TECHNICAL FIELD

The present disclosure generally relates to electronic systems such as communication systems. More particularly, the present disclosure is related to an apparatus for protecting a circuit that may be included in such systems from damage that may occur during a surge energy event.

BACKGROUND

Any background information described herein is intended to introduce the reader to various aspects of art, which may be related to the present embodiments that are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light.

Surge energy from an electrical discharge occurrence may be imposed on an outdoor unit, such as a satellite dish, that is coupled to an indoor signal receiving device, such as a set top box or gateway device via, for example, coaxial cable. During an electrical discharge occurrence, surge energy may enter the indoor device and damage one or more of the components therein. Although many devices include surge protection circuits, in some configurations, the surge protection circuits may include a low impedance path that allows the surge energy to pass the surge protection circuit and damage certain components within the indoor device. Therefore, a need exists for surge protection circuits that sufficiently block surge energy imposed on an indoor device during an electrical discharge event. SUMMARY

In one aspect of the present disclosure, an apparatus is provided including: a voltage step- up circuit, the voltage step-up circuit further including a switch, a filter, and a linear regulator, the voltage step-up circuit configured to receive an input direct current (DC) voltage and to produce an output DC voltage higher than the received input DC voltage; a surge energy protection circuit coupled between the output of the voltage step-up circuit and an interface connector on the apparatus, the interface connector coupling the apparatus to an outdoor unit for receiving broadcast signals, the surge energy protection circuit passing the output DC voltage from the voltage step-up circuit to the interface connector on the apparatus, the surge energy protection circuit further suppressing undesired energy that enters the apparatus through the interface connector; and a diode, disposed between the filter and the linear regulator in the voltage step-up circuit, wherein the diode prevents the undesired energy from passing into the voltage step-up circuit.

In accordance with an aspect of the present disclosure, an embodiment of apparatus comprises a voltage control circuit including a filter and a linear regulator configured to produce an operating voltage of the apparatus; a control circuit coupled between an input of the apparatus and the voltage control circuit and configured to reduce an energy surge entering the apparatus through the input; and a diode disposed between the filter and the linear regulator in the voltage control circuit and configured to inhibit passing of energy from the energy surge into the voltage control circuit.

In accordance with another aspect, an embodiment of apparatus including a voltage control circuit comprises a voltage step-up circuit including a switch, a filter, and a linear regulator configured to receive an input direct current (DC) voltage and to produce an operating voltage comprising an output DC voltage higher than the received input DC voltage.

In accordance with another aspect, an embodiment of a control circuit included in various embodiments of apparatus as described herein may comprise a surge energy protection circuit coupled between the output of the voltage control circuit and an interface connector at the input to the apparatus, the interface connector coupling the apparatus to an outdoor unit for receiving broadcast signals, the surge energy protection circuit passing the output DC voltage from the voltage step-up circuit to the interface connector on the apparatus, the surge energy protection circuit further suppressing undesired energy of the energy surge that enters the apparatus through the interface connector.

In accordance with another aspect, an embodiment of apparatus comprises: a voltage step-up circuit, the voltage step-up circuit further including a switch, a filter, and a linear regulator, the voltage step-up circuit configured to receive an input direct current (DC) voltage and to produce an output DC voltage higher than the received input DC voltage; a surge energy protection circuit coupled between the output of the voltage step-up circuit and an interface connector on the apparatus, the interface connector coupling the apparatus to an outdoor unit for receiving broadcast signals, the surge energy protection circuit passing the output DC voltage from the voltage step-up circuit to the interface connector on the apparatus, the surge energy protection circuit further suppressing undesired energy that enters the apparatus through the interface connector; and a diode, disposed between the filter and the linear regulator in the voltage step-up circuit, wherein the diode prevents the undesired energy from passing into the voltage step-up circuit. In accordance with another aspect, one or more of various embodiments of apparatus including a linear regulator as described herein may comprise the linear regulator being configured to receive an output DC voltage from the filter and produce the output DC voltage from the voltage step-up circuit, the output DC voltage from the voltage step-up circuit being lower than the output DC voltage from the filter and higher than the input DC voltage.

In accordance with another aspect, one or more of various embodiments of apparatus including a diode as described herein may comprise the diode including an anode and a cathode, the anode coupled to the filter and the cathode coupled to the linear regulator.

