# US 8,787,964 B2 · Integrated radio frequency front-end circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,787,964 B2 - Document ID: US8787964B2 - Status: Granted - Kind: B2 - Application number: 12/875,131 - Filed: 2010-09-03 - Published: 2011-12-29 - Granted: 2014-07-22 - Earliest claimed: 2010-06-23 - Assignees: MindTree Limited - Applicants: Manoj Shridhar Soman - Inventors: Manoj Shridhar Soman - Web page: https://patentgrep.com/patent/US8787964B2 ## CPC - H04B 1/18: Input circuits, e.g. for coupling to an antenna or a transmission line (coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H) - H03F 3/45188: {Non-folded cascode stages} - H04B 1/40: Circuits - H04B: TRANSMISSION - H03F: AMPLIFIERS ## Abstract An integrated RF front-end circuit comprising a balun, a receiver amplifier, a power amplifier, and a selector circuit is provided. The balun comprises a center-tapped inductor having a first node, a center-tap switchlessly coupled to a fixed voltage, and a second node. The balun receives a single-ended signal through the first node to produce a differential signal at the first and second nodes. The differential signal is provided to balanced input lines of the receiver amplifier. Balanced output lines of the power amplifier provide a differential signal to the first and second nodes. The balun converts the differential signal to a single-ended signal. The single-ended signal is available at the first node of the center-tapped inductor. The selector circuit activates the receiver amplifier and deactivates the power amplifier, and vice versa. The power amplifier may comprise only a single-ended output line connected to either the first or the second node. ## Claims ### Claim 1 A radio frequency front-end circuit, comprising: a balun, comprising: a single coil center-tapped inductor having a center-tap drawn from center of the single coil, said single coil center-tapped inductor comprising a first node and a second node, said center-tap switchlessly coupled to a fixed voltage, wherein said balun is configured to receive a single-ended signal through said first node of said single coil center-tapped inductor and convert said single-ended signal to a differential signal, wherein said balun is configured to receive said differential signal through said first node and said second node and convert said differential signal to said single-ended signal, and wherein said differential signal is available at said first node and said second node, and said single-ended signal is available at said first node; a receiver radio frequency amplifier having balanced input lines connected to said first node and said second node, said receiver radio frequency amplifier configured for receiving and amplifying said differential signal, wherein said receiver radio frequency amplifier comprises one or more active components; a radio frequency power amplifier having balanced output lines connected to said first node and said second node, said radio frequency power amplifier configured for providing an amplified differential signal to said balun, wherein said radio frequency power amplifier comprises one or more active components; and a selector circuit in communication with said receiver radio frequency amplifier and said radio frequency power amplifier, said selector circuit configured for activating said active components of said receiver radio frequency amplifier and deactivating said active components of said radio frequency power amplifier during said conversion of said single-ended signal to said differential signal, and vice versa during said conversion of said differential signal to said single-ended signal; whereby said balun is switchlessly and selectively coupled to said receiver radio frequency amplifier during said conversion of said single-ended signal to said differential signal and said radio frequency power amplifier during said conversion of said differential signal to said single-ended signal. ### Claim 2 (depends on 1) The radio frequency front-end circuit of claim 1, wherein said fixed voltage is a supply ground. ### Claim 3 (depends on 1) The radio frequency front-end circuit of claim 1, wherein said fixed voltage is a supply voltage. ### Claim 4 (depends on 1) The radio frequency front-end circuit of claim 1, wherein said active components of said receiver radio frequency amplifier comprise one or more transistors, and wherein said selector circuit switches on said one or more transistors during said conversion of said single-ended signal to said differential signal. ### Claim 5 (depends on 1) The radio frequency front-end circuit of claim 1, wherein said active components of said radio frequency power amplifier comprise one or more transistors, and wherein said selector circuit switches on said one or more transistors during said conversion of said differential signal to said single-ended signal. ### Claim 6 (depends on 1) The radio frequency front-end circuit of claim 1, further comprising an antenna coupled to one of said first node and said second node of said single coil center-tapped inductor. ### Claim 7 (depends on 6) The radio frequency front-end circuit of claim 6, wherein impedance of said antenna approximately matches input impedance of said receiver radio frequency amplifier. ### Claim 8 (depends on 6) The radio frequency front-end circuit of claim 6, wherein impedance of said antenna approximately matches output impedance of said radio frequency power amplifier. ### Claim 9 (depends on 6) The radio frequency front-end circuit of claim 6, wherein impedance of said antenna is Rin and impedance of each of said balanced input lines of said receiver radio frequency amplifier is 2Rin. ### Claim 10 (depends on 6) The radio frequency front-end circuit of claim 6, wherein impedance of said antenna is RL and impedance of each of said balanced output lines of said radio frequency power amplifier is about 2RL. ### Claim 11 (depends on 1) The radio frequency front-end circuit of claim 1, further comprising a programmable logic circuit for programming said selector circuit for activating said active