CN100490516C - Ditial light display rear projection VGA extension circuit - Google Patents
Ditial light display rear projection VGA extension circuit Download PDFInfo
- Publication number
- CN100490516C CN100490516C CNB2006100329724A CN200610032972A CN100490516C CN 100490516 C CN100490516 C CN 100490516C CN B2006100329724 A CNB2006100329724 A CN B2006100329724A CN 200610032972 A CN200610032972 A CN 200610032972A CN 100490516 C CN100490516 C CN 100490516C
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- Prior art keywords
- vga
- interface circuit
- projector
- digital optical
- display rear
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Abstract
The invention comprises a directly-outputting interface circuit (CON1) for sending VGA signals to a display. It also comprises more than one interface expanding circuit with high input impedance and low output resistance. The interface expanding circuit outputs the VGA signals to a corresponding interface circuit that is connected to a corresponding display. The invention can avoid bad display situation such as: no image or image distortion.
Description
Affiliated technical field
The present invention relates to a kind of VGA expanded circuit, particularly digital optical display rear-projector VGA out-expander.
Background technology
In teaching such as gave lessons at the field, often a display was not enough, needed a computer join plural display, if the VGA output signal of computer directly promotes plural display, display can occur not having bad phenomenon such as image or scalloping.If the circuit cost that use IC etc. sets up is too high again.
Summary of the invention
Technical problem to be solved of the present invention provides a kind of digital optical display rear-projector VGA expanded circuit that can allow the VGA output signal directly promote plural display.
The present invention includes a direct output interface circuit CON1, directly output interface circuit CON1 directly delivers to the VGA signal display, it is characterized in that: also comprise more than one input impedance height, the little expansion interface circuit of output impedance, expansion interface circuit outputs to corresponding interface circuit with the VGA signal, and interface circuit connects corresponding display.
Above-mentioned expansion interface circuit is one, and expansion interface circuit outputs to corresponding interface circuit CON3 with the VGA signal, and interface circuit CON3 connects second corresponding display.
Above-mentioned expanded circuit specifically is made up of three triode Q1, Q2, Q3, the rgb signal of VGA is the base stage that is coupled to triode Q1, Q11, Q21 of process C1, C11, C21 electrochemical capacitor respectively, export rgb signal respectively to interface circuit by transistor emitter, the row of VGA (HSYNC) (VSYNC) pulse signal is directly linked interface circuit, be respectively equipped with R1, R2, R11, R12, R21, R22 biasing resistor up and down at transistor base, be connected with resistance R 3, R13, R23 respectively between the emitter of triode and GND, the collector electrode of triode meets power supply VCC.
Above-mentioned power supply VCC is the 5V power supply.
Above-mentioned C1, C11, C21 select common electrochemical capacitor 10UF/16V for use.
Above-mentioned R3, R13, R23 are 75 Europe resistance.
At row (HSYNC) (VSYNC) pulse signal inter-burst hundreds of Europe resistance of CON1 to CON3.
Be parallel with a power filtering capacitor C2 at the above-mentioned two ends of biasing resistor up and down, a capacitor C 3 of eliminating the power supply High-frequency Interference.
Above-mentioned C2 selects the 220UF/16 electrochemical capacitor for use, and C3 selects 0.1UF magnetic sheet electric capacity for use.
The present invention is owing to adopt input impedance height, the little expansion interface circuit of output impedance to realize that the signal of VGA connects, and bad phenomenon such as image or scalloping therefore can not occur not having.And it also has plurality of advantages such as making is simple, debugging is easy, cost is cheap.
Description of drawings
Fig. 1 is the electrical block diagram of the embodiment of the invention.
The invention will be further described below in conjunction with the drawings and specific embodiments.
Embodiment
The circuit theory diagrams of the technical scheme of embodiment see also Fig. 1, mainly are made up of elements such as NPN triode, resistance, electric capacity.It utilizes the low characteristics of input impedance high output impedance.Because the overall volume of this device is very little, can be directly installed on household electrical appliance the insides such as rear-projection TV, CRT TV, plasm TV.Add it and directly utilize 5V power supply (Fig. 1 VCC), as it self working power, thus can not do big change to the connection line in these electrical equipment, because the 5V power supply is the power supply that the electrical equipment the inside all has.
Selection of components and making: the Q1 among Fig. 1, Q11, Q21 can select commercially available 2N3904 triode for use.In general electronic market, very difficult to find and price is extremely low.C1, C11, C21 select common electrochemical capacitor 10UF/16V for use, and C2 selects the 220UF/16 electrochemical capacitor for use, and C2 is a power filtering capacitor, and C3 selects 0.1UF magnetic sheet electric capacity for use, and C3 is an electric capacity of eliminating the power supply High-frequency Interference.R3, R13, R23 are 75 Europe resistance.Other electronic components do not have any specific (special) requirements.
Further specify VGA transmission method of signal among the embodiment below.