In accordance with another aspect, one or more of various embodiments of apparatus as described herein may comprise a set top box.

In accordance with another aspect, one or more of various embodiments of apparatus including an outdoor unit as described herein may comprise the outdoor unit including a satellite antenna.

In accordance with another aspect, one or more of various embodiments of apparatus including a surge energy protection circuit as described herein may comprise the surge energy protection circuit including at least one transient-voltage suppressor diode and at least one gas discharge tube.

In accordance with another aspect, one or more of various embodiments of apparatus including an interface connector as described herein may comprise the interface connector including an F-connector.

In accordance with another aspect, one or more of various embodiments of apparatus including a voltage step-up circuit as described herein may comprise the voltage step-up circuit including a step-up controller and a feedback network, the feedback network being configured to sense input voltage of the linear regulator and provide a signal to the step-up controller indicating the sensed voltage at the input of the linear regulator.

In accordance with another aspect, one or more of various embodiments of apparatus including a step-up controller as described herein may comprise the step-up controller being configured to adjust an on/off ratio of the switch based on the sensed voltage indicated in the signal.

In accordance with another aspect, one or more of various embodiments of apparatus including a step-up controller configured to adjust an on/off ratio of the switch as described herein may comprise when the on/off ratio of the switch is increased the output DC voltage is increased by the voltage step-up circuit and when the on/off ratio of the switch is decreased the output DC voltage is decreased by the voltage step-up circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

These, and other aspects, features and advantages of the present disclosure will be described or become apparent from the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings.

FIG. 1 is a system for receiving signals in accordance with an embodiment of the present disclosure;

FIG. 2 is a surge energy protection and power supply circuit in accordance with an embodiment of the present disclosure; and

FIG. 3 is another surge energy protection and power supply circuit in accordance with an embodiment of the present disclosure. It should be understood that the drawing(s) are for purposes of illustrating the concepts of the disclosure and is not necessarily the only possible configuration for illustrating the disclosure. DESCRIPTION OF EMBODIMENTS

It should be understood that the elements shown in the figures may be implemented in various forms of hardware, software or combinations thereof. Preferably, these elements are implemented in a combination of hardware and software on one or more appropriately programmed general-purpose devices, which may include a processor, memory and input/output interfaces. Herein, the phrase "coupled" is defined to mean directly connected to or indirectly connected with or through one or more intermediate components. Such intermediate components may include both hardware and software based components.

The present description illustrates the principles of the present disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its scope. Further, other embodiments beyond those described are contemplated and intended to be encompassed within the scope of the present disclosure. For example, additional embodiments may be created by combining, deleting, modifying, or supplementing various features of the disclosed embodiments.

All examples and conditional language recited herein are intended for educational purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the art that the block diagrams presented herein represent conceptual views of illustrative circuitry embodying the principles of the disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, read only memory (ROM) for storing software, random access memory (RAM), and nonvolatile storage.

Other hardware, conventional and/or custom, may also be included. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementer as more specifically understood from the context.

In the claims hereof, any element expressed as a means for performing a specified function is intended to encompass any way of performing that function including, for example, a) a combination of circuit elements that performs that function or b) software in any form, including, therefore, firmware, microcode or the like, combined with appropriate circuitry for executing that software to perform the function. The disclosure as defined by such claims resides in the fact that the functionalities provided by the various recited means are combined and brought together in the manner which the claims call for. It is thus regarded that any means that can provide those functionalities are equivalent to those shown herein.

Surge energy from an electrical discharge occurrence may be imposed on an outdoor unit, such as satellite dish, that is coupled to an indoor signal receiving device, such as a set top box or gateway device via, for example, coaxial cable. During an electrical discharge occurrence, surge energy may enter the indoor device and cause one or more of the components in the indoor device to be damaged. For example, the surge energy may enter the power supply for the outdoor unit that is disposed in the indoor device. Although indoor devices may include surge protection circuits placed between the outdoor unit and the power supply circuit for the outdoor unit, in some configurations, the surge protection circuits may include a low impedance path that allows the surge energy to pass the surge protection circuit and damage certain components within the power supply circuit for the outdoor unit. To overcome this problem, the present disclosure provides a surge protection and outdoor unit power supply circuit that includes a diode disposed between a filter circuit and a linear regulator. The diode between the filter circuit and the linear regulator eliminates the low impedance path that allows surge energy to enter the outdoor unit power supply circuit during an electrical discharge occurrence.

