Chip external interface

Abstract

A transceiver circuit implemented on one or more integrated circuits, the transceiver comprising: a signal transmitter for forming a radio signal for transmission; the signal receiver is used for carrying out receiving processing on the received radio signals; and a cancellation circuit for at least partially cancelling a component of the signal for transmission in the signal receiver, the cancellation circuit being arranged to receive an input from the signal transmitter and to provide a cancellation output to the signal receiver, the cancellation circuit is configured to form the cancellation output as a function of both the input from the signal transmitter and a response received from a first external connection pad of one of the integrated circuits.

Description

[0001] The present invention relates to an integrated circuit having an interface to an external component.

[0002] Figure 1 The overall architecture of a radio transceiver common in a portable device such as a mobile phone is shown. The transmission section 1 generates a signal for transmission. The signal for transmission is amplified by an amplifier 2, band-pass filtered by a transmission filter 3, and then fed to an antenna 4 for transmission. The signal received by the antenna 4 is band-pass filtered by a reception filter 5, amplified by an amplifier 6, and then processed by a reception section 7. Both the transmit filter and the receive filter are connected to the antenna 4. Thus, it is possible for the transmit signal from the filter 3 to reach the input of the filter 5. If the transmit and receive frequency bands do not overlap, in principle the filters 3 and 5 can be coordinated to completely suppress the transmit signal from reaching the reception section 7. However, this is actually very difficult to achieve without using large or expensive filters.

[0003] Figure 2 An alternative arrangement is shown. The reference numerals of similar components are Figure 1 consistent. A cancellation path 10 is coupled between the input 8 of the transmit filter 3 and the output 9 of the receive filter 5. The purpose of the cancellation path is to generate at 9 a signal that cancels any transmit signal components that may have been passed by the receive filter 5. This type of cancellation path can be configured in different ways. In Figure 2 the example, it includes tunable filters 11 and 12, a transformer 13, and a balanced impedance 14. The filters 11 and 12 are tuned with the aim of generating the desired cancellation signal at 9. The balanced impedance is intended to balance the impedance of the antenna. In an actual circuit, it may be difficult to properly balance the impedance of the antenna, especially when the cancellation path is implemented on an integrated circuit.

[0004] There is a need for an improved form of transceiver circuit and / or cancellation circuit.

[0005] According to one aspect, there is provided a transceiver circuit implemented on one or more integrated circuits, the transceiver circuit comprising: a signal transmitter for forming a radio signal for transmission; a signal receiver for receiving and processing a received radio signal; and a cancellation circuit for at least partially canceling components of the signal for reception in the signal receiver, the cancellation circuit being arranged to receive an input from the signal transmitter and provide a cancellation output to the signal receiver, the cancellation circuit being configured to form the cancellation output based on both the input from the signal transmitter and a response received from the integrated circuit or a first external connection pad of one of the integrated circuits.

[0006] The response can be a reactance response to a signal formed by the cancellation circuit based on the input from the signal transmitter.

[0007] The cancellation circuit can include a first filter and a second filter. The first filter is coupled between the signal transmitter and the external connection pad, and the second filter is coupled between the external connection pad and the signal receiver. The first filter can be fixed or adjustable. The second filter can be fixed or adjustable. The filters can be interconnected on the integrated circuit or on one of the integrated circuits in the integrated circuit. Thus, the cancellation circuit can be embodied in an operational form on the integrated circuit. The filters can be coupled to the connection pads, whereby the filters and the connection pads can be interconnected with the link between the pads external to the integrated circuit. In such embodiments, the filters may not be interconnected on the integrated circuit or on one of the integrated circuits in the integrated circuit. Thus, the cancellation circuit may not be embodied in an operational form on the integrated circuit.

[0008] The cancellation circuit can include a first adjustable filter and a second adjustable filter. The first adjustable filter is coupled between the signal transmitter and the external connection pad, and the second adjustable filter is coupled between another external connection pad and the signal receiver, whereby the first adjustable filter and the second adjustable filter can be interconnected by an external filter coupled between the external connection pad and the another connection pad.

[0009] The signal transmitter can be coupled to a second external connection pad of the integrated circuit to provide the signal for transmission to an antenna external to the integrated circuit or each integrated circuit.

[0010] The signal receiver can be coupled to the second external connection pad of the integrated circuit to receive the received radio signal from the antenna external to the integrated circuit or each integrated circuit.

[0011] The signal receiver can be coupled to a third external connection pad of the integrated circuit to receive the received radio signal from an antenna external to the integrated circuit or each integrated circuit.

[0012] The transceiver circuit can include an antenna balancing circuit coupled to a fourth external connection pad of the integrated circuit. Through the fourth pad, the balancing circuit can be coupled to the first external connection pad through a transmission line external to the integrated circuit or each integrated circuit in the integrated circuit.

[0013] The antenna balancing circuit may have a ground node for grounding the antenna balancing circuit. The ground node may be coupled to a fifth external connection pad of the integrated circuit.

[0014] The transceiver circuit may include a switch for selectively coupling the fourth external connection pad to the first external connection pad.

[0015] The balancing circuit or each balancing circuit may include a network including one or more capacitors and one or more inductors.

[0016] A single integrated circuit may carry at least part of the cancellation circuit and a duplexer for coupling the transmitter and the receiver to the antenna. The transmitter and the receiver may be implemented outside the integrated circuit.

[0017] According to another aspect, a transceiver device may be provided, including: the transceiver circuit as described above; one or more antennas outside the integrated circuit, each antenna being coupled to one or both of the signal transmitter and the signal receiver; and a matching circuit outside the integrated circuit and coupled to the first external connection pad to at least partially match the response of the antenna.

[0018] The matching circuit may include a first transmission line.

[0019] The antenna or at least one of the antennas may be coupled to the integrated circuit through a second transmission line. The length of the first transmission line may match the length of the second transmission line.

[0020] The transmission line may couple the first external connection pad to the fourth external connection pad.

[0021] The matching circuit may include a balancing circuit including a network including one or more capacitors and one or more inductors.

