Primary color video signal output circuit

• US 6,023,305 A
• Filed: 06/10/1997
• Issued: 02/08/2000
• Est. Priority Date: 06/10/1996
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Adachi, Hitoshi, Kinugawa, Hiroki, Shimaoka, Hiroyasu, Matsukura, Tsuneo, Kanegami, Yoichi, Ando, Hiroshi, Taketani, Nobuo
• Primary Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US08/872,300
• Time in Patent Office: 973 Days
• Field of Search: 348/678, 348/679, 348/690, 348/691, 348/692
• US Class Current: 348/679
• CPC Class Codes: G09G 1/002 Intensity circuits G09G1/06 - G09G1/28 take precedence
• CPC Class Codes: G09G 3/28 using luminous gas-discharge panels, e.g. plasma panels
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 5/04 using circuits for interfacing with colour displays
• CPC Class Codes: G09G 5/10 Intensity circuits
• CPC Class Codes: H04N 9/68 for controlling the amplitude of colour signals, e.g. automatic chroma control circuits H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86

Abstract

A primary color video output circuit for limiting an input video signal. The circuit includes a clipping circuit, a reference voltage generating circuit and an amplifier. The clipping circuit limits the level of the input video signal based on a reference voltage generated by the reference voltage generating circuit. The amplifier is then used to amplify the clipped video signal.

Claims

1. A primary color video signal output circuit for limiting input of a video signal comprising:

a reference voltage generating circuit for outputting a reference voltage,

a clip circuit for receiving said reference voltage for clipping said video signal based on said reference voltage,

a band gap voltage source wherein said reference voltage generating circuit is coupled to the band gap voltage source, and

an amplifying circuit for amplifying the video signal.

3. A primary color video signal output circuit according to claim 1, further comprising a cutoff/drive adjusting circuit coupled to the clip circuit for cutoff/drive adjustment of the video signal.

7. A primary color video signal output circuit according to claim 1, wherein the clip circuit comprises a transistor having a base terminal which is connected to the reference voltage generating circuit, an emitter terminal which is connected to an input terminal of the amplifying circuit, and a collector terminal which is grounded.

8. A primary color video signal output circuit according to claim 7, further comprising a band gap voltage source wherein the reference voltage generating circuit is coupled to the band gap voltage source.

9. A primary color video signal output circuit according to claim 7, wherein the reference voltage is divided by a resistance coupled to the base terminal of the transistor.

10. A primary color video signal output circuit according to claim 7, further comprising a cutoff/drive adjusting circuit coupled to the clip circuit for cutoff/drive adjustment of the video signal.

2. A primary color video signal output circuit for limiting input of a video signal comprising:

a reference voltage generating circuit for outputting a reference voltage,

a clip circuit for receiving said reference voltage for clipping said video signal based on said reference voltage,

cutoff/drive adjusting circuit coupled to the clip circuit for cutoff/drive adjustment of the video signal, and

an amplifying circuit for amplifying the video signal.

4. A primary color video signal output circuit for limiting input of a video signal comprising:

an adjustable reference voltage generating circuit for outputting a reference voltage,

a clip circuit for receiving said reference voltage for clipping said video signal based on said reference voltage,

a cutoff/drive adjusting circuit coupled to the clip circuit for cutoff/drive adjustment of the video signal, and

an amplifying circuit for amplifying the video signal.

5. A display device for use with a display element, comprising:

a primary color video signal output circuit which includes a reference voltage generating circuit for outputting a reference voltage, and a clip circuit for receiving said reference voltage and for clipping said video signal to limit input of said video signal, and

an amplifying circuit for driving said display element.

6. A television receiver comprising:

a display element,

a primary color video signal output circuit which includes a reference voltage generating circuit for outputting a reference voltage, and a clip circuit for receiving said reference voltage and for clipping a video signal to limit input of said video signal, and

an amplifying circuit for driving said display element.