Driving apparatus, display driver and electronic apparatus
The driving device used for drive control of a driven device having driven elements arranged to commonly receive a common voltage at common terminals and individually receive drive signals at data terminals has: a drive voltage-producing circuit which produces drive voltages; a driver circuit which accepts input of the drive voltages produced by the drive voltage-producing circuit and outputs, as drive signals, signals selected from the drive voltages according to drive data from data output terminals in parallel; and a common voltage-producing circuit which produces a common voltage to output from a common-voltage-output terminal. In the driving device, the drive voltage-producing circuit detects a change in the common voltage output from the common-voltage-output terminal, and changes the drive voltages in the direction of the change.
1. A display driving device comprising:
a drive voltage-producing circuit configured to produce a plurality of drive voltages;
a driver circuit configured to accept input of the drive voltages produced by the drive voltage-producing circuit, and output, as drive signals, signals selected from the drive voltages according to drive data from a plurality of data output terminals in parallel; and
a common voltage-producing circuit configured to produce a common voltage to output from a common-voltage-output terminal,
wherein the drive voltage-producing circuit is configured to detect a change in the common voltage output from the common-voltage-output terminal and change the drive voltages to follow a direction of the change.
2. The display driving device according to claim 1 further comprising: a common-voltage-input terminal for accepting input of a common voltage output from the common-voltage-output terminal from outside the driving device and providing the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit includes:
a first non-inverting amplifier arranged so that a division voltage of an output voltage of the first non-inverting amplifier relative to a reference node voltage is fed back thereto; and
a second non-inverting amplifier arranged so that a division voltage of its output voltage relative to the reference node voltage is fed back thereto, wherein the drive voltage-producing circuit is configured to produce drive voltages by division of a voltage between the output voltage of the first non-inverting amplifier and the output voltage of the second non-inverting amplifier; and
wherein the drive voltage-producing circuit further includes an inverting amplifier which forms a correction voltage depending on a difference between an input common voltage input through the common-voltage-input terminal and a target voltage of the common voltage output from the common-voltage-output terminal, and provides the correction voltage to the reference node.
3. The display driving device according to claim 1 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a first non-inverting amplifier configured to amplify a first reference voltage in a non-inverting manner to output a first voltage, and whose feedback quantity is determined by a first voltage-dividing circuit provided between a reference node and an output terminal;
a second non-inverting amplifier configured to amplify a second reference voltage in a non-inverting manner to output a second voltage, and whose feedback quantity is decided by a second voltage-dividing circuit provided between the reference node and an output terminal;
a voltage-dividing circuit configured to generate, by division of a voltage between the first and second voltages, a plurality of division voltages to be used for producing drive voltages; and
an inverting amplifier configured to generate a correction voltage depending on a difference between an input common voltage input from the common-voltage-input terminal and a target voltage of a common voltage output from the common-voltage-output terminal, provided that an output of the inverting amplifier is connected to the reference node.
4. The display driving device according to claim 1 , further comprising: a voltage input terminal configured to: accept input of a voltage corresponding to a fluctuation of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit includes:
a first non-inverting amplifier arranged so that a division voltage of an output voltage of the first non-inverting amplifier relative to a reference node voltage is fed back thereto;
a second non-inverting amplifier arranged so that a division voltage of an output voltage of the second non-inverting amplifier relative to the reference node voltage is fed back thereto;
a reference voltage-producing circuit configured to produce:
a reference voltage of the first non-inverting amplifier at an upstream node of an upstream side resistance located upstream of an intermediate node where a predetermined current is passed; and reference voltage of the second non-inverting amplifier at a downstream node of a downstream side resistance located downstream of the intermediate node; and
an input amplifier configured to produce a shift voltage depending on the voltage corresponding to a fluctuation input from the voltage input terminal, wherein the shift voltage is applied to the intermediate node, thereby causing the respective reference voltages to reflect a voltage change at the intermediate node, wherein the shift voltage is applied to the reference node, thereby causing output voltages of the first and second non-inverting amplifiers to reflect a voltage change at the reference node, and
wherein the drive voltage-producing circuit is further configured to produce a plurality of drive voltages by division of a voltage between the output voltages of the first and second non-inverting amplifiers.
5. The display driving device according to claim 1 , further comprising: a common-voltage-input terminal configured to: accept input of a voltage corresponding to fluctuation of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a reference voltage-producing circuit configured to produce:
a first reference voltage at an upstream node of an upstream side resistance located upstream of an intermediate node where a predetermined current is passed; and
a second reference voltage at a downstream node of a downstream side resistance located downstream of the intermediate node;
a first non-inverting amplifier configured to amplify the first reference voltage in a non-inverting manner to output a first voltage, and a feedback quantity of the first non-inverter amplifier is decided by a first voltage-dividing circuit provided between a reference node and an output terminal;
a second non-inverting amplifier configured to amplify the second reference voltage in a non-inverting manner to output a second voltage, and a feedback quantity of the second non-inverter amplifier is decided by a second voltage-dividing circuit provided between the reference node and an output terminal;
a voltage-dividing circuit configured to generate, by division of a voltage between the first and second voltages, a plurality of division voltages to be used for producing drive voltages; and
an input amplifier configured to: produce a shift voltage depending on a voltage of fluctuation input from the common-voltage-input terminal; and provide the shift voltage to the intermediate node and the reference node.