[0022] According to a further aspect, there is provided a transceiver circuit implemented on one or more integrated circuits, the transceiver circuit comprising: a signal transmitter for forming a radio signal for transmission; a signal receiver for receiving and processing a received radio signal; and a cancellation circuit for at least partially cancelling components of the signal for transmission in the signal receiver, the cancellation circuit comprising a first circuit path and a second circuit path, the first circuit path being arranged to receive an input from the signal transmitter and extend to a first external connection pad of the integrated circuit or one of the integrated circuits, the second circuit path extending between a second external connection pad of the integrated circuit or one of the integrated circuits and a cancellation path for providing cancellation feedback to the signal receiver, the first path and the second path being connectable to each other by components external to the integrated circuit.

[0023] At least one of the first path and the second path may comprise an adjustable filter.

[0024] The signal transmitter may be coupled to a third external connection pad of the integrated circuit to provide the signal for transmission to an antenna external to the integrated circuit or each integrated circuit.

[0025] The signal receiver may be coupled to the third external connection pad of the integrated circuit to receive the received radio signal from the antenna external to the integrated circuit or each integrated circuit.

[0026] The signal receiver may be coupled to a fourth external connection pad of the integrated circuit to receive the received radio signal from an antenna external to the integrated circuit or each integrated circuit.

[0027] The transceiver circuit may comprise an antenna balun circuit coupled to a fifth external connection pad of the integrated circuit, whereby the balun circuit is capable of being coupled to the first external connection pad and / or the second external connection pad via a transmission line external to the integrated circuit or each integrated circuit.

[0028] The antenna balun circuit may have a ground node for grounding the antenna balun circuit. The ground node may be coupled to a sixth external connection pad of the integrated circuit.

[0029] The transceiver circuit may comprise a switch for selectively coupling the fifth external connection pad to the first external connection pad.

[0030] The balancing circuit or each balancing circuit may include a network including one or more capacitors and one or more inductors.

[0031] A single integrated circuit may carry at least part of the cancellation circuit and a duplexer for coupling the transmitter and the receiver to the antenna. The transmitter and the receiver may be implemented outside the integrated circuit.

[0032] There may be components external to the integrated circuit that connect the first path and the second path to each other. The components may be passive conductors. The components may be filters, optionally adjustable filters.

[0033] According to a further aspect, there is provided a transceiver device comprising: a transceiver circuit as described above; one or more antennas, the one or more antennas being external to the integrated circuit, each antenna being coupled to one or both of the signal transmitter and the signal receiver; and a matching circuit, the matching circuit being external to the integrated circuit and coupled to one or both of the first external connection pad and the second external connection pad to at least partially match the response of the antenna.

[0034] The matching circuit may include a first transmission line.

[0035] The antenna or at least one of the antennas may be coupled to the integrated circuit via a second transmission line, and the length of the first transmission line matches the length of the second transmission line.

[0036] The matching circuit may include a balancing circuit, the balancing circuit including a network including one or more capacitors and one or more inductors.

[0037] The matching circuit may be configured to simulate the response of the antenna as affected by any one or more of: the length of one or more signal lines coupling the antenna to the transceiver circuit, the positioning of the antenna relative to other components of the transceiver device, the mechanical housing of the transceiver device, and one or more ground planes of the transceiver device associated with the antenna.

[0038] According to a further aspect, there is provided a transceiver circuit comprising: a signal transmitter for forming a radio signal for transmission; a signal receiver for receiving and processing a received radio signal; a balun circuit; and a cancellation circuit for at least partially cancelling components of the signal for transmission in the signal receiver, the cancellation circuit being arranged to receive an input from the signal transmitter and provide a cancellation output to the signal receiver, the cancellation circuit being configured to form the cancellation output based on both the input from the signal transmitter and the response of the balun circuit to an intermediate signal formed by the cancellation circuit based on the input from the signal transmitter; wherein: the balun circuit comprises one or more elements configured to be switchably enabled or disabled to change the response of the balun circuit.

[0039] The balun circuit and the cancellation circuit may be formed on a single integrated circuit.

[0040] The cancellation circuit may be formed on an integrated circuit having a first substrate. At least one of the elements may be formed on a second substrate.

[0041] The first substrate and the second substrate may have different materials.

[0042] At least one of the elements may be a transmission line.

[0043] The transmission line may be coupled to carry a surface wave originating from the intermediate signal.

[0044] The transceiver circuit may be implemented on a single integrated circuit.

[0045] The response received from a first external connection pad of one of the integrated circuits may be an analog signal.

[0046] The cancellation circuit may form the cancellation output by electrically combining the input from the signal transmitter and the response received from the first external connection pad of one of the integrated circuits. The combination may be performed simultaneously with the cancellation.

[0047] The response received from the first external connection pad of one of the integrated circuits may originate from the output of the signal transmitter.

[0048] The response received from the first external connection pad of one of the integrated circuits may originate from the input of the cancellation circuit. The input may be formed based on the input from the signal transmitter.

[0049] The cancellation circuit includes a first adjustable filter and a second adjustable filter. The first adjustable filter is coupled between the signal transmitter and the external connection pad, and the second adjustable filter is coupled between additional external connection pads. The external connection pad and the additional connection pad may not be interconnected on the integrated circuit. Thus, when the cancellation circuit is enabled through an external connection between two or more nodes of the cancellation circuit, the cancellation circuit can operate. Alternatively, the cancellation circuit can also be embodied on the integrated circuit such that it can operate without an external connection between two nodes of the cancellation circuit.

[0050] All of the transceiver circuit can be implemented on a single integrated circuit. The integrated circuit can have a single semiconductor die or multiple semiconductor dies. The integrated circuit can be packaged to have multiple pads for electrical connection to external components. The transceiver device can include a circuit board on which the integrated circuit is mounted. The transceiver device can include an external housing that contains the circuit board. The antenna or each antenna can be included in the housing. For example, the transceiver device can be a mobile phone or a cellular phone, or another form of end-user device or terminal device or user equipment device. The transceiver device can be a base station or a base station transceiver or a network equipment device.

[0051] The transceiver can include a transmit circuit and a receive circuit. The transmit circuit can include a bandpass filter that has a bandpass covering the transmit band of the transceiver and a bandstop covering the receive band of the receiver. The control circuit can control the response of the first filter and the second filter in response to a signal input to the bandpass filter or according to which inputs form the bandpass filter. The receive circuit can include a bandpass filter that has a bandpass covering the receive band of the transceiver and a bandstop covering the transmit band of the receiver. The output of the cancellation circuit can be fed to the output of the bandpass filter of the receive circuit or to a signal formed based on the output.

