Function use base_convert

<?php
function big_convert ($number,$to_base) {
$result = "";
switch ($to_base) {
case "2":
$temp = preg_split('//', $number, -1, PREG_SPLIT_DELIM_CAPTURE);
$lng = strlen($number);
for ($i = 1;$i <= $lng;$i++) { $result .= str_pad(base_convert($temp[$i], 16, 2), 4, '0', STR_PAD_LEFT); }
return $result;
break;

case "16":
$bin = substr(chunk_split (strrev($number), 4,'-'), 0, -1);
$temp = preg_split('[-]', $bin, -1, PREG_SPLIT_DELIM_CAPTURE);
for ($i = count($temp)-1;$i >= 0;$i--) { $result = $result . base_convert(strrev($temp[$i]), 2, 16); }
return strtoupper($result);
break;
}
}

$bin = "1011010011110010100100101011011101100101001101001111";
echo $hex = big_convert ($bin,16);
echo big_convert ($hex,2);
?>