Patent Application
20250211281
In a radio, a transmitter and receiver can be combined and connected to a single antenna to transmit (Tx) a transmission signal and to receive (Rx) a receive signal transmitted from another radio source. The combination of the transmitted signal and received signal may be accomplished by an Rx/Tx switch. In many applications, a power amplifier (PA) for signal transmission and a low noise amplifier (LNA) for signal receiving cannot be connected together due to the voltage swing on the output of the power amplifier being very large and the LNA input needing to be protected from such large signals.
The transmitter and receiver may be combined on a single common substrate such as silicon. The voltage needs of the Rx/Tx switch, however, commonly finds the Rx/Tx switch formed on an external component such as a printed circuit board (PCB) external to the single common substrate to provide satisfactory performance. While existing Rx/Tx switches can be integrated on silicon using CMOS technology, this type of construction may be quite poor. Due to the Rx/Tx switch being an external component to the single common substrate of the transmitter and receiver, separate pins may be needed for the connections of the transmitter to the PA and of the receiver to the LNA.
In accordance with one aspect of the present disclosure, a communication integrated circuit (IC) device comprises a silicon substrate and a radio circuit formed on the silicon substrate. The radio circuit comprises a receive and transmit circuit comprises a cascode amplifier and a low-noise amplifier coupled with the cascode amplifier. The radio circuit also comprises a radio frequency input/output channel configured to be coupled with a radio antenna. The communication IC further comprises a receive modem coupled with the low-noise amplifier and a transmit modem coupled with the cascode amplifier.
In accordance with another aspect of the present disclosure, a receive and transmit (Rx/Tx) circuit formed on a silicon substrate comprises a first cascode amplifier that comprises a radio frequency (RF) input/output (IO) node and a first low-noise amplifier node. The RF IO node is configured to output a first transmit signal via an antenna. The Rx/Tx circuit also comprises a low-noise amplifier coupled with the first low-noise amplifier node and having a first low-noise output configured to output a first low noise signal to a first receive channel formed on the silicon substrate. The Rx/Tx circuit further comprises a first transmitter input coupled with the first cascode amplifier and configured to supply a first input signal from a first transmit channel formed on the silicon substrate to the first cascode amplifier. The first cascode amplifier is configured to generate the first transmit signal based on the first input signal.
In accordance with another aspect of the present disclosure, a radio communication circuit comprises a cascode amplifier formed on a silicon substrate that comprises a first transistor, a second transistor, an amplifier coupled with the first and second transistors, and an input coupled with the second transistor. The amplifier comprises an output. The radio communication circuit also comprises a transmit circuit formed on the silicon substrate and coupled with the input and comprises a receive circuit formed on the silicon substrate and coupled with the output.
In the drawings:
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the examples disclosed herein. It will be apparent, however, to one skilled in the art that the disclosed example implementations may be practiced without these specific details. In other instances, structure and devices are shown in block diagram form in order to avoid obscuring the disclosed examples. Moreover, the language used in this disclosure has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the inventive subject matter, resorting to the claims being necessary to determine such inventive subject matter. Reference in the specification to “one example” or to “an example” means that a particular feature, structure, or characteristic described in connection with the examples is included in at least one implementation.
The transmitter 101 includes a transmit modem 104 coupled with a transmit circuit 105 having an in-phase (I) channel 106 and a quadrature (Q) channel 107. Each of the I and Q channels 106, 107 includes a digital-to-analog converter (DAC) 108, 109 coupled with the transmit modem 104 configured to convert a respective digital signal from the transmit modem 104 into an analog signal. A pair of filters 110, 111 filter the analog-converted signals and output the filtered signals to a respective mixer 112, 113. The mixers 112, 113 mix the filtered signals with high frequency signals provided by local oscillators (not shown) to increase the frequency of the filtered signals for transmission from a radio antenna 114. A summer 115 sums the high-frequency signals output from the mixers 112, 113 of the I and Q channels 106, 107 and generates an output signal 116 to be transmitted.
A power amplifier circuit 117 of a receive/transmit (Rx/Tx) circuit 118 receives the output signal 116 and generates a transmission signal 119. As illustratated in
As stated, the power amplifier circuit 117 receives the received signal 121 during the receive mode and provides the received signal 121 to the low-noise amplifier 122. The received signal 121 is typically a high-frequency signal that has a very low power level as compared with the power level of the transmission signal 119. The low-noise amplifier 122 is sensitive to low input level signals and is used to amplify the received signal 121 while attempting to keep the noise of the received signal 121 low. The amplified signal 123 is supplied to a receive circuit 124 of the receiver 102 as an input signal. An I channel 125 and a Q channel 126 of the receiver 102 include mixers 127, 128 that receive the amplified signal 123 and convert the amplified signal 123 into respective lower frequency signals. For example, the I channel 125 receives an I channel local oscillator signal for generating an I channel frequency signal 129 based on the amplified signal 123. The Q channel 126 receives a Q channel local oscillator signal for generating a Q channel frequency signal 130 based on the amplified signal 123. The I and Q channel frequency signals 129, 130 are respectively filtered by filters 131, 132, amplified by amplifiers 133, 134, filtered by filter 135, 136, and converted to digital signals by analog-to-digital controllers (ADCs) 137, 138. A receive modem 139 receives the digital signals from the ADCs for communicating the signals downstream.
