PHP: Converting UTF-8 string to Ansi?

Try:

$csv = iconv("UTF-8", "Windows-1252", $csv);

But you will eventually lose data because ANSI can only encode a small subset of UTF-8. If you don't have a very strong reason against it, serve your files UTF-8 encoded.

Since there is a misunderstanding about ISO-8859-1, Windows-1252 & ANSI in your question an important thing to note here is that:

The so-called Windows character set (WinLatin1, or Windows code page 1252, to be exact) uses some of those positions for printable characters. Thus, the Windows character set is NOT identical with ISO 8859-1. The Windows character set is often called "ANSI character set", but this is SERIOUSLY MISLEADING. It has NOT been approved by ANSI.

Historical background: Microsoft based the design of the set on a draft for an ANSI standard. A glossary by Microsoft explicitly admits this.

Some more resources: here and here.

So just FYI for other people that end up in this question.

Here's MS's exact explanation on this:

The term “ANSI” as used to signify Windows code pages is a historical reference, but is nowadays a misnomer that continues to persist in the Windows community. The source of this comes from the fact that the Windows code page 1252 was originally based on an ANSI draft—which became International Organization for Standardization (ISO) Standard 8859-1. “ANSI applications” are usually a reference to non-Unicode or code page–based applications.