[0052] The present invention will now be described by way of example with reference to the accompanying drawings. In the drawings:

[0053] Figure 1 A transceiver circuit is shown

[0054] Figure 2 A transceiver circuit with a cancellation path is shown.

[0055] Figure 3 is a block diagram of a transceiver formed on an integrated circuit.

[0056] Figure 4 Shows in more detail Figure 3 the transceiver of

[0057] Figure 5 Part of the circuit showing an alternative design of the transceiver.

[0058] Figure 6 Part of the circuit showing another alternative design of the transceiver.

[0059] Figure 7 Part of the circuit for use with a series external filter.

[0060] Figure 3 Shows a radio frequency architecture for transmitting and receiving radio signals. The transceiver is formed on a single integrated circuit (IC) 20. The transceiver includes a transmit module 21, a receive module 22, and a cancellation module 23. The transmit module forms a signal for transmission. The receive module processes the received signal. The cancellation module generates a cancellation signal based on an input from the transmit module and feeds the cancellation signal to the receive module to at least partially cancel any component of the transmit signal that may have been fed to the receive module.

[0061] In this example, the transmit module 21 includes a digital section 24 and a radio frequency (RF) section 25. The digital section forms a digital data signal for transmission. The signal is passed to the RF section 25. The RF section converts the digital signal to a radio frequency signal and amplifies it such that it is suitable for output to an antenna 26. The details of the digital signal will depend on the protocol used and the content of the information to be transmitted. The form and spectrum of the radio frequency spectrum will depend on the air interface protocol used. The output of the RF section 25 is passed to a signal line 27. The signal line 27 is connected to an external pad 28 of the integrated circuit 20. The antenna 26 is connected to the antenna pad 28 via a transmission line 29. This circuit can have various variations. For example, the digital section 24 can be implemented outside the integrated circuit 20. Examples of functions that the RF transmitter section can perform include any one or more of digital-to-analog conversion, modulation, mixing, amplification, and filtering.

[0062] In this example, the receive module 22 includes an RF receiver section 30 and a digital receiver section 31. The RF receiver section 30 is coupled to the antenna 26 via the transmission line 29, the pad 28, and the signal line 27. Thus, the RF signal received by the antenna 26 can be passed to the RF receiver section 30. The RF receiver section processes the received signal to convert it into a signal suitable for input to the digital section 31. Then, the digital section 31 further processes the signal to detect and analyze its data content. This circuit can have various variations. For example, the digital section 31 can be implemented outside the integrated circuit 20. Examples of functions that the RF receiver section can perform include any one or more of analog-to-digital conversion, demodulation, mixing, amplification, and filtering.

[0063] A signal transmitter can be regarded as those components that form signals for transmission, such as components that generate, encode, filter, modulate, or amplify the signal. Such components can operate in the analog or digital domain. Such components can operate at radio frequency or baseband. A signal receiver can be regarded as those components that process the received signal, such as components that detect, decode, demodulate, filter, or amplify the signal. Such components can operate in the analog or digital domain. Such components can operate at radio frequency or baseband. In one example, a signal receiver can include a receive signal chain from a node where the receive signal chain and the transmit signal chain are combined to an interface that outputs a digital representation of the received signal.

[0064] The cancellation module 23 receives an input from the transmit module 24. The input represents an analog signal fed by the transmit module to the signal line 27 connecting the transmit module and the receive module. The cancellation module includes circuitry for generating, based on the input, at the output of the cancellation module a signal suitable for at least partially canceling at the receive module 22 components of the transmit signal that may have been transmitted to the receive module. To this end, the cancellation module includes a signal shaping module 32 and a balanced impedance module 33. The signal shaping module 32 processes the signal received from the transmit module 24 to generate a signal in a suitable form for providing cancellation at the receive module. Generating this signal may require compensating for the impedance of the antenna using a balanced impedance. The balanced impedance module 33 provides an impedance connected to the signal shaping module to at least partially mimic the effect of the impedance load on the signal line 27. It can essentially mimic such an effect. The balanced impedance module can be invoked in two modes. In the first mode, the switch 34 is closed, coupling the balanced impedance module to the signal shaping module through a path that is entirely located on the integrated circuit on which the signal shaping module and the balanced impedance module are defined. In the second mode, components outside the integrated circuit couple the signal shaping module 32 to the balanced impedance module. The off-chip components are connected between the external connection pads 35 and 36 of the integrated circuit. Pad 35 is coupled on the chip to the signal shaping module 32. Pad 36 is coupled on the chip to the balanced impedance module 33. In the second mode, the switch 34 can be open or closed. If the switch is open, module 32 is coupled to module 33 only through a path extending from the integrated circuit. If the switch is closed, module 32 is coupled to module 33 through (i) a first path that is entirely located on the integrated circuit and (ii) a second path that is partially located outside the integrated circuit.

[0065] Figure 3 The circuit shown in [Figure] can provide many advantages. It is common to produce an IC 20 for a variety of different communication products. These products may have antennas and transmission lines 29 of different lengths and configurations, depending on the size, shape, and internal packaging of the product. However, it is desirable for the balanced impedance to closely balance the impedance of the antenna 26 and the transmission line 29. ByFigure 3 With this arrangement, the product manufacturer can connect suitable circuit components between pads 35 and 36 so as to closely balance the specific impedance characteristics of the antenna assembly in the product. The product manufacturer is not limited to the components on the IC 20. The product manufacturer can provide passive or active components that are coupled between pads 35 and 36, or between one or both of pads 35 and 36 and an external node such as a circuit ground. In this way, the product manufacturer can adjust the performance of the integrated circuit according to a specific product design. This facility can allow the manufacturer of the IC 20 to reduce the complexity of the IC 20 while still making the IC compatible with a large number of end products. It can also allow the product manufacturer to use large-size components in the balanced circuit without the IC manufacturer providing these components on the IC. Some components such as inductors and / or transmission lines may occupy a relatively large area of the IC die.