A controller 140 may be coupled with the transmit and receive modems 104, 139 for controlling communications with additional systems or circuits on the silicon substrate 103 in an example. However, it is also contemplated that the transmit and receive modems 104, 139 may each have its own controller instead of or in addition to the controller 140. The controller 140 is coupled with the Rx/Tx circuit 118 for controlling the transmit and receive modes of the power amplifier circuit 117 and may also control the local oscillators coupled with mixers 112-113 and 127-128.
In the transmit mode, the cascode amplifier 201 operates to convert an input transmission signal 217 (e.g., the output signal 116 from the transmitter 101 (
By supplying the supply voltage to both the gate 208 and the drain of the first transistor 202 during the transmit mode, the gate 208 and drain are at the same voltage potential, allowing the cascode amplifier 201 to amplify the input transmission signal 217 for supply to an RF_IO output 222 coupled with an RF_IO channel 223. As shown, a filter/matching network 224 of the RF_IO channel 223 is coupled between the RF_IO output 222 and the antenna 219. The amplified transmission signal 218 is transmitted from the antenna 219 as outgoing radio waves 225.
In the receive node, the cascode amplifier 201 operates to pass received low-noise radio waves 226 converted into a received signal 227 to a low-noise amplifier 228 having an amplifier output 229. The switch 221 is controlled to couple the Rx/Tx input 207 with ground. In addition, the control transistor 209 is controlled into a switched-off state that allows the control resistor 210 to provide a high impedance to the gate 208 of the first transistor 202 to allow the first transistor 202 to act as a switch. In this manner, the low-noise received signal 227 is provided, via the low-noise node 206, to the low-noise amplifier 228 for low-noise amplification and passing on to the receiver 102 (
In one embodiment, a controller such as the controller 140 of
Similar to the cascode amplifier 201 of
The second cascode amplifier 302 is a cascode amplifier with an inductive load and includes a third transistor 317 and a fourth transistor 318 coupled in series with the inductive load including a second inductor 319 coupled in series with the inductor 311. A parallel arrangement of a control transistor or switch 320 and a control resistor 321 is coupled with a gate 322 of the third transistor 317 and with the control voltage input 315. A node 323 coupling the third and fourth transistors 317, 318 in series is further connected to a second input of the low-noise amplifier 308.
Each of the second and fourth transistors 310, 314 includes a gate 324, 325 coupled with a respective power amplifier input 326, 327 via a respective capacitor 328, 329. The gates 324, 325 are further coupled with a bias voltage through respective voltage bias inputs 330, 331 and bias resistor 332, 333.
In a transmit mode, power amplifier inputs 326, 327 receive first and second input transmission signals 334, 335 from a transmitter such as transmitter 101 of
A balun 338 converts a differential signal to a single-ended signal. In one example, balun 338 may be implemented as an LC balun as illustrated. However, balun 338 may be alternatively implemented as a different type of balun such as a transformer-based balun or a balun having other suitable architecture. The balun 228 converts differential transmit signals 336, 337 into the single-ended amplified transmission signal 303 that is provided to a filter/matching network 339 for RF transmission. In a receive mode, the control transistors 312, 320 are turned off by the controller, and the received signal 307 is provided as separate received signals 340, 341 by the balun 338 for inputs to the low-noise amplifier 308 via respective low-noise nodes 316, 323. A pair of low-noise amplifier outputs 342, 343 provide the received signals to a receiver such as receiver 102 of
In one embodiment, the transmitters, receivers, power amplifiers, low-noise amplifiers, and all other components described herein as being form on a same silicon substrate (e.g., silicon substrate 103 illustrated in
A device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or reconfigurable) by a user after manufacturing to perform the function and/or other additional or alternative functions. The configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof.
In this description, the term “couple” may cover connections, communications, or signal paths that enable a functional relationship consistent with this description. For example, if device A generates a signal to control device B to perform an action: (a) in a first example, device A is coupled to device B by direct connection; or (b) in a second example, device A is coupled to device B through intervening component C if intervening component C does not alter the functional relationship between device A and device B, such that device B is controlled by device A via the control signal generated by device A.
The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.
