Protective circuit for transistor amplifier

Claim 2

A protective circuit for a transistor amplifier comprising: a. an amplifying stage including first and second opposite conductivity transistors each having base, emitter and collector electrodes and connected in series across a voltage source; b. a signal input circuit coupled to the base electrodes of said transistors; c. an output terminal connected to the connection point between said first and second transistors; d. a load connected between said output terminal and a reference point through a first resistor; e. a first diode and a first capacitor connected in series across said first resistor; f. a second diode connected with the same polarity with respect to said first diode between the connection point of said first diode with said first capacitor and said reference point; g. a third diode and a second capacitor connected in series across said first resistor, the polarity of said third diode being opposite in polarity with respect to said first diode; h. a fourth diode connected with the same polarity with respect to said third diode between the connection point of said third diode between the connection point of said third diode with said second capacitor and said reference point; i. a third transistor the base and emitter electrodes of which are connected across said first capacitor and the collector electrodes of which is connected to the base electrode of said first transistor; and j. a fourth transistor the base and emitter electrodes of which are connected across said second capacitor and the collector electrode of which is connected to the base electrode of said second transistor.

Claim 3

A protective circuit for a transistor amplifier as claimed in claim 1, further including a driver stage having input and output terminals the output signal from which is applied across the base electrodes of said first and second transistors, and a pre-amplifying stage having input and output terminals to the input terminal of which an input signal is applied and an output signal of which is applied to said input terminal of said driver stage.

Claim 4

A protective circuit for a transistor amplifier comprising: a. first and second transistors each of which has base, emitter and collector electrodes and which are connected between electric power sources in series with opposite polarities; b. a signal input circuit coupled to the base electrodes of said first and second transistors; c. an output terminal connected to the connection point between said first and second transistors; d. a load connected through a first resistor between said output terminal and a reference point; e. a series connection of a second resistor and a first diode, said series connection being connected in parallel between the collector and emitter electrodes of said first transistor, said first diode being connected with the same polarity with respect to said first transistor; f. a series connection of a second diode and a first capacitor connected in parallel between the connection point of said second resistor with said first diode and the connection point of said first resistor with said load, the anode of said second diode being commonly connected to the anode of said first diode; g. a third diode connected between the connection point of said second diode with said first capacitor and the reference point, the anode of said third diode being connected commonly to the cathode of said second diode; h. a third transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said first capacitor and the collector electrode of which is connected to the base electrode of said first transistor; i. a series connection of a third resistor and a fourth diode connected between the collector and emitter electrodes of said second transistor, said fourth diode being connected with the same polarity as that of said second transistor; j. a series connection of a fifth diode and a second capacitor connected between the connection point of said third resistor with said fourth diode and the connection point of said first resistor with said load, the cathode of said fifth diode being connected commonly to the cathode of said fourth diode; k. a sixth diode connected between the connection point of said fifth diode with said second capacitor and the reference point, the cathode of said sixth diode being connected commonly to the anode of said fifth diode; and l. a fourth transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said second capacitor and the collector electrode of which is connected to the base of said second transistor.

Claim 5

A protective circuit for a transistor amplifier comprising: a. first and second transistors each of which has base, emitter and collector electrodes and which are connected between electric power sources in series with opposite polarities; b. a signal input circuit coupled to the base electrodes of said first and second transistors; c. an output terminal connected to the connection point between said first and second transistors; d. a load connected through a first resistor between said output terminal and a reference point; e. a series connection of a second resistor and a first diode, said series connection being connected in parallel between the collector and emitter electrodes of said first transistor, said first diode being connected with the same polarity with respect to said first transistor; f. a series connection of a second diode and a first capacitor connected in parallel between the connection point of said second resistor with said first diode and the connection point of said first resistor with said load, the anode of said second diode being commonly connected to the anode of said first diode; g. a third diode connected between the connection point of said second diode with said first capacitor and the reference point, the anode of said third diode being connected commonly to the cathode of said second diode; h. a third transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said first capacitor and the collector electrode of which is connected to the base electrode of said first transistor; i. a series connection of a third resistor and a fourth diode connected between the collector and emitter electrodes of said second transistor, said fourth diode being connected with the same polarity as that of said second transistor; j. a series connection of a fifth diode and a second capacitor connected between the connection point of said third resistor with said fourth diode and the connection point of said first resistor with said load, the cathode of said fifth diode being connected commonly to the cathode of said fourth diode; k. a sixth diode connected between the connection point of said fifth diode with said second capacitor and the reference point, the cathode of said sixth diode being connected commonly to the anode of said fifth diode; and l. a fourth transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said second capacitor and the collector electrode of which is connected to the base of said second transistor.

Claim 6

A protective circuit for a transistor amplifier comprising: a. first and second transistors each of which has base, emitter and collector electrodes and which are connected between electric power sources in series with opposite polarities; b. a signal input circuit coupled to the base electrodes of said first and second transistors; c. an output terminal connected to the connection point between said first and second transistors; d. a load connected through a first resistor between said output terminal and a reference point; e. a series connection of a first diode and a first capacitor said series connection being connected between the base electrode of said first transistor and the connection point of said first resistor with said load, the anode of said first diode being connected to the base electrode of said first transistor; f. a second diode the anode of which is connected to the cathode of said first diode and the cathode of which is connected to said reference point; g. a third transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said first capacitor and the collector electrode of which is connected to the base electrode of said first transistor; h. a series connection of a third diode and a second capacitor connected between the base electrode of said first transistor and the connection point of said first resistor with said load, the cathode of said third diode being connected to the base electrode of said second transistor; i. a fourth diode the cathode of which is connected to the anode of said third diode and the anode of which is connected to said reference point; and j. a fourth transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said second capacitor and the collector electrode of which is connected to the base electrode of said second transistor.

