Abstract:
A video server device provides digitization and networking functions to a CCTV camera. To make installation of a video server device easier, the video server device includes a network connector for carrying first data signals, second data signals, and direct current power, an interface circuit including transformers for splitting the data signals and the power signals and/or traces for carrying the direct current, a DC/DC converter for tapping the direct current power from the transformers and/or the traces of the network connector for generating a first voltage source, and an output power connector for providing the fourth voltage source to the CCTV camera.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to closed circuit television, and more particularly, to a video server device with a power port for powering a closed circuit television camera. 
         [0003]    2. Description of the Prior Art 
         [0004]    Closed-circuit television (CCTV) differs from broadcast television in that video signals captured by CCTV cameras are viewable only at specified locations. CCTV is utilized by banks, schools, and even governments to prevent crimes, such as theft, and as an aid to law enforcement officials in solving crimes. CCTV may also be utilized in plants, where conditions are unsafe for a human observer to be present, but monitoring of events is necessary. 
         [0005]    As Internet infrastructure has grown in scale, and network equipment costs have come down, Internet Protocol cameras (IPCAMs) are growing in popularity as a potential replacement for traditional CCTV cameras. IPCAMs combine digital video capture technology with data networking technology to provide remote access and control of the IPCAM. An IPCAM may utilize a digital sensor to capture digital video signals, and a network transceiver for transmitting the digital video signals over a network connection to another networked device, such as a personal computer, or a monitoring station. The network transceiver may also receive control signals for controlling pan, tilt, and zoom (PTZ) of the IPCAM. The digital video signals and the control signals may be transmitted/received to/from the other networked device over a wired network connection or a wireless network connection. 
         [0006]    Although IPCAMs provide many benefits to users, much security camera infrastructure utilizing traditional CCTV technology already exists. To provide the networking advantages of IPCAM technology to an existing CCTV system, a video server may be installed alongside each CCTV camera. The video server may include digitization circuitry for receiving analog video signals from the CCTV camera, and converting the analog video signals into digital video signals. The video server may also include network circuitry for serving the digital video signals through a network connection. Thus, a traditional CCTV camera video signal feed may be viewed through the Internet by connecting to the video server. 
         [0007]    Please refer to  FIG. 1 , which is a diagram of a video server  100 . The video server  100  is connected to a CCTV camera  110  through a video line for receiving analog video signals from the CCTV camera  110 . The CCTV camera  110  further requires power to operate, and thus is connected to a power socket  120  through a power line for receiving direct current power, e.g. 12 Volts. When installing the video server  100 , the power socket  120  may not be conveniently located in the vicinity of the CCTV camera  110 . Thus, it may be necessary to spend time trying to find the power socket  120 , which may make installation both difficult and inconvenient. Further, if the power socket  120  is located far from the CCTV camera  110 , installation becomes even more of a problem, increasing length of a power cable used for connecting the CCTV camera  110  to the power socket  120 . 
       SUMMARY OF THE INVENTION 
       [0008]    A video server device for receiving video signals from a CCTV camera and providing power to the CCTV camera comprises a network connector, and interface circuit, a first DC/DC converter, and an output power connector. The network connector comprises a first wire pair for carrying first data signals and power and a second wire pair for carrying second data signals and power. The interface circuit comprises a first transformer for splitting direct current and data signals of the first wire pair, and a second transformer electrically connected to the second wire pair for splitting direct current and data signals of the second wire pair. A center-tap of the first transformer and a center-tap of the second transformer form a current circuit. The first DC/DC converter has a first input terminal electrically connected to the center-tap of the first transformer, a second input terminal electrically connected to the center-tap of the second transformer, and an output terminal for outputting a fourth voltage source. The output power connector has an input terminal electrically connected to the output terminal of the first DC/DC converter for receiving the fourth voltage source, and an output terminal for providing the fourth voltage source to the CCTV camera. 
         [0009]    A video server device for receiving video signals from a CCTV camera and providing power to the CCTV camera comprises a network connector, and interface circuit, a first DC/DC converter, and an output power connector. The network connector comprises a first wire pair for carrying first data signals, and a second wire pair for carrying second data signals. The network connector comprises a first spare wire pair and a second spare wire pair for carrying power. The interface circuit is electrically connected to the network connector for merging the first spare wire pair into a first trace for carrying direct current at a first voltage level, and merging the second spare wire pair into a second trace for carrying direct current at a second voltage level. The first trace and the second trace form a current circuit. Voltage difference between the first voltage level and the second voltage level may then be used to form the first voltage source, e.g. 48 Volts. The first DC/DC converter has a first input terminal electrically connected to the first trace and a second input terminal electrically connected to the second trace. The first DC/DC converter converts first voltage source to a fourth voltage source, and outputs the fourth voltage source. The output power connector has an input terminal e to the output terminal of the first DC/DC converter for receiving the fourth voltage source, and an output terminal for providing the fourth voltage source to the CCTV camera. 
