Patent ID: 12255394

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a figure and/or a subset of the elements illustrated in a figure. Further, some embodiments can incorporate any suitable combination of features from two or more figures.

There is a desire for a relatively low cost packaging technology to shield circuits to reduce radiated harmonics and also allow for an antenna unshielded from receiving and/or transmitting signals. Aspects of this disclosure relate to a shielded package with an integrated antenna. A laminated substrate can be fabricated in which an antenna is printed on the top layer and a ground plane for shielding is included in a layer underneath the top layer. Other layers of the laminate substrate can implement signal routing. An electronic component, such as a radio frequency (RF) component, can be disposed along a bottom layer of the laminate substrate. Bumps can be disposed around the electronic component and electrically connected to the ground plane. The bumps can be solder bumps in certain applications. The bumps can include copper pillars in various applications. The bumps can attach the module to a carrier or directly to a system board. The electronic component can be surrounded by bumps. For example, outside edges of the electronic component can have ground bumps that are connected to the ground plane by way of vias. The ground bumps around the electronic component can be connected to ground of a carrier or system board. Accordingly, a shielding structure with can be completed when the module is placed onto a carrier or system board. The shielding structure can function as a Faraday cage around the electronic component. The shielding structure around the electronic component can shield the electronic component from signals external to the shielding structure and/or shield circuits outside of the shielding structure from the electronic component.

One aspect of this disclosure is a module that includes a multi-layer substrate, an antenna, a radio frequency (RF) component, and conductive features disposed around the RF component. The multi-layer substrate has a first side and a second side opposite to the first side. The multi-layer substrate includes a ground plane. The antenna is on the first side of the multi-layer substrate. The RF component is on the second side of the multi-layer substrate such that the ground plane is positioned between the antenna and the RF component. The conductive features are disposed around the RF component and electrically connected to the ground plane. The conductive features and the ground plane configured to provide shielding for the RF component.

Another aspect of this disclosure is an RF circuit assembly that includes a laminate substrate having a first side and a second side opposite the first side, a printed antenna on the first side of the laminate substrate, an RF component attached on the second side of the laminate substrate, and a plurality of bumps disposed around the RF component. The laminate substrate includes a ground plane that is positioned between the printed antenna and the RF component. The bumps form at least a portion of an electrical connection to the ground plane to thereby form at least a portion of a shielding structure around the RF component. The bumps can include solder bumps and/or copper pillars.

Another aspect of this disclosure is system board assembly that includes a laminate substrate having a first side and a second side opposite to the first side, a printed antenna on the first side of the laminate substrate, an RF component attached on the second side of the laminate substrate, a plurality of bumps disposed around the RF component, and a system board. The laminate substrate includes at least one layer forming a ground plane. The ground plane is positioned between the printed antenna and the RF component. The plurality of bumps is electrically connected to the ground plane. The system board includes ground pads electrically connected to ground plane by way of the plurality of bumps such that a shielding structure is formed around the RF component.

FIG.1Ashows a cross section of an antenna in a package system10according to an embodiment. The antenna in a package system10is an example of a radio frequency module. The antenna in a package system10includes an antenna integrated with and shielded from an RF component. The antenna is unshielded from transmitting RF signals to and receiving RF signals from remote to the system. Accordingly, the antenna can transmit and/or receive any suitable RF signal. The antenna can transmit and/or receive RF signals for a system on a chip (SOC). In certain embodiments, the antenna of the antenna in a package system10can be arranged to transmit and/or receive Bluetooth and/or ZigBee signals.

The illustrated antenna in a package system10includes a multi-layer substrate12that includes an antenna layer14, a ground plane16, an insulating layer20, and an other layer22. An RF component18is attached to the multi-layer substrate12on a side opposite the antenna layer14. The ground plane16is disposed between the antenna layer14and the RF component18such that the ground plane16provides shielding between the RF component18and the antenna layer14. The antenna14can be in communication with the RF component18by way of one or more wire bonds, by way of one or more vias extending through the substrate12outside of the shielding structure, by way of magnetic coupling, or any suitable combination thereof.