[0066] Figure 4 is shown in more detail a circuit for implementing Figure 3 of the architecture. In Figure 4 the reference numerals of like components are consistent with Figure 3

[0067] Digital sections 24 and 31 respectively contain digital signal processors (DSPs) 50 and 51. These processors can be constituted by the same physical processor or different processors.

[0068] The RF and / or analog transmitter section 25 contains a preprocessing unit 52, an amplifier 53, and a filter 54. The preprocessing unit performs functions such as digital-to-analog conversion, modulation, frequency shift, and signal conditioning of signals from the digital module 24. The output from the preprocessing unit 52 is a radio frequency signal. The amplifier 53 is a power amplifier for amplifying the radio frequency signal. The filter 54 is a filter for filtering the output of the amplifier 53. The output of the filter reaches line 27 that is coupled to the antenna. Conveniently, the filter 54 is a band-pass filter arranged to attenuate frequencies outside the desired transmission band of the system. Alternatively, it can be a low-pass filter or a high-pass filter. Preferably, the filter 54 significantly attenuates the frequencies in the desired receiving band of the system to reduce the occurrence of such frequencies at the input of the receiver module 30. For example, it can attenuate the power in the receiving section or each receiving section by 10 or 100 times or more relative to the power in the transmitting band or each transmitting band. There can be multiple amplifiers 53 and / or multiple filters 54. They can be arranged in series or in parallel. In some embodiments, as will be further described below, the system can have multiple transmission bands.

[0069] ​The RF and / or analog receiver section 30 includes a filter 55, an amplifier 56, and an analog processing unit 57. The filter 55 is a filter for filtering signals present at the connection 28 of the antenna 26. These signals can include signals generated by the transmitter section as well as signals received by the antenna 26. The purpose of the filter 55 is to reduce the impact of signals generated by the transmitter section on the receiver section. Conveniently, the filter 55 is a band-pass filter arranged to attenuate frequencies outside the desired receive band of the system. Alternatively, it can be a low-pass filter or a high-pass filter. Preferably, the filter 55 significantly attenuates frequencies in the desired transmit band of the system to reduce the occurrence of such frequencies at the input of the amplifier 56. For example, it can attenuate the power in the transmit band or each transmit band by 10 or 100 times or more relative to the power in the receive band or each receive band. The amplifier 56 amplifies the output of the filter 55. The signal processing unit 57 performs functions such as analog-to-digital conversion, demodulation, frequency shifting, and signal conditioning of the signals from the amplifier 56. The output of the signal processing unit 57 will be passed to the DSP 51 for further processing and interpretation.

[0070] Filters 54 and 55 themselves may not be able to completely remove elements of the transmit signal from the receive path. For this purpose, the cancellation circuit, which will be further described below, can provide active cancellation of the components of the transmit signal in the receive path.

[0071] The signal shaping module 32 includes two adjustable filters 58 and 59. Filter 58 receives an input from a tap 60 at the output of the transmit amplifier 53. Alternatively, it can be located at another position in the analog transmit path, such as at the input of the amplifier or within the signal processing unit 52. Conveniently, the tap is located before filter 54. This avoids the received band components of the input being attenuated by filter 54. Conveniently, the tap is located immediately before filter 54 and / or after amplifier 53. Filter 58 can be a band-pass filter, a low-pass filter, or a high-pass filter. Conveniently, filter 58 is a band-pass filter. Conveniently, filter 58 is arranged to have a behavior similar to that of filter 55. Conveniently, filter 58 is a band-pass filter arranged to attenuate frequencies outside the received band desired by the system. Preferably, filter 58 substantially attenuates the frequencies in the transmit band desired by the system. For example, relative to the power in the transmit band or each transmit band, it can attenuate the power in the transmit section or each transmit section by 10 or 100 times or more. Filter 59 receives the output of filter 58 as an input. Filter 59 can be a band-pass filter, a low-pass filter, or a high-pass filter. Conveniently, filter 59 is a band-pass filter. Conveniently, filter 59 is arranged to have a behavior similar to that of filter 54. Conveniently, filter 59 is a band-pass filter arranged to attenuate frequencies outside the transmit band desired by the system. Preferably, filter 59 substantially attenuates the frequencies in the received band desired by the system. For example, relative to the power in the transmit band or each transmit band, it can attenuate the power in the receive section or each receive section by 10 or 100 times or more.

[0072] The output of filter 59 is passed to a transformer 61. The purpose of transformer 61 is to invert the output signal so that it can perform cancellation with the correct phase in the input chain. Other mechanisms can also be used to invert the filter output, such as an inverting amplifier. The output of the transformer is passed to a tap 69 in the receiver section 30. Conveniently, the tap is located between filter 55 and amplifier 56, but it can be located at other positions in the receiver chain. Transformer 61 can be included at an alternative position within the signal shaping unit. Alternatively, for example, transformer 61 can be connected between the output of filter 58 and the input of filter 59 instead of between the output of filter 59 and tap 69.

[0073] The signal path 62 extends from the node 63 between the filters 58 and 59 to the pad 35. The pad 35 is exposed to the outside of the integrated circuit 20. A circuit 64 formed outside the integrated circuit can be connected to the pad 35 to act as a balanced impedance. For example, the circuit can consist of a combination of one or more resistors, inductors, and / or capacitors. One or more of these components can optionally be tunable. The circuit can be formed to balance the impedance of the antenna 26. Since the antenna is outside the integrated circuit and the manufacturer of the integrated circuit may not know the impedance of the antenna, this method allows the manufacturer of the integrated circuit to provide a suitable balancing circuit without customizing the integrated circuit. To tune the behavior of the filters 58 and 59, a control circuit 65 can be provided. It obtains the inputs of the transmitting unit and the receiving unit and provides a control output to the filters 58 and 59. The control circuit can be provided by a digital processor programmed with strategies developed for the effective cancellation of the transmitted signal components in the receiving section 30. Various self-interference cancellation algorithms known in the art can be applied to this example.

[0074] Optionally, the balanced impedance circuit 33 can be formed on the integrated circuit. It can consist of one or more resistors, inductors, and / or capacitors. The on-chip balanced impedance circuit can be switched by a switch 34 on the integrated circuit or by a connection 66 from the pad 35 to the pad 36.