         [0010]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a diagram of a video server connected to a CCTV camera. 
           [0012]      FIG. 2  is a diagram of a video server connected to a CCTV camera according to an embodiment of the present invention 
           [0013]      FIG. 3  is a diagram of a first embodiment of the video server of  FIG. 2 . 
           [0014]      FIG. 4  is a diagram of a second embodiment of the video server of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Please refer to  FIG. 2 , which is a diagram of a video server  200  connected to a CCTV camera  210  according to an embodiment of the present invention. The video server  200  may be a device for receiving video signals from a video camera, such as the CCTV camera  210 , and providing power to the CCTV camera. The video server  200  and the CCTV camera  210  may form a networked camera system. The video server  200  may be connected to the CCTV camera  210  through a video line for receiving video signals from the CCTV camera  210 . The video server  200  may comprise a power connector  201  for providing power, e.g. 12 Volts direct current (DC) power, to the CCTV camera  210 . The CCTV camera  210  may receive the power from the video server  200  through the power connector  201  and a power line, such as a power cable. 
         [0016]    Please refer to  FIG. 3 , which is a diagram of a video server  300  according to a first embodiment. The video server  300  may be utilized as the video server  200  in the networked camera system shown in  FIG. 2 . The video server  300  may comply with a Power over Ethernet (PoE) standard, such as IEEE 802.3af-2003, and may comprise video server internal circuitry  310 , an output power connector  320 , a network connector  330 , a first DC/DC converter  340  for providing power to a CCTV camera, such as the CCTV camera  210 , an over-current protection circuit  350 , and a PoE interface  360 . The PoE interface  360  may include a second DC/DC converter  365  for providing power to the video server internal circuitry  310 . The video server  300  may further comprise an analog video signal input connector  370  electrically connected to the video server internal circuit  310  and the CCTV camera. The analog video signal input connector  370  may be a VGA (Video Graphics Array) connector, a composite video connector, an S-Video (Separate Video) connector, or a component video connector. The output power connector  320  may be utilized as the power connector  201  shown in  FIG. 2 . The video server internal circuitry  310  may include application circuitry of the video server  300 , such as analog-to-digital converters, video encoder circuits, and network circuits for digitizing a video signal received from the CCTV camera  210 , encoding the digitized video signal, and transmitting the encoded video signal to a networked device. The network connector  330  may be an RJ-45 connector, and may comprise a plurality of wire pairs  331 ,  332 ,  333 , and  334 . The wire pair  331  may correspond to pins  4  and  5  of the RJ-45 connector, and may be a spare pair. The wire pair  332  may correspond to pins  1  and  2  of the RJ-45 connector, and may be a signal pair. The wire pair  333  may correspond to pins  3  and  6  of the RJ-45 connector, and may be a signal pair. The wire pair  334  may correspond to pins  7  and  8  of the RJ-45 connector, and may be a spare pair. The wire pair  332  may be utilized as a receiving pair, and the wire pair  333  may be utilized as a transmitting pair. The wire pair  332  may also be utilized as the transmitting pair, and the wire pair  333  may also be utilized as the receiving pair. The PoE interface  360  may be connected to the network connector  330  through the plurality of wire pairs  331 ,  332 ,  333 , and  334 . The wire pair  332  may be electrically connected to a primary winding  361 A of a first transformer, and the wire pair  333  may be electrically connected to a primary winding  362 A of a second transformer. The first transformer may comprise the primary winding  361 A and a secondary winding  361 B. The second transformer may comprise the primary winding  362 A and a secondary winding  362 B. The first transformer may be utilized to split power, e.g. direct current, on the wire pair  332  from data signals on the wire pair  332 . The second transformer may be utilized to split power, e.g. direct current, on the wire pair  333  from data signals on the wire pair  333 . The primary winding  361 A may have a first terminal electrically connected to a first wire of the wire pair  332 , and a second terminal electrically connected to a second wire of the wire pair  332 . The primary winding  362 A may have a first terminal electrically connected to a first wire of the wire pair  333 , and a second terminal electrically connected to a second wire of the wire pair  333 . The second DC/DC converter  365  of the PoE interface  360  may receive power by tapping a center-tap of the primary winding  361 A and a center-tap of the primary winding  362 A to receive a first voltage source, e.g. 48 Volts. The center-tap of the first transformer and the center-tap of the second transformer may form a current circuit. The center-tap of the first transformer may form a first voltage level. The center-tap of the second transformer may form a second voltage level. Voltage difference between the first voltage level and the second voltage level may then be used to form the first voltage source, e.g. 48 Volts. 
