Driver unit including common level shifter circuit for display panel and nonvolatile memory

• US 20070001981A1
• Filed: 06/27/2006
• Published: 01/04/2007
• Est. Priority Date: 06/29/2005
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Tahata, Takashi
• Granted Patent: US 8,269,708 B2
• Time in Patent Office: Days
• US Class Current: 345/98
• CPC Class Codes: G09G 2310/0289 Details of voltage level shifters arranged for use in a driving circuit
• CPC Class Codes: G09G 3/3674 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

In a driver unit for driving a display panel and a nonvolatile memory, a level shifter circuit receives a driver control signal to generate a level-shifted driver control signal. A display panel driver circuit drives the display panel in accordance with the level-shifted driver control signal. A nonvolatile memory driver circuit drives the nonvolatile memory in accordance with the level-shifted driver control circuit. A selection circuit selects one of the display panel driver circuit and the nonvolatile memory driver circuit.

Claims

1. A driver unit for driving a display panel and a nonvolatile memory, comprising:

a level shifter circuit adapted to receive a driver control signal to generate a level-shifted driver control signal;

a display panel driver circuit connected between said level shifter circuit and said display panel and adapted to drive said display panel in accordance with said level-shifted driver control signal;

a nonvolatile memory driver circuit connected between said level shifter circuit and said nonvolatile memory to drive said nonvolatile memory in accordance with said level-shifted driver control circuit; and

a selection circuit connected to said display panel driver circuit and said nonvolatile memory driver circuit and adapted to select one of said display panel driver circuit and said nonvolatile memory driver circuit.

2. The driver unit as set forth in claim 1, wherein said display panel driver circuit receives all bits of said level-shifted driver control signal and said nonvolatile memory driver circuit receives at least a part of the bits of said level-shifted driver control signal.

3. The driver unit as set forth in claim 1, wherein said nonvolatile memory driver circuit receives all bits of said level-shifted driver control signal and said display panel driver circuit receives at least a part of the bits of said level-shifted driver control signal.

4. The driver unit as set forth in claim 1, wherein said selection circuit comprises an additional level shifter circuit adapted to receive a selection signal to generate a level-shifted selection signal and transmit it to said display panel driver circuit and said nonvolatile memory driver circuit so that one of said display panel driver circuit and said nonvolatile memory driver circuit is activated and the other is deactivated.

5. The driver unit as set forth in claim 1, wherein said display panel driver circuit comprises:

a first decoder connected to said level shifter circuit and adapted to decode an output signal of said level shifter circuit to generate a gate selection signal; and

a first driver circuit connected to said first decoder and adapted to buffer said gate selection signal to drive one of gate lines of said display panel.

6. The driver unit as set forth in claim 1, wherein said nonvolatile memory driver circuit comprises:

a second decoder connected to said level shifter circuit and adapted to decode an output signal of said level shifter circuit to generate a nonvolatile memory row selection signal; and

a second driver circuit connected to said second decoder and adapted to buffer said nonvolatile memory row selection signal to drive one of word lines of said display panel.

7. The driver unit as set forth in claim 1, further comprising:

a first step-up circuit adapted to generate a first voltage for powering said display panel driver circuit;

a second step-up circuit adapted to generate a second voltage for powering said nonvolatile memory driver circuit; and

a switch circuit connected between said first and second step-up circuits and said level shifter circuit and adapted to power said level shifter circuit with one of said first and second voltages in accordance with whether said selection circuit selects said display panel driver circuit or said nonvolatile memory driver circuit.

8. The driver unit as set forth in claim 7, wherein said first voltage is higher than said second voltage.

9. The driver unit as set forth in claim 8, wherein said level shifter circuit, said selection circuit and said display panel driver circuit have higher breakdown voltage characteristics than those of said nonvolatile memory driver circuit.

10. The driver unit as set forth in claim 1, further comprising:

a common step-up circuit adapted to generate one of first and second voltages in accordance with whether said selection circuit selects said display panel driver circuit or said nonvolatile memory driver circuit,

said level shifter circuit, said selection circuit, said display panel driver circuit and said nonvolatile memory driver circuit being powered with the one of first and second voltages.

11. The driver unit as set forth in claim 10, wherein said first voltage is higher than said second voltage.

12. The driver unit as set forth in claim 11, wherein said level shifter circuit, said selection circuit and said display panel driver circuit and said nonvolatile memory driver circuit have higher breakdown voltage characteristics than definite breakdown voltage characteristics.

13. A display apparatus comprising:

a display panel;

a nonvolatile memory;

a level shifter circuit adapted to receive a first control signal to generate a level-shifted first control signal;

a display panel driver circuit connected between said level shifter circuit and said display panel and adapted to drive said display panel in accordance with said level-shifted control signal;

a nonvolatile memory driver circuit connected between said level shifter circuit and said nonvolatile memory to drive said nonvolatile memory in accordance with said level-shifted control circuit;

a selection circuit connected to said display panel driver circuit and said nonvolatile memory driver circuit and adapted to select one of said display panel driver circuit and said nonvolatile memory driver circuit.