Current mode phase shifter, mixer and amplifier

• US 20070058703A1
• Filed: 09/12/2005
• Published: 03/15/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Afsahi, Ali, Behzad, Arya
• Granted Patent: US 7,545,856 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/91 the amplifier has a current mode topology
• CPC Class Codes: H03F 2203/45522 the FBC comprising one or more potentiometers
• CPC Class Codes: H03F 2203/45592 the IC comprising one or more buffer stages other than emitter or source followers between the input signal leads and input leads of the dif amp, e.g. inverter stages
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/45188 Non-folded cascode stages
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit
• CPC Class Codes: H03H 11/20 Two-port phase shifters providing an adjustable phase shift
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/206 using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/362 Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated H04L27/366 takes precedence

Abstract

An integrated circuit radio transceiver includes a phase shift block that is operable to produce a phase shifted current signal at an output of the phase shift block and a mixer with a low input impedance that is operable to produce a phase and frequency shifted output current signal based upon the phase shifted current signal. One aspect of the present invention is that the phase shift block produces an output as a current signal and the mixer block is operably disposed and formed to receive the current signal produced by the phase shift block. Similarly, an operational amplifier configured in a low input impedance mode is provided to receive and amplify a current signal mixer output, all to maximize signal processing head room reduce circuit noise and improve linearity

Claims

1. An integrated circuit radio transceiver, comprising:

a baseband processor operable to process ingoing digital communication signals and to produce outgoing digital communication signals;

a transmitter front end operable to process and transmit outgoing RF signals based upon the outgoing digital communication signals;

a receiver front end operable to receive ingoing RF signals and to process the ingoing RF signals to produce the ingoing digital communication signals to the baseband processor, wherein the receiver front end further includes a current mixing and amplification stage for generating an amplified frequency shifted output signal to at least a portion of one of the transmitter and receiver front ends, the current mixing and amplification stage further including;

a current mixer operable to produce a frequency shifted output current signal based upon an oscillation and an input signal, the current mixer characterized by an output impedance; and

an amplifier block operably disposed to produce an amplified signal based upon the frequency shifted output current signal, the amplifier block consisting of an amplifier with at least one feedback resistor wherein gain of the amplifier block is based substantially upon a product of a gain characteristic of the current mixer and a resistance value of the at least one feedback resistor and further wherein the at least one feedback resistor is coupled directly to an input of the amplifier and to a mixer output of the current mixer.

2. The integrated circuit radio transceiver of claim 1 further comprising a phase shifter operably disposed to produce a phase shifted signal to the current mixer based upon a received ingoing RF signal.

3. The integrated circuit radio transceiver of claim 2 wherein the phase shifted signal is produced to the current mixer of the current mixing and amplification stage and further wherein the current mixer produces a phase and frequency shifted signal based upon the phase shifted signal.

4. The integrated circuit radio transceiver of claim 3 wherein the phase shifter produces the phase shifted signal as a current signal and further wherein an output of a phase shift block is coupled to a high impedance load.

5. The integrated circuit radio transceiver of claim 4 wherein the current mixer comprises a low impedance input to prompt the phase shifted current signal to flow into the current mixer instead of the high impedance load coupled to the output of the phase shift block.

6. An integrated circuit radio receiver, comprising:

a first block operably disposed to receive a signal, wherein the first amplification block produces an amplified current signal based upon the signal to a first block output;

a first high impedance load operably disposed to receive the amplified current signal from the first block output; and

a second block operably disposed to receive the amplified current signal from the first block output wherein the second block includes input circuitry operably disposed to provide a substantially low input impedance in relation to the first high impedance load to prompt the amplified current signal to flow into the input circuitry instead of the first high impedance load.

7. The integrated circuit radio receiver of claim 6 wherein the first block comprises a low noise amplifier and the second block comprises a mixer block.

8. The integrated circuit radio receiver of claim 6 wherein the first block comprises a mixer block and the second block comprises an operational amplifier.

9. The integrated circuit radio receiver of claim 6 wherein the first block comprises a phase shift block and the second block comprises a mixer block.

10. The integrated circuit radio receiver of claim 9 further including a third block comprising an operational amplifier operably disposed to receive a phase and frequency shifted output of the mixer block as a current signal.

11. The integrated circuit radio receiver of claim 10 further including a second high impedance load operably disposed to the output of the output of the mixer block and the input of the third block.

12. The integrated circuit radio receiver of claim 11 wherein an input impedance of the third block is substantially lower than an impedance of the second high impedance load to prompt the phase and frequency shifted output current signal to flow into the input of the third block.

13. An integrated circuit radio transceiver, comprising:

a baseband processor operable to process ingoing digital communication signals and to produce outgoing digital communication signals;

a transmitter front end operable to process and transmit outgoing RF signals based upon the outgoing digital communication signals;

a receiver front end operable to receive ingoing RF signals and to process the ingoing RF signals to produce the ingoing digital communication signals to the baseband processor, wherein the receiver front end further includes;

a first block that produces an amplified output current signal into a first high output impedance load;

a second block further including a current mixer that produces a frequency shifted output current signal into a second high output impedance load; and

a third block further including an amplifier for providing an amplified frequency shifted output signal to at least a portion of one of the transmitter and receiver front ends, the third block operably disposed to produce an amplified signal based upon the frequency shifted output current signal, the third block consisting of an amplifier with at least one feedback resistor wherein gain of the third block is based substantially upon a product of a gain characteristic of the current mixer and a resistance value of the at least one feedback resistor and further wherein the at least one feedback resistor is coupled directly to an input of the amplifier and to a mixer output of the second block.

14. The integrated circuit radio transceiver of claim 13 wherein the first block comprises a low noise amplifier operably disposed to produce an amplified signal for mixing with a local oscillation in the current mixer.

15. The integrated circuit radio transceiver of claim 13 wherein the first block comprises a phase shifter operably disposed to produce a phase shifted output to the second block.

16. A method for processing an ingoing RF signal to produce an ingoing digital signal to a baseband processor, comprising:

receiving an RF signal and amplifying the RF signal to produce an amplified RF signal;

mixing the amplified RF signal with a local oscillation and producing a frequency shifted current signal; and

prompting the frequency shifted current signal to flow into a low impedance input of an amplifier.

17. The method for processing an ingoing RF signal to produce an ingoing digital signal to a baseband processor of claim 16 further including phase shifting the amplified RF signal prior to the mixing step to produce a phase shifted and amplified RF current signal and prompting the phase shifted and amplified RF current signal to flow into a mixer input for mixing in the mixing step.

18. The method for processing an ingoing RF signal to produce an ingoing digital signal to a baseband processor of claim 17 wherein the step of amplifying the RF signal further includes producing an amplified RF current signal and prompting the amplified RF current signal to flow into a phase shifter for phase shifting in the phase shifting step.

19. The method for processing an ingoing RF signal to produce an ingoing digital signal to a baseband processor of claim 18 further including, at each stage in which an output signal is produced as a current signal, prompting the output signal to not flow into an output load device by providing a high impedance output load device at an output of each stage.

20. The method for processing an ingoing RF signal to produce an ingoing digital signal to a baseband processor of claim 18 further including, at each stage in which an output signal is produced as a current signal, prompting the output signal to not flow into an output load device by providing a subsequent signal processing circuit with a low impedance operably disposed to receive the output signal of each stage in which the output signal is produced as a current signal.