Showing papers on "Static induction transistor published in 1974"

Level shifter circuit

Abstract: An improved TTL to MOS voltage level shifter circuit utilizes a totem pole output stage consisting of a pull-up junction transistor and a pull-down saturation junction transistor, an intermediate stage consisting essentially of a saturation junction transistor, an input stage consisting essentially of a diode and a saturation junction transistor, and current spike inhibit circuitry which consists essentially of a saturation junction transistor connected between the input stage and the base of the pull-down transistor. The current spike inhibit transistor, which turns on with the pull-down transistor, has a greater turnoff time than the pull-down transistor and consequently provides a relativley low impedance discharge path connected to the base of the pull-down transistor which allows the pull-down transistor to turn off before the pull-up transistor turns on. This helps insure against output current spikes that occur if the pull-up and pull-down transistors conduct simultaneously.

D.C. power source with temperature compensation

Abstract: An improved D. C. power source whose output voltage is independent of changes in temperature is disclosed. Compensation for changes in temperature is established by three features. For a change of the voltage drop in the forward direction between the base and the emitter of a transistor, a plurality of diodes provided in a bias circuit in the transistor are utilizied; for a change of the current amplification factor β of a transistor, an additional transistor is attached to the transistor, and; for a change of the value of an emitter resistor connected between the emitter of the transistor and the ground, an external stable resistor is utilized. The D. C. power source of the present invention is, in particular, useful for an integrated circuit.

Amplifier circuit having power supply voltage responsive to amplitude of input signal

Abstract: There is provided an amplifier circuit wherein the changing of power supply voltages is effected in accordance with the amplitude of an input signal. The amplifier circuit comprises an amplifying transistor having its base adapted to receive an input signal and its emitter connected to a load, a switching transistor having its base and emitter connected respectively to the base and collector of the amplifying transistor, a first power source for supplying power to the collector of the switching transistor, and a second power source for generating a voltage lower than the output voltage of the first power source and supplying power to the collector of the amplifying transistor.

Integrated power transistor with ballasting resistance and breakdown protection

Abstract: An integrated power transistor has at least one emitter region, having a ballasting resistance to reduce the possibility of second breakdown. Also integrated within the device is a voltage control diode, located between the collector terminal and the emitter terminal, to protect against high voltages caused by transient surges, particularly during switching times.

DC Motor stall protection circuit

Abstract: A series of electrical signals of a frequency directly proportional to the speed of a motor controlled by a speed control circuit of the type which completes an energizing circuit for the motor through the current carrying electrodes of a switching transistor is generated. These signals are employed to produce a direct current reference potential signal which increases rapidly in magnitude when the motor becomes stalled. The reference potential signal is applied across the series combination of a Zener diode and the base-emitter electrodes of an NPN transistor for supplying base-emitter drive current to the transistor when the potential level thereof reaches a magnitude equal to the inverse breakdown potential of the Zener diode. The collector-emitter electrodes of the NPN transistor are connected in circuit with the motor speed control circuit in such a manner that the control circuit switching transistor is maintained not conductive while base-emitter drive current is supplied to the NPN transistor.

Power circuit with shunt transistor

Abstract: A power circuit is comprised of a control transistor connected in series between one terminal of a power source and one terminal of a load, an error detecting amplifier circuit for detecting and amplifying changes of the load voltage, a drive transistor for driving the control transistor in response to the output current from the error detecting amplifier circuit, an input-output voltage difference detecting transistor which conducts when the difference between the input and the output voltages of the control transistor decreases to below a predetermined value, and a shunt transistor for shunting the current supplied to the drive transistor when it is activated by the output current of the input-output voltage difference detecting transistor. The power circuit operates as a constant voltage circuit when the input voltage is not lower than the predetermined value, while it operates as a ripple filter with a wide operable range when the input voltage decreases to below the predetermined value.

Temperature compensating transistor bias device

Abstract: The base-to-emitter bias voltage and current of a high frequency transistor, operating class AB or class A, is derived from a semiconductive bias device consisting of a semiconductive diode junction fed with current from a constant current source to derive a V BE voltage thereacross which is the bias source voltage. This source voltage is applied across the base-to-emitter junction of the RF transistor via the intermediary of a positive temperature coefficient silicon resistor. The diode and silicon resistor are packaged together for mounting on a heat sink common to the transistor, whereby the transistor is compensated for temperature dependent changes in V BE and h FE .

Integrated multiple transistors with different current gains

Abstract: A multiple transistor consists of vertical and lateral transistors, the collector region of the lateral transistor is formed by diffusion within the diffused base region of the vertical transistor simultaneously with the emitter region of the vertical transistor, into a structure in which the base of the vertical transistor and the collector of the lateral transistor are short-circuited. As a result the current gain of the lateral transistor can be varied by changing the area of the collector region.