Turning now to the drawings and referring initially to FIG. 1, an exemplary embodiment of a system 100 for receiving signals using aspects of the present disclosure is shown. System

100 primarily receives signals from one or more satellites as well as multiple television broadcast transmission sites. The signals are provided by one or more service providers and represent broadcast audio and video programs and content. System 100 is described as including components that reside both inside and outside a user's premises. It is important to note that one or more components in system 100 may be moved from inside to outside the premises. Further, one or more components may be integrated with a display device, such as a television or display monitor (not shown). In either case, several components and interconnections necessary for complete operation of system 100 are not shown in the interest of conciseness, as the components not shown are well known to those skilled in the art.

An outdoor unit (ODU) 101 receives signals from satellites and from terrestrial transmission towers through an over the air and/or near earth orbit communications link. ODU

101 is connected to set top box 102. In one embodiment, ODU 101 is connected to set top box

102 via a coaxial cable and an F-connector. Within set top box 102, the input is connected to filter 103. Filter 103 connects to three signal processing paths. A first path includes tuner 105, link circuit 106, and transport decoder 108 connected together serially. A second path includes tuner 110, link circuit 112, and transport decoder 114 connected together serially. A third path includes MoCA circuit 134 which further connects to controller 116. The outputs of transport decoder 108 and transport decoder 114 each connect to controller 116. Controller 116 connects to security interface 118, external communication interface 120, user panel 122, remote control receiver 124, audio/video output 126, power supply 128, memory 130, and ODU control 132. External communication interface 120, remote control receiver 124, audio/video output 126, and power supply 128 provide external interfaces for the set top box 102. Although not shown, ODU control 132 may also connect to the filter 103.

Satellite signal streams, each containing a plurality of channels, are received by ODU

101. ODU 101 includes a dish for capturing and focusing the propagated radio wave from the atmosphere onto one or more antennas contained within a structure known as a low noise block converter (L B). ODU 101 may be configured to receive the signal streams from satellite transponders located on one or more satellites. In one embodiment, two sets of sixteen channels are received by ODU 101, and converted, using one or more L Bs to a frequency range of 950 Megahertz (MHz) to 2, 150 MHz, referred to as L-band. ODU 101 also includes a terrestrial antenna for receiving over the air broadcasts. In one embodiment, ODU 101 includes a multiple element antenna array for receiving ISDBT signals in the frequency range from 174 MHz to 806 MHz.

ODU 101 provides a converted signal stream to the set top box 102 through radio frequency (RF) coaxial cable that is coupled to set top box 102 via an F-connector (not shown). The converted signal stream is provided to filter 103. In one embodiment, filter 103 operates as a multiplex filter with up to three separate filter sections or interfaces. The frequency response properties of filter 103 may include separate highpass filters, lowpass filters and band pass filters such that the frequency passbands of each may be split at each tuner input. In one embodiment, filter 103 includes a lowpass filter portion that allows a terrestrial signal in the frequency range from 174 MHz to 806 MHz to pass through to subsequent blocks while attenuating, or not passing through, a satellite signal in a frequency range from 950 MHz to 2,150 MHz. Filter 103 also includes a band pass filter that only allows MoCA signals in the frequency range from 950 MHz to 1050 MHz to pass through to subsequent blocks and a highpass filter portion that only allows satellite signals in the frequency range from 1250 MHz to 2150 MHz to pass through to subsequent blocks. The high pass filter portion may also filter any electrical supply or communication signals provided to the ODU 101. Other embodiments may be possible and some of these embodiments are described in further detail below. Filter 103 may also include surge or transient voltage protection devices.

The output signal from the high pass filter portion of filter 103 is provided to a first signal path containing a tuner 105, a link circuit 106, and a transport decoder 108 connected in a serial fashion. The output signal from the low pass filter portion of the filter 103 is provided to a second signal path. The second signal path also contains a tuner 110, a link circuit 112, and a transport decoder 114 connected in a serial fashion. Each processing path may perform similar processing on the filtered signal streams, the processing being specific to the transmission protocol used.