[0075] As indicated above, an off-chip balancing circuit can be formed to balance the impedance of the antenna 26. In addition, the off-chip balancing circuit can be coupled to the pin 35 by a transmission line. The length of the transmission line can be selected to match the length of the transmission line 29 that connects the antenna to the pin 28 of the integrated circuit. The transmission line 29 will introduce a delay that depends on its length. If the balanced impedance is not coupled in a similar manner, the cancellation effect of the circuit 23 may be impaired due to frequency-dependent phase shifts. By providing the manufacturer with the ability to implement a matching transmission line off-chip, the inventive circuit allows the manufacturer to achieve a good match with an off-chip antenna whose connection details are unknown to the manufacturer of the integrated circuit. In an alternative arrangement, a transmission line of an appropriate length can be coupled between the pads 35 and 36, thereby coupling the on-chip balanced impedance 33 into the circuit with a delay that matches the antenna. For example, this is convenient if the antenna has a standard impedance, but the length of the transmission line 29 of the antenna is specific to a particular implementation. Other circuits can be connected between the pads 35 and 36. For example, filters can be connected here to provide phase shift and / or delay. A matching network can be connected here to convert the impedance of the on-chip balanced circuit at the pad 36 to another impedance for connection at the pad 35. This can change the impedance of the on-chip balanced impedance 35 in a way that improves the correspondence between the antenna impedance and the balanced impedance. This may increase the level of self-interference cancellation.

[0076] The balun circuit may simulate antenna connections or other aspects of the packaging in a particular embodiment or end product. This may help to improve the level of self-interference cancellation at the receiver. These aspects may include the positioning of the antenna relative to other components of the product, the characteristics of the mechanical housing of the product, and the nature and / or size of one or more ground planes that may be associated with the antenna.

[0077] The balun circuit may also be adjustable. This may enable the balun circuit to compensate for dynamic changes in the local environment that may alter the effective impedance and / or reflection coefficient of the antenna 26. For example, this may be caused by the influence of a user's hand or other objects near the antenna. The adjustment of the balun circuit may be achieved through tunable or adjustable components in the circuit. This may include a set of capacitors and switches to form one or more adjustable capacitances within the balun network. Individual capacitors or capacitor banks may be coupled to the switches so that they can be selectively switched into or out of the circuit, thereby changing the overall capacitance of the corresponding adjustable capacitor. One or more components in the balun network, such as such adjustable capacitances, may be controlled by the controller 65. The controller 65 may be configured to adjust the balun network to improve the level of self-interference cancellation. Optionally, one or more connections may be included external to the integrated circuit to enable the controller 65 to be connected to adjustable components outside the integrated circuit. This may be able to adjust the impedance of the off-chip balun impedance. This may improve the level of self-interference cancellation.

[0078] In the above example, a single antenna is connected to the antenna port 28, and the antenna port is electrically coupled to the transmit circuitry and the receive circuitry. Alternatively, multiple antennas may be connected to a single antenna port. Optionally, these antennas may provide spatial diversity and / or be adapted to transmit and / or receive different frequency bands. In another alternative arrangement, the integrated circuit may have a first antenna port coupled to the transmit circuitry and a second antenna port coupled to the receive circuitry. These ports may not be directly electrically connected together. A first antenna may be connected to the first antenna port and a second antenna may be connected to the second antenna port. Then, the cancellation circuit may cancel signals that may wirelessly leak from one antenna to the other. Thus, the antennas for transmission and reception may be separate. The output of the filter 54 may be passed to the transmit antenna. The input of the filter 55 may come from the receive antenna. There may be no wired connection between the transmit antenna and the receive antenna. However, the receive antenna may pick up signals radiated by the transmit antenna, and thus may also require self-interference cancellation. In this case, the circuit 32 and its associated components, including the pad 35 and optionally the pad 36, may also be used.

[0079] The circuit 64 may be formed on the circuit board 67 on which the IC 20 is mounted.

[0080] In the above example, the circuit for forming the cancellation signal includes two filters (11, 12) and a balancing impedance 14. The filters can be on a single integrated circuit. The balancing impedance can be at least partially outside the integrated circuit. Other circuit designs can be used to form the cancellation circuit. For example, filters 11, 12 can be replaced by a single filter or more than two filters, or by any circuit designed to have an adjustable frequency response (such as a network of one or more resistors, capacitors, and / or inductors), where one or more of the components are tunable or adjustable components, or can be selectively switched into or out of the circuit. If there are multiple filters, the multiple filters can be in series or in parallel. One or more filters can be replaced by an active circuit for generating the cancellation signal. Thus, in one embodiment, there may be no filters in the circuit for generating the cancellation signal. For example, the circuit for generating the cancellation signal can include an amplifier arranged to receive a signal from the transmitter and amplify the signal to form a cancellation signal to be output to the receiver. The amplifier can be selected to produce a suitable signal for at least partially canceling the components of the transmitted signal that may leak into the receiver. In each case, the response or behavior of the circuit for forming the cancellation signal and thus the cancellation signal generated by the circuit in response to a given signal induced at the transmitter can be adjusted by one or more external components. Most of the cancellation circuit can be formed on a circuit carrier (such as a circuit board or an integrated circuit). The portion of the cancellation circuit may expose at least one connection outside the circuit carrier where an external component may be connected. The portion of the cancellation circuit can be configured such that its response depends on components outside the circuit carrier that carry the portion of the circuit. It is known that there are various types of cancellation circuits and they can be implemented in this way.

[0081] Thus, the system can provide a transmitter circuit and a receiver circuit. They may be arranged in such a way that the receiver circuit may receive interference from the transmitter circuit. This can be referred to as self-interference. There can be, for example, a cancellation circuit arranged as described above, i.e., receiving an input from the transmitter circuit and generating an output based on the input. The cancellation circuit can be configured to generate an output such that it can at least partially cancel the self-interference in the receiver. The output can be provided to the receiver for canceling components in the signal at the receiver. The response of the cancellation circuit to generating such signals may depend on external components connected to the cancellation circuit. Conveniently, the response of the cancellation circuit may depend on the reactance characteristics of the external components. Alternatively, the response of the cancellation circuit may depend on another characteristic of the external components. For example, the cancellation circuit can have multiple operating modes, and it can select which operating mode to operate in response to the characteristics of the external components. For example, the characteristic can be a digital or analog signal provided by the external components.

