TW201511541A - Video graphic array interface protection circuit - Google Patents

Abstract

A VGA interface protection circuit comprises a signal generating unit, a switching unit, a first power generating unit and a first VGA interface unit. The signal generating unit generates a signal associated with displaying image. The switching unit coupled to the signal generating unit transforms the signal associated with displaying image to a first display signal and to generate a first trigger signal. The first power generating unit coupled to the switching unit provides a first power signal according to the first trigger signal. The first VGA interface unit coupled to the first power generating unit and the switching unit receives the first display signal and the first power signal for a display unit to display image.

Description

Video image array (VGA) interface protection circuit

The present invention relates to a protection circuit, and more particularly to a Video Graphic Array (VGA) interface protection circuit.

The Video Graphic Array (VGA) interface unit is widely used in various electronic products, such as displays, computer mainframes, etc., and is used to transmit color analog signals to a display.

Traditionally, the VGA interface unit has 15 pins, and at least three pins are respectively used for receiving red (R) color analog signals, blue (B) color analog signals, and green (G) color analog signals, and the other two are connected. The pin is used to receive the horizontal sync signal and the vertical sync signal, and the other pin is used to receive the VCC DC signal for driving the external display. Generally, the VCC DC signal is provided by a switching unit inside the host, wherein the switching unit is configured to convert the VGA signal to the VGA interface unit for display by the external display. Under this architecture, once the external display is leaky, the external voltage will be sent to the host through the VGA interface unit to receive the VCC DC signal pin, which will damage the switching unit coupled to the VGA interface unit. Providing a VGA signal to the VGA interface unit will prevent the external display from being displayed. Therefore, there is a need to avoid this situation. The new circuit design.

In view of the above, the present invention provides a VGA interface protection circuit to solve the problem that components are destroyed by external voltage passing through the VGA interface unit pins into the host.

One aspect of the present invention is to provide a video image array (VGA) interface protection circuit. The VGA interface protection circuit includes a signal generating unit, a switching unit, a first power generating unit, and a first VGA interface unit. The signal generating unit generates a signal related to the displayed image. The switching unit is coupled to the signal generating unit to convert the signal related to the display image into a first displayable signal and generate a first trigger signal. The power generating unit is coupled to the switching unit, and provides a first power signal according to the first trigger signal. The first VGA interface unit is coupled to the first power generating unit and the switching unit, and receives the first displayable signal and the first power signal to provide a display unit for display.

Another aspect of the present invention provides a video image array (VGA) interface protection circuit. The VGA interface protection circuit includes a signal generating unit, a switching unit, a first power generating unit, a second power generating unit, a first VGA interface unit, and a second VGA interface unit. The signal generating unit is configured to generate a signal related to the displayed image and a control signal. The switching unit is coupled to the signal generating unit for converting the signal related to the display image to a first displayable signal or a second displayable signal, and generating a first trigger signal or a second trigger signal according to the control signal. The first power generating unit is coupled to the switching unit for providing the first power signal. The second power generating unit is coupled to the switching unit for providing the second Power signal. The first VGA interface unit is coupled to the first power generating unit and the switching unit. The second VGA interface unit is coupled to the second power generating unit and the switching unit. When the switching unit generates the first trigger signal, the first power generating unit provides a first power signal to the first VGA interface unit, so that a display unit displays the first displayable signal, and when the switching unit generates the second When the signal is triggered, the second power generating unit provides a second power signal to the second VGA interface unit, so that a display unit displays the second displayable signal.

In summary, the present invention provides a DC signal required by the VGA interface unit by a power generating unit independent of the switching unit, so as to prevent the external burst voltage from directly damaging the switching unit via the DC signal pin of the VGA interface unit. The external display unit can still be displayed normally.

100‧‧‧VGA interface protection circuit

101‧‧‧Signal generating unit

102‧‧‧Switch unit

103‧‧‧First VGA interface unit

104‧‧‧First power generation unit

105 and 108‧‧‧ capacitors

106‧‧‧Second VGA interface unit

107‧‧‧Second power generation unit

108, 109 and 110‧‧‧ filters

1061 and 1062‧‧‧Inductors

1063, 1064 and 1065‧‧‧ capacitors

EN1‧‧‧ first trigger signal

EN2‧‧‧ second trigger signal

CN‧‧‧Control signal

IS‧‧‧Signal related signals

DS1‧‧‧The first display signal

DS2‧‧‧Second display signal

FIG. 1 is a schematic diagram showing a VGA interface protection circuit according to an embodiment of the invention.