Tuner 105 processes the split signal stream by selecting or tuning one of the channels provided from a satellite service provider in the highpass filtered signal stream to produce one or more baseband signals. Tuner 105 contains circuits (e.g., amplifiers, filters, mixers, and oscillators) for amplifying, filtering and frequency converting the satellite signal stream. Tuner 105 typically is controlled or adjusted by link circuit 106. Alternately, tuner 105 may be controlled by another controller, such as controller 116, which will be described later. The control commands include commands for changing the frequency of an oscillator used with a mixer in tuner 105 to perform the frequency conversion. Tuner 110 processes the lowpass filtered signal stream by selecting or tuning one of the terrestrial channels in the split signal stream to produce one or more baseband signals. Tuner 110 contains circuits (e.g., amplifiers, filters, mixers, and oscillators) for amplifying, filtering and frequency converting the signal stream. Tuner 110 may be controlled or adjusted in a manner similar to that described earlier for tuner 105.

In another embodiment, the filter 103 may only include a bandpass filter portion and a highpass filter portion. In this embodiment, the bandpass filter portion may only allow MoCa signals in a frequency range from 400 MHz to 700 MHz to pass to subsequent block (i.e., to accommodate MoCA 2.0 standards) while attenuating, or not passing through, a satellite signal in a frequency range from 950 MHz to 2, 150 MHz. The highpass filter portion may only allow satellite signals in the frequency range from 1250 MHz to 2150 MHz to pass through to subsequent blocks. In this embodiment, the output of the bandpass filter portion is provided to MoCA circuit 134 and the output from the highpass filter portion is provided to first signal path (i.e., tuner 105, link circuit 106, and transport decoder 108) for further processing. It is to be appreciated that in this embodiment, the second signal path (i.e., tuner 110, link circuit 112, and transport decoder 114) may not be used, or alternatively, may be configured as a second satellite path.

Typically, the baseband signals at the output of tuner 105 or tuner 110 may collectively be referred to as the desired received signal and represent one satellite channel selected out of a group of channels that were received as the input signal stream. Although the signal is described as a baseband signal, this signal may actually be positioned at a frequency that is only near to baseband. The one or more baseband signals from the satellite service provider are provided to link circuit 106 through tuner 105. Link circuit 106 typically contains the processing circuits needed to convert the one or more baseband signals into a digital signal for demodulation by the remaining circuitry of link circuit 106. In one embodiment the digital signal may represent a digital version of the one or more baseband signals. In another embodiment the digital signal may represent the vector form of the one or more baseband signals. Link circuit 106 also demodulates and performs error correction on the digital signal from the satellite service provider to produce a transport signal. The transport signal may represent a data stream for one program, often referred to as a single program transport streams (SPTS), or it may represent multiple program streams multiplexed together, referred to as a multiple program transport stream (MPTS).

The one or more baseband signals from the broadcast service provider are provided to link circuit 112 through tuner 110. Link circuit 112 typically contains the processing circuits needed to convert the one or more baseband signals into a digital signal for demodulation by the remaining circuitry of link circuit 112 in a manner similar to link circuit 106 described earlier. Link circuit 112 also demodulates, performs broadcast channel equalization error correction on the digital signal from the broadcast service provider to produce a transport signal. As described earlier, the transport signal may represent a data stream for one program or it may represent multiple program streams multiplexed together.

The transport signal from link circuit 106 is provided to transport decoder 108. Transport decoder 108 typically separates the transport signal, which is provided as either a SPTS or MPTS, into individual program streams and control signals. Transport decoder 108 also decodes the program streams, and creates audio and video signals from these decoded program streams. In one embodiment, transport decoder 108 is directed by user inputs or through a controller such as controller 116 to decode only the one program stream that has been selected by a user and create only one audio and video signal corresponding to this one decoded program stream. In another embodiment, transport decoder 108 may be directed to decode all of the available program streams and then create one more audio and video signals depending on user request.

The transport signal from link circuit 112 is similarly provided to transport decoder 114. Transport decoder 114 decodes the program streams, and creates audio and video signals from these decoded program streams as directed by user inputs or a controller in a manner similar to that described earlier for transport decoder 108.