[0082] A portion of the self-interference canceller may be formed on a single integrated circuit. The response of the portion may be sensitive to off-chip components connected to the self-interference canceller.

[0083] Figure 5 Another arrangement is shown. Figure 5 Only a portion of the IC 20 is shown. A balun circuit 33 is provided on the integrated circuit 20. The pad 68 is exposed outside the integrated circuit and is coupled to the ground point of the balun circuit. The off-chip circuit ground can be connected to the pad 68. This can allow for improved grounding of the balun circuit, for example, better matching with the ground of the antenna 26. This method can be used with any on-chip balun circuit implementation described herein.

[0084] Figure 6 Another arrangement is shown. Figure 5Only a portion of the IC 20 is shown. A plurality of LC networks 75, 76, 77 are provided on the integrated circuit. On the integrated circuit, each of the LC networks in the LC network may not be connected to other networks. On the chip, one or more LC networks (such as network 75) may be connected to node 63. Another point on the network or those networks may be connected to the pad 71 exposed outside the chip. On the integrated circuit, the network or those networks may not be connected to the ground point. On the integrated circuit, one or more LC networks (such as network 76) in the LC network may not be connected to node 63 and any ground point. Two points on the network / those networks may be connected to the corresponding pads 72 and 73 exposed outside the chip. On the integrated circuit, one or more LC networks (such as network 77) in the LC network may not be connected to node 63, but on the integrated circuit it may be connected to the ground. The point on the network / those networks may be connected to the pad 74 exposed outside the chip. Outside the chip, by applying connections between the selected pads 35, 71, 72, 73, and 74, these networks can be connected together to configure a balanced network with the desired response through the external connections of the chip. These connections can be achieved through transmission lines and / or traces on the circuit board or circuit carrier on which the integrated circuit is mounted. Alternatively or additionally, these connections can be achieved via other components (such as capacitors and / or inductors connected between two or more of the pads 35, 72, 72, 73, and / or 74). This can allow the manufacturer to provide a suitable balanced network for a specific implementation. The manufacturer can form a balanced network by optionally connecting the components inside and / or outside the integrated circuit together to form a network. One or more connections between those pads can be achieved through a transmission line having a selected length to match the transmission line 29. One or more of the components in the networks 75, 76, 77 may be tunable or adjustable. One or more of the external components in the balanced network may be adjustable. The networks 75, 76, and / or 77 may optionally be adjusted by the controller 65.

[0085] In the above embodiments, the transmitter circuit, the receiver circuit, and the cancellation circuit may be implemented on a single common integrated circuit. Other configurations are possible. For example, the cancellation circuit may be implemented on an integrated circuit that does not carry the transmitter circuit and the receiver circuit. The integrated circuit may optionally include a duplexer, an output, and ports, the duplexer having an input for receiving a transmit signal input from the transmit circuit, the output for providing a receive signal output to the receive circuit, and the ports for connection to an antenna. The input, output, and ports may be connections external to the integrated circuit (e.g., contact pads) for connection to external components. The integrated circuit may have additional connections external to the integrated circuit (e.g., contact pads) for connection to external components on which the response of the cancellation circuit depends. In one example, the integrated circuit may include a self-interference cancellation circuit 32 and a duplexer for coupling the transmit circuit and the receive circuit to the antenna, and other portions of the transmitter and receiver may be omitted from the integrated circuit. They may be implemented elsewhere. For example, the integrated circuit may not include a transmit amplifier and / or a receive amplifier and / or a transmit filter and / or a receive filter. Any one or more of those components may be implemented on a second integrated circuit.

[0086] The self-interference cancellation path extends from the transmit section 21 through the circuit block 32 to the receive section 22. As indicated above, a functional external circuit may be connected to the node 35 to vary the response of the self-interference cancellation circuit. An active circuitry may be provided to vary the response of the external circuit. The active circuit may vary the response in response to any one or more of, for example, the following factors: an input representing the configuration of the antenna and / or the connection to an antenna configuration selected from a predetermined set of configurations; a measurement indication of the physical characteristics of the antenna and / or its connection, such as its impedance or frequency response; the degree of self-interference cancellation achieved by the self-interference cancellation circuit at the receiver. The active circuitry may be on or off the integrated circuit on which the self-interference cancellation circuit is defined. For example, it may include a processor configured to execute code stored in a non-transitory form and having an output that can vary the behavior of the functional external circuit, such as by switching its components into or out of the circuit. The controller 65 may provide some or all of the functionality.

[0087] As indicated by 33, some or all of the balun circuits may be implemented on an integrated circuit shared with the self-interference cancellation circuit. The balun circuit portion may include a plurality of reactance elements, which may be switched into or out of the circuit through switches provided on the integrated circuit or one or more other circuit carriers (such as an integrated circuit or a circuit board). This can change the behavior of the balun circuit. One aspect of an antenna implementation that may be desirable to compensate with such a circuit is the length of any connection from the antenna port (e.g., 28) to the antenna. One way to compensate is through a portion of the balun circuit that includes a plurality of transmission line segments that can be switched into or out of the circuit to together form a transmission line of a selected length. One or more of those transmission lines may be composed of a material in which signals travel slower than on a wire or slower than other transmission lines among those transmission lines. For example, one or more of those transmission lines may be formed on a ceramic substrate. It may carry signals as surface waves. This method may allow the transmission lines used to compensate for longer antenna connections to be more easily packaged on a small circuit carrier. In this arrangement, the external connection 35 may be omitted.

