Level detection by voltage addition/subtraction

摘要

A circuit is designed with a first transistor (661) having a current path coupled between a supply terminal (32) and a first output terminal (665). A second transistor has a current path coupled between the first output terminal and a reference terminal. The current path of the second transistor current path has substantially the same width and length as the first transistor current path. A first comparator circuit (679, 685) has first (668) and second (23) input terminals and a second output terminal (681). The first input terminal is coupled to the first output terminal. The first comparator circuit produces a control signal in response to a voltage between the first and second input terminals. A generator circuit (80) receives the control signal and produces an output voltage at the supply terminal.