The audio and video signals, along with any necessary control signals, from both transport decoder 108 and transport decoder 114 are provided to controller 116. Controller 116 manages the routing and interfacing of the audio, video, and control signals and, further, controls various functions within set top box 102. For example, the audio and video signals from transport decoder 108 may be routed through controller 116 to an audio/video (A/V) output 126. A/V output 126 supplies the audio and video signals from set top box 102 for use by external devices (e.g., televisions, display monitors, and computers). Also, the audio and video signals from transport decoder 114 may be routed through controller 116 to memory block 130 for recording and storage.

Memory block 130 may contain several forms of memory including one or more large capacity integrated electronic memories, such as static random access memory (SRAM), dynamic RAM (DRAM), or hard storage media, such as a hard disk drive or an interchangeable optical disk storage system (e.g., compact disk drive or digital video disk drive). Memory block 130 may include a memory section for storage of instructions and data used by controller 116 as well as a memory section for audio and video signal storage. Controller 116 may also allow storage of signals in memory block 130 in an alternate form (e.g., an MPTS or SPTS from transport decoder 108 or transport decoder 114).

Controller 116 is also connected to an external communications interface 120. External communication interface 120 may provide signals for establishing billing and use of the service provider content. External communications interface 120 may include a phone modem for providing phone connection to a service provider. External communications interface 120 may also include an interface for connection to an Ethernet network and/or to home wireless communications network. The Ethernet network and/or home wireless network may be used for communication data, audio, and/or video signals and content to and from other devices connected to the Ethernet network and/or home wireless network (e.g., other media devices in a home).

Controller 116 also connects to a security interface 118 for communicating signals that manage and authorize use of the audio/video signals and for preventing unauthorized use. Security interface 118 may include a removable security device, such as a smart card. User control is accomplished through user panel 122, for providing a direct input of user commands to control the set top box and remote control receiver 124, for receiving commands from an external remote control device. Although not shown, controller 116 may also connect to the tuners 105, 110, link circuits 106, 112, and transport decoders 108, 114 to provide initialization and set-up information in addition to passing control information between the blocks. Finally, power supply 128 typically connects to all of the blocks in set top box 102 and supplies the power to those blocks as well as providing power to any of the elements needing power externally, such as the ODU 101. Controller 116 also controls ODU control 132. ODU control 132 provides signaling back to the ODU 101 through a control circuit such as surge protection circuit 131 (described below). ODU control 132 provides these signals onto the coaxial cable(s) running between ODU 101 and set top box 102. The ODU control 132 receives inputs from controller 116 and from link circuit 106 and link circuit 112 and provides a separate tuning control signal to ODU 101 using low frequency carrier based frequency shift keying modulation.

MoCA circuit 134 amplifies and processes the MoCA signal both for reception and transmission. As described above the MoCA interface permits communications of audio and video signals in a home network and may operate bi-directionally. MoCA circuit 134 includes a low noise amplifier for improving reception performance of a MoCA signal received by signal receiving device 100 from another network connected device. The received and amplified signal is tuned, demodulated, and decoded. The decoded signal may be provided to a number of other circuits, including audio and video outputs as well as a mass storage device (e.g., hard disk drive, optical drive, and the like), not shown. Additionally, MoCA circuit 134 generates and formats the MoCA transmit signal using audio and video content available in signal receiving device, including content received from the input (e.g., satellite signal) and content from the mass storage device. MoCA circuit 134 also includes a power amplifier for increasing the transmitted signal level of the MoCA signal sent by signal receiving device 100 to another network connected device. Adjustment of the receive signal amplification as well as the transmit signal amplification in MoCA circuit 134 may be controlled by controller 116.

It should be appreciated by one skilled in the art that the blocks described inside set top box 102 have important interrelations, and some blocks may be combined and/or rearranged and still provide the same basic overall functionality. For example, transport decoder 108 and transport decoder 114 may be combined and further integrated along with some or all of the functions of controller 116 into a System on a Chip (SoC) that operates as the main controller for set top box 102. Further, control of various functions may be distributed or allocated based on specific design applications and requirements. As an example, link circuit 106 may provide control signals to ODU control 132 and no connection may exist between link circuit 112 and ODU control 132.

