Transmit Architecture for Wireless Multi-Mode Applications

• US 20100295599A1
• Filed: 05/19/2010
• Published: 11/25/2010
• Est. Priority Date: 05/19/2009
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Yang, Chao, Venca, Alessandro, Leroux, Marc, Castello, Rinaldo, Brunn, Brian, Uehara, Gregory, De Bernardinis, Fernando, Jiang, Ruoxin
• Granted Patent: US 8,868,015 B2
• Time in Patent Office: Days
• US Class Current: 327/355
• CPC Class Codes: H04B 1/0071 using a common intermediate frequency for more than one band H04B1/0075 takes precedence

Abstract

In one embodiment, an apparatus includes an upconversion unit configured to upconvert a baseband signal to a radio frequency (RF) signal. A plurality of baluns for a plurality of wireless bands are provided. Multiplexing circuitry is coupled to the plurality of baluns where the upconversion unit is coupled to each balun through the multiplexing circuitry. The multiplexing circuitry is configured to multiplex the radio frequency signal from the upconversion unit to one of the plurality of baluns based on a wireless band being used.

Claims

1. An apparatus comprising:

an upconversion unit configured to upconvert a baseband signal to a radio frequency (RF) signal;

a plurality of baluns for a plurality of wireless bands; and

multiplexing circuitry coupled to the plurality of baluns,

wherein the upconversion unit is coupled to each balun through the multiplexing circuitry, and

wherein the multiplexing circuitry is configured to multiplex the radio frequency signal from the upconversion unit to one of the plurality of baluns based on a wireless band being used.

2. The apparatus of claim 1, wherein multiplexing circuitry comprises a plurality of sets of transistors, wherein each set is associated with a balun in the plurality of baluns.

3. The apparatus of claim 2, further comprising a plurality of upconversion units, wherein each of the plurality of upconversion units is coupled to the plurality of sets of transistors.

4. The apparatus of claim 3, wherein, through the multiplexing circuitry, one set of transistors are coupled to one of the plurality of baluns to send the radio frequency signal from the upconversion unit through the one of the plurality of baluns.

5. The apparatus of claim 4, wherein the one set of transistors is coupled to the one of the plurality of baluns by biasing the one set of transistors to be on and biasing the other sets of transistors to be off.

6. The apparatus of claim 1, wherein the upconversion unit comprises:

a Gm transistor biased in a saturation region; and

a mixer transistor biased in a triode region,

wherein the multiplexing circuitry comprises a multiplexing transistor biased in the saturation region.

7. The apparatus of claim 1, wherein the one of the plurality of baluns comprises a differential output or a single-ended output.

8. The apparatus of claim 1, further comprising:

a filter; and

a mirror buffer,

wherein a pole of the filter is coupled in between the mirror buffer and the upconversion unit.

9. The apparatus of claim 8, wherein the filter comprises a pair of transmitter poles coupled to an input of the mirror buffer.

10. The apparatus of claim 1, wherein the upconversion unit comprises:

a first mixer configured to mix an in phase (I) signal with a first local oscillator signal to generate a first radio frequency signal; and

a second mixer configured to mix a quadrature (Q) signal with a second local oscillator signal to generate a second radio frequency signal,

wherein the multiplexing circuitry is configured to couple the first mixer to the one of the baluns and not couple the second mixer to the one of the baluns.

11. An apparatus comprising:

a pole pair of a filter configured to filter a signal, the first pole pair including a first pole and a second pole;

a mirror buffer configured to buffer the signal; and

a third pole of the filter coupled to the mirror buffer and configured to filter the signal buffered by the mirror buffer.

12. The apparatus of claim 11, wherein the pole pair comprises a first pole pair, wherein the apparatus further comprises a second pole pair including fourth and fifth transmitter poles coupled to the first pole pair.

13. The apparatus of claim 11, wherein the third pole of the filter comprises:

a first resistor;

a second resistor;

a capacitor; and

switch circuitry configured to select one of the first resistor or the second resistor.

14. The apparatus of claim 13, wherein the switch circuitry comprises:

a first transistor coupled to a first switch;

a second transistor coupled to a second switch;

wherein when the first switch is closed, the second switch is out of a first signal path coupling the pole pair to the first resistor,

wherein when the second switch is closed, the first switch is out of a second signal path coupling the pole pair to the second resistor.

15. The apparatus of claim 13, wherein the switch circuitry comprises:

a first transistor coupled to a first switch, the first switch coupled to the pole pair;

a second transistor coupled to;

a second switch coupled to a voltage supply; and

a third switch coupled to ground;

a third transistor coupled to a fourth switch, the fourth switch coupled to the pole pair;

a fourth transistor coupled to;

a fifth switch coupled to a voltage supply; and

a sixth switch coupled to ground.

16. A method comprising:

upconverting a baseband signal to a radio frequency (RF) signal;

determining a wireless band in a plurality wireless bands for a multimode transmitter; and

multiplexing the RF signal to a balun in a plurality of baluns based on a wireless band being used.

17. The method of claim 16, wherein multiplexing comprises coupling the RF signal through a set of transistors in a plurality of sets of transistors, wherein each set of transistors is associated with one balun in the plurality of baluns.

18. The method of claim 17, wherein coupling comprises biasing the one set of transistors to be on and biasing the other sets of transistors to be off.

19. The method of claim 16, further comprising:

filtering the baseband signal using a first filter;

buffering the baseband signal using a mirror circuit; and

filtering the baseband signal from the mirror circuit using a second filter.

20. The method of claim 19, wherein the first filter and the second filter form an Nth order filter.