Here is a quick hack of a working example:

#!/usr/bin/perl

use strict;
use warnings;
use DBI;

my $dbname = 'testdb';
my $server = 'localhost';
my $user   = 'user';
my $pass   = 'pass';

my $dbh = DBI->connect(
    "DBI:Pg:dbname=".$dbname.";host=".$server, $user, $pass );

# The \n at the end of each row is required
my @ArrayInMemory = (
    "1/value 12/value 13\n",
    "2/value 22/value 23\n",
    "3/value 32/value 33\n",
);

$dbh->do("COPY testcp (col1, col2, col3) FROM STDIN WITH DELIMITER '/'
+");

foreach my $row (@ArrayInMemory) {
    # Alternative if the array elements doesn't contain \n
    # $row .= "\n";

    $dbh->pg_putcopydata($row);
}

$dbh->pg_putcopyend();
[download]

Regards, Stefan