Current drive system
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsYoshito Date, Tetsuro Omori, Makoto Mizuki
Life of this patent
Estimating the term…
Abstract
In a current drive system for current-driving a display panel such as an organic EL panel, display crosstalk caused by a bias-voltage variation due to induction from the display panel is prevented. For this prevention, the current drive system includes: a plurality of drivers for current-driving a plurality of display element circuits in the display panel; and a bias circuit with a low output impedance for generating a bias voltage and supplying the bias voltage to each of the drivers through a bias line. The output impedance of the bias circuit is set sufficiently low so that a voltage variation caused on the bias line due to switching operation of each switch in the drivers converges within a period during which display data is written.
Claims22
A current drive system for current-driving a plurality of display element circuits in a display panel, the system comprising:
- a plurality of drivers associated with the respective display element circuits, each of the drivers including
- at least one transistor whose gate is connected to a bias line and which allows a current in an amount corresponding to a bias voltage applied through the bias line to flow between the source and drain of the transistor and
- at least one switch associated with the transistor and performing switching operation based on display data to electrically connect or disconnect the transistor to/from a drive line for driving an associated one of the display element circuits;
- and
- a bias circuit having an output impedance which is low enough to have a voltage variation occurring on the bias line due to the switching operation of the switch converge within a period during which the display data is written, the bias circuit generating the bias voltage and outputting the bias voltage to the bias line.
A current drive system for current-driving a plurality of display element circuits in a display panel, the system comprising:
- a plurality of drivers associated with the respective display element circuits, each of the drivers including
- at least one transistor whose gate is connected to a bias line and which allows a current in an amount corresponding to a bias voltage applied through the bias line to flow between the source and drain of the transistor and
- at least one switch associated with the transistor and performing switching operation based on display data to electrically connect or disconnect the transistor to/from a drive line for driving an associated one of the display element circuits;
- a bias circuit for generating the bias voltage and outputting the bias voltage to the bias line;
- and
- an output impedance switching circuit for setting an output impedance of the bias circuit relatively low in accordance with a pulse signal indicating a timing of writing the display data, during a given period starting with reception of the pulse signal.
A current drive system for current-driving a plurality of display element circuits in a display panel, the system comprising a plurality of drivers associated with the respective display element circuits,
- wherein each of the drivers includes:
- at least one transistor whose gate is connected to a bias line and which allows a current in an amount corresponding to a bias voltage applied through the bias line to flow between the source and drain of the transistor;
- and
- at least one switch associated with the transistor and performing switching operation based on display data to electrically connect or disconnect the transistor to/from a drive line for driving an associated one of the display element circuits;
- and
- current limiting means for limiting a current flowing from the drive line while the switch is ON such that a voltage variation on the bias line caused by the current converges within a period during which the display data is written.
A current drive system for current-driving a plurality of display element circuits in a display panel, the system comprising:
- a plurality of drivers associated with the respective display element circuits, each of the drivers including
- at least one transistor whose gate is connected to a bias line and which allows a current in an amount corresponding to a bias voltage applied through the bias line to flow between the source and drain of the transistor and
- at least one switch associated with the transistor and performing switching operation based on display data to electrically connect or disconnect the transistor to/from a drive line for driving an associated one of the display element circuits;
- a bias circuit for generating the bias voltage and outputting the bias voltage to the bias line;
- and
- an output impedance switching circuit for switching an output impedance of the bias circuit in accordance with a static characteristic of the display panel.
Dependencies are inferred from the claim text.