Display driver, electro-optical device, and electronic apparatus
A display driver includes an operational amplifier, a D/A conversion circuit, a resistance circuit, and a resistance element. The D/A conversion circuit includes first and second variable resistance circuits including one end to which first and second voltages are input and another end connected to an inverting input node. The resistance circuit is provided between the inverting input node and an output node. The resistor is provided between the output node and the inverting input node. A resistance value of the first variable resistance circuit is set based on upper bit data of display data. A resistance value of the second variable resistance circuit is set based on lower bit data of the display data.
1. A display driver comprising:
a first operational amplifier including a first non-inverting input node to which a reference voltage is input, the first operational amplifier being configured to drive a data line of an electro-optical panel;
a first D/A conversion circuit including a first variable resistance circuit including one end to which a first voltage is input and another end connected to a first inverting input node of the first operational amplifier;
a first resistance circuit provided between the first inverting input node and a first output node of the first operational amplifier;
a second operational amplifier including a second non-inverting input node to which a reference voltage is input;
a resistance element provided between a second output node of the second operational amplifier and the first inverting input node;
a second D/A conversion circuit including a second variable resistance circuit including one end to which a second voltage is input and another end connected to a second inverting input node of the second operational amplifier; and
a second resistance circuit provided between the second inverting input node and the second output node, wherein
a resistance value of the first variable resistance circuit is set based on upper bit data of display data, and
a resistance value of the second variable resistance circuit is set based on lower bit data of the display data.
2. The display driver according to claim 1 , wherein
when the first operational amplifier drives the data line in a positive polarity, a resistance value of the first resistance circuit is set to a first resistance value, and a resistance value of the second resistance circuit is set to a second resistance value; and
when the first operational amplifier drives the data line in a negative polarity, the resistance value of the first resistance circuit is set to a third resistance value different from the first resistance value, and the resistance value of the second resistance circuit is set to a fourth resistance value different from the second resistance value.
3. The display driver according to claim 1 , wherein
when the first operational amplifier drives the data line in a positive polarity, the first voltage is set to a first power supply voltage that is lower than the reference voltage, and the second voltage is set to a second power supply voltage that is higher than the reference voltage; and
when the first operational amplifier drives the data line in a negative polarity, the first voltage is set to the second power supply voltage, and the second voltage is set to the first power supply voltage.
4. The display driver according to claim 1 , comprising:
a monitor circuit configured to monitor an output of the first operational amplifier; and
a processing circuit configured to perform an adding process of adding offset correction data based on a monitoring result and the lower bit data, and to output a result of the adding process to the second D/A conversion circuit, wherein
the offset correction data is data for correcting an offset of a data voltage output by the first operational amplifier.
5. The display driver according to claim 1 , comprising:
a third operational amplifier including a third non-inverting input node to which a reference voltage is input;
a second resistance element provided between a third output node of the third operational amplifier and the second inverting input node of the second operational amplifier;
a third D/A conversion circuit including a third variable resistance circuit including one end to which the first voltage is input and another end connected to a third inverting input node of the third operational amplifier; and
a third resistance circuit provided between the third inverting input node and the third output node, wherein
a resistance value of the third variable resistance circuit is set based on offset correction data for correcting an offset of a data voltage output by the first operational amplifier.
6. The display driver according to claim 5 , comprising:
a monitor circuit configured to monitor an output of the first operational amplifier; and
a processing circuit configured to output the offset correction data based on a monitoring result to the third D/A conversion circuit.
7. The display driver according to claim 1 , wherein
a third operational amplifier including a third non-inverting input node to which a reference voltage is input;
a second resistance element provided between a third output node of the third operational amplifier and the first inverting input node;
a third D/A conversion circuit including a third variable resistance circuit including one end to which the second voltage is input and another end connected to a third inverting input node of the third operational amplifier; and
a third resistance circuit provided between the third inverting input node and the third output node, wherein
a resistance value of the third variable resistance circuit is set based on offset correction data for correcting an offset of a data voltage output by the first operational amplifier.
8. The display driver according to claim 7 , comprising:
a monitor circuit configured to monitor an output of the first operational amplifier; and
a processing circuit configured to output the offset correction data based on a monitoring result to the third D/A conversion circuit.
9. An electro-optical device comprising:
the display driver according to claim 1 ; and
the electro-optical panel.
10. An electronic apparatus comprising:
the display driver according to claim 1 .