Claim 7

A protective circuit for a transistor amplifier comprising: a. first and second transistors each of which has base, emitter and collector electrodes and which are connected between electric power sources in series with opposite polarities; b. a signal input circuit coupled to the base electrodes of said first and second transistors; c. an output terminal connected to the connection point between said first and second transistors; d. a load connected through a first resistor between said output terminal and a reference point; e. a series connection of a first diode and a first capacitor said series connection being connected between the base electrode of said first transistor and the connection point of said first resistor with said load, the anode of said first diode being connected to the base electrode of said first transistor; f. a second diode the anode of which is connected to the cathode of said first diode and the cathode of which is connected to said reference point; g. a third transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said first capacitor and the collector electrode of which is connected to the base electrode of said first transistor; h. a series connection of a third diode and a second capacitor connected between the base electrode of said first transistor and the connection point of said first resistor with said load, the cathode of said third diode being connected to the base electrode of said second transistor; i. a fourth diode the cathode of which is connected to the anode of said third diode and the anode of which is connected to said reference point; and j. a fourth transistor having base, emitter and collector electrodes the base and emitter electrodes of which are connected in parallel to said second capacitor and the collector electrode of which is connected to the base electrode of said second transistor.

Claim 8

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, d. a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor; f. first circuit means including a first diode and a second resistor connected in series between said one side of said first capacitor and one side of said first resistor to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circuit means including a second diode and a third resistor connected in series between said one side of said first capacitor and said reference point to supply a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; h. detecting means comprising a secoNd transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.

Claim 9

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, d. a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor; f. first circuit means including a first diode and a second resistor connected in series between said one side of said first capacitor and one side of said first resistor to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circuit means including a second diode and a third resistor connected in series between said one side of said first capacitor and said reference point to supply a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; h. detecting means comprising a secoNd transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.

Claim 10

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor having a pair of terminals; f. first circuit means including a first diode and a second resistor connected in series between one terminal of said first capacitor and said first electrode of said first transistor, the other terminal of said first capacitor connected to a connection point of said first resistor and said load, and said first circuit means supplying a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circuit means including a second diode and a third resistor connected in series between said one terminal of said first capacitor and said reference point for supplying a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; h. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.

Claim 11

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor having a pair of terminals; f. first circuit means including a first diode and a second resistor connected in series between one terminal of said first capacitor and said first electrode of said first transistor, the other terminal of said first capacitor connected to a connection point of said first resistor and said load, and said first circuit means supplying a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circuit means including a second diode and a third resistor connected in series between said one terminal of said first capacitor and said reference point for supplying a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; h. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.

Claim 12

A protective circuit for a transistor amplifier according to claim 6, further including a second transistor having first, second and third electrodes and connected to said first transistor with a Darlington configuration.

Claim 13

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a load connected between said third electrode of said first transistor and a reference point through a first resistor; d. a first capacitor; e. first circuit means including first and second diodes, second and third resistors, said first diode and second resistor connected in series between one side of said capacitor and one side of said second diode, to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity, said second diode and third resistor connected in series between said DC voltage source and said third electrode of said first transistor; f. second circuit means including a third diode and fourth resistor each connected in series between said one side of said capacitor and said reference point to supply a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; g. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in Response to the voltage across said first capacitor.

Claim 14

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a load connected between said third electrode of said first transistor and a reference point through a first resistor; d. a first capacitor; e. first circuit means including first and second diodes, second and third resistors, said first diode and second resistor connected in series between one side of said capacitor and one side of said second diode, to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity, said second diode and third resistor connected in series between said DC voltage source and said third electrode of said first transistor; f. second circuit means including a third diode and fourth resistor each connected in series between said one side of said capacitor and said reference point to supply a second DC voltage in proportion to a voltage across said load to said first capacitor with the other polarity; g. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in Response to the voltage across said first capacitor.

Claim 15

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, d. a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor; f. first circuit means including a first diode and a second resistor connected in series between one side of said first capacitor and one side of said first resistor to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circiut means including a second diode and a third resistor connected in series between said one side of said first capacitor and said reference point to supply a second DC voltage in proportion the voltage acrosss said load to said first capacitor with the other polarity; and h. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.

Claim 16

A protective circuit for a transistor amplifier comprising: a. a DC voltage source; b. a first transistor having first, second and third electrodes, said first electrode supplied with an input signal to be amplified and said second electrode connected to said DC voltage source; c. a first resistor, d. a load connected between said third electrode of said first transistor and a reference point through said first resistor; e. a first capacitor; f. first circuit means including a first diode and a second resistor connected in series between one side of said first capacitor and one side of said first resistor to supply a first DC voltage in proportion to a voltage across said first resistor to said first capacitor with one polarity; g. second circiut means including a second diode and a third resistor connected in series between said one side of said first capacitor and said reference point to supply a second DC voltage in proportion the voltage acrosss said load to said first capacitor with the other polarity; and h. detecting means comprising a second transistor having first second and third electrodes, a third diode connected to said third electrode, said first and second electrodes of said second transistor connected across said first capacitor respectively, said third diode connected to said first electrode of said first transistor, and operative to substantially reduce the amplification of said first transistor in response to the voltage across said first capacitor.