[0088] In another embodiment, external components may be connected in series in the cancellation path. In such embodiments, a self-interference cancellation circuit may not be formed to provide a continuous cancellation path within the integrated circuit. In this sense, the self-interference cancellation circuit may be incomplete within the integrated circuit or only partially located within the integrated circuit. For example, there may be no connection on the integrated circuit between the output of filter 58 and the input of filter 59. The output of filter 58 and the input of filter 59 may instead be connected to separate external connections. A series network including one or more external components and / or transmission lines may then be connected between the output of filter 58 and the input of filter 59. The series network may include one or more of the following: inductors, capacitors, resistors, active components (e.g., amplifiers), filters, transmission lines, hybrid circuits, and / or transformers. The series network may include components in series and / or in parallel. The series network may include one or more connections to electrical ground. The series network may be connected to complete the self-interference canceller circuit. For example, this may enable selection of the cancellation network topology or modification of the behavior or response of the cancellation network after the integrated circuit has been manufactured. This may be beneficial for the manufacturer to tailor the cancellation circuit for a particular application. For example, in the case of using separate transmit and receive antennas, the series network may be designed using knowledge of the antenna structure that may not have been available during the design of the integrated circuit. This may enable the cancellation circuit to be adapted to improve cancellation of self-interference that may couple between the transmit antenna and the receive antenna. One or more components within the integrated circuit may optionally be included in the series network using optional connections external to the integrated circuit or using switches within the integrated circuit. The construction and / or connection and / or configuration of the series network may be performed in a manner similar to that described above with reference to the external circuit connected via external connection 35, but with the external components of the series network connected in series to complete the self-interference cancellation circuit rather than the balancing network being connected in parallel to adjust the response of the self-interference cancellation circuit.

[0089] Figure 7 illustrates Figure 4 a portion of the circuit suitable for the above arrangement. The output of filter 58 is coupled to pad 80 external to the integrated circuit. The input of filter 59 is coupled to pad 81 external to the integrated circuit. In the absence of any connection between pads 80 and 81, filters 58 and 59 are also not interconnected. Filter 82 may be connected between pads 80 and 81 to complete the circuit. Filter 82 may take any form. Pads 80 and 81 may be directly connected together with no external filter. In this case, the entire filter circuit system may be formed on the integrated circuit.

[0090] Pads 35, etc. may take any suitable form. For example, it may be a conductive solder pad, a conductive pin, or a solder ball for receiving solder.

[0091] Some radio transceivers implement carrier aggregation. In carrier aggregation, multiple transmit signals with different carrier frequencies are transmitted to a common antenna, and multiple receive signals with different carrier frequencies are received by the common antenna. The above circuit can be used for a carrier aggregation transceiver. Filters 58 and 59 can be combined filters for matching the effects of multiple corresponding filters in the transmit and receive sections.

[0092] A balanced circuit or an LC network or each balanced circuit or LC network can be constituted by any suitable reactive components and / or resistive components (e.g., inductors, capacitors, and resistors). The components can be selected and connected together so as to provide a suitable response for the circuit. The circuit can be a filter circuit. The circuit can have a frequency-dependent response. The circuit can provide reactance.

[0093] Transceivers of the type described herein can be suitable for transmitting and receiving signals of protocols such as 5G, 4G, 3G, WiFi / IEEE 802.11, or Bluetooth.

[0094] The applicant hereby independently discloses each individual feature described herein and any combination of two or more such features to the extent that such features or combinations can be implemented based on the whole of this specification in view of the common general knowledge of those skilled in the art, regardless of whether such features or combinations of features solve any of the problems disclosed herein, and without limiting the scope of the claims. The applicant points out that various aspects of the present invention can consist of any such individual feature or combination of features. In view of the foregoing description, it will be apparent to those skilled in the art that various modifications can be made within the scope of the present invention.

[0095] The phrase "configured to" or "arranged to" followed by a term defining a condition or a function is used herein to indicate that the object of the phrase is in a state in which it has the said condition or is capable of performing the said function without modification or further configuration of the object.

Claims

1. A transceiver circuit implemented on one or more integrated circuits, the transceiver circuit comprising: A signal transmitter for forming a radio signal for transmission; A signal receiver for receiving and processing a received radio signal; and A cancellation circuit for at least partially canceling components of the signal for transmission in the signal receiver, the cancellation circuit being arranged to receive an input from the signal transmitter and provide a cancellation output to the signal receiver, the cancellation circuit being configured to form the cancellation output based on both the input from the signal transmitter and a response received from the integrated circuit or a first external connection pad of one of the integrated circuits.

2. The transceiver circuit according to claim 1, wherein the response is a reactance response to a signal formed by the cancellation circuit based on the input from the signal transmitter.

3. The transceiver circuit according to claim 1 or 2, wherein the cancellation circuit comprises a first adjustable filter and a second adjustable filter, the first adjustable filter being coupled between the signal transmitter and the external connection pad, and the second adjustable filter being coupled between the external connection pad and the signal receiver.

4. The transceiver circuit according to claim 1 or 2, wherein the cancellation circuit comprises a first adjustable filter and a second adjustable filter, the first adjustable filter being coupled between the signal transmitter and the external connection pad, and the second adjustable filter being coupled between an additional external connection pad and the signal receiver, whereby the first adjustable filter and the second adjustable filter can be interconnected by an external filter coupled between the external connection pad and the additional connection pad.

5. The transceiver circuit according to any one of the preceding claims, wherein the signal transmitter is coupled to a second external connection pad of the integrated circuit to provide the signal for transmission to an antenna external to the integrated circuit or each integrated circuit.

6. The transceiver circuit according to claim 5, wherein the signal receiver is coupled to the second external connection pad of the integrated circuit to receive the received radio signal from the antenna external to the integrated circuit or each integrated circuit.

7. The transceiver circuit according to any one of claims 1 to 5, wherein the signal receiver is coupled to a third external connection pad of the integrated circuit to receive the received radio signal from an antenna external to the integrated circuit or each integrated circuit.

8. The transceiver circuit according to any one of the preceding claims, wherein the transceiver circuit comprises an antenna balancing circuit coupled to a fourth external connection pad of the integrated circuit, whereby the balancing circuit can be coupled to the first external connection pad through a transmission line external to the integrated circuit or each integrated circuit.

9. The transceiver circuit according to claim 8, wherein the antenna balancing circuit has a ground node for grounding the antenna balancing circuit, and the ground node is coupled to a fifth external connection pad of the integrated circuit.

10. The transceiver circuit according to claim 8 or 9, wherein the transceiver circuit includes a switch for selectively coupling the fourth external connection pad to the first external connection pad.

11. The transceiver circuit according to any one of claims 8 to 10, wherein the balancing circuit or each balancing circuit includes a network comprising one or more capacitors and one or more inductors.

