Electricity: power supply or regulation systems – Self-regulating – Using a three or more terminal semiconductive device as the...
Reexamination Certificate
2000-07-20
2001-10-16
Han, Jessica (Department: 2838)
Electricity: power supply or regulation systems
Self-regulating
Using a three or more terminal semiconductive device as the...
C323S316000, C363S073000, C330S252000
Reexamination Certificate
active
06304070
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a voltage/current converter circuit and a high-gain amplifying circuit, and particularly relates to a voltage/current converter circuit and a high-gain amplifying circuit wherein a high-gain amplifying circuit with improved linearity is realized by using MOS transistor differential pair circuits.
2. Description of the Related Art
Conventionally, in conjunction with increased speed of communication devices and data recording devices, high gain and improved linearity of amplifiers has been required.
FIG. 5
is a circuit diagram illustrating the circuit configuration of a conventional voltage/current converter circuit containing a MOS transistor differential pair circuit.
With the voltage/current converter circuit containing a conventional MOS transistor differential pair circuit shown in
FIG. 5
, the drain currents I
1
and I
2
are obtained by a later-described Expression (1).
Accordingly, with conventional voltage/current converter circuits, the action properties graph indicating the voltage/current conversion ratio thereof has exhibited a very narrow range where linearity is good.
Accordingly, a method for expanding the dynamic range by inserting a resistor between the sources of the MOS transistor differential pair has been conceived as means for securing the necessary linearity.
However, the above conventional method has adverse effects in that the conductance and gain of the amplifier are lowered. Accordingly, various methods for increasing linearity without inserting a resistor between the sources of the MOS transistor differential pair have been proposed.
FIG. 6
is a circuit diagram illustrating the circuit configuration of a conventional voltage/current converter circuit containing a MOS transistor differential pair circuit intending improved linearity.
The circuit shown in
FIG. 6
realizes output current of i=I
1
− I
2
using a current mirror circuit, thus allowing the output current to be accurately proportionate to the input voltage.
However, with the conventional art, an N-MOS and P-MOS are used in junction as circuit components as can be understood from the voltage/current converter circuit shown in
FIG. 6
, so the power source voltage must be set high. Further, the output thereof is single output, which leads to the output current leaking to other circuits, consequently having markedly adverse effects on circuit operation.
As can be understood from the above examples, attempting to secure linearity with conventional voltage/current converter circuits using MOS transistor differential pair circuits results in high gain being unobtainable, and a differential output configuration cannot be used so the output current leaks to other circuits or circuit components. This has been a hindrance in advancement in application of high-frequency linear circuits with MOS transistors.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above problems in conventional voltage/current converter circuits, and accordingly, it is an object of the present invention to realize a high-gain amplifier with improved linearity with fewer elements, and to provide a voltage/current converter circuit and high-gain amplifying circuit capable of realizing reduced electric power consumption and reduced IC chip surface area.
In order to solve the above problems, the present invention provides a voltage/current converter circuit, comprising a first MOS transistor differential pair circuit, a second MOS transistor differential pair circuit wherein the drain terminal thereof are connected to each of the source terminals of the first MOS transistor differential pair circuit, and a resistor element connected between the sources of the second MOS transistor differential pair circuit, wherein the gate terminals of the first MOS transistor differential pair circuit serve as input voltage terminals and the drain terminals serve as output current terminals, and wherein the gates of the two mutually complementary MOS transistors of the second MOS transistor differential pair circuit are mutually connected to the drains of the MOS transistors of the other side, and the sources of the two MOS transistors are each grounded via an electric current source.
Also, in order to solve the above problems, the present invention provides a voltage/current converter circuit, comprising a first MOS transistor differential pair circuit, and a second MOS transistor differential pair circuit wherein the drain terminal thereof are connected to each of the source terminals of the first MOS transistor differential pair circuit, and wherein the gate terminals of the first MOS transistor differential pair circuit serve as input voltage terminals and the drain terminals serve as output current terminals, and wherein the gates of the two mutually complementary MOS transistors of the second MOS transistor differential pair circuit are mutually connected to the drains of the MOS transistors of the other side, and the sources of the two MOS transistors are each grounded via a resistor element.
Also, in order to solve the above problems, the present invention provides a high-gain amplifying circuit, comprising a first MOS transistor differential pair circuit, a second MOS transistor differential pair circuit wherein the drain terminal thereof are connected to each of the source terminals of the first MOS transistor differential pair circuit via first resistor elements, second resistor elements connected between the sources of the second MOS transistor differential pair circuit, and impedance elements connected between the drains of the second MOS transistor differential pair circuit, wherein the gate terminals of the first MOS transistor differential pair circuit serve as input voltage terminals and the drain terminals serve as output current terminals, and wherein the gates of the two mutually complementary MOS transistors of the second MOS transistor differential pair circuit are mutually connected to the drains of the MOS transistors of the other side, and the sources of the two MOS transistors are each grounded via an electric current source.
Further, in order to solve the above problems, the present invention provides a high-gain amplifying circuit, comprising a first MOS transistor differential pair circuit, a second MOS transistor differential pair circuit wherein the drain terminal thereof are connected to each of the source terminals of the first MOS transistor differential pair circuit via first resistor elements, and impedance elements connected between the drains of the second MOS transistor differential pair circuit, wherein the gate terminals of the first MOS transistor differential pair circuit serve as input voltage terminals and the drain terminals serve as output current terminals, and wherein the gates of the two mutually complementary MOS transistors of the second MOS transistor differential pair circuit are mutually connected to the drains of the MOS transistors of the other side, and the sources of the two MOS transistors are each grounded via second resistor elements.
That is to say, the present invention first comprises a submissively-connected first MOS transistor differential pair circuit and second MOS transistor differential pair circuit, i.e., two MOS transistor differential pair circuits, wherein the gates of the second MOS transistor differential pair circuit are mutually connected to the drains of the transistor on the other side, a resistor is connected between the sources of the second MOS transistor differential pair circuit, and differential signal input is input between the gates of the first MOS transistor differential pair circuit, thereby providing a voltage/current converter circuit for extracting output current from drain terminals, and an equivalent circuit thereof.
Next, of the submissively-connected first MOS transistor differential pair circuit and second MOS transistor differential pair circuit, i.e., the two MOS transistor differential pair circuits, first resisto
Frommer William S.
Frommer Lawrence & Haug LLP.
Han Jessica
Sony Corporation
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