The multi-layer substrate12can be a laminate substrate. The insulating layer20can be disposed between the antenna layer14and the ground plane16. The insulating layer20can include any suitable dielectric material. The multi-layer substrate12can include one or more other layers22, which can implement signal routing and/or passive components. Vias24extending from the ground plane16to the bottom side of the multi-layer substrate12shown inFIG.1Acan provide ground connections at the bottom side of the multi-layer substrate12. In some implementations, each of the vias24can be implemented by several vias through different insulating layers connected to each other by metal in component layers disposed between insulating layers.

The RF component18can include any suitable circuitry configured to receive and/or provide an RF signal. For instance, the RF component18can include a power amplifier, a low-noise amplifier, an RF switch, a filter, a matching network, or any combination thereof. An RF signal can have a frequency in the range from about 30 kHz to 300 GHz. In accordance with certain communications standards, RF signal can be in a range from about 450 MHz to about 6 GHz, in a range from about 700 MHz to about 2.5 GHZ, or in a range from about 2.4 GHz to about 2.5 GHZ. In certain implementations, the RF component18can receive and/or provide signals in accordance with a wireless personal area network (WPAN) standard, such as Bluetooth, ZigBee, Z-Wave, Wireless USB, INSTEON, IrDA, or Body Area Network. In some other implementations, the RF component and receive and/or provide signals in accordance with a wireless local area network (WLAN) standard, such as Wi-Fi.

The RF component18can be encapsulated in molding material26. Through mold vias28can extend through the molding material26to bumps29. The bumps29can be any suitable conductive bumps, such as solder bumps, solder balls, copper pillars, or the like. The bumps29can facilitate mounting of the antenna in a package system10onto a system board. Bumps29can be in physical contact with through mold vias28. Accordingly, the bumps29can be electrically connected to the ground plane16by way of through mold vias28and vias24in the multi-layer substrate12. While two bumps29, two through mold vias28, and two vias24are illustrated in the cross section ofFIG.1A, any suitable number of such elements can be included in the antenna in a package system10to provide a suitable ground connection and/or to provide suitable shielding around the RF component18. For instance, the bumps29can extend along outer edges of the antenna in a package system10to surround the RF component18in plan view. Corresponding through mold vias28and vias24can be implemented with such bumps29.

FIG.1Bshows a cross section of an antenna in a package system10′ according to an embodiment. The antenna in a package system10′ is another example of a radio frequency module. The antenna in a package system10′ ofFIG.1Bis similar the antenna in a package system10ofFIG.1Aexcept that the RF component18is unencapsulated in the antenna in a package system10′ and the bumps29are in physical contact with vias24in the multi-layer substrate12. In some applications, the antenna in a package system10′ can be mounted onto a carrier.

FIG.2shows a cross section of an antenna in a package system30with bumps providing standoff according to an embodiment.FIG.2shows that after reflow bumps32can extend farther from a module than a solder resist34. This can enable the bumps32to provide standoff between an RF component and a system board or other substrate on which an antenna in a package system30is disposed. Any suitable features shown inFIG.2can be implemented in connection with any of the antenna in a package systems discussed herein.

FIGS.3A to3Cillustrate example system board assemblies. Any suitable principles and advantages associated with these system board assemblies can be implemented with any of the antenna in a package systems and/or any of the RF modules discussed herein.FIG.3Aillustrates a system board assembly40with an antenna in a package system10and other component(s)42disposed on a system board44according to an embodiment. The system board44can be any suitable application board, such as a phone board for a mobile phone. Bumps29of the antenna in a package system10can be in physical contact with one or more ground connections of the system board44. Accordingly, a shielding structure can surround the RF component18of the antenna in a package system10in three dimensions. The shielding structure can provide shielding between the RF component18and the antenna layer14of the antenna in a package system10. The shielding structure can provide shielding between the RF component18and one or more other components42disposed on the system board44. Accordingly, the RF component18can be shielded from radiation emitted by the one or more other components42. At the same time, the other component(s)42can be shielded from radiation emitted from the RF component18. The other component(s)42can include any other circuitry on the system board44, such as other RF circuitry, a baseband processor, memory, the like, or any suitable combination thereof.

