It's also very common in switching power supplies as it allows N-type devices to be used in the high side improving efficiency for "high" output current supplie

It's also very common in switching power supplies as it allows N-type devices to be used in the high side improving efficiency for "high" output current supplies. Here is an excellent summary of the various techniques. https://www.onsemi.com/pub/Collateral/AN-6076.pdf.pdf https://www.onsemi.com/pub/Collateral/AN-6076.pdf.pdf