Source driver output stage circuit, buffer circuit and voltage adjusting method thereof

• US 9,413,310 B2
• Filed: 11/09/2006
• Issued: 08/09/2016
• Est. Priority Date: 11/09/2005
• Status: Active Grant

• Current Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Original Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Inventors: Huang, Kuo-Chan, Huang, Chih-Haur
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Shapiro, Leonid
• Application Number:
  US11/594,774
• Publication Number:
  US 20070103208A1
• Time in Patent Office: 3,561 Days
• Field of Search: 345/204, 345/76, 345/55
• US Class Current: 1/1
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: H03F 2200/78 A comparator being used in a controlling circuit of an amplifier
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers

Abstract

A buffer circuit applied to a source driver output stage circuit includes a buffer and a D-class amplifier. The buffer is coupled to an input voltage for accordingly outputting an output voltage. The D-class amplifier includes a comparator and a switch device. The comparator is for comparing the input voltage and the output voltage and accordingly outputting a comparison signal. The switch device is coupled to an operational voltage for adjusting the output voltage according to the comparison signal.

Claims

1. A voltage adjusting method, applied to a source driver output stage circuit, the source driver output stage circuit comprising a buffer coupled to an input voltage for accordingly outputting an output voltage and adjusting the output voltage towards the input voltage at a predetermined voltage adjusting rate, the voltage adjusting method comprising:

determining if the absolute value of the difference between the output voltage and the input voltage is larger than an offset voltage, and if the absolute value of the difference between the output voltage and the input voltage is larger than the offset voltage, adjusting the output voltage toward the input voltage at a first voltage adjusting rate, wherein the first voltage adjusting rate is larger than the predetermined voltage adjusting rate; and

adjusting the output voltage towards the input voltage at a second voltage adjusting rate if the absolute difference between the output voltage and the input voltage is smaller than the offset voltage, wherein the first voltage adjusting rate is larger than the second voltage adjusting rate.

2. The voltage adjusting method according to claim 1, wherein the output voltage has an initial voltage value, and the absolute difference between the initial voltage value and the input voltage is larger than the offset voltage.

3. The voltage adjusting method according to claim 1, wherein the offset voltage is for controlling power consumption of the source driver output stage circuit.