FIG.3Billustrates cross section of a system board assembly40with an antenna in a package module and another component42disposed on a system board44according to an embodiment. As illustrated, the system board44includes ground pads41A in contact with bumps29. InFIG.3B, inner bumps43are surrounded by a shielding structure that includes bumps29. The inner bumps43can provide electrical connections between circuitry of the RF component18and the system board44. Pads41B on the system board44can be electrically connected to the RF component18by way of respective bumps43, vias28′, routing metal47, and vias45. The antenna in the antenna layer14can be electrically connected to a pad41C of the system board44. As illustrated, a wire bond46electrically connects the antenna to the pad41C. The system board44can provide signal routing between the antenna and the RF component18and/or the other components42.

FIG.3Cillustrates cross section of a system board assembly40′ with an antenna in a package module and another component42disposed on a system board44according to an embodiment. The system board assembly40′ is like the system board assembly40ofFIG.3Bexcept that a different antenna in a package system is implemented. In the system board assembly40′, pads41B on the system board44can be electrically connected to the RF component18by way of respective bumps43, vias45, and routing metal47.

FIG.4is a cross sectional view of an antenna in a package system48according to an embodiment. The illustrated antenna in a package system48includes several components of the antenna in a package systems ofFIGS.1A and1B. InFIG.4, more details regarding the layers22are illustrated. In the illustrated antenna in a package system48, the layers22can implement signal routing. As shown inFIG.4, the RF component18and the molding material26can be thicker in the illustrated vertical dimension than the multi-layer substrate12.

FIGS.5A and5Bare example cross sectional views of layers radio frequency circuit assemblies50and50′, respectively, with integrated antennas according to certain embodiments. These figures generally illustrate the layers of the radio frequency circuit assemblies. Details of some examples of the illustrated layers ofFIGS.5A and5Bare provided in connection withFIGS.6A to7D.

InFIG.5A, the illustrated radio frequency circuit assembly50includes an antenna layer14, a ground plane16, an insulating layer20disposed between the antenna layer14and the ground plane16, a component layer51, routing layers52,55,57, and insulating layers53,54,56, and58. The routing layers52,55,57, the insulating layers20,53,54,56, and58, and the ground plane16can be included in a laminated substrate. The antenna layer14can also be considered part of the laminated substrate. The component layer51can be integrated with the laminated substrate. The component layer51can include any of the RF components discussed herein, such as the RF component18. The component layer51can include a semiconductor die that includes RF circuits.

Each of the routing layers can have insulating layers on opposing sides to insulate the routing layers from others routing layers and/or other layers, such as the ground plane16or the component layer51. As illustrated, an insulating layer53is disposed between the ground plane16and the routing layer52closest to the ground plane16. As also shown inFIG.5A, an insulating layer58is disposed between the component layer51and the routing layer57closest to the component layer51. The insulating layers can be formed of, for example, any suitable dielectric material. The routing layers can implement metal routing. Vias (not illustrated inFIG.5A) extending through an insulating layer can provide connections between metal in layers on opposing sides of the insulating layer.

Any suitable number of routing layers can be included in a radio frequency circuit assembly. For instance, the radio frequency circuit assembly50′ ofFIG.5Bincludes one routing layer52. As another example, the radio frequency circuit assembly50ofFIG.5Aincludes three routing layers52,55,57. Relatively more routing layers can be implemented to handle an increasing amount of signal routing between circuitry of the component layer51. Alternatively or additionally, relatively more routing layers can be implemented to handle an increasing amount of signal routing between circuitry of the component layer51and circuitry external to a radio frequency circuit assembly50and/or50′. Signal routing can be shielded by a shielding structure that includes the ground plane16and vias through the insulating layers of the radio frequency circuit assembly50and/or50′ connected with ground solder bumps and disposed around an RF component of the component layer51. Such vias can be electrically connected to conductive features, such as bumps, disposed around the RF component in the component layer51. Passive components, such as one or more spiral inductors, can be implemented in one or more of the routing layers. One or more passive components in routing layer(s) can be included in a matching network associated with radio frequency circuitry of the component layer51.

