Multi-function passive frequency mixer

• US 7,668,527 B2
• Filed: 02/16/2007
• Issued: 02/23/2010
• Est. Priority Date: 06/30/2006
• Status: Expired due to Fees

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Vaisanen, Risto
• Primary Examiner(s): Jackson, Blane J
• Application Number:
  US11/707,021
• Publication Number:
  US 20080003973A1
• Time in Patent Office: 1,103 Days
• Field of Search: 455/323, 455/324, 455/325, 455/326, 455/333, 455/334, 455/341
• US Class Current: 455/323
• CPC Class Codes: H02M 7/25 arranged for operation in series, e.g. for multiplication of voltage
• CPC Class Codes: H03D 2200/0025 Gain control circuits
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1458 Double balanced arrangements, i.e. where both input signals are differential
• CPC Class Codes: H03D 7/1466 Passive mixer arrangements
• CPC Class Codes: H03D 7/1483 comprising components for selecting a particular frequency component of the output

Abstract

A frequency-mixing device performing voltage multiplying and low-pass filtering operations in addition to the frequency mixing is provided. The three operations may be carried out with the same components by designing the frequency mixer appropriately. The frequency mixer comprises a balanced input port to receive a balanced input signal, an oscillator signal input port to receive a first and a second oscillator signal and a first, a second, and a third capacitance. First switching means are arranged to connect, in response to the first oscillator signal, the first and the second capacitance between a first and a second input port of the balanced input port. Second switching means are arranged to connect, in response to the second oscillator signal, the first capacitance between the first input port and the third capacitance and the second capacitance between the second input port and the third capacitance. An output port is connected to terminals of the third capacitance.

Claims

1. An apparatus, comprising:

an input interface comprising a balanced input port configured to receive a balanced input signal and an oscillator signal input port configured to receive a first oscillator signal and a second oscillator signal;

a first capacitance;

a second capacitance;

a third capacitance;

a first set of switches responsive to the first oscillator signal and configured to connect, in response to the first oscillator signal, the first capacitance and the second capacitance between a first input port and a second input port of the balanced input port;

a second set of switches responsive to the second oscillator signal and configured to connect, in response to the second oscillator signal, the first capacitance between the first input port and the third capacitance and the second capacitance between the second input port and the third capacitance; and

an output port connected to terminals of the third capacitance.

2. The apparatus of claim 1, wherein a first terminal of the first capacitance is connected to the first input port and a first terminal of the second capacitance is connected to the second input port, wherein the first set of switches is configured to connect, when closed, a second terminal of the first capacitance to the second input port and a second terminal of the second capacitance to the first input port, and wherein the second set of switches is configured to connect, when closed, the second terminal of the first capacitance to a first terminal of the third capacitance and the second terminal of the second capacitance to a second terminal of the third capacitance.

3. The apparatus of claim 1, wherein the first oscillator signal and the second oscillator signal are a same oscillator signal.

4. The apparatus of claim 1, further comprising:

a local oscillator signal generator configured to generate and apply to the oscillator input port the first oscillator signal and the second oscillator signal, wherein the first oscillator signal and the second oscillator signal have opposite phases.

5. The apparatus of claim 4, wherein the apparatus is configured to receive a radio frequency input signal through the balanced input port, and the local oscillator signal generator is configured to produce the first oscillator signal and the second oscillator signal to have a frequency suitable for converting the frequency of the input signal to a desired target frequency.

6. The apparatus according to claim 1, further comprising:

a controllable switching mechanism configured to connect, when the first set of switches is closed, the first capacitance and the second capacitance between the first input port and the second input port either in series or in parallel depending on a desired voltage multiplication factor effected by the apparatus on an input signal input to the balanced input port.

7. The apparatus of claim 6, wherein the switching mechanism is configured to connect the first capacitance and the second capacitance between the first input port and the second input port in series when the desired voltage multiplication factor is two and in parallel when the desired voltage multiplication factor is three.

8. The apparatus of claim 6, wherein the switching mechanism is further configured to connect, when the first set of switches is closed, two terminals of the first capacitance to the first input port and two terminals of the second capacitance to the second input port when the desired voltage multiplication factor is one.

