Display device, CMOS operational amplifier, and driving method of display device

• US 9,613,584 B2
• Filed: 03/14/2014
• Issued: 04/04/2017
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Inventors: Kishikawa, Teisuke
• Primary Examiner(s): OLSON, JASON C
• Application Number:
  US14/212,391
• Publication Number:
  US 20140292735A1
• Time in Patent Office: 1,117 Days
• Field of Search: 345211
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3685 Details of drivers for data electrodes

Abstract

A display device includes a display unit which has a plurality of pixels and a plurality of driving lines for driving the plurality of pixels; a driving circuit which drives the plurality of pixels through the plurality of driving lines; and a control unit which adjusts a driving capability of the driving circuit according to the number of simultaneous driving lines of the driving circuit.

Claims

1. A display device comprising:

a display unit which includes a plurality of pixels and a plurality of driving lines for driving the plurality of pixels;

a driving circuit which drives the plurality of pixels through the plurality of driving lines, the driving circuit including an amplifier with an output selectively coupled to any number of the driving lines; and

a control unit which adjusts a driving capability of the driving circuit according to the number of simultaneous driving lines of the driving circuit.

2. The display device according to claim 1, wherein the control circuit adjusts the driving circuit in such a manner that the driving capability is approximately proportional to the number of simultaneous driving lines.

3. A display device comprising:

a display unit which includes a plurality of pixels and a plurality of driving lines for driving the plurality of pixels;

a driving circuit which drives the plurality of pixels through the plurality of driving lines; and

a control unit which adjusts a driving capability of the driving circuit according to the number of simultaneous driving lines of the driving circuit,

wherein,

the driving circuit includes a CMOS operational amplification circuit,

the CMOS operational amplification circuit includes an output stage of a push-pull type output circuit which is configured by a source current output transistor supplying a current to an output terminal, and a sink current output transistor pulling a current from the output terminal, and

the control unit adjusts the driving capability of the driving circuit by adjusting size corresponding values of the source current output transistor and the sink current output transistor.

4. The display device according to claim 3, wherein a ratio between a sum of a transconductance of the source current output transistor and a transconductance of the sink current output transistor, and a capacitance of a load which is driven by the output circuit, is constant before and after the adjustment of the size corresponding value.

5. The display device according to claim 3, further comprising a differential amplification circuit which amplifies and outputs a difference between two inputs, wherein:

the output circuit amplifies the output of the differential amplification circuit and outputs the amplified outputs to the output terminal, and

the adjustment of the size corresponding value and a change of an amount of current flowing in the differential amplification circuit are not in conjunction with each other.

6. The display device according to claim 3, wherein:

the output circuit includes a configuration in which the source current output transistor and the sink current output transistor are connected in series to each other between a power supply and a ground, and outputs a voltage of a connection point of the source current output transistor and the sink current output transistor,

the source current output transistor includes a plurality of transistor elements, and one or more transistor elements selected by an adjustment circuit from among the plurality of transistor elements are connected in parallel between the power supply and the sink current output transistor, and

the sink current output transistor includes a plurality of transistor elements, and one or more transistor elements selected by the adjustment circuit from among the plurality of transistor elements are connected in parallel between the source current output transistor and the ground.

7. A control method of a display device that includes a display unit which has a plurality of pixels and a plurality of driving lines for driving the plurality of pixels, and a driving circuit which drives the plurality of pixels through the plurality of driving lines, the method comprising:

selectively coupling an output of an amplifier of the driving circuit to one or more of the driving lines; and

adjusting a driving capability of the driving circuit according to the number of simultaneous driving lines of the driving circuit.