2 is a schematic illustration of a VGA interface unit in accordance with an embodiment of the present invention.

FIG. 3A is a schematic diagram showing a VGA interface unit coupling filter according to an embodiment of the invention.

Fig. 3B is a schematic diagram showing the structure of a filter according to an embodiment of the present invention.

The following is a detailed description of the preferred embodiment of the present invention with the accompanying drawings The same reference numerals are used to designate the same or similar elements, and are omitted when the same or similar elements are repeatedly described.

FIG. 1 is a schematic diagram showing a VGA interface protection circuit according to an embodiment of the invention. The VGA interface protection circuit 100 of the present invention includes: a signal generating unit 101, a switching unit 102, a first VGA interface unit 103, a first power generating unit 104, a second VGA interface unit 106, and a second power generating unit. Unit 107. The first VGA interface unit 103 and the second VGA interface unit 106 can be externally connected to the display unit (not shown). The signal generating unit 101 generates a control signal CN and a signal IS related to the display image to be transmitted to the switching unit 102, wherein the signal IS related to the display image includes at least a red (R) color analog signal, a blue (B) color analog signal, Green (G) color analog signal, horizontal sync signal, vertical sync signal, start signal, and display data channel signal. The switching unit 102 is coupled to the signal generating unit 101, and selects, according to the control signal CN, the conversion of the display image related signal IS generated by the signal generating unit 101 to the first displayable signal DS1 or the second displayable signal DS2 for transmission to the first A VGA interface unit 103 or a second VGA interface unit 106 is provided for display to an external display unit. In addition, the switching unit 102 also generates a first trigger signal (EN1) or a second trigger signal (EN2) according to the internally detected output first displayable signal or second displayable signal, and transmits the first trigger signal (EN1) to the first power generating unit 104. Or the second power generating unit 107 supplies power to the first VGA interface unit 103 or the second VGA interface unit 106. That is, the switching unit 102 can select one of the first VGA interface unit 103 or the second VGA interface unit 106 to transmit the relevant displayable signal and the power signal according to the control signal CN. It should be noted that, in this embodiment, the selection of the displayable signal and the two power generating units 104 and 107 respectively respectively pair the two VGA interface units 103 and 106 The power supply is taken as an example to illustrate the application of the present invention. However, the present invention can also be applied to other numbers of VGA interface units, and is not limited to two. For example, in an embodiment with only a single VGA interface unit, only a single power generating unit is needed, and the switching unit 102 directly converts the signal related to the display image generated by the signal generating unit 101 into a display image. The display signal can be transmitted to the VGA interface unit. In addition, the first power generating unit 104 and the second power generating unit 107 are independent of the switching unit 102 and can be output according to the first trigger signal (EN1) and the second trigger signal (EN2) generated by the switching unit 102. The VCC DC signal is applied to the first VGA interface unit 103 and the second VGA interface unit 106 to drive the external display unit. The first power generating unit 104 and the second power generating unit 107 are provided separately from the switching unit 102 to provide a VCC DC signal to the first VGA interface unit 103 and the second VGA interface unit 106 to drive the external display unit. The problem that the external burst voltage is prevented from passing through the first VGA interface unit 103 and the second VGA interface unit 106 to drive the external display unit to damage the switching unit 102 can be avoided. In an embodiment, the signal generating unit 101 is a basic controller of a server for managing the control system, and the I/O device can be controlled independently of other hardware parts of the server to implement data between the I/O device and the server. exchange.