The VGA signal mainly is made up of a rgb signal and row (HSYNC) (VSYNC) pulse, VGA signals such as computer are imported by CON1, one the tunnel directly exports CON2 delivers to a display, realize through expanded circuit on another road, rgb signal passes through C1 respectively, C11, the C21 electrochemical capacitor be coupled to triode Q1, Q11, the base stage of Q21, R1, R2, R11, R12, R21, R22 is the biasing resistor up and down of triode, because the very high not influence of first via display of circuit input impedance to CON2, export rgb signal respectively by the triode transmitter utmost point, the impedance of output is in R3, R13, the value of R23 parallel connection, so output impedance is very little, increased load-carrying ability, can be because of a little less than the signal and a little less than not causing display image, row (HSYNC) (VSYNC) pulse signal directly outputs to CON3 by CON1, and CON3 connects the second road display.If owing to VGA input signal strength or other reason cause signal skew, can be at row (HSYNC) (VSYNC) pulse signal inter-burst hundreds of Europe resistance of CON1 to CON3, display image can be normal.
Claims (7)
1, a kind of digital optical display rear-projector VGA expanded circuit, comprise a direct output interface circuit, directly output interface circuit is directly delivered to the VGA signal display, it is characterized in that: also comprise more than one input impedance height, the expansion interface circuit that output impedance is little, each expansion interface circuit outputs to corresponding interface circuit with the VGA signal, each interface circuit connects corresponding display, expansion interface circuit is specifically by the triode Q1 of three parallel connections, Q11, Q21 forms, the rgb signal of VGA passes through C1 respectively, C11, the C21 electrochemical capacitor is coupled to triode Q1, Q11, the base stage of Q21, export rgb signal respectively to interface circuit by transistor emitter, the capable field pulse signal of VGA is directly linked interface circuit, be respectively equipped with R1 at transistor base, R2, R11, R12, R21, R22 is biasing resistor up and down, between the emitter of triode and GND, be connected with resistance R 3 respectively, R13, R23, the collector electrode of triode meets power supply VCC.
2, digital optical display rear-projector VGA expanded circuit according to claim 1, it is characterized in that: above-mentioned power supply VCC is the 5V power supply.
3, digital optical display rear-projector VGA expanded circuit according to claim 1, it is characterized in that: above-mentioned C1, C11, C21 select common electrochemical capacitor 10UF/16V for use.
4, digital optical display rear-projector VGA expanded circuit according to claim 1 is characterized in that: above-mentioned R3, R13, R23 are 75 Europe resistance.
5, digital optical display rear-projector VGA expanded circuit according to claim 1 is characterized in that: at direct output interface circuit hundreds of Europe resistance of capable field pulse signal centre series connection to interface circuit.
6, digital optical display rear-projector VGA expanded circuit according to claim 1 is characterized in that: be parallel with a power filtering capacitor C2 at the above-mentioned two ends of biasing resistor up and down, a capacitor C 3 of eliminating the power supply High-frequency Interference.
7, digital optical display rear-projector VGA expanded circuit according to claim 6, it is characterized in that: above-mentioned C2 selects the 220UF/16 electrochemical capacitor for use, and C3 selects 0.1UF magnetic sheet electric capacity for use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100329724A CN100490516C (en) | 2006-01-16 | 2006-01-16 | Ditial light display rear projection VGA extension circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100329724A CN100490516C (en) | 2006-01-16 | 2006-01-16 | Ditial light display rear projection VGA extension circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101005596A CN101005596A (en) | 2007-07-25 |
| CN100490516C true CN100490516C (en) | 2009-05-20 |
Family
ID=38704419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100329724A Expired - Fee Related CN100490516C (en) | 2006-01-16 | 2006-01-16 | Ditial light display rear projection VGA extension circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100490516C (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2562528Y (en) * | 2002-04-08 | 2003-07-23 | 黄阿前 | TV receiving and DVD device separated from display screen |
| CN1586397A (en) * | 2004-10-19 | 2005-03-02 | 天津师范大学 | Intelligent full automatic dead-beat device of multiple display screens |
| US6942521B1 (en) * | 2004-08-10 | 2005-09-13 | Nvidia Corporation | VGA connector with integral filter |
| CN1704896A (en) * | 2004-06-01 | 2005-12-07 | 联想(北京)有限公司 | Portable equipment video switching equipment and switching method thereof |
-
2006
- 2006-01-16 CN CNB2006100329724A patent/CN100490516C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2562528Y (en) * | 2002-04-08 | 2003-07-23 | 黄阿前 | TV receiving and DVD device separated from display screen |
| CN1704896A (en) * | 2004-06-01 | 2005-12-07 | 联想(北京)有限公司 | Portable equipment video switching equipment and switching method thereof |
| US6942521B1 (en) * | 2004-08-10 | 2005-09-13 | Nvidia Corporation | VGA connector with integral filter |
| CN1586397A (en) * | 2004-10-19 | 2005-03-02 | 天津师范大学 | Intelligent full automatic dead-beat device of multiple display screens |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101005596A (en) | 2007-07-25 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090520 Termination date: 20100219 |