9. The apparatus according to claim 1, wherein the apparatus is configured to function as a low-pass filter having a corner frequency defined by the ratios of the capacitance values of the first capacitance and the third capacitance and the second capacitance and the third capacitance, respectively.

10. The apparatus according to claim 1, wherein a first terminal of the first capacitance is connected to the first input port and a first terminal of the second capacitance is connected to the second input port, wherein the first set of switches comprises a first switch connected between a second terminal of the first capacitance and the second input port and a second switch connected between a second terminal of the second capacitance and the first input interface, and wherein the second set of switches comprises a third switch connected between the second terminal of the first capacitance and a first terminal of the third capacitance and a fourth switch connected between the second terminal of the second capacitance and a second terminal of the third capacitance.

11. The apparatus according to claim 1, further comprising:

a fourth capacitance,

wherein the first set of switches is configured to connect, when closed, the fourth capacitance together with the first capacitance and the second capacitance in series between the first input port and the second input port of the balanced input port.

12. The apparatus of claim 11, further comprising:

an adjustment circuit configured to adjust the capacitance value of the fourth capacitance, and to control a voltage multiplication factor of the apparatus.

13. The apparatus according to claim 1, wherein the apparatus is further configured to function as a voltage multiplier by configuring the first oscillator signal to close the first set of switches and accordingly charge the first and the second capacitance during the first half cycle of the first oscillator signal, and configuring the second oscillator signal to close the second set of switches and accordingly release the charge in the first capacitance together with the input signal to the second capacitance during the second half cycle of the second local oscillator signal, in order to sum the voltages charged into the first capacitance and the second capacitance and the voltage over the first input port and the second input port.

14. The apparatus of claim 1, having a dual balanced structure.

15. A frequency mixing device, comprising:

an input interface comprising a balanced input port configured to receive a balanced input signal and an oscillator signal input port configured to receive a first oscillator signal and a second oscillator signal;

a first capacitance;

a second capacitance;

a third capacitance;

a first set of switches responsive to the first oscillator signal and configured to connect, in response to the first oscillator signal, the first capacitance and the second capacitance between a first input port and a second input port of the balanced input port;

a second set of switches responsive to the second oscillator signal and configured to connect, in response to the second oscillator signal, the first capacitance between the first input port and the third capacitance and the second capacitance between the second input port and the third capacitance; and

an output port connected to terminals of the third capacitance.

16. A radio apparatus comprising a frequency-mixing device apparatus, comprising:

an input interface comprising a balanced input port configured to receive a balanced input signal and an oscillator signal input port configured to receive a first oscillator signal and a second oscillator signal;

a first capacitance;

a second capacitance;

a third capacitance;

a first set of switches responsive to the first oscillator signal and configured to connect, in response to the first oscillator signal, the first capacitance and the second capacitance between a first input port and a second input port of the balanced input port;

a second set of switches responsive to the second oscillator signal and configured to connect, in response to the second oscillator signal, the first capacitance between the first input port and the third capacitance and the second capacitance between the second input port and the third capacitance; and

an output port connected to terminals of the third capacitance.

17. The radio apparatus of claim 16, wherein the radio transceiver is configured to receive a radio frequency signal comprising an in-phase component and a quadrature component, and the radio transceiver further comprises a separate frequency mixer for the in-phase component and a separate frequency mixer for the quadrature component.

18. The radio apparatus of claim 17, wherein phases of oscillator signals applied to the separate frequency mixer associated with the quadrature component differ 90 degrees from respective phases of oscillator signals applied to the separate frequency mixer associated with the in-phase component, and wherein local oscillator signals have a maximum pulse ratio of 25/75.

19. The radio apparatus of claim 17, further comprising:

a separate amplifier for each of the separate frequency mixers to precede the separate frequency mixers,

wherein phases of local oscillator signals applied to the separate frequency mixer associated with the quadrature component differ 90 degrees from respective phases of local oscillator signals applied to the separate frequency mixer associated with the in-phase component and wherein the local oscillator signals have a maximum pulse ratio of 50/50.

20. The radio apparatus of claim 17, further comprising:

a phase shifter preceding at least one of the separate frequency mixers,

wherein the phase shifter preceding the at least one of the frequency mixers is configured to shift the phase of at least one of the in-phase component and the quadrature component to produce a 90-degree phase difference between the in-phase component and the quadrature component.

