ACTIVE MIXER CIRCUIT AND A RECEIVER CIRCUIT OR A MILLIMETER-WAVE COMMUNICATION UNIT USING IT

• US 20090221259A1
• Filed: 02/12/2009
• Published: 09/03/2009
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tanabe, Masamichi, Nakamura, Takahiro, Masuda, Toru, Washio, Katsuyoshi, SHIRAMIZU, Nobuhiro
• Granted Patent: US 8,121,579 B2
• Time in Patent Office: Days
• US Class Current: 455/334
• CPC Class Codes: H03D 2200/0023 Balun circuits
• CPC Class Codes: H03D 2200/0043 Bias and operating point
• CPC Class Codes: H03D 7/1433 using bipolar transistors H03D7/145 takes precedence
• 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: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

The present invention provides a semiconductor integrated circuit including an active mixer circuit that is operated at low voltage, low noise, and low power consumption. It includes a transconductance amplifier, a transformer, and a multiplier, connects a transformer between the transconductance amplifier and the multiplier, and separates between the transconductance amplifier and the multiplier with respect to direct current inside the transformer. Further, each of the tranconductance amplifier and the multiplier is configured of transistors that are single-stacked between the supply voltage terminal and ground terminal.

Claims

1. An active mixer circuit, comprising:

a voltage-to-current converter;

a multiplier; and

a transformer that is connected between the voltage-to-current converter and the multiplier,

wherein the voltage-to-current converter is configured of one transistor or a plurality of transistors connected in parallel,

wherein the transformer includes primary winding and secondary winding,

wherein the voltage-to-current converter is connected in series between a pair of terminals of a reference voltage that supply the supply voltage to the transformer via the primary winding of the transformer,

wherein an output terminal of the secondary winding of the transformer is connected to the multiplier, and

wherein the primary winding and the secondary winding of the transformer are separated from each other with respect to direct current inside the transformer.

2. The active mixer circuit according to claim 1,

wherein the voltage-to-current converter includes an input terminal that receives an input signal of a first frequency, an output terminal that is connected to an input terminal of the primary winding of the transformer, and a ground terminal that is connected to a first reference voltage,

wherein the terminal of the reference voltage of the input signal of the transformer is connected to a second reference voltage and the output terminal of the transformer is connected to the multiplier, and

wherein the terminal of the reference voltage of the input signal of the transformer and the terminal of the reference voltage of the output signal of the transformer are separated from each other with respect to direct current inside the transformer.

3. The active mixer circuit according to claim 2,

wherein the multiplier includes a first input terminal, a second input terminal, a supply voltage terminal, and an output terminal,

wherein a first node of an end of the primary winding of the transformer is connected to the output terminal of the voltage-to-current converter,

wherein a second node of the end of the primary winding is connected to a terminal of a second reference voltage VCC1,

wherein a first node of an end of the secondary winding of the transformer is connected to the first input terminal of the multiplier,

wherein a second node of the end of the secondary winding is connected to a terminal of a reference voltage GND of the transformer,

wherein the second input terminal of the multiplier is supplied with the input signal of the second frequency and the supply voltage terminal is connected to a third reference voltage VCC2, and

wherein an output signal of a third frequency, which is a difference between the first frequency and the second frequency, is output from the output terminal of the multiplier.

4. The active mixer circuit according to claim 1,

wherein the first node of the end of the primary winding is connected to an input terminal of a single-ended signal of the transformer,

wherein the second node of the end of the primary winding is connected to a terminal of a reference voltage of the single-ended input signal of the transformer,

wherein the first node of the end of the secondary winding is connected to an output terminal of a differential positive phase signal of the transformer,

wherein the second node of the end of the secondary winding is connected to an output terminal of a differential negative phase signal of the transformer,

wherein a third node at the middle of the secondary winding is connected to a terminal of a reference voltage of a different output signal of the transformer, and

wherein a signal, which is converted from the single-ended signal input to the input terminal of the transformer into the differential signal, is output from a differential output terminal of the transformer.

5. The active mixer circuit according to claim 1,

wherein the transformer includes the primary winding, the secondary winding having an intermediate node, a load element, and a capacitor,

wherein a first node of the capacitor is connected to an input terminal of a single-ended input signal,

wherein a second node of the capacitor, a first node of the load element, and a first node of the primary winding are mutually connected to the single-ended input terminal,

wherein a second node of the load element is connected to a terminal of a reference voltage of the single-ended input signal of the transformer,

wherein the second node of the end of the primary winding is connected to a terminal of a reference voltage of the differential output signal of the transformer,

wherein the first node of the end of the secondary winding is connected to the differential positive phase output terminal of the transformer,

wherein the second node of the end of the secondary winding is connected to the differential negative phase output terminal of the transformer,

wherein the intermediate node of the secondary winding is connected to the terminal of the reference voltage of the differential signal of the transformer, and

wherein a signal, which is converted from the single-ended signal input to the single-ended input terminal of the transformer into the differential signal, is output from the differential output terminal of the transformer.