2 is a schematic illustration of a VGA interface unit in accordance with an embodiment of the present invention. The first VGA interface unit 103 and the second VGA interface unit 106 each have 15 pins. The pin 1 is for receiving a red (R) color analog signal; the pin 2 is for receiving a green (G) color analog signal; the pin 3 is for receiving a blue (B) color analog signal; and the pin 4 is not connected; Pin 5 is grounded; pin 6 red (R) color analog signal is grounded; pin 7 green (G) color analog signal is grounded; pin 8 blue (B) color analog signal is grounded; pin 9 is used to receive VCC DC signal ; pin 10 is grounded; pin 11 The connection is not made; the pin 12 is for receiving the data signal; the pin 13 is for receiving the horizontal synchronization signal; the pin 14 is for receiving the vertical synchronization signal; and the pin 15 is for receiving the clock signal. Wherein, according to the embodiment, the VCC DC signal received by the pin 9 is provided by the power generating unit 104. The red (R) color analog signal received by the pin 1, the green (G) color analog signal received by the pin 2, the blue (B) color analog signal received by the pin 3, and the received data signal of the pin 12 The horizontal synchronizing signal received by the pin 13 and the vertical synchronizing signal received by the pin 14 and the clock signal received by the pin 15 are all provided by the switching unit 102.

Accordingly, in the architecture of the present invention, the signals related to the display image received by the first VGA interface unit 103 and the second VGA interface unit 106 are transmitted by the switching unit 102, and the first VGA interface unit 103 and the second VGA are The VCC DC signals received by the interface unit 106 are respectively provided by a first power generating unit 104 and a second power generating unit 107 which are independent of the switching unit 102. Therefore, even if the first VGA interface unit 103 and the second VGA interface unit 106 are coupled to each other, the external display voltage does not pass through the first VGA interface unit 103 and the second VGA interface unit 106. The pin damage switching unit 102 receives the VCC DC signal, and the first power generating unit 104 and the second power generating unit 107 also have anti-interference capability for the burst voltage. Therefore, the switching unit 102 can still normally output the signal generating unit 101. The generated signal related to the display image is transmitted to the corresponding first VGA interface unit 103 or the second VGA interface unit 106, so that the external display unit can still be displayed normally.

In addition, in another embodiment, in order to prevent the first VGA interface unit 103 and the first power generating unit 104 from being damaged due to electrostatic discharge (ESD), the present invention is further applied to the first power generating unit 104 and the first VGA. Interface list A capacitor 105 is externally connected between the elements 103 and placed adjacent to the first VGA interface unit 103. One end of the capacitor 105 is grounded to serve as an ESD protection circuit to provide an ESD current path during an ESD event, preventing the sudden electrostatic current from flowing into the first power generating unit 104 and the first VGA interface unit 103 to cause damage. . Similarly, in order to prevent the second VGA interface unit 106 and the second power generating unit 107 from being damaged due to electrostatic discharge (ESD), a capacitor 108 is externally connected between the second power generating unit 107 and the second VGA interface unit 106. And placed close to the second VGA interface unit 106. One end of the capacitor 108 is grounded to serve as an electrostatic discharge protection circuit to provide a current path of electrostatic discharge during an electrostatic discharge event, so as to prevent the sudden electrostatic current from flowing into the second power generating unit 107 and the second VGA interface unit 106 to cause damage. .

In an implementation, as shown in FIG. 3A, the present invention further includes a plurality of filters 108, 109, and 110 coupled to the first VGA interface unit 103 for performing analog signals transmitted to the first VGA interface unit 103. Filtering. For example, the filter 108 is used to filter the red analog signal, the filter 109 is used to filter the green analog signal, and the filter 110 is used to filter the blue analog signal to filter out the noise in the signal. It should be noted that the second VGA interface unit 106 can also be designed in the same manner, and the second VGA interface unit 106 is coupled to the second VGA interface unit 106 to filter the analog signal transmitted to the second VGA interface unit 106. FIG. 3B is a schematic diagram showing the structure of a filter according to an embodiment of the present invention, wherein the filters 108, 109, and 110 can adopt the same filter circuit structure. Taking the filter 108 as an example, the two inductors 1081 and 1082 and a dual-inductive π-type LC low-pass filter composed of three capacitors 1083, 1084 and 1085. It should be noted that in this embodiment, the filters 108, 109 and 110 are disposed in the first VGA interface unit 103. And the switching unit 102, and close to the first VGA interface unit 103.