The antenna layer14of any of the antenna in a package systems discussed herein can include any suitable printed antenna. A printed antenna can be formed from one or more conductive traces on a substrate. The one or more conductive traces can be formed by etching a metal pattern on the substrate. A printed antenna can be a microstrip antenna. Printed antennas can be manufactured relatively inexpensively and compactly due to, for example, their 2-dimensional physical geometries. Printed antennas can have a relatively high mechanical durability.

FIGS.6A and6Billustrate example printed antennas of radio frequency circuit assemblies according to certain embodiments. These figures illustrate examples of a top view of a radio frequency circuit assembly, such as the radio frequency circuit assembly50and/or50′. The antenna60can be any suitable shape. For instance, the antenna60can be U-shaped as shown inFIG.6A. The antenna60inFIG.6Acan be a folded quarter wave antenna. As another example, the antenna60′ can be a meandering shape as shown inFIG.6B. The antenna can be coil shaped in certain implementations. The antenna can be a loop antenna in some implementations. The antenna of the antenna layer14and/or14′ can serve as an antenna for a system on a chip. The antenna can transmit and/or receive any suitable wireless communication signal. Such antennas can be configured to transmit and/or receive Bluetooth and/or ZigBee signals, for example. The antenna of the antenna layer can be in communication with transmit and/or receive circuitry by way of one or more wire bonds, by way of one or more vias extending through a substrate on which the antenna is disposed (e.g., outside of the shielding structure), by way of magnetic coupling, or any suitable combination thereof. The antenna of the antenna layer can be in communication with an RF component shielded from an antenna by a shielding structure by way of one or more wire bonds, by way of one or more vias extending through a substrate on which the antenna is disposed (e.g., outside of the shielding structure), by way of magnetic coupling, or any suitable combination thereof.

FIGS.7A to7Dillustrate example component layers of radio frequency circuit assemblies according to certain embodiments. These figures include schematic views of a bottom view of a radio frequency circuit assembly, such as the radio frequency circuit assembly50and/or50′.

As illustrated inFIGS.7A to7D, ground bumps29can surround an RF component and form a portion of a shielding structure around the RF component. The ground bumps29can be disposed along each edge of the component layer51. The ground bumps29can be soldered or otherwise connected to a ground connection of a carrier assembly such that the ground plane16, the bumps29, and ground of the carrier assembly together provide three-dimensional shielding of the RF component. The carrier assembly can be implemented by ethylvinylbenzene (EVB) or another laminate, for example.

As illustrated, the ground bumps29surround signal routing bumps71. The signal routing bumps71can provide at least a portion of a connection between circuitry of the component layer51with metal routing in a routing layer that is disposed between the component layer51and the ground plane16. Alternatively or additionally, the signal routing bumps71can provide at least a portion of an electrical connection between circuitry of the RF component18and a system board on which an antenna in a package system is disposed.

The example component layers ofFIGS.7A to7Dillustrate various electronic components that can be shielded from the antenna of the antenna layer14by the ground plane16. Each of these figures illustrates circuitry that can be included within a shielding structure. Other circuitry and/or components can alternatively or additionally be included within such a shielding structure. For instance, one or more of a crystal, a front end integrated circuit, or a system on a chip can be included within the shielding structure. As one example, a crystal, a front end integrated circuit, and a system on a chip can be implemented within the shielding structure and shielded from an integrated antenna by the shielding structure.