components of said receiver radio frequency amplifier and deactivating said active components of said radio frequency power amplifier during said conversion of said single-ended signal to said differential signal, and vice versa during said conversion of said differential signal to said single-ended signal. ### Claim 12 A radio frequency front-end circuit, comprising: a balun, comprising: a single coil center-tapped inductor having a center-tap drawn from center of the single coil, said single coil center-tapped inductor comprising a first node and a second node, said center-tap switchlessly coupled to a fixed voltage, wherein said balun is configured to receive a said single-ended signal through said first node of said single coil center-tapped inductor and convert said single-ended signal to a differential signal, wherein said balun is configured to receive said differential signal through said first node and said second node and convert said differential signal to said single-ended signal, and wherein said differential signal is available at said first node and said second node, and said single-ended signal is available at said first node; a receiver radio frequency amplifier having balanced input lines connected to said first node and said second node, said receiver radio frequency amplifier configured for receiving and amplifying said differential signal, wherein said receiver radio frequency amplifier comprises one or more active components; a radio frequency power amplifier having a single-ended output line connected to one of said first node and said second node, said radio frequency power amplifier configured for providing an amplified single-ended signal for transmission, wherein said radio frequency power amplifier comprises one or more active components; and a selector circuit in communication with said receiver radio frequency amplifier and said radio frequency power amplifier, said selector circuit configured for activating said active components of said receiver radio frequency amplifier and deactivating said active components of said radio frequency power amplifier during said conversion of said single-ended signal to said differential signal, and vice versa during said conversion of said differential signal to said single-ended signal; whereby said balun is switchlessly and selectively coupled to said receiver radio frequency amplifier during said conversion of said single-ended signal to said differential signal and said radio frequency power amplifier during said conversion of said differential signal to said single-ended signal. ### Claim 13 (depends on 12) The radio frequency front-end circuit of claim 12, wherein said fixed voltage is a supply ground. ### Claim 14 (depends on 12) The radio frequency front-end circuit of claim 12, wherein said fixed voltage is a supply voltage. ### Claim 15 (depends on 12) The radio frequency front-end circuit of claim 12, further comprising an antenna coupled to one of said first node and said second node of said single coil center-tapped inductor. ### Claim 16 (depends on 15) The radio frequency front-end circuit of claim 15, wherein impedance of said antenna approximately matches input impedance of said receiver radio frequency amplifier. ### Claim 17 (depends on 12) The radio frequency front-end circuit of claim 12, further comprising a programmable logic circuit for programming said selector circuit for activating said active components of said receiver radio frequency amplifier and deactivating said active components of said radio frequency power amplifier during said conversion of said single-ended signal to said differential signal, and vice versa during said conversion of said differential signal to said single-ended signal. ### Claim 18 A method of selectively accessing a balun in a radio frequency front-end circuit, comprising: providing said balun comprising a single coil center-tapped inductor with a center-tap drawn from center of the single coil; switchlessly coupling said center-tap of said single coil center-tapped inductor to a fixed voltage; providing a receiver radio frequency amplifier and a radio frequency power amplifier, wherein said receiver radio frequency amplifier and said radio frequency power amplifier comprise active components; coupling a first node and a second node of said single coil center-tapped inductor to balanced input lines of said receiver radio frequency amplifier and balanced output lines of said radio frequency power amplifier; and switchlessly coupling one of said receiver radio frequency amplifier and said radio frequency power amplifier to said single coil center-tapped inductor of said balun by performing one of: activating active components of said receiver radio frequency amplifier and converting a single-ended signal received at one of said first node and said second node to a differential signal, wherein said differential signal is obtained at said first node and said second node, and wherein said differential signal is provided to said balanced input lines of said receiver radio frequency amplifier; and activating active components of said radio frequency power amplifier and constructively combining an amplified differential signal along said first node and said second node for obtaining a single-ended signal at said first node, wherein said amplified differential signal is received from said radio frequency power amplifier through said balanced output lines. ### Claim 19 (depends on 18) The method of claim 18, wherein said fixed voltage is a supply ground. ### Claim 20 (depends on 18) The method of claim 18, wherein said fixed voltage is a supply voltage. ### Claim 21 (depends on 18) The method of claim 18, wherein said step of activating active components of said receiver radio frequency amplifier comprises deactivating said active components of said radio frequency power amplifier. ### Claim 22 (depends on 18) The method of claim 18, wherein said step of activating active components of said radio frequency power amplifier comprises deactivating said active components of said receiver radio frequency amplifier. ### Claim 