6. The display driving device according to claim 5 , wherein the input amplifier is configured to further provide the shift voltage to an intermediate node of the voltage-dividing circuit.
7. The display driving device according to claim 1 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a voltage-to-current conversion circuit configured to convert a difference voltage between an input common voltage input from the common-voltage-input terminal, and a target voltage of a common voltage output from the common-voltage-output terminal into current; and
a plurality of buffer amplifiers configured to form an offset voltage by passing therethrough a current resulting from conversion by the voltage-to-current conversion circuit is used, and
wherein the drive voltage-producing circuit is configured to produce, based on outputs of the plurality of buffer amplifiers, the plurality of drive voltages reflecting a difference voltage between the input common voltage and the target voltage.
8. The display device according to claim 1 , further comprising:
a common-voltage-input terminal configured to accept input of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a voltage-to-current conversion circuit configured to convert a difference voltage between an input common voltage input from the common-voltage-input terminal and a target voltage of a common voltage output from the common-voltage-output terminal into a current;
a voltage-dividing circuit configured to produce a plurality of division voltages; and
a correction circuit configured to correct voltage curves according to a plurality of division voltages produced by the voltage-dividing circuit to produce the drive voltages,
wherein the correction circuit has a plurality of buffer amplifiers configured to receive the division voltages, and wherein each of the plurality of buffer amplifiers has a feedback route and is configured to form an offset voltage with a current produced by the voltage-to-current conversion circuit passed therethrough.
9. The display driving device according to claim 1 , wherein the display driving device is configured to control a display device comprising a plurality of liquid crystal display elements.
10. A display driver for a display panel having a plurality of display elements arranged like a matrix, configured to receive a common voltage at common terminals and drive signals at data terminals, the display driver comprising:
a gradation voltage-producing circuit configured to produce a plurality of gradation voltages;
a driver circuit which configured to accept input of the plurality of gradation voltages produced by the gradation voltage-producing circuit and output, as drive signals, the gradation voltages selected according to display data from a plurality of data output terminals in parallel; and
a common voltage-producing circuit configured to produce a common voltage output from a common-voltage-output terminal,
wherein the gradation voltage-producing circuit is configured to detect a change in a common voltage output from the common-voltage-output terminal and vary the gradation voltages to follow a direction of the change.
11. The display driver according to claim 10 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the display driver; and provide the common voltage to the gradation voltage-producing circuit,
wherein the gradation voltage-producing circuit comprises:
a first non-inverting amplifier arranged so that a division voltage of its output voltage relative to a reference node voltage is fed back thereto;
a second non-inverting amplifier arranged so that a division voltage of its output voltage relative to the reference node voltage is fed back thereto; and
an inverting amplifier configured to form a correction voltage corresponding to a difference between an input common voltage input from the common-voltage-input terminal, and a target voltage of a common voltage output from the common-voltage-output terminal, and provides the correction voltage to the reference node, wherein the gradation voltage-producing circuit is configured to produce the plurality of gradation voltages by division of a voltage between the output voltage of the first non-inverting amplifier and the output voltage of the second non-inverting amplifier.
12. The display driver according to claim 10 , further comprising: a voltage input terminal configured to: accept input of a voltage corresponding to a fluctuation of a common voltage output from the common-voltage-output terminal from outside the display driver; and provide the input voltage to the gradation voltage-producing circuit,
wherein the gradation voltage-producing circuit includes:
a first non-inverting amplifier arranged so that a division voltage of its output voltage relative to a reference node voltage is fed back thereto,
a second non-inverting amplifier arranged so that a division voltage of its output voltage relative to the reference node voltage is fed back thereto
a reference voltage-producing circuit configured to: produce a reference voltage of the first non-inverting amplifier at an upstream node of an upstream side resistance located upstream of an intermediate node where a predetermined current is passed; and produce a reference voltage of the second non-inverting amplifier at a downstream node of a downstream side resistance downstream of the intermediate node; and
an input amplifier configured to produce a shift voltage depending on a change of a voltage of fluctuation input from the voltage input terminal, wherein the shift voltage is applied to the intermediate node, thereby causing the reference voltages to reflect a voltage change at the intermediate node, and the shift voltage is applied to the reference node, thereby causing output voltages of the first and second non-inverting amplifiers to reflect a voltage change at the reference node, and wherein the gradation voltage-producing circuit is configured to produce the plurality of gradation voltages by division of a voltage between the output voltage of the first non-inverting amplifier and the output voltage of the second non-inverting amplifier.
