Patent ID: 7667538
Filing Date: 2010-02-23
Classification: H03F

Abstract:
1. A differential amplifier comprising: first and second terminals for receiving signals; a third terminal for outputting a signal; first and second differential pairs, each having an input pair and an output pair, said first and second differential pairs being supplied with currents from associated current sources, respectively; a load circuit connected to output pairs of said first and second differential pairs; an amplifier stage for receiving, as an input, a signal of at least one connection node of a connection node pair of said load circuit and output pairs of said first and second differential pairs, said amplifier stage having an output connected to said third terminal; and a connection switching circuit for controlling the switching between a first connection state in which first and second inputs of the input pair of said first differential pair are connected to said first and second terminals, respectively, and in which first and second inputs of the input pair of said second differential pair are connected to said first terminal and to said third terminal, respectively, and a second connection state in which the first and second inputs of the input pair of said first differential pair are connected to said third and first terminals, respectively, and in which the first and second inputs of the input pair of said second differential pair are connected to said second terminal and to said first terminal, respectively.