In one embodiment, ODU 101 includes a satellite dish, an L B, a Single Wire Multiswitch (SWM) module for use with satellite signals and a terrestrial antenna, other embodiments may use separate structures. In some embodiments, the satellite dish, LNB, and SWM module are included in one structure and the terrestrial antenna is part of a second structure. The outputs of both satellite dish/LNB/SWM module structure and terrestrial antenna are combined using a signal combining circuit and provided to set top box 102.

Although set top box 102 is described above as receiving a single converted signal stream, set top box 102 may also be configured to receive two or more separate converted signal streams supplied by ODU 101 in some modes of operation. Operation in these modes may include additional components including switches and/or further tuning and signal receiving components, not shown. Further, set top box 102 may be designed to operate only on a home network using the Ethernet or home wireless network interfaces described above. In this case, the elements associated with operation in a MoCA network may be removed from set top box 102.

In one embodiment, power supply 128 is further coupled to an ODU power supply or voltage control circuit such as a voltage step-up circuit 129. ODU power supply 129 may power one or more of the components in ODU 101. That is, voltage control circuit 129 includes components configured to produce an operating voltage of the apparatus. For example, ODU 101 may include an SWM module (as described above) and L B for receiving satellite signals to be provided to set top box 102. The SWM module ODU 101 may be powered by ODU power supply 129. The SWM module then powers the LNB. In one embodiment, the ODU power supply 129 may receive an input direct current (DC) voltage from power supply 128 (e.g., 12 V) and produce an output DC voltage higher than the input DC voltage (e.g., 20.5 V) suitable to power components in the ODU 101, such as an SMW module. The output DC voltage is then provided from ODU power supply 129 to ODU 101.

The ODU power supply 129 may further be coupled to a control circuit to reduce the effects of or provide protection from energy surges. For example, a control circuit 131 providing surge reduction or surge protection may be coupled to ODU 101. Surge protection circuit 131 is disposed between ODU 101 and ODU power supply 129 to protect one or more components within ODU power supply 129 from damage that may occur during a surge in energy imposed on ODU 101, for example, during a lightning strike. It is to be appreciated that although ODU power supply 129 and surge protection circuit 131 are shown as separate blocks in FIG. 1, in some embodiments the components of ODU power supply 129 and surge protection circuit 131 may be combined into one block or circuit.

For example, referring to FIG. 2, an exemplary circuit 200 for powering an outdoor unit (such as ODU 101) and reducing or suppressing surge energy imposed on an outdoor unit is shown in accordance with the present disclosure. It is to be appreciated that circuit 200 may be used for powering one or more of the components of ODU 101 and protecting one or more of the components of set top box 102 from a power surge imposed on ODU 101. In one embodiment, circuit 200 is included in set top box 102 and includes at least some of the components of surge protection circuit 131 and ODU power supply 129. Furthermore, it is to be appreciated that some components have been omitted from circuit 200 for the sake of clarity and simplicity.

As shown in FIG. 2, circuit 200 is coupled to power supply 128 via inductor 202 and to ODU 101 via F-connector 250, where F-connector 250 is coupled to ODU 101 via a coaxial cable. Inductor 202 is further coupled to diode 204 and switch 228. Diode 204 is further coupled to inductor 208 and capacitor 210. Capacitor 210 is further coupled to ground 212 and inductor 208 is further coupled to capacitor 214. Capacitor 214 is further coupled to ground 216. It is to be appreciated that inductor 208, capacitors 210, 214 and grounds 212 and 216 together form filter 206, which will be described in greater detail below.

Inductor 208 and capacitor 214 are each further coupled to diodes 218 and 222, linear regulator 224, and feedback network 225. Diodes 218 and 222 and linear regulator 224 are each coupled to ferrite bead 232 and diode 234. Feedback network 225 is coupled to step-up controller 226. Step-up controller 226 is further coupled to switch 228, where switch 228 is further coupled to ground 230. It is to be appreciated that diode 222, linear regulator 224, feedback network 225, step-up controller 226, switch 228, and ground 230 together form an integrated circuit (IC) 220, which will be described in greater detail below.