In summary, the present invention provides a VCC DC signal required by the VGA interface unit by a power generation unit independent of the switching unit, so as to avoid external burst voltage switching directly through the VCC DC signal pin of the VGA interface unit. The unit, in other words, the switching unit can still normally transmit the display signal to the VGA interface unit, so that the external display unit can still display normally.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧VGA interface protection circuit

101‧‧‧Signal generating unit

102‧‧‧Switch unit

103‧‧‧First VGA interface unit

104‧‧‧First power generation unit

105 and 108‧‧‧ capacitors

106‧‧‧Second VGA interface unit

107‧‧‧Second power generation unit

EN1‧‧‧ first trigger signal

EN2‧‧‧ second trigger signal

CN‧‧‧Control signal

IS‧‧‧Signal related signals

DS1‧‧‧The first display signal

DS2‧‧‧Second display signal

Claims (11)

A video image array (VGA) interface protection circuit includes at least one signal generating unit for generating a signal related to a display image, and a switching unit coupled to the signal generating unit for converting the display image The signal is a first displayable signal associated with the display image, and generates a first trigger signal; a first power generating unit is coupled to the switching unit for providing a first power signal according to the first trigger signal; And a first VGA interface unit coupled to the first power generating unit and the switching unit for receiving the first displayable signal and the first power signal to provide a display unit for display. The video image array interface protection circuit of claim 1, further comprising three filters coupled between the first VGA interface unit and the switching unit, wherein the three filters are respectively used to respectively A red analog signal, a blue analog signal, and a green analog signal in the display signal are filtered, and the filtered red analog signal, the blue analog signal, and the green analog signal are transmitted to the first VGA interface unit. . The video image array interface protection circuit of claim 2, wherein each of the filters is a dual-inductive π-type LC low-pass filter composed of two inductors and three capacitors. The video image array interface protection circuit of claim 1, further comprising a capacitor disposed between the first power generating unit and the first VGA interface unit, wherein one end of the capacitor is grounded. The video image array interface protection circuit of claim 1, further comprising a second power generating unit coupled to the switching unit, and a second VGA interface unit coupled to the second power generating unit and the switching unit. The video image array interface protection circuit of claim 5, wherein the second power generation unit provides a second power signal according to the second trigger signal generated by the switching unit, and the second VGA interface unit receives A second displayable signal and the second power signal are provided to provide a display unit for display. The video image array interface protection circuit of claim 5, further comprising a capacitor disposed between the second power generating unit and the second VGA interface unit, wherein one end of the capacitor is grounded. The video image array interface protection circuit of claim 6, further comprising three filters coupled between the second VGA interface unit and the switching unit, wherein the three filters are respectively used for the second A red analog signal, a blue analog signal, and a green analog signal in the signal can be displayed for filtering, and the filtered red analog signal, the blue The analog signal and the green analog signal convey the second VGA interface unit. A video image array (VGA) interface protection circuit includes at least a signal generating unit for generating a signal related to a display image and a control signal; a switching unit coupled to the signal generating unit, and selecting according to the control signal Converting the signal related to the display image to a first displayable signal or a second displayable signal, the switching unit generating a first according to the internally detected output of the first displayable signal or the second displayable signal a triggering signal or a second triggering signal; a first power generating unit coupled to the switching unit for providing a first power signal; a second power generating unit coupled to the switching unit for providing a second power signal a first VGA interface unit coupled to the first power generating unit and the switching unit; and a second VGA interface unit coupled to the second power generating unit and the switching unit; wherein when the switching unit generates the a first power generating unit provides a first power signal to the first VGA interface unit to enable a display unit to display The first displayable signal, and when the switching unit generates the second trigger signal, the second power generating unit provides a second power signal to the second VGA interface unit, so that a display unit displays the second displayable signal. The video image array interface protection circuit of claim 9, further comprising a first capacitor disposed between the first power generating unit and the first VGA interface unit, wherein one end of the first capacitor is grounded; And a second capacitor is disposed between the second power generating unit and the second VGA interface unit, wherein one end of the second capacitor is grounded. The video image array interface protection circuit of claim 9, further comprising: three filters coupled between the first VGA interface unit and the switching unit, wherein the three filters are respectively used to a red analog signal, a blue analog signal, and a green analog signal in the display signal are filtered, and the filtered red analog signal, the blue analog signal, and the green analog signal are transmitted to the first VGA interface. And a third filter coupled between the second VGA interface unit and the switching unit, wherein the three filters are respectively used for one red analog signal, one blue analog signal, and one of the second displayable signals The green analog signal is filtered, and the filtered red analog signal, the blue analog signal, and the green analog signal are transmitted to the second VGA interface unit.