6. The active mixer circuit according to claim 2,

wherein the voltage-to-current converter includes a first transistor that configures a transconductance amplifier,

wherein a collector or a drain of the first transistor is connected to the first node of the primary winding of the transformer,

wherein an emitter or a source of the first transistor is connected to a predetermined second reference voltage GND,

wherein the second node of the first primary winding of the transformer is connected to a third reference voltage VCC1, and

wherein the intermediate node of the secondary winding of the transformer is connected to the second reference voltage GND.

7. The active mixer circuit according to claim 6,

wherein the transistor configuring the multiplier is configured of a plurality of transistors that are connected in parallel between the first node of the secondary winding of the transformer and a fifth reference voltage VCC2.

8. The active mixer circuit according to claim 1, further comprising:

a transconductance amplifier having a first transistor, a transformer, and a multiplier that includes second to fifth transistors, first and second load elements,

wherein a first input node RFIN of a base or a gate of the first transistor is connected to a predetermined first reference voltage VRF and is supplied with an input signal of a first frequency,

wherein a collector or a drain of the first transistor is connected to the first node of the primary winding of the transformer,

wherein an emitter or a source of the first transistor is connected to the predetermined second reference voltage GND,

wherein the second node of the primary winding of the transformer is connected to the third reference voltage VCC1,

wherein the second input node that mutually connects bases or gates of the second and fifth transistors are connected to a predetermined fourth reference voltage VLO and is supplied with a predetermined positive phase input signal of a second frequency,

wherein the third input node that mutually connects bases or gates of the third and fourth transistors are connected to a predetermined fourth reference voltage VLO and is supplied with a predetermined negative phase input signal of the second frequency,

wherein emitters or sources of the second and fifth transistors are connected to each other and are connected to the first node of the secondary winding of the transformer,

wherein emitters or sources of the third and fourth transistors are connected to each other and are connected to the second node of the secondary winding of the transformer,

wherein the intermediate node of the secondary winding of the transformer is connected to the second reference voltage GND,

wherein a first load element is connected between the first output node, which mutually connects collectors or drains of the second and third transistors, and the fifth reference voltage VCC2,

wherein a second load element is connected between the second output node, which mutually connects collectors or drains of the fourth and fifth transistors, and the fifth reference voltage VCC2,

wherein the first output node receives a negative signal of a third frequency, the second output node receives positive signals of the third frequency, whereby the third frequency, which is the output signal, is a difference between the first frequency and the second frequency of the input signals, and

wherein the third reference voltage VCC1 of the primary winding of the transformer and the intermediate node GND of the secondary winding of the transformer are separated from each other with respect to direct current inside the transformer.

9. The active mixer circuit according to claim 8,

wherein the voltage, which is a difference between the third reference voltage VCC1 and the second reference voltage GND of the mixer circuit and the voltage, which is a difference between the fifth reference voltage VCC2 and the second reference voltage GND are set to 0.5 V or more to 1.5 V or less.

10. The active mixer circuit according to claim 1,

wherein the voltage-to-current converter includes the transconductance amplifier that is configured of the first and second transistors,

wherein a collector or a drain of the first transistor is connected to the first node of the primary winding of the transformer and a collector or a drain of the second transistor is connected to the second node of the primary winding of the transformer,

wherein the intermediate node of the primary winding of the transformer is connected to the third reference voltage VCC1,

wherein an emitter or a source of the first and second transistor are connected to the predetermined second reference voltage GND, and

wherein the intermediate node of the secondary winding of the transformer is connected to the second reference voltage GND.

11. The active mixer circuit according to claim 1, further comprising:

a transconductance amplifier that includes the first and second transistors and configures the voltage-to-current converter, the transformer, and the multiplier that includes the third to sixth transistors and the first and second load elements,

wherein the first input node of the base or gate of the first transistor is connected to the predetermined first reference voltage VRF and is supplied with the positive phase input signal of the first frequency,

wherein the second input node of the base or gate of the second transistor is connected to the predetermined first reference voltage VRF and is supplied with the negative phase input signal of the first frequency,

wherein the collector or the drain of the first transistor is connected to the first node of the primary winding of the transformer and the collector or the drain of the second transistor is connected to the second node of the primary winding of the transformer,

wherein the intermediate node of the primary winding of the transformer is connected to the third reference voltage VCC1,

wherein the emitters and the sources of the first and second transistors are connected to the predetermined second reference voltage GND,

wherein the third input node, which mutually connects the bases or the gates of the third and sixth transistors, is connected to the predetermined fourth reference voltage VLO and is supplied with the positive phase input signal of the second frequency,

wherein the fourth input node, which mutually connects the bases or the gates of the fourth and fifth transistors, is connected to the predetermined fourth reference voltage VLO and is supplied with the negative phase input signal of the second frequency,

wherein the emitters or the sources of the third and sixth transistors are connected to each other and are connected to the first node of the secondary winding of the transformer,

wherein the emitters or the sources of the fourth and fifth transistors are connected to each other and are connected to the second node of the secondary winding of the transformer,

wherein the intermediate node of the secondary winding of the transformer is connected to the second reference voltage GND,

wherein the first load element is connected between the first output node, which mutually connects the collectors or the drains of the third and fourth transistors, and the fifth reference voltage VCC2,

wherein the second load element is connected between the second output node, which mutually connects the collectors or the drains of the fifth and sixth transistors, and the fifth reference voltage VCC2,

wherein the first output node receives the negative phase signal of the third frequency, the second output node receives the positive signal of the third frequency, and the third frequency, which is the output signal, is a difference between the first frequency and the second frequency of the input signals, and

wherein the intermediate node VCC1 of the primary winding of the transformer and the intermediate node GND of the secondary winding of the transformer are separated from each other with respect to direct current inside the transformer.

