Fast gate driver circuit
AssigneeApple Inc.
InventorJames E. C. Brown
Life of this patent
Estimating the term…
Abstract
A gate line driver circuit for a display panel includes a pull up circuit to drive a gate line of a display panel to a positive voltage that causes display panel switch elements that are coupled to the gate line to transition into an on state, a first pull down transistor to drive the gate line to a first negative voltage that causes the coupled display panel switch elements to transition into an off state, and a second pull down transistor to maintain the gate line at a second negative voltage that is less negative than the first negative voltage so as to maintain the coupled display panel switch elements in the off state. Other embodiments are also described and claimed.
Claims20
A gate line driver circuit for a display panel, comprising:
- a pull up circuit to drive a gate line of a display panel to a positive voltage that causes a plurality of display panel switch elements that are coupled to the gate line to transition into an on state;
- a first pull down transistor to directly drive the gate line to a first negative voltage that causes the coupled display panel switch elements to transition into an off state;
- and
- a second pull down transistor to directly drive and maintain the gate line at a second negative voltage, wherein the first voltage is more negative than the second voltage, and the second voltage maintains the coupled display panel switch elements in the off state.
A display system comprising:
- an array of display elements;
- a plurality of gate lines coupled to the display elements;
- a plurality of switch elements each being coupled to a respective combination of display element and gate line;
- a signal generator to produce a positive voltage clock signal, and first and second negative voltage clock signals wherein the first negative voltage clock signal is more negative than the second negative voltage clock signal;
- and
- a plurality of gate drivers each being coupled to drive a respective one of the gate lines, each of the gate drivers having an output stage in which there are a high side transistor and first and second low side transistors, wherein the high side transistor is coupled to directly drive the respective gate line responsive to the positive voltage clock signal, and the first and second low side transistors are coupled to directly drive the respective gate line responsive to the first and second negative voltage clock signals.
A method for driving a gate line of a display panel, comprising:
- pulling up a gate line of a display panel to a positive voltage that causes a plurality of display panel switch elements, that are coupled to the gate line, to turn on;
- then
- pulling down the gate line to a first negative voltage that causes the switch elements to turn off;
- and then
- maintaining the gate line at a second negative voltage, wherein the first voltage is more negative than the second voltage, and the second voltage maintains the switch elements in the off state.
Dependencies are inferred from the claim text.