Diode 234 is further coupled to ground 236 and ferrite bead 232 is further coupled to inductor 238 and transient voltage suppressor diode (TVS) 240. TVS 240 is further coupled to ground 242 and inductor 238 is further coupled to inductor 244 and gas discharge tube (GDT) 246. GDT 246 is further coupled to ground 248 and inductor 244 is further coupled to F- connector 250, where, as stated above, F-connector 250 is coupled to ODU 101 via coaxial cable. Diodes 218, 222, 234, inductors 238, 244, ferrite bead 232, TVS 240, GDT 246, and grounds 236, 242, 248 together form an exemplary embodiment of surge protection circuit 131. In accordance with an aspect of the present principles, an exemplary embodiment of voltage control or voltage step-up circuit 129 includes a filter and a linear regulator as described herein. In accordance with the another aspect, inductor 202, diode 204, and the components of filter 206 (i.e., 208, 210, 212, 214, 216) and IC 220 (i.e., 224, 226, 228, 230) together form an exemplary embodiment of the ODU power supply or voltage step-up circuit 129. It is to be appreciated that one or more of the components of circuit 200 may be shared among ODU power supply circuit 129 and surge protection circuit 131. For example, diode 222 is shared by both ODU power supply circuit 129 and surge protection circuit 131.

In one embodiment, the components within circuit 200 corresponding to ODU power supply circuit 129 are configured as a voltage control circuit or voltage step-up circuit to step up input voltage provided from power supply 128 to a higher voltage that is suitable to provide an operating voltage for components within ODU 101 receiving power from ODU power supply circuit 129. Within IC 220, switch 228 is controlled (i.e., turned on and off) by step-up controller 226. When switch 228 is turned on, inductor 202 becomes charged up and increases or steps up the input voltage from power supply 128 (e.g., 12 V) to a higher voltage (e.g., 20.9 V). The stepped-up voltage outputted by inductor 202 is provided through diode 204 to filter 206. The stepped-up voltage is then provided from filter 206 to the input of linear regulator 224 (i.e., the side of linear regulator that is coupled to filter 206 and feedback network 225). Feedback network 225 is configured to continuously sense the input voltage provided to linear regulator 224 and provide signals indicative of the sensed input voltage to step-up controller 226. Based on the received signals from feedback network 225, step-up controller 226 is configured to adjust the on/off ratio of switch 228 to increase or decrease the input voltage at linear regulator 224 (i.e., by charging and discharging inductor 202). For example, if, based on the input voltage sensed by feedback network 225, step-up controller 226 determines the input voltage at linear regulator 224 is too low, step-up controller 226 is configured to turn switch 228 on for a longer duration of time so that inductor 202 becomes more charged and the input voltage at linear regulator 224 is increased. Furthermore, if, based on the input voltage sensed by feedback network 225, step-up controller 226 determines the input voltage at linear regulator 224 is too high, step-up controller 226 is configured to turn switch 228 off for a longer duration of time so that inductor 202 becomes more discharged and the input voltage at linear regulator 224 is decreased. In this way, step-up controller 226 is configured to maintain the stepped-up input voltage at linear regulator 224 within a desired range.

The increased or stepped-up voltage that is provided to the input of linear regulator 224 is then converted by linear regulator 224 to an output voltage (e.g., 20.5 V) that is lower the input voltage at linear regulator 224 and suitable for the components of ODU 101. The voltage outputted by linear regulator 224 is provided through surge protection circuit 131 and F- connector 250 to ODU 101.

It is to be appreciated that when switch 228 is turned on and off, a ripple is created in the voltage outputted by inductor 202. Filter 206 is configured to receive the outputted voltage from inductor 202 and stabilize the voltage to remove this ripple. In this way, a stable voltage is provided to the input of linear regulator 224.

As stated above, surge protection circuit 131 (i.e., 218, 222, 232, 234, 236, 238, 240, 242,

244, 246, and 248) in circuit 200 is used to protect one or more of the components of ODU power supply 129 from a surge in power or energy that may occur, for example, during a lightning strike. However, under certain conditions, circuit 200 may include a low impedance path that still allows a significant and damaging amount of voltage to be applied to one or more of the components of ODU power supply 129 during a surge in power.