         [0017]    The second DC/DC converter  365  may have a first input terminal electrically connected to the center-tap on the primary winding  361 A, and a second input terminal electrically connected to the center-tap on the primary winding  362 A. Then, the second DC/DC converter  365  may convert the first voltage source to a second voltage source, e.g. 12 Volts, and a third voltage source, e.g. 5 Volts, for powering the video server internal circuitry  310 . In addition to receiving the second voltage source and the third voltage source from the PoE interface  360 , the video server internal circuitry  310  may also transmit and receive data to and from the second transformer and the first transformer of the PoE interface  360 , respectively. 
         [0018]    To provide power to the CCTV camera  210 , the first DC/DC converter  340  may also tap the primary windings  361 A,  362 A of the first transformer and the second transformer to receive the first voltage source at a first input terminal and a second input terminal, respectively, of the first DC/DC converter  340 . Then, the first DC/DC converter  340  may convert the first voltage source to a fourth voltage source, e.g. 12 Volts, and output the fourth voltage source at an output terminal of the first DC/DC converter  340 . The fourth voltage source may then be provided to the CCTV camera  210  through the output power connector  320 . The over-current protection circuit  350  may be electrically connected between the output terminal of the first DC/DC converter  340  and an input terminal of the output power connector  320  for protecting the CCTV camera  210  from an over-current event in the fourth voltage source. It should be noted that, while preferably both the first and second DC/DC converters  340 ,  365  are utilized in the video server  300 , the first DC/DC converter  340  may be optional, and the second DC/DC converter  365  may be utilized to power the CCTV camera  210  through the over-current protection circuit  350  and the output power connector  320 . The second voltage source of the second DC/DC converter  365  may be utilized for powering the CCTV camera  210 . However, it is preferable to have both the first DC/DC converter  340  and the second DC/DC converter  365 . Powering the CCTV camera  210  through the second DC/DC converter  365  may cause noise in the second and third voltage sources, and if the CCTV camera  210  draws too much current, the video server internal circuitry  310  may be starved of current, causing failures. By utilizing the first DC/DC converter  340 , the CCTV camera  210  may draw power from the first DC/DC converter  340  without affecting operation of the video server internal circuitry  310 . 
         [0019]    Please refer to  FIG. 4 , which is a diagram of a video server  400  according to a second embodiment. The video server  400  may utilize a second PoE architecture different from that used by the video server  300 , in that data and power signals in the second PoE architecture are not sent over single signal pairs. Instead, the second PoE architecture provides data signals on two signal pairs, and power signals on two spare pairs, as described below. The video server  400  may be utilized as the video server  200  in the networked camera system shown in  FIG. 2 . The video server  400  may comply with the Power over Ethernet (PoE) standard described above, and may comprise video server internal circuitry  410 , an output power connector  420 , a network connector  430 , a first DC/DC converter  440 , an over-current protection circuit  450 , and a PoE interface  460 . The video server  400  may further comprise an analog video signal input connector  470  electrically connected to the video server internal circuit  410  and the CCTV camera. The analog video signal input connector  470  may be a VGA (Video Graphics Array) connector, a composite video connector, an S-Video (Separate Video) connector, or a component video connector. The output power connector  420  may be utilized as the power connector  201  shown in  FIG. 2 . The video server internal circuitry  410  may include application circuitry of the video server  400 , such as analog-to-digital converters, video encoder circuits, and network circuits for digitizing a video signal received from the CCTV camera  210 , encoding the digitized video signal, and transmitting the encoded video signal to a networked device. The network connector  430  may be an RJ-45 connector, and may comprise a plurality of wire pairs  431 ,  432 ,  433 , and  434 . The wire pair  431  may correspond to pins  4  and  5  of the RJ-45 connector, and may be a spare pair. The wire pair  432  may correspond to pins  1  and  2  of the RJ-45 connector, and may be a signal pair. The wire pair  433  may correspond to pins  3  and  6  of the RJ-45 connector, and may be a signal pair. The wire pair  434  may correspond to pins  7  and  8  of the RJ-45 connector, and may be a spare pair. The wire pair  432  may be utilized as a receiving pair, and the wire pair  433  may be utilized as a transmitting pair. The wire pair  432  may also be utilized as