Output amplifier circuit, display driver and display device

A display driver, comprising:

• a gradation voltage generation circuit, generating first to nth (where n is an integer of 2 or more) gradation voltages each having a voltage value corresponding to a brightness level of each of pixels based on a video signal;
• first to nth amplifiers, receiving the first to nth gradation voltages, and supplying first to nth output voltages by amplifying the respective first to nth gradation voltages to first to nth data lines of a display panel;
• first to Kth bias circuits, provided corresponding to each of first to Kth amplifier groups formed by grouping the first to nth amplifiers into K (where K is an integer of 2 or more) groups, and each generating a bias voltage for setting a current value of an operating current of the amplifiers;
• first to Kth wirings which are independent of one another, supplying the bias voltage generated by each of the first to Kth bias circuits to the first to Kth amplifier groups respectively;
• a switch circuit, when in an ON state, connecting one wiring among the first to Kth wirings with another wiring among the first to Kth wirings that is different from the one wiring;
• and
• a control unit configured to set the switch circuit to an ON state or an OFF state,
• wherein, for each of the data periods comprising a first period immediately after a start of the data period and a second period subsequent to the first period, the control unit is configured to:
• set the switch circuit to an OFF state during the first period, thereby disconnecting a connection between the one wiring and the another wiring;
• and
• set the switch circuit to an ON state at least throughout the second period.

A display device, comprising:

• a display panel, comprising first to nth (where n is an integer of 2 or more) data lines extending along a horizontal direction of a display screen;
• a gradation voltage generation circuit, generating first to nth gradation voltages each having a voltage value corresponding to a brightness level of each of pixels based on a video signal;
• first to nth amplifiers, receiving the first to nth gradation voltages, and supplying first to nth output voltages by amplifying the respective first to nth gradation voltages to the first to nth data lines of the display panel;
• first to Kth bias circuits, provided corresponding to each of first to Kth amplifier groups formed by grouping the first to nth amplifiers into K (where K is an integer of 2 or more) groups, and each generating a bias voltage for setting a current value of an operating current of the amplifiers;
• first to Kth wirings which are independent of one another, supplying the bias voltage generated by each of the first to Kth bias circuits to the first to Kth amplifier groups respectively;
• a switch circuit, when in an ON state, connecting one wiring among the first to Kth wirings with another wiring among the first to Kth wirings that is different from the one wiring;
• and
• a control unit configured to set the switch circuit to an ON state or an OFF state,
• wherein, for each of the data periods comprising a first period immediately after a start of the data period and a second period subsequent to the first period, the control unit is configured to:
• set the switch circuit to an OFF state during the first period, thereby disconnecting a connection between the one wiring and the another wiring;
• and
• set the switch circuit to an ON state at least throughout the second period.