12. The transceiver circuit according to any one of the preceding claims, wherein a single integrated circuit carries at least part of the cancellation circuit and a duplexer for coupling the transmitter and the receiver to the antenna, and the transmitter and the receiver are implemented outside the integrated circuit.

13. A transceiver device, comprising: The transceiver circuit according to any one of claims 1 to 12; One or more antennas, the one or more antennas being external to the integrated circuit, each antenna being coupled to one or both of the signal transmitter and the signal receiver; and A matching circuit, the matching circuit being external to the integrated circuit and coupled to the first external connection pad to at least partially match the response of the antenna.

14. The transceiver device according to claim 13, wherein the matching circuit includes a first transmission line.

15. The transceiver device according to claim 14, wherein the antenna or at least one of the antennas is coupled to the integrated circuit by a second transmission line, and the length of the first transmission line matches the length of the second transmission line.

16. The transceiver device according to claim 14 or 15, wherein the transceiver circuit is the transceiver circuit according to claim 8, and the transmission line couples the first external connection pad to the fourth external connection pad.

17. The transceiver device according to any one of claims 13 to 16, wherein the matching circuit includes a balancing circuit, the balancing circuit including a network comprising one or more capacitors and one or more inductors.

18. A transceiver circuit implemented on one or more integrated circuits, the transceiver circuit comprising: A signal transmitter for forming a radio signal for transmission; A signal receiver for receiving and processing received radio signals; and A cancellation circuit for at least partially canceling components of the signal for transmission in the signal receiver, the cancellation circuit comprising a first circuit path and a second circuit path, the first circuit path being arranged to receive an input from the signal transmitter and extend to a first external connection pad of the integrated circuit or one of the integrated circuits in the integrated circuit, the second circuit path extending between a second external connection pad of the integrated circuit or one of the integrated circuits and a cancellation path for providing cancellation feedback to the signal receiver, the first path and the second path being connectable to each other by components external to the integrated circuit.

19. The transceiver circuit according to claim 18, wherein at least one of the first path and the second path comprises an adjustable filter.

20. The transceiver circuit according to claim 18 or 19, wherein the signal transmitter is coupled to a third external connection pad of the integrated circuit to provide the signal for transmission to an antenna external to the integrated circuit or each integrated circuit.

21. The transceiver circuit according to claim 20, wherein the signal receiver is coupled to the third external connection pad of the integrated circuit to receive the received radio signal from the antenna external to the integrated circuit or each integrated circuit.

22. The transceiver circuit according to any one of claims 18 to 21, wherein the signal receiver is coupled to a fourth external connection pad of the integrated circuit to receive the received radio signal from an antenna external to the integrated circuit or each integrated circuit.

23. The transceiver circuit according to any one of claims 18 to 22, wherein the transceiver circuit comprises an antenna balun circuit coupled to a fifth external connection pad of the integrated circuit, whereby the balun circuit can be coupled to the first external connection pad and / or the second external connection pad via a transmission line external to the integrated circuit or each integrated circuit.

24. The transceiver circuit according to claim 23, wherein the antenna balun circuit has a ground node for grounding the antenna balun circuit, and the ground node is coupled to a sixth external connection pad of the integrated circuit.

25. The transceiver circuit according to claim 23 or 24, wherein the transceiver circuit comprises a switch for selectively coupling the fifth external connection pad to the first external connection pad.

26. The transceiver circuit according to any one of claims 23 to 25, wherein the balun circuit or each balun circuit comprises a network including one or more capacitors and one or more inductors.

27. The transceiver circuit according to any one of claims 18 to 26, wherein a single integrated circuit carries at least part of the cancellation circuit and a duplexer for coupling the transmitter and the receiver to the antenna, and the transmitter and the receiver are implemented outside the integrated circuit.

28. A transceiver device comprising: The transceiver circuit according to any one of claims 18 to 27; One or more antennas, the one or more antennas being external to the integrated circuit, each antenna being coupled to one or both of the signal transmitter and the signal receiver; and A matching circuit, the matching circuit being external to the integrated circuit and coupled to one or both of the first external connection pad and the second external connection pad to at least partially match the response of the antenna.

29. The transceiver device according to claim 28, wherein the matching circuit comprises a first transmission line.

30. The transceiver device according to claim 29, wherein the antenna or at least one of the antennas is coupled to the integrated circuit via a second transmission line, and the length of the first transmission line matches the length of the second transmission line.

31. The transceiver device according to any one of claims 28 to 30, wherein the matching circuit comprises a balun circuit, the balun circuit comprising a network including one or more capacitors and one or more inductors.

32. The transceiver device according to any one of claims 28 to 31, wherein the matching circuit is configured to simulate the response of the antenna as affected by any one or more of: the length of one or more signal lines coupling the antenna to the transceiver circuit, the positioning of the antenna relative to other components of the transceiver device, the mechanical housing of the transceiver device, and one or more ground planes of the transceiver device associated with the antenna.

33. A transceiver circuit, comprising: A signal transmitter for forming a radio signal for transmission; A signal receiver for receiving and processing a received radio signal; A balun circuit; And A cancellation circuit for at least partially canceling components of the signal for transmission in the signal receiver, the cancellation circuit being arranged to receive an input from the signal transmitter and provide a cancellation output to the signal receiver, the cancellation circuit being configured to form the cancellation output based on both the input from the signal transmitter and the response of the balun circuit to an intermediate signal formed by the cancellation circuit based on the input from the signal transmitter; Wherein: The balun circuit comprises one or more elements configured to be switchably enabled or disabled to change the response of the balun circuit.

34. The transceiver circuit according to claim 33, wherein the balun circuit and the cancellation circuit are formed on a single integrated circuit.

35. The transceiver according to claim 34, wherein the cancellation circuit is formed on an integrated circuit having a first substrate, and at least one of the elements is formed on a second substrate.

36. The transceiver according to claim 35, wherein the first substrate and the second substrate have different materials.

37. The transceiver according to any one of claims 33 to 36, wherein at least one of the elements is a transmission line.

38. The transceiver according to claim 37, wherein the transmission line is coupled to carry a surface wave originating from the intermediate signal.

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