LCD with power conversion capability

• US 7,053,891 B2
• Filed: 11/18/2002
• Issued: 05/30/2006
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: Wistron Corporation
• Original Assignee: Lite-On Technology Corporation
• Inventors: Kee, Yew-Peng
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US10/298,986
• Publication Number:
  US 20030107540A1
• Time in Patent Office: 1,289 Days
• Field of Search: 345 87- 96, 345/204, 345210-215, 363 17- 55, 363130-133, 307 64- 87
• US Class Current: 345/211
• CPC Class Codes: H02M 3/335 using semiconductor devices only

Abstract

An LCD with power conversion capability. The LCD implements a power conversion model inside to convert AC input into DC operating voltage for the LCD. The power conversion model can provide functionalities of output voltage adjustment, voltage overload protection, output short-circuited protection and optimized DC conversion efficiency, thereby achieving the desired reliability.

Claims

1. An LCD with power conversion capability comprising:

a built-in power conversion module to convert AC input into DC operating voltage for the LCD, wherein the power conversion module comprises;

a rectification/filter unit, to convert the AC input into a ripple DC voltage;

a power conversion unit coupled to the rectification/filter unit, to convert the ripple DC voltage into DC operating voltage for a main board in the LCD;

an output rectification/filter unit coupled to the power conversion unit, to filter the DC operating voltage;

a driving unit coupled to the power conversion unit, to control the power conversion unit for conversion of the AC input to DC operating voltage;

a feedback unit coupled to the output rectification/filter unit, to detect the DC operating voltage variation from the output rectification/filter unit; and

a power management unit coupled between the driving unit and the feedback unit, to receive a start voltage output by the rectification/filter unit, output a series of impulses to the driving unit for operation and adjust the impulses'"'"' width according to the variation of the DC operating voltage detected by the feedback unit; and

wherein an output terminal of the built-in power conversion module is coupled to the main board in the LCD using a power output bus.

2. The LCD of claim 1, further comprising a linear filter unit prior to the rectification/filter unit to filter the AC input, thereby reducing electromagnetic interference.

3. The LCD of claim 1, wherein the power management unit receives a sensing voltage output by the power conversion unit when the DC operating voltage raises sharply and thus does not output the impulses.

4. A power conversion module for an LCD with power conversion capability, comprising:

a rectification/filter unit to convert the AC input into a ripple DC voltage;

a power conversion unit coupled to the rectification/filter unit, to convert the ripple DC voltage into a DC operating voltage for supplying a main board in said LCD;

an output rectification/filter unit coupled to the power conversion unit, to filter the DC operating voltage;

a driving unit coupled to the power conversion unit, to control the power conversion unit for conversion of the AC input to the DC operating voltage;

a feedback unit coupled to the output rectification/filter unit, to detect the DC operating voltage variation from the output rectification/filter unit; and

a power management unit coupled between the driving unit and the feedback unit, to receive a start voltage output by the rectification/filter unit, output a series of impulses to the driving unit for operation and adjust the impulses'"'"' width according to the variation of the DC operating voltage detected by the feedback unit.

5. The power conversion module of claim 4, further comprising a linear filter unit prior to the rectification/filter unit to filter the AC input, thereby reducing electromagnetic interference.

6. The power conversion module of claim 4, wherein the power management unit receives a sensing voltage output by the power conversion unit when the DC operating voltage raises sharply and thus does not output the impulses.