13. The display driver according to claim 10 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the display driver and provide the common voltage to the gradation voltage-producing circuit,
wherein the gradation voltage-producing circuit comprises: a voltage-to-current conversion circuit configured to convert a difference voltage between an input common voltage input from the common-voltage-input terminal, and a target voltage of a common voltage output from the common-voltage-output terminal into current; and
a plurality of buffer amplifiers on which an offset voltage formed by passing therethrough a current resulting from conversion by the voltage-to-current conversion circuit is used, and
the gradation voltage-producing circuit is further configured to produce, based on outputs of the plurality of buffer amplifiers, the plurality of drive voltages each reflecting a difference voltage between the input common voltage and the target voltage.
14. The display driver according to claim 10 , wherein the plurality of display elements comprises a plurality of liquid crystal display elements.
15. An electronic apparatus comprising:
a driven device having a plurality of driven elements arranged to commonly receive a common voltage at common terminals and individually receive drive signals at data terminals; and
a driving device used configured for drive control of the driven device,
wherein the driving device comprises:
a drive voltage-producing circuit configured to produce drive voltages having plurality of levels;
a driver circuit configured to accept input of the plurality of drive voltages produced by the drive voltage-producing circuit, and output, as drive signals, drive voltages selected according to drive data in parallel from a plurality of data output terminals; and
a common voltage-producing circuit configured to produce a common voltage to be output from a common-voltage-output terminal,
wherein the drive voltage-producing circuit is configured to: detect a change in a common voltage output from the common-voltage-output terminal; and change the drive voltages to follow a direction of the change.
16. The electronic apparatus according to claim 15 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit includes:
a first non-inverting amplifier arranged so that a division voltage of its output voltage relative to a reference node voltage is fed back thereto;
a second non-inverting amplifier arranged so that a division voltage of its output voltage relative to the reference node voltage is fed back thereto;
an inverting amplifier configured to form: a correction voltage corresponding to a difference between an input common voltage input from the common-voltage-input terminal; and a target voltage of a common voltage output from the common-voltage-output terminal wherein the drive voltage-producing circuit is configured to produce gradation voltages having a plurality of levels by division of a voltage between the output voltage of the first non-inverting amplifier and the output voltage of the second non-inverting amplifier, and wherein the correction voltage is provided to the reference node.
17. The electronic apparatus according to claim 15 , further comprising: a voltage input terminal configured to: accept input of a voltage corresponding to a fluctuation of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a first non-inverting amplifier arranged so that a division voltage of its output voltage relative to a reference node voltage is fed back thereto;
a second non-inverting amplifier arranged so that a division voltage of its output voltage relative to the reference node voltage is fed back thereto;
a reference voltage-producing circuit configured to: produce a reference voltage of the first non-inverting amplifier at an upstream node of an upstream side resistance located upstream of an intermediate node where a predetermined current is passed; and produce a reference voltage of the second non-inverting amplifier at a downstream node of a downstream side resistance downstream of the intermediate node; and
an input amplifier configured to produce a shift voltage depending on a change of a voltage of the fluctuation input from the voltage input terminal,
wherein the shift voltage is applied to the intermediate node, thereby causing the reference voltages to reflect a voltage change at the intermediate node, and
the shift voltage is applied to the reference node, thereby causing output voltages of the first and second non-inverting amplifiers to reflect a voltage change at the reference node, and wherein the drive voltage-producing circuit is configured to produce a plurality of gradation voltages by division of a voltage between the output voltage of the first non-inverting amplifier and the output voltage of the second non-inverting amplifier.
18. The electronic apparatus according to claim 15 , further comprising: a common-voltage-input terminal configured to: accept input of a common voltage output from the common-voltage-output terminal from outside the driving device; and provide the common voltage to the drive voltage-producing circuit,
wherein the drive voltage-producing circuit comprises:
a voltage-to-current conversion circuit configured to convert a difference voltage between an input common voltage input from the common-voltage-input terminal, and a target voltage of a common voltage output from the common-voltage-output terminal into a current; and
a plurality of buffer amplifiers on which an offset voltage formed by passing therethrough a current resulting from conversion by the voltage-to-current conversion circuit is used, and
the drive voltage-producing circuit is configured to produce, based on outputs of the plurality of buffer amplifiers, a plurality of drive voltages reflecting a difference voltage between the input common voltage and the target voltage.
19. The electronic apparatus according to claim 15 , wherein the plurality of driven elements comprises a plurality of liquid crystal display elements.
20. The display driver according to claim 19 , wherein the plurality of liquid crystal display elements include pixels configured to receive gradation voltages from the drive voltage-producing circuit.