Programmable logic integrated circuit devices with differential signaling capabilities

A differential output circuit comprising:

• at least one of (a) a voltage source, and (b) a ground terminal;
• a pair of output terminals;
• a differential output driver for driving said pair of output terminals in accordance with a differential signaling scheme;
• and
• a programmable current-limiting circuit operatively connected to said differential output driver for selectably configuring said differential output driver for use with any one of a plurality of differential signaling schemes;
• wherein:
• said programmable current-limiting circuit comprises at least one programmable current-limiting portion connected between (1) said differential output driver, and (2) said one of (a) said voltage source, and (b) said ground terminal;
• and
• said at least one programmable current-limiting portion comprises:
• at least one current-limiting component, and
• for each one of said at least one current-limiting component, a programmable switch for selectably connecting said one of said at least one current-limiting component between (1) said differential output driver, and (2) said one of (a) said voltage source, and (b) said ground terminal.