12. The active mixer circuit according to claim 8, further comprising:

a feedback differential amplifier,

wherein the first output node and a first input node of the feedback differential amplifier are connected to each other and the second output node and a second input node of the feedback differential amplifier are connected to each other.

13. The active mixer circuit according to claim 8, further comprising:

a transconductance amplifier that includes the first transistor and configures the voltage-to-current converter, the transformer, and the multiplier that includes the third to sixth transistors, the first and second load elements, and the feedback differential amplifier,

wherein the second output node of the multiplier and the first input node of the feedback differential amplifier are connected to each other and the first output node of the multiplier and the second input node of the feedback differential amplifier are connected to each other, and

wherein the first output node and the first input node of the feedback differential amplifier are connected to each other via a first feedback resistor and the second output node and the second input node of the feedback differential amplifier are connected to each other via a second feedback resistor.

14. The active mixer circuit according to claim 1,

wherein the transistor is a bipolar transistor.

15. The active mixer circuit according to claim 14,

wherein the transistor is a silicon germanium (SiGe) hetero-junction bipolar transistor.

16. The active mixer circuit according to claim 1,

wherein the transistor is a metal-oxide semiconductor (MOS) transistor.

17. A receiver circuit, comprising:

a low-noise amplifier;

an active mixer circuit;

a local oscillator;

a first differential amplifier; and

a second differential amplifier,

wherein the active mixer circuit includes a voltage-to-current converter, a multiplier, and a transformer that is connected between the voltage-to-current converter and the multiplier,

wherein the voltage-to-current converter is configured of one transistor or a plurality of transistors connected in parallel,

wherein the transformer includes primary winding and secondary winding,

wherein the voltage-to-current converter is connected in series between a pair of terminals of a reference voltage that supply the supply voltage to the transformer via the primary winding of the transformer,

wherein an output terminal of the secondary winding of the transformer is connected to the multiplier, and

wherein the primary winding and the secondary winding of the transformer are separated from each other with respect to direct current inside the transformer.

18. The receiver circuit according to claim 17,

wherein the voltage-to-current converter includes an input terminal that receives an input signal of a first frequency, an output terminal that is connected to an input terminal of the transformer, and a ground terminal that is connected to a first reference voltage,

wherein the terminal of the reference voltage of the input signal of the transformer is connected to a second reference voltage and the output terminal of the transformer is connected to the multiplier,

wherein the voltage-to-current converter is configured of one transistor or a plurality of transistors connected in parallel,

wherein the transistor configuring the multiplier is configured of the plurality of transistors that are connected in parallel between the output terminal of the secondary winding of the transformer and a third reference voltage, and

wherein the terminal of the reference voltage of the input signal of the transformer and the terminal of the reference voltage of the output signal of the transformer are separated from each other with respect to direct current inside the transformer.

19. A millimeter-wave communication unit, comprising:

a front-end circuit block; and

an IF-band circuit/base-band circuit block,

wherein the front-end circuit block includes a low-noise amplifier, an active mixer circuit, a local oscillator, a first differential amplifier, and a second differential amplifier,

wherein the IF-band circuit/base-band circuit block includes a signal processing circuit that demodulates an output signal from the front-end circuit block,

wherein the active mixer circuit includes a voltage-to-current converter, a multiplier, and a transformer that is connected between the voltage-to-current converter and the multiplier,

wherein the voltage-to-current converter is configured of one transistor or a plurality of transistors connected in parallel,

wherein the transformer includes primary winding and secondary winding,

wherein the voltage-to-current converter is connected in series between a pair of terminals of a reference voltage that supply the supply voltage to the transformer via the primary winding of the transformer,

wherein an output terminal of the secondary winding of the transformer is connected to the multiplier,

wherein the primary winding and the secondary winding of the transformer are separated from each other with respect to direct current inside the transformer, and

wherein the low-noise amplifier, the first differential amplifier, the mixer circuit, the second differential amplifier, and the signal processing circuit of the IF band circuit/baseband circuit are commonly connected to the reference voltage VCC.

20. The millimeter-wave communication unit according to claim 19,

wherein the voltage-to-current amplifier of the active mixer circuit and each transistor configuring the multiplier are configured of a bipolar transistor,

wherein each transistor configuring the signal processing circuit is configured of a MOS transistor, and

wherein the common reference voltage VCC is set to a range of 0.5 or more to 1.5 or less.