US 9,985,589 B2Granted

System and method for improving total harmonic distortion of an amplifier

AssigneeTexas Instruments Incorporated

InventorsSrinivas K. Pulijala, Steven G. Brantley, Bharath K. Vasan

Life of this patent

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Abstract

A voltage-to-current converter includes a first differential pair of transistors, a second differential pair of transistors, and a first resistor. The first differential pair of transistors includes a first transistor and a second transistor. An emitter of the first transistor is directly connected to an emitter of the second transistor. The second differential pair of transistors includes a third transistor and a fourth transistor. An emitter of the third transistor is directly connected to an emitter of the fourth transistor. The first resistor is connected to the emitter of the first transistor, the emitter of the second transistor, the emitter of the third transistor, and the emitter of the fourth transistor.

Claims14

Dependent claims

A voltage-to-current converter, comprising:

a first differential pair of transistors including a first transistor and a second transistor, an emitter of the first transistor directly connected to an emitter of the second transistor;
a second differential pair of transistors including a third transistor and a fourth transistor, an emitter of the third transistor directly connected to an emitter of the fourth transistor;
a first resistor connected to the emitter of the first transistor, the emitter of the second transistor, the emitter of the third transistor, and the emitter of the fourth transistor;
a fifth transistor comprising an emitter directly connected to a base of the first transistor;
a sixth transistor comprising an emitter directly connected to a base of the second transistor,
a seventh transistor comprising an emitter directly connected to a base of the third transistor;
an eighth transistor comprising an emitter directly connected to a base of the fourth transistor;
a second resistor directly connected to the base of the first transistor and the emitter of the fifth transistor;
a third resistor directly connected to the base of the second transistor and the emitter of the sixth transistor;
a fourth resistor directly connected to the base of the third transistor and the emitter of the seventh transistor;
and
a fifth resistor directly connected to the base of the fourth transistor and the emitter of the eighth transistor.

9 more elements

An operational amplifier, comprising:

a stage circuit including a voltage-to-current converter configured to receive a differential voltage input signal and generate a current output signal, the input stage circuit including a first differential pair of transistors that includes a first transistor and a second transistor, a second differential pair of transistors that includes a third transistor and a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, and an eighth transistor, and a linearization resistor;
an output stage circuit configured to generate a gained current output signal;
wherein an emitter of the first transistor is directly connected to an emitter of the second transistor, an emitter of the third transistor directly connected to an emitter of the fourth transistor, and the linearization resistor is connected to the emitter of the first transistor, the emitter of the second transistor, the emitter of the third transistor, and the emitter of the fourth transistor, and
an emitter of the fifth transistor being directly connected to a base of the first transistor, an emitter of the sixth transistor being directly connected to a base of the second transistor, an emitter of the seventh transistor being directly connected to a base of the third transistor, and an emitter of the eighth transistor being directly connected to a base of the fourth transistor;
a first resistor directly connected to the base of the first transistor and the emitter of the fifth transistor;
a second resistor directly connected to the base of the second transistor and the emitter of the sixth transistor;
a third resistor directly connected to the base of the third transistor and the emitter of the seventh transistor;
and
a fourth resistor directly connected to the base of the fourth transistor and the emitter of the eighth transistor.

6 more elements

A voltage-to-current converter, comprising:

a first differential pair of transistors comprising a first transistor and a second transistor;
a second differential pair of transistors comprising a third transistor and a fourth transistor;
a fifth transistor;
a sixth transistor;
a seventh transistor;
an eighth transistor;
and
a linearization resistor;
emitters of the first and second transistors being directly connected to each other and to the linearization resistor, and emitters of the third and fourth transistors being directly connected to each other and to the linearization resistor, and
an emitter of the fifth transistor being directly connected to a base of the first transistor, an emitter of the sixth transistor being directly connected to a base of the second transistor, an emitter of the seventh transistor being directly connected to a base of the third transistor, and an emitter of the eighth transistor being directly connected to a base of the fourth transistor, further comprising:
a first resistor directly connected to the base of the first transistor and the emitter of the fifth transistor;
a second resistor directly connected to the base of the second transistor and the emitter of the sixth transistor;
a third resistor directly connected to the base of the third transistor and the emitter of the seventh transistor;
and
a fourth resistor directly connected to the base of the fourth transistor and the emitter of the eighth transistor.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/242,203Filed 19 Aug 2016 · us provisional application
Priority: 21 Aug 2015
Published: US 2017/0054417 A123 Feb 2017
Granted: 29 May 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

H03F 1/3211
Modifications of amplifiers to reduce non-linear distortion: in differential amplifiers
G05F 1/561
Using semiconductor devices in series with the load as final control devices: voltage to current converters
H03F 3/26
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements: push-pull amplifiers; Phase-splitters therefor
H03F 3/45139
Using bipolar transistors as the active amplifying circuit: complementary long tailed pairs having parallel inputs and being supplied in series