Patent ID: 6965266
Filing Date: 2005-11-15
Classification: H03F

Abstract:
1. A high voltage differential amplifier, comprising: an input differential pair of low voltage transistors having a pair of control terminals receiving a differential input signal with a common mode voltage, a pair of first current terminals, and a pair of second current terminals coupled together at an input bias node; a sense differential pair of low voltage transistors having a pair of control terminals receiving said differential input signal, a pair of first current terminals coupled together at a first sense node, and a pair of second current terminals coupled together at a second sense node, said first and second sense nodes each following said common mode voltage; a first high voltage transistor having a first current terminal coupled to said second sense node, and a control terminal and a second current terminal coupled together at an output bias node that follows said common mode voltage; a second high voltage transistor having a control terminal coupled to said output bias node, a first current terminal that develops a cascade bias node that follows said common mode voltage, and a second current terminal referenced to a power supply terminal; a low voltage bias transistor having a first current terminal coupled to said first sense node, and a control terminal and a second current terminal coupled together at said cascade bias node; a cascaded pair of low voltage transistors, each having a first current terminal coupled to a corresponding one of said pair of second current terminals of said input differential pair, a control terminal coupled to said cascade bias node, and a second current terminal; and an output pair of high voltage transistors, each having a control terminal coupled to said output bias node, a first current terminal coupled to a corresponding one of said pair of second current terminals of said cascaded pair, and a second current terminal providing a corresponding polarity of a differential output signal.