US 2006/0066362 A1Published application

Voltage-current conversion circuit, amplifier, mixer circuit, and mobile appliance using the circuit

AssigneeSharp Kabushiki Kaisha

InventorsMasato Koutani, Kunihiko Iizuka

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Abstract

A cross-coupled low-distortion voltage-current conversion circuit has transistors T1 to T6. At least one of the transistors has parallel connections of two or more transistors. By arbitrarily setting the number of parallel connections of the transistors T1 to T6, the current distributions of the circuits are optimized while maintaining the conventional low-distortion operation. The invention finds applications in amplifiers and mixers that need to be operated with low distortion and low power consumption. The invention provides a cross-coupled low-distortion voltage-current conversion circuit that has freedom of design and improved performance without increasing power consumption over the entire circuit.

Claims32

Dependent claims

A voltage-current conversion circuit comprising a transconductance stage for carrying out voltage-current conversion, the transconductance stage comprising:

a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-connected to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein:
a resistor is located between the emitters of the fifth transistor and the sixth transistor;
and
the number of parallel connections of or sizes in the first to sixth transistors has an arbitrary ratio, setting such an arbitrary ratio adjusting the amount of signal currents flowing through the fifth transistor and the sixth transistor relative to the entire amount of current.

5 more elements

An amplifier comprising:

a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-coupled to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein:
a resistor is provided between the emitters of the fifth transistor and the sixth transistor;
a negative feedback resistor is added each between an emitter terminal of the fifth transistor and the ground, and between an emitter terminal of the sixth transistor and the ground, and an output load resistor is connected to each collector terminal of the fifth transistor and the sixth transistor;
at least one of the first to sixth transistors comprises parallel connections comprising two or more transistors;
and
the number of parallel connections of the first to sixth transistors has an arbitrary ratio, setting such an arbitrary ratio adjusting the amount of signal currents flowing through the fifth transistor and the sixth transistor relative to the entire amount of current.

7 more elements

A mixer circuit comprising:

a frequency conversion circuit for generating, from a first signal and a second signal, a third signal as a product;
and
a transconductance stage for receiving the first signal and carrying out voltage-current conversion of the first signal;
the transconductance stage comprising:
a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-coupled to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein
a resistor is provided between the emitters of the fifth transistor and the sixth transistor, and a current source is added to an emitter terminal of each of the fifth transistor and the sixth transistor.

7 more elements

A mixer circuit comprising:

a frequency conversion circuit for generating, from a first signal and a second signal, a third signal as a product;
and
a transconductance stage for receiving the first signal and carrying out voltage-current conversion of the first signal;
the transconductance stage comprising:
a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-coupled to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein
a resistor is provided between the emitters of the fifth transistor and the sixth transistor, and a negative feedback resistor is added each between an emitter terminal of the fifth transistor and the ground, and between an emitter terminal of the sixth transistor and the ground.

7 more elements

A quadrature mixer circuit comprising:

a first frequency conversion circuit for generating, from a first signal and a second signal, a third signal as a product;
a second frequency conversion circuit for generating, from the first signal and a fourth signal, a fifth signal as a product, wherein
a transconductance stage for inputting the first signal is shared,
the transconductance stage for receiving the first signal and carrying out voltage-current conversion of the first signal comprising:
a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-coupled to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein
a resistor is provided between the emitters of the fifth transistor and the sixth transistor, and a current source is added to an emitter terminal of each of the fifth transistor and the sixth transistor.

7 more elements

A quadrature mixer circuit comprising:

a first frequency conversion circuit for generating, from a first signal and a second signal, a third signal as a product;
a second frequency conversion circuit for generating, from the first signal and a fourth signal, a fifth signal as a product, wherein
a transconductance stage for inputting the first signal is shared,
the transconductance stage for receiving the first signal and carrying out voltage-current conversion of the first signal comprising:
a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-coupled to a base of the third transistor;
a fifth transistor for acquiring a current signal from a collector of the fifth transistor, the fifth transistor and the third transistor sharing the base and an emitter:
and
a sixth transistor for acquiring a current signal from a collector of the sixth transistor, the sixth transistor and the fourth transistor sharing the base and an emitter, wherein
a resistor is provided between the emitters of the fifth transistor and the sixth transistor, and a negative feedback resistor is added each between an emitter terminal of the fifth transistor and the ground, and between an emitter terminal of the sixth transistor and the ground.

7 more elements

A transconductance stage for carrying out voltage-current conversion, the transconductance stage comprising:

a first transistor and a second transistor each comprising a collector connected to a respective power source terminal, and each receiving an input signal from a respective base;
a third transistor comprising a collector connected to an emitter terminal of the first transistor and a fourth transistor comprising a collector connected to an emitter terminal of the second transistor, the collector of the third transistor being cross-coupled to a base of the fourth transistor, and the collector of the fourth transistor being cross-connected to a base of the third transistor;
and
a fifth transistor and the third transistor sharing the base and an emitter, and a sixth transistor and the third transistor sharing the base and an emitter, the fifth transistor and the sixth transistor each comprising parallel connections comprising a plurality of transistors connected in parallel, wherein:
a resistor is provided between the emitters of the fifth transistor and the sixth transistor;
and
the fifth transistor and the sixth transistor each comprise switching transistors connected to respective collectors, the number of the switching transistors being equal to the number of the parallel connections of each transistor, the switching transistors being controlled to adjust the amount of an output signal current relative to the entire current amount.

4 more elements

Dependencies are inferred from the claim text.