RADIO TRANSCEIVER CIRCUIT

• US 20170077984A1
• Filed: 09/09/2016
• Published: 03/16/2017
• Est. Priority Date: 09/11/2015
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Catena Holding B.V. (NXP Semiconductors NV)
• Inventors: Esmaeilzadeh Najari, Omid, Carlsson, Mats Lennart
• Granted Patent: US 9,941,923 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The disclosure relates to transceivers incorporating a transmit-receive switching circuit, embodiments of which include a radio transceiver circuit comprising: a first amplifier for amplifying signals received from an antenna via an antenna connection; a second amplifier for amplifying signals to be transmitted by the antenna via the antenna connection; and a switching circuit connected between an input of the first amplifier and the antenna connection, the switching circuit comprising a capacitor, a switching element and an impedance matching element, wherein the switching element is configured to connect a node between the capacitor and the impedance matching element to a signal ground when the transceiver is in a transmit mode.

Claims

1. A radio transceiver circuit comprising:

a first amplifier for amplifying signals received from an antenna via an antenna connection;

a second amplifier for amplifying signals to be transmitted by the antenna via the antenna connection; and

a switching circuit connected between an input of the first amplifier and the antenna connection, the switching circuit comprising a capacitor, a switching element and an impedance matching element,

wherein the switching element is configured to connect a node between the capacitor and the impedance matching element to a signal ground when the transceiver is in a transmit mode.

2. The radio transceiver circuit of claim 1 comprising a transformer connected between an output of the second amplifier and the antenna connection.

3. The radio transceiver circuit of claim 2 wherein the transformer is a balance to unbalance transformer.

4. The radio transceiver circuit of claim 1, wherein the impedance matching element includes or is an inductor and the switching element includes a transistor.

5. The radio transceiver circuit of claim 1, comprising a bond wire inductance connected between the switching circuit and the antenna connection.

6. The radio transceiver circuit of claim 1, wherein the switching element is a transistor connected between the impedance matching element and the signal ground to provide a short therebetween when activated.

7. The radio transceiver circuit of claim 1, wherein the impedance matching element transforms an input impedance of the first amplifier to an impedance looking into the impedance matching circuit from the node that is a complex conjugate of an impedance looking into the capacitor from the node.

8. The radio transceiver of claim 1, wherein the second amplifier is operable to amplify signals to be transmitted according to a first wireless communications standard, and further comprising a third amplifier operable to amplify signals to be transmitted according to a second wireless communications standard by the antenna via the antenna connection.

9. The radio transceiver circuit of claim 8, wherein an output of the third amplifier is connected between the impedance matching element and the input of the first receiving amplifier.

10. The radio transceiver circuit of claim 8, further comprising a fourth amplifier operable to amplify signals to be transmitted according to the second wireless communications standard by the antenna via the antenna connection, wherein an output of the fourth amplifier is connected to a node between the impedance matching element and the capacitor.

11. The radio transceiver circuit of claim 10, wherein the fourth amplifier is a switching power amplifier comprising first and second transistors, the first transistor connected between the node and signal ground to provide a short therebetween when activated.

12. The radio transceiver circuit of claim 10, further comprising a fifth amplifier for amplifying signals received from the antenna via the antenna connection, a second impedance matching element connected between the node and an input of the fifth amplifier.

13. The radio transceiver circuit of claim 12, wherein the second impedance matching element transforms an input impedance of the fifth amplifier to an impedance looking into the impedance matching element from the node that is a complex conjugate of an impedance looking into the capacitor from the node.

14. The radio transceiver circuit of claim 8, wherein the first or second wireless communications standard is consistent with a Bluetooth®

standard or an IEEE 802.11x standard.

15. An integrated circuit comprising a radio transceiver circuit according to claim 1.

16. A radio transceiver circuit comprising:

a first amplifier for amplifying signals received from an antenna via an antenna connection;

a second amplifier for amplifying signals to be transmitted by the antenna via the antenna connection;

a switching circuit connected between an input of the first amplifier and the antenna connection, the switching circuit comprising a capacitor, a switching element and an impedance matching element;

wherein the switching element is configured to connect a node between the capacitor and the impedance matching element to a signal ground when the transceiver is in a transmit mode;

wherein the impedance matching element transforms an input impedance of the first amplifier to an impedance looking into the impedance matching circuit from the node that is a complex conjugate of an impedance looking into the capacitor from the node; and

wherein the second amplifier is operable to amplify signals to be transmitted according to a first wireless communications standard, and further comprising a third amplifier operable to amplify signals to be transmitted according to a second wireless communications standard by the antenna via the antenna connection.

17. The radio transceiver circuit of claim 16, further comprising a fourth amplifier operable to amplify signals to be transmitted according to the second wireless communications standard by the antenna via the antenna connection, wherein an output of the fourth amplifier is connected to a node between the impedance matching element and the capacitor.

18. The radio transceiver circuit of claim 16, further comprising a fifth amplifier for amplifying signals received from the antenna via the antenna connection, a second impedance matching element connected between the node and an input of the fifth amplifier.

19. The radio transceiver circuit of claim 18, wherein the second impedance matching element transforms an input impedance of the fifth amplifier to an impedance looking into the impedance matching element from the node that is a complex conjugate of an impedance looking into the capacitor from the node.

20. A method for using a radio transceiver circuit, the method comprising:

amplifying signals, through a first amplifier, received from an antenna via an antenna connection;

amplifying signals, through a second amplifier, to be transmitted by the antenna via the antenna connection; and

providing a switching circuit connected between an input of the first amplifier and the antenna connection, the switching circuit comprising a capacitor, a switching element and an impedance matching element, and controlling the switching element to connect a node between the capacitor and the impedance matching element to a signal ground when the transceiver is in a transmit mode.