Patent ID: 7623054

Claim:
A differential amplifier comprising: first and second input terminals and an output terminal; a differential pair having a pair of inputs thereof connected to said first terminal and said second input terminal, respectively, said differential pair for performing voltage-to-current conversion of voltages at said first and second input terminals to output differential currents to first and second nodes, respectively; a first current source for supplying a current to said differential pair; a first load circuit connected to said first node, said first load circuit for performing current-to-voltage conversion of a current at said first node to a voltage at a third node; a second load circuit connected to said second node, said second load circuit for reversibly performing mutual conversion between a current at said second node and a voltage at a fourth node and for supplying a voltage signal to a fifth node; a capacitance element connected between said third node and said fourth node; and an amplifier circuit for charging or discharging said output terminal based on the voltage signal at said fifth node; wherein responsive to a control signal, said differential amplifier is subjected to switching control between first and second states, wherein in said first state, a first signal is supplied to said first input terminal, a second signal is supplied to said second input terminal, and a potential difference between the voltages at said third and fourth nodes output by said first and second load circuits, respectively, are stored in said capacitance element; and wherein in said second state, a third signal is supplied to said second input terminal, a signal at said output terminal is fed back to said first input terminal, and the potential difference stored in said capacitance element in said first state is held and a voltage signal is output to said fifth node based on the potential difference.