the transmitting pair, and the wire pair  433  may also be utilized as the receiving pair. The PoE interface  460  may be connected to the network connector  430  through the plurality of wire pairs  431 ,  432 ,  433 , and  434 . The PoE interface  460  may be electrically connected to the network connector  430  for merging the first spare wire pair  431  into a first trace carrying the power signal, and merging the second spare wire pair  434  into a second trace carrying the power signal. The first trace and the second trace form a current circuit. The wire pair  432  may be electrically connected to a primary winding  461 A of a first transformer, and the wire pair  433  may be electrically connected to a primary winding  462 A of a second transformer. The first transformer may comprise the primary winding  461 A and a secondary winding  461 B. The second transformer may comprise the primary winding  462 A and a secondary winding  462 B. The primary winding  461 A may have a first terminal electrically connected to a first wire of the wire pair  432 , and a second terminal electrically connected to a second wire of the wire pair  432 . The primary winding  462 A may have a first terminal electrically connected to a first wire of the wire pair  433 , and a second terminal electrically connected to a second wire of the wire pair  433 . A second DC/DC converter  465  of the PoE interface  460  may receive power from the wire pair  431  and the wire pair  434  through the first trace and the second trace to receive a first voltage source, e.g. 48 Volts. The first trace may form a first voltage level. The second trace may form a second voltage level. Voltage difference between the first voltage level and the second voltage level may then be used to form the first voltage source, e.g. 48 Volts. 
         [0020]    The second DC/DC converter  465  may have a first input terminal electrically connected to the wire pair  431  through the first trace, and a second input terminal electrically connected to the wire pair  434  through the second trace. Then, the second DC/DC converter  465  may convert the first voltage source to a second voltage source, e.g. 12 Volts, and a third voltage source, e.g. 5 Volts, for powering the video server internal circuitry  410 . In addition to receiving the second voltage source and the third voltage source from the PoE interface  460 , the video server internal circuitry  410  may also transmit and receive data to and from the second transformer and the first transformer of the PoE interface  460 , respectively. 
         [0021]    To provide power to the CCTV camera  210 , the first DC/DC converter  440  may also receive power from the first trace and the second trace to receive the first voltage source at a first input terminal and a second input terminal, respectively, of the first DC/DC converter  440 . Then, the first DC/DC converter  440  may convert the first voltage source to a fourth voltage source, e.g. 12 Volts, and output the fourth voltage source at an output terminal of the first DC/DC converter  440 . The fourth voltage source may then be provided to the CCTV camera  210  through the output power connector  420 . The over-current protection circuit  450  may be electrically connected between the output terminal of the first DC/DC converter  440  and an input terminal of the output power connector  420  for protecting the CCTV camera  210  from an over-current event in the fourth voltage source. It should be noted that, while preferably both the first and second DC/DC converters  440 ,  465  are utilized in the video server  400 , the first DC/DC converter  440  may be optional, and the second DC/DC converter  465  may be utilized to power the CCTV camera  410  through the over-current protection circuit  450  and the output power connector  420 . The second voltage source of the second DC/DC converter  465  may be utilized for powering the CCTV camera  210 . However, it is preferable to have both the first DC/DC converter  440  and the second DC/DC converter  465 . Powering the CCTV camera  210  through the second DC/DC converter  465  may cause noise in the second and third voltage sources, and if the CCTV camera  210  draws too much current, the video server internal circuitry  410  may be starved of current, causing failures. By utilizing the first DC/DC converter  440 , the CCTV camera  210  may draw power from the first DC/DC converter  440  without affecting operation of the video server internal circuitry  410 . 
         [0022]    The video servers  300 ,  400  of the above embodiments include the first DC/DC converter  340 ,  440  and the output power connectors  320 ,  420  for providing convenient power connection with the CCTV camera  210 , which makes installation more convenient and easier compared to the prior art, and also shortens length of a power cable utilized to connect the CCTV camera  210  to the output power connector  320 ,  420 . The video servers  300 ,  400  are applicable to different PoE architectures, respectively, providing flexibility in application. 
         [0023]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.