23 A method of selectively accessing a balun in a radio frequency front-end circuit, comprising: providing said balun comprising a single coil center-tapped inductor with a center-tap drawn from center of the single coil; switchlessly coupling said center-tap of said single coil center-tapped inductor to a fixed voltage; providing a receiver radio frequency amplifier and a radio frequency power amplifier, wherein said receiver radio frequency amplifier and said radio frequency power amplifier comprise active components; coupling a first node and a second node of said single coil center-tapped inductor to balanced input lines of said receiver radio frequency amplifier; coupling one of said first node and said second node to a single-ended output line of said radio frequency power amplifier; and switchlessly coupling one of said receiver radio frequency amplifier and said radio frequency power amplifier to said single coil center-tapped inductor of said balun by performing one of: activating active components of said receiver radio frequency amplifier and converting a single-ended signal received at one of said first node and said second node to a differential signal, wherein said differential signal is obtained at said first node and said second node, and wherein said differential signal is provided to said balanced input lines of said receiver radio frequency amplifier; and activating active components of said radio frequency power amplifier and providing an amplified single-ended signal to one of said first node and said second node, wherein said amplified single-ended signal is received from said radio frequency power amplifier through said single-ended output line. ### Claim 24 (depends on 23) The method of claim 23, wherein said fixed voltage is a supply ground. ### Claim 25 (depends on 23) The method of claim 23, wherein said fixed voltage is a supply voltage. ### Claim 26 (depends on 23) The method of claim 23, wherein said step of activating active components of said receiver radio frequency amplifier comprises deactivating said active components of said radio frequency power amplifier. ### Claim 27 (depends on 23) The method of claim 23, wherein said step of activating active components of said radio frequency power amplifier comprises deactivating said active components of said receiver radio frequency amplifier. ### Claim 28 A method of manufacturing a radio frequency front-end circuit, comprising: integrating on a single semiconductor integrated circuit chip: a balun comprising a single coil center-tapped inductor having a center-tap drawn from center of the single coil, said single coil center-tapped inductor comprising a first node and a second node, said center-tap coupled to a fixed voltage, wherein said single coil center-tapped inductor configured to convert between a single-ended signal and a differential signal; a receiver radio frequency amplifier having balanced input lines coupled to said first node and said second node of said single coil center-tapped inductor; a radio frequency power amplifier having balanced output lines coupled to said first node and said second node of said single coil center-tapped inductor; and a selector circuit for selectively activating active components of said receiver radio frequency amplifier and deactivating active components of said radio frequency power amplifier, and vice versa. ### Claim 29 (depends on 28) The method of claim 28, wherein coupling said center-tap to said fixed voltage comprises coupling said fixed voltage to a supply ground. ### Claim 30 (depends on 28) The method of claim 28, wherein coupling said center-tap to said fixed voltage comprises coupling said fixed voltage to a supply voltage. ### Claim 31 (depends on 28) The method of claim 28, further comprising integrating on said single semiconductor integrated chip, a receiving module coupled to outputs of said receiver radio frequency amplifier. ### Claim 32 (depends on 28) The method of claim 28, further comprising integrating on said single semiconductor integrated chip, a transmitter module coupled to inputs of said radio frequency power amplifier. ### Claim 33 (depends on 28) The method of claim 28, further comprising integrating on said single semiconductor integrated chip, a programmable logic circuit for programming said selector circuit to selectively operate one of said receiver radio frequency amplifier and said radio frequency power amplifier. ### Claim 34 A method of manufacturing a radio frequency front-end circuit, comprising: integrating on a single semiconductor integrated circuit chip: a balun comprising a single coil center-tapped inductor having a center-tap drawn from center of the single coil, said single coil center-tapped inductor comprising a first node and a second node, said center-tap coupled to a supply voltage, wherein said single coil center-tapped inductor configured to convert between a single-ended signal and a differential signal; a receiver radio frequency amplifier having balanced input lines coupled to said first node and said second node of said single coil center-tapped inductor; a radio frequency power amplifier having a single-ended output line coupled to said first node of said single coil center-tapped inductor; and a selector circuit for selectively activating active components of said receiver radio frequency amplifier and deactivating active components of said radio frequency power amplifier, and vice versa. ### Claim 35 (depends on 34) The method of claim 34, wherein coupling said center-tap to said fixed voltage comprises coupling said fixed voltage to a supply ground. ### Claim 36 (depends on 34) The method of claim 34, wherein coupling said center-tap to said fixed voltage comprises coupling said fixed voltage to a supply voltage. ### Claim 37 (depends on 34) The method of claim 34, further comprising integrating on said single semiconductor integrated chip, a programmable logic circuit for programming said selector circuit to selectively operate one of said receiver radio frequency amplifier and said radio frequency power amplifier.