For example, during a lightning strike, while set top box 102 is powered off (and therefore IC 220 within circuit 200 is also powered off), a 1 kV surge may be applied to circuit 200 via ODU 101 and F-connector 250. GDT 246 is configured to clamp the 1 kV surge to approximately 300-400 V. The 300-400 V surge is further clamped to approximately 30 V by TVS 240. However, ferrite bead 232, diode 218, inductor 208 and capacitor 210 form a low impedance path that allows the remaining 30 V of surge energy to enter the ODU power supply circuit 129 and charge filter 206. The 30 V surge energy is applied to diodes 218 and 222, which creates a large voltage difference across the input and output of linear regulator 224 (e.g., across two pins of IC 220). The high voltage difference across the input and output of linear regulator 224 (i.e., 30 V) may cause IC 220 to enter an abnormal state. For example, the high voltage difference across linear regulator 224 may cause switch 228 to permanently be turned on. Since switch 228 has been permanently turned on, when IC 220 is powered on (i.e., when STB 102 is power on), a very large current flows through switch 228 to ground 230 and burns or destroys IC 220 instantly.

It is to be appreciated that if surge energy from an electrical discharge (e.g., a lightning strike) is applied to circuit 200 via F-connector 250 while circuit 200 is powered on (i.e., STB 102 is powered on), the IC 220 may not be damaged. In this case, when circuit 200 is powered on there is a 20.9 V input voltage on linear regulator 224. When the surge occurs and the remaining 30 V is applied to linear regulator 224, the voltage difference across the input and output of linear regulator 224 is less than 10 V (as opposed to 30 V when circuit 200 is powered off). Therefore, in this case, IC 220 may not enter an abnormal state. In this way, the low impedance path within circuit 200 leaves IC 220 susceptible to damage that may occur when sufficient surge energy is applied to circuit 200 when IC 200 is powered off. To overcome this problem, the present disclosure provides for an outdoor power supply and surge protection circuit that moves diode 218 to be disposed between filter 206 and the input of linear regulator 224. For example, referring to FIG. 3, a circuit 300 for powering an outdoor unit (such as ODU 101) and suppressing surge energy imposed on an outdoor unit is shown in accordance with the present disclosure. Circuit 300 includes the same components as circuit 200, however, in circuit 300 diode 218 has been moved to be disposed between filter 206 and linear regulator 224 input, such that, the anode of diode 218 is coupled to filter 206 and the cathode of diode 218 is coupled to linear regulator 224. In one embodiment, the anode of diode 218 is coupled to inductor 208 and capacitor 214 and the cathode of diode 218 is coupled to diode 222, linear regulator 224, and feedback network 225.

By moving the diode 218 to be disposed between filter 206 and the input of linear regulator 224, the low impedance path that enabled surge energy to enter the ODU power supply circuit 129 when IC 220 is powered off and cause IC 220 to enter an abnormal state (i.e., by creating a large voltage difference across linear regulator 224 and turning switch 228 on permanently) is removed. In the new position, diode 218 provides a high impedance path that prevent surge energy from entering the ODU power supply circuit 129 if IC 220 is off and an electrical discharge occurrence, such as a lightning strike, occurs and imposes a significant surge energy onto circuit 300. When diode 218 is disposed between filter 206 and IC 220, as shown in circuit 300 in FIG. 3, any remaining surge energy that is not clamped by the surge protection circuit 131 is blocked or reduced or inhibited to an extent sufficient to prevent IC 220 from entering an abnormal state. The list below provides information related to exemplary values of the components of the exemplary embodiments illustrated by circuits 200 and 300 in Figures 2 and 3, respectively. In the list, component values of "N/A" indicate that a particular value for that component is "not applicable", i.e., there is no particular value associated with the component.

Although circuit 300 in FIG. 3 is described above as being used in a set top box, such as set top box 102, it is to be appreciated that circuit 300 may be used with any device coupled to an outdoor unit that is susceptible to electrical discharge occurrences, such as lightning strikes, to protect the components of the device from surge energy.

It is to be appreciated that the various features shown and described are interchangeable, that is a feature shown in one embodiment may be incorporated into another embodiment.

Although embodiments which incorporate the teachings of the present disclosure have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. Having described embodiments of apparatuses surge energy protection, it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the disclosure disclosed which are within the scope of the disclosure as outlined by the appended claims.