script>