FIG.7Aillustrates a component layer51that includes an RF component18connected to signal routing bumps71. Some example RF components are illustrated inFIGS.7B to7D.FIG.7Billustrates a component layer51′ that includes a low noise amplifier (LNA)72and a matching network73.FIG.7Cillustrates a component layer51″ that includes a power amplifier74and a matching network75.FIG.7Dillustrates a component layer51″″ that includes an LNA72, a power amplifier74, and matching networks73and75. The circuits illustrated inFIGS.7A to7Dare connected to signal routing bumps71and are surrounded by the ground bumps29in a respective component layer. In some other implementations, the matching network73and/or the matching network75can include one or more passive component (e.g., one or more resistors, one or more capacitors, and/or one or more inductors implemented in a routing layer disposed between a component layer and a ground plane.

FIGS.8A,8B, and8Care schematic block diagrams of front end modules with integrated antennas according to certain embodiments. An RF front end can include circuits in a signal path between an antenna and a baseband system. Some RF front ends can include circuits in signal paths between one or more antennas and a mixer configured to module a signal to RF or to demodulate an RF signal.

The front end modules ofFIGS.8A,8B, and8Ccan be packaged modules. Such packaged modules can include relatively low cost laminate based front end modules that combine low noise amplifiers with power noise amplifiers and/or RF switches in certain implementations. Some such packaged modules can be multi-chip modules. In the modules ofFIGS.8A,8B, and8C, an antenna is integrated with the RF front end. The integrated antenna of such RF front end modules can be implemented in accordance with any of the principles and advantages discussed herein. These RF front end modules can be antenna in a package systems. The integrated antenna can be implemented in an antenna layer on a first side of a substrate that is shielded from the circuits of the RF front end on a second side of the substrate at least partly by a ground plane implemented in a layer of the substrate.

FIG.8Ais a schematic block diagram of an RF front end module80according to an embodiment. The RF front end module80is configured to receive RF signals from an integrated antenna60and to transmit RF signals by way of the integrated antenna60. The integrated antenna60can be implemented in accordance with any of the principles and advantages discussed herein. The illustrated front end module80includes a first multi-throw switch82, a second multi-throw switch83, a receive signal path that includes an LNA72, a bypass signal path that includes a bypass network84, and a transmit signal path that includes a power amplifier74. The low noise amplifier72can be any suitable low noise amplifier. The bypass network84can include any suitable network for matching and/or bypassing the receive signal path and the transmit signal path. The bypass network84can be implemented by a passive impedance network and/or by a conductive trace or wire. The power amplifier74can be implemented by any suitable power amplifier. The LNA72, the switches82and83, and the power amplifier74can be shielded from the antenna60by a shielding structure in accordance with any of the principles and advantages discussed herein.

The first multi-throw switch82can selectively electrically connect a particular signal path to the antenna60. The first multi-throw switch82can electrically connect the receive signal path to the antenna60in a first state, electrically connect the bypass signal path to the antenna60in a second state, and electrically connect the transmit signal to the antenna60in a third state. The antenna60can be electrically connected to the switch82by way of a capacitor87. The second multi-throw switch83can selectively electrically connect a particular signal path to an input/output port of the front end module80, in which the particular signal path is the same signal path electrically connected to the antenna60by way of the first multi-throw switch82. Accordingly, second multi-throw switch83together with the first multi-throw switch82can provide a signal path between the antenna60and an input/output port of the front end module80. A system on a chip (SOC) can be electrically connected to the input/output port of the front end module80.

The control and biasing block86can provide any suitable biasing and control signals to the other circuits of the front end module80. For example, the control and biasing block86can provide bias signals to the LNA72and/or the power amplifier74. Alternatively or additionally, the control and biasing block86can provide control signals to the multi-throw switches82and83to set the state of these switches.

FIG.8Bis a schematic block diagram of an RF front end module80′ according to an embodiment. The RF front end module80′ ofFIG.8Bis similar to the RF front end module80ofFIG.8A, except that a transmit signal path is omitted and the multi-throw switches82′ and83′ each have one fewer throw than corresponding multi-throw switches in the front end module80ofFIG.8A. The illustrated front end module80′ includes a receive signal path and a bypass signal path and does not include a transmit signal path.