21. The radio apparatus of claim 20, wherein a same local oscillator signal is applied to both separate frequency mixers.

22. A method, comprising:

receiving an input signal through a first input port and a second input port of a balanced input port and a first oscillator signal and a second oscillator signal through an oscillator signal input port;

connecting, in a first stage in response to a first oscillator signal, a first capacitance and a second capacitance between the first input port and the second input port of the balanced input port;

connecting, in a second stage in response to a second oscillator signal, the first capacitance between the first input port and a third capacitance and the second capacitance between the second input port and the third capacitance, and

obtaining a voltage over the third capacitance as an output voltage.

23. The method of claim 22, further comprising:

connecting a first terminal of the first capacitance connected to the second input port in the first stage to the third capacitance at the second stage; and

connecting a first terminal of the second capacitance to the first input port in the first stage is connected to a second terminal of the third capacitance in the second stage.

24. The method of claim 22, further comprising:

charging, in the first stage, the first capacitance and the second capacitance with a voltage corresponding to a voltage over the first input port and the second input port; and

releasing, in the second stage, the charge in the first capacitance and the second capacitance into the third capacitance in series with a current voltage over the first input port and the second input port, in order to produce, over the third capacitance, a voltage that is the sum of the voltage charged into the first capacitance at the first stage, the voltage charged into the second capacitance at the first stage, and the current voltage over the first input port and the second input port.

25. The method of claim 22, further comprising:

configuring the first oscillator signal and the second oscillator signal to be a same oscillator signal.

26. The method of claim 22, further comprising:

configuring the first oscillator signal and the second oscillator signal to have a same frequency and different phases.

27. The method of claim 22, further comprising:

configuring the received input signal to be a radio frequency input signal; and

configuring the first oscillator and the second oscillator signal to have a frequency suitable for converting a frequency of the radio frequency input signal to a desired target frequency.

28. The method of claim 22, further comprising:

connecting, in the first stage, the first capacitance and the second capacitance between the first input port and the second input port either in series or in parallel depending on a desired voltage multiplication factor of the output signal relative to the input signal.

29. The method of claim 28, further comprising:

connecting, in the first stage, the first capacitance and the second capacitance between the first input port and the second input port in series when the desired voltage multiplication factor is two and in parallel when the desired voltage multiplication factor is three.

30. The method of claim 28, further comprising:

connecting two terminals of the first capacitance to the first input port in the first stage; and

connecting two terminals of the second capacitance to the second input port in the first stage when the desired voltage multiplication factor is one.

31. The method of claim 28, further comprising:

connecting, in the first stage, the first capacitance and the second capacitance in series between the first input port and the second input port; and

providing, in series with the first capacitance and the second capacitance, an additional capacitance having a capacitance value determined according to the desired voltage multiplication factor.

32. The method of claim 22, further comprising:

defining a corner frequency of a low-pass filter with the capacitance values of the first capacitance, the second capacitance, and the third capacitance; and

low-pass filtering the input signal input to the first input port and the second input port.

33. The method of claim 22, further comprising:

connecting, in the first stage, the first capacitance and the second capacitance between the first input port and the second input port in series;

providing a fourth capacitance in series between the first capacitance and the second capacitance in the first stage; and

adjusting a capacitance value of the fourth capacitance according to a desired voltage multiplication factor of the output signal relative to the input signal.

34. The method of claim 22, further comprising:

charging the first capacitance and the second capacitance alternately with the third capacitance.

35. The method of claim 22, which method is carried out in an apparatus having a dual balanced structure.

36. An apparatus, comprising:

input means comprising a first and a second input port of a balanced input port configured to receive a balanced input signal and an oscillator signal input means configured to receive a first oscillator and a second oscillator signal;

first capacitance means for storing charge;

second capacitance means for storing charge;

third capacitance means for storing charge;

first connection means for connecting, in a first stage in response to the first oscillator signal, the first capacitance means and the second capacitance means between the first input port and the second input port of the balanced input port;

second connection means for connecting, in a second stage in response to the second oscillator signal, the first capacitance means between the first input port and the third capacitance means and the second capacitance means between the second input port and the third capacitance means, and

output means for obtaining a voltage over the third capacitance means as an output voltage.