DRIVING APPARATUS, DRIVING APPARATUS OPERATING METHOD, AND SELF-JUDGEMENT SLEW RATE ENHANCING AMPLIFIER

• US 20130286002A1
• Filed: 04/29/2013
• Published: 10/31/2013
• Est. Priority Date: 04/27/2012
• Status: Active Grant

• Current Assignee: Raydium Semiconductor Corporation
• Original Assignee: Raydium Semiconduction Corporation
• Inventors: Huang, Chih Chuan
• Granted Patent: US 9,305,499 B2
• Time in Patent Office: Days
• US Class Current: 345/213
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A driving apparatus applied in a liquid crystal display is disclosed. The driving apparatus at least includes a first latch, a second latch, an output buffer, and a slew rate enhancing module. The first latch is used to store a second data signal. The second latch is used to store a first data signal. The first data signal is previous to the second data signal. The slew rate enhancing module is used to compare the first data signal and the second data signal to generate a compared result, and correspondingly output a control signal to the output buffer according to the compared result to control a driving current of the output buffer.

Claims

1. A driving apparatus, applied to a liquid crystal display, the driving apparatus comprising:

a first latch, for storing a second data signal;

a second latch, coupled to the first latch, for storing a first data signal, wherein the first data signal is previous to the second data signal;

an output buffer; and

a slew rate enhancing module, coupled to the first latch, the second latch, and the output buffer respectively, for comparing the first data signal and the second data signal to generate a compared result, and correspondingly output a control signal to the output buffer according to the compared result to control a driving current of the output buffer.

2. The driving apparatus of claim 1, wherein the slew rate enhancing module comprises:

a comparing unit having two input terminals and an output terminal, the two input terminals are coupled to the first latch and the second latch respectively and receive the second data signal and the first data signal, the comparing unit compares the first data signal and the second data signal to generate the compared result and the output terminal outputs the compared result; and

a level shifting unit coupled to the output terminal of the comparing unit and the output buffer, the level shifting unit correspondingly converts the compared result with low level into the control signal with high level and outputs the control signal to the output buffer.

3. The driving apparatus of claim 2, wherein the comparing unit is a logical judgment circuit.

4. The driving apparatus of claim 1, further comprising:

a level shifter, coupled to the second latch, for converting the first data signal and the second data signal from low level to high level respectively; and

a digital-analog converter, coupled to the level shifter, for converting the first data signal and the second data signal from digital voltage to analog voltage respectively.

5. The driving apparatus of claim 4, wherein the digital-analog converter is an N-type digital-analog converter or a P-type digital-analog converter used for outputting a negative analog voltage or a positive analog voltage.

6. The driving apparatus of claim 5, further comprising:

an exchanging switch, coupled between the digital-analog converter and the output buffer, for selectively transmitting the negative analog voltage or the positive analog voltage outputted by the digital-analog converter to the output buffer.

7. A driving apparatus operating method, for operating a driving apparatus applied to a liquid crystal display, the driving apparatus comprising a first latch, a second latch, and an output buffer, a first data signal stored in the second latch being previous to a second data signal stored in the first latch, the method comprising steps of:

(a) comparing the first data signal with the second data signal to generate a compared result; and

(b) correspondingly output a control signal to the output buffer according to the compared result to dynamically adjust a driving current of the output buffer.

8. The driving apparatus operating method of claim 7, wherein the step (b) is to correspondingly convert the compared result with low level into the control signal with high level and output the control signal to the output buffer.

9. The driving apparatus operating method of claim 7, further comprising the steps of:

(c) converting the first data signal and the second data signal from low level to high level respectively; and

(d) converting the first data signal and the second data signal from digital voltage to analog voltage respectively.

10. The driving apparatus operating method of claim 9, wherein the step (d) is to output a negative analog voltage or a positive analog voltage.

11. The driving apparatus operating method of claim 10, further comprising the step of:

(e) selectively transmitting the negative analog voltage or the positive analog voltage outputted in the step (d) to the output buffer.

12. A self-judgment slew rate enhancing amplifier, applied to a driving apparatus of a liquid crystal display, the driving apparatus comprising a first latch, a second latch, and an output buffer, the self-judgment slew rate enhancing amplifier comprising:

two input terminals, coupled to the first latch and the second latch respectively and receiving the second data signal and the first data signal from the first latch and the second latch respectively;

a comparing unit, coupled to the two input terminals, for comparing the first data signal and the second data signal to generate a compared result; and

an output terminal, coupled to the comparing unit, for outputting the compared result.

13. The self-judgment slew rate enhancing amplifier of claim 12, wherein the driving apparatus further comprises a level shifting unit coupling to the output terminal and the output buffer, the level shifting unit correspondingly converts the compared result with low level into the control signal with high level and outputs the control signal to the output buffer.

14. The self-judgment slew rate enhancing amplifier of claim 12, wherein the comparing unit is a logical judgment circuit.