Differential amplifier, digital-to-analog converter and display device

A differential amplifier comprising:

• first and second input terminals;
• an output terminal;
• first and second differential pairs;
• a current source circuit that supplies currents to respective ones of said first and second differential pairs;
• a first node connected in common with first outputs of each of output pairs of said first and second differential pairs;
• a second node connected in common with second outputs of each of output pairs of said first and second differential pairs;
• a load circuit connected to said first and second nodes;
• an amplifier stage that receives a signal from at least one node of said first and second nodes as an input and has an output end connected to said output terminal;
• a capacitance element;
• and
• a changeover circuit that controls changeover between a first connection state and a second connection state, responsive to a control signal input thereto, wherein
• in said first connection state,
• a first input of each input pair of said first and second differential pairs is made a non-inverting input and a second input of each input pair of said first and second differential pairs is made an inverting input,
• the first input of the input pair of said first differential pair is connected to said first input terminal,
• the first input of the input pair of said second differential pair is connected to said second input terminal, and
• the second inputs of the input pairs of said first and second differential pairs are connected in common with one end of said capacitance element and in common with said output terminal;
• and
• in said second connection state,
• the first input of each input pair of said first and second differential pairs is made an inverting input and a second input of each input pair of said first and second differential pairs is made a non-inverting input,
• the first inputs of the input pairs of said first and second differential pairs are connected in common with said output terminal, and
• the second inputs of the input pairs of said first and second differential pairs are connected to the one end of said capacitance element;
• a first period in which the first connection state is selected and a second period which follows the first period and in which the second connection state is selected forming a data output period.

A differential amplifier comprising:

• first and second input terminals;
• an output terminal;
• first to third differential pairs;
• first to third current source circuits that supply currents individually to respective ones of said first to third differential pairs;
• a first node forming a common connection node of first outputs of each of output pairs of said first to third differential pairs;
• a second node forming a common connection node of second outputs of each of output pairs of said first and second differential pairs;
• a load circuit connected to said first and second nodes;
• an amplifier stage that receives a signal from at least one node of said first and second nodes as an input and has an output end connected to said output terminal;
• a single capacitance element;
• and
• a changeover circuit that controls changeover between a first connection state and a second connection state, responsive to a control signal supplied thereto;
• wherein
• first and second input voltages of mutually different voltage values are applied to said first and second input terminals, respectively;
• element sizes of said first to third differential pairs are all made identical;
• current quantities of said first to third current sources are all made identical;
• and
• first inputs of input pairs of said first and second differential pairs are connected together and second inputs of input pairs of said first and second differential pairs are connected together;
• and wherein
• in said first connection state,
• a first input of each input pair of said first to third differential pairs is made a non-inverting input and a second input of each input pair of said first to third differential pairs is made an inverting input,
• the first input voltage is applied to the first inputs of said first and second differential pairs,
• the second input voltage is applied to the first input of said first third differential pair, and
• the second inputs of the input pairs of said first to third differential pairs are connected in common with one end of said capacitance element and in common with said output terminal;
• and
• in the second connection state,
• a first input of each input pair of said first to third differential pairs is made an inverting input and a second input of each input pair of said first to third differential pairs is made a non-inverting input,
• the first inputs of the input pairs of said first to third differential pairs are connected in common with said output terminal,
• the second inputs of the input pairs of said first to third differential pairs are connected in common with one end of said capacitance element, and
• a voltage obtained by internally dividing the first and second input voltages at 1:2 is amplified and output;
• a first period in which the first connection state is selected and a second period which follows the first period and in which the second connection state is selected forming a data output period.