FIG.8Cis a schematic block diagram of an RF front end module80″ according to an embodiment. The RF front end module80″ ofFIG.8Cis like the RF front end module80ofFIG.8A, except that a power amplifier of the transmit signal path is omitted from the RF front end module80″. The RF front end module80″ includes input/output ports for coupling to throws of the multi-throw switches82and83. A power amplifier external to the front end module80″ can be electrically connected between these input/output ports such that the power amplifier is included in the transmit signal path between the multi-throw switches82and83. The power amplifier can be included in a different packaged module than the illustrated elements of the RF front end module80″.

FIGS.9A and9Bare schematic block diagrams of illustrative wireless communication devices that include a shielded package with an integrated antenna in accordance with one or more embodiments. The wireless communication device90can be any suitable wireless communication device. For instance, wireless communication device90device can be a mobile phone such as a smart phone. As illustrated, the wireless communication device90includes a first antenna60integrated with a wireless personal area network (WPAN) system91, a transceiver92, a processor93, a memory94, a power management block95, a second antenna96, and an RF front end system97. Any of the integrated antennas and shielding structures discussed herein can be implemented in connection with the WPAN system91. The WPAN system91is an RF front end system configured for processing RF signals associated with personal area networks (PANs). The WPAN system91can be configured to transmit and receive signals associated with one or more WPAN communication standards, such as signals associated with one or more of Bluetooth, ZigBee, Z-Wave, Wireless USB, INSTEON, IrDA, or Body Area Network. In another embodiment, a wireless communication device can include a wireless local area network (WLAN) system in place of the illustrated WPAN system. Such a WLAN system can process Wi-Fi signals or other WLAN signals. Any of the integrated antennas and shielding structures discussed herein can be integrated with the RF front end system97.

The illustrated wireless communication device90′ ofFIG.9Bis a device configured to communicate over a WPAN. The wireless communication device90′ can be relatively less complex than the wireless communication device ofFIG.9A. As illustrated, the wireless communication device90′ includes an antenna60integrated with a WPAN system91, a transceiver92′, a processor93, and a memory94. An integrated antenna and a shielding structure can be implemented in connection with the WPAN system91in accordance with any of the principles and advantages discussed herein. The wireless communication device90′ can include a WLAN system in place of the illustrated WPAN system in another embodiment. Such a WLAN system can process Wi-Fi signals or other WLAN signals.

Some of the embodiments described above have provided examples in connection with RF components, front end modules and/or wireless communications devices. However, the principles and advantages of the embodiments can be used for any other systems or apparatus that could benefit from any of the circuits described herein. Although described in the context of RF circuits, one or more features described herein can also be utilized in packaging applications involving non-RF components. Similarly, one or more features described herein can also be utilized in packaging applications without the electromagnetic isolation functionality. Any of the principles and advantages of the embodiments discussed can be used in any other systems or apparatus that could benefit from the antennas and/or the shielding structures discussed herein.

Aspects of this disclosure can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products, electronic test equipment, cellular communications infrastructure such as a base station, etc. Examples of the electronic devices can include, but are not limited to, a mobile phone such as a smart phone, a wearable computing device such as a smart watch or an car piece, a telephone, a television, a computer monitor, a computer, a modem, a hand-held computer, a laptop computer, a tablet computer, a personal digital assistant (PDA), a microwave, a refrigerator, a vehicular electronics system such as an automotive electronics system, a stereo system, a DVD player, a CD player, a digital music player such as an MP3 player, a radio, a camcorder, a camera such as a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, peripheral device, a clock, etc. Further, the electronic devices can include unfinished products.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise.” “comprising.” “include,” “including” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above.” “below.” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description of Certain Embodiments using the singular or plural number may also include the plural or singular number, respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

Moreover, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or whether these features, elements and/or states are included or are to be performed in any particular embodiment.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.