US 4,229,705 AGranted

Differential amplifiers

AssigneeSansui Electric Co., Ltd.

InventorsSusumu Takahashi, Tadaaki Chikashige

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Abstract

A differential amplifier able to produce differential-mode output signals different from one another in DC voltage level, is formed by connecting a pair of NPN transistors and another pair of PNP transistors so that the emitter electrodes of these four transistors are coupled to one another by a resistive coupling circuit. The resistive coupling circuit is so arranged that the resistance between the emitter electrodes of the NPN transistors is equal to that between the emitter electrodes of the PNP transistors, with the resistances between the emitter electrodes of one of the NPN transistors and of one of the PNP transistors being equal to that between the emitter electrodes of the other NPN transistor and the other PNP transistor. When one of two input signals is applied to the base electrodes of one of the NPN transistors and of one of the PNP transistors, with the other of the input signals applied to the base electrodes of the other NPN and PNP transistors, differential-mode output signals are obtained at the collector electrodes of the NPN transistors and differential-mode output signals of a different DC voltage level are obtained at the collector electrodes of the PNP transistors.

Claims6

Dependent claims

A transistor differential amplifier comprising:

first and second transistors of a first conductive type;
third and fourth transistors of a second conductive type, each of said first, second, third and fourth transistors having carrier extraction, carrier injection and control electrodes;
first means for coupling a first electric power supply line to a carrier extraction electrode of each of said first and second transistors;
second means for coupling a second electric power supply line to a carrier extraction electrode of each of said third and fourth transistors;
an electrical resistive coupling circuit connected between said carrier injection electrodes of said first, second, third and fourth transistors wherein the resistance of a circuit path between said first and second transistors is equal to the resistance of a circuit path between said third and fourth transistors, and the resistance of a circuit path between said first and third transistors is equal to the resistance of a circuit path connecting between said second and fourth transistors,
said resistive coupling circuit comprising four resistors connected to a common connection point and connected to said carrier injection electrodes of first to fourth transistors, respectively;
input signal applying circuits coupled with said control electrodes of said first, second, third and fourth transistors;
and
at least two output terminals, with one of said output terminals connected to said carrier extraction electrode of said first transistor and the other of said output terminals connected to said carrier extraction electrode of one of said third and fourth transistors whereby a differential signal may be obtained at said output terminals with different DC levels.

6 more elements

A transistor differential amplifier comprising:

first and second transistors of a first conductive type;
third and fourth transistors of a second conductive type, each of said first, second, third and fourth transistors having carrier extraction, carrier injection and control electrodes;
first means for coupling a first electric power supply line to a carrier extraction electrode of each of said first and second transistors;
second means for coupling a second electric power supply line to a carrier extraction electrode of each of said third and fourth transistors;
an electrical resistive coupling circuit connected between said carrier injection electrodes of said first, second, third and fourth transistors wherein the resistance of a circuit path between said first and second transistors is equal to the resistance of a circuit path between said third and fourth transistors, and the resistance of a circuit path between said first and third transistors is equal to the resistance of a circuit path connecting between said second and fourth transistors,
said resistive coupling circuit comprising five resistors, with two of said five resistors connected in series with one another at a first point and between said carrier injection electrodes of said first and second transistors, and with another two resistors of said five resistors connected in series with one another at a second point and between said carrier injection electrodes of said third and fourth transistors, and with the other of said five resistors connected between said first and second points;
input signal applying circuits coupled with said control electrodes of said first, second, third and fourth transistors;
and
at least two output terminals, with one of said output terminals connected to said carrier extraction electrode of said first transistor and the other of said output terminals connected to said carrier extraction electrode of one of said third and fourth transistors whereby a differential signal may be obtained at said output terminals with different DC levels.

6 more elements

A transistor differential amplifier comprising:

first and second transistors of a first conductive type;
third and fourth transistors of a second conductive type, each of said first, second, third and fourth transistors having carrier extraction, carrier injection and control electrodes;
first means for coupling a first electric power supply line to a carrier extraction electrode of each of said first and second transistors;
second means for coupling a second electric power supply line to a carrier extraction electrode of each of said third and fourth transistors;
An electrical resistive coupling circuit connected between said carrier injection electrodes of said first, second, third and fourth transistors wherein the resistance of a circuit path between said first and second transistors is equal to the resistance of a circuit path between said third and fourth transistors, and the resistance of a circuit path between said first and third transistors is equal to the resistance of a circuit path connecting between said second and fourth transistors,
said resistive coupling circuit comprising four resistors, with one of said four resistors connected between said carrier injection electrodes of said first and second transistors, and with another of said four resistors connected between said carrier injection electrodes of said third and fourth transistors, and with another of said four resistors coupled between said carrier injection electrodes of said first and third transistors, and with the other of said four resistors connected between said carrier injection electrodes of said second and fourth transistors;
input signal applying circuits coupled with said control electrodes of said first, second, third and fourth transistors;
and
at least two output terminals, with one of said output terminals connected to said carrier extraction electrode of said first transistor and the other of said output terminals connected to said carrier extraction electrode of one of said third and fourth transistors whereby a differential signal may be obtained at said output terminals with different DC levels.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/936,905Filed 25 Aug 1978
Priority: JP 52/10356331 Aug 1977
Granted: 21 Oct 1980
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H03F 3/45139
Using bipolar transistors as the active amplifying circuit: complementary long tailed pairs having parallel inputs and being supplied in series
H03F 3/3077
With symmetrical driving of the end stage: using Darlington transistors
H03F 3/3081
Single-ended push-pull [SEPP] amplifiers ; Phase-splitters therefor: duplicated single-ended push-pull arrangements, i.e. bridge circuits
H03F 3/45143
Complementary long tailed pairs having parallel inputs and being supplied in series: non-folded cascode stages