Switching circuit for ignition system

Abstract: The invention relates to a breakerless ignition system with a magneto supply for use in an internal combustion engine. The system includes a transistorized circuit for interrupting the current flow in the primary winding of the coil to thereby produce the firing voltage in the secondary which is connected to the spark plug. The circuit includes either a single transistor, or two transistors in a Darlington arrangement, connected in series in the circuit of the primary winding. A switching transistor is connected to the control electrode of either the first transistor or the Darlington pair to be adaptable to turn it off. A first resistor has one end connected to the base of the switching transistor. A parallel resistor-capacitor combination is connected in series with a further resistor, and the serial combination is connected in parallel with the Darlington arrangement or the single transistor. The junction of the further resistor and the parallel combination is connected to the other end of the first resistor. The circuit is arranged so that the first transistor, or the Darlington pair, is biased on at the start of a cycle and the switching transistor is non-conductive. The capacitor charges up, through the parallel and further resistors, to turn the switching transistor on, which in turn turns off the first transistor, or Darlington pair. The time interval elapsed before the switching transistor turns on is dependent on a first time constant formed by the parallel and further resistors and the capacitor. The capacitor then discharges through the first resistor and the base-emitter path of the switching transistor until the voltage of the capacitor reaches a predetermined value at which the switching transistor is turned off. The second time interval is dependent on a second time constant formed by the first resistor, the resistance of the base-emitter path of the switching transistor, and the capacitor.

Inductive base drive for transistor switching in DC converters

Abstract: A DC voltage converter utilizing a switching transistor for switching the primary of a transformer, the transistor including an inductive base drive circuit. The transistor is initially turned on by a relatively small current from a high resistance connected between the DC voltage source and the base of the transistor. As current in the transformer primary increases, requiring increasing base current to sustain transistor conduction, another current derived from a secondary winding of the transformer is applied through an inductor to the base of the transistor. When the transistor is turned off by connection of the transistor emitter and base terminals the energy stored in the inductor and in the transformer is transferred to another secondary winding of the transformer that is connected to the load.

Negative resistance of a modified insulated-gate field-effect transistor

Abstract: The current-voltage characteristics of a new circuit element showing negative resistance are described and analyzed. The device is an enhancement field-effect transistor interacting with a bipolar transistor.

Photodiode biasing circuit

Abstract: A biasing circuit for a photodiode including a source follower circuit with a field effect transistor having its gate and source terminals adapted to be coupled across the photodiode A transistor is serially connected to the source of the FET for providing a constant current to the FET A control circuit including a diode is connected between the base and emitter of the transistor for providing a bias thereto A constant current circuit including a self-biased field effect transistor is serially coupled to the diode The self-biased FET produces a constant current flowing through the diode, which in turn produces a constant current through the transistor The current through the transistor causes a voltage drop which is equal and opposite that of the gate to source voltage of the FET, whereby there is provided an effective short circuit across the photodiode

Temperature compensated voltage reference device

Abstract: A temperature compensated voltage reference device has a field effect transistor that is reverse biased at a particular operating point so that temperature Variation of the biasing voltage across the gate to source junction of the field effect transistor is substantially negated by a forward biased bipolar transistor that has a temperature dependent voltage across its base to emitter junction.

Signal level control circuit

Abstract: A signal level control circuit having an amplifying transistor in combination with a resistive layer insulator semiconductor field effect transistor in which the drain and source electrodes of the field effect transistor are connected in series with the base and emitter electrodes of the amplifying transistor. A main input signal is applied to the base electrode of the amplifying transistor, a control voltage of either D.C. or lower frequency than said main signal is applied to the first and second gate electrodes of the field transistor and a level controlled output signal is obtained from the collector electrode of the amplifying transistor whereby the output signal level is made to be a linear function of the control voltage applied to the gate electrodes of the field effect transistor.

Speed control device for transistor motor

Abstract: A speed control device for a transistor motor having a stator provided with a plurality of field windings and a rotor consisting of a permanent magnet comprises position detecting means for detecting the position of the rotor, a plurality of driving transistors whose emitter-collector circuits are respectively connected in series to the field windings and whose bases are respectively supplied with the output from the position detecting means, a base current control transistor for the driving transistors whose emitter-collector circuit is connected through diodes to the respective bases of the driving transistors, and a servo circuit for maintaining the base current control transistor to be inoperative during the starting period of the transistor motor and, as the transistor motor approaches a specified rotation speed, controlling the base current of the driving transistors in accordance with a speed control signal.

Switching transistor drive apparatus

Abstract: Switching transistor drive apparatus having a first transistor for receiving a signal condition, a resistance, capacitor and transformer primary for charging the capacitor when the transistor is saturated and for discharging the capacitor when the transistor is OFF, a relationship of the primary and in-phase relationship of secondaries to saturate and regeneratively saturate a second transistor, and turn-off operation of the second transistor when a positive pulse is applied to the base of the first transistor. One alternate embodiment enables circuit operation at higher currents by utilizing a switchable impedance network for said resistance. Another alternative approach decreases the fall time of the second transistor by the addition of a resistor-diode network connected from base to emitter of the second transistor.

Integrated circuit transistor switch

Abstract: An integrated circuit including a transistor with a diode shunted between the emitter and base to improve switching time. A method of forming a pn diffused junction or Schottky barrier diode in a monolithic integrated structure including a transistor or Darlington circuit so that the diode shunts the emitter base diode of the transistor, or in the case of the Darlington circuit, the input transistor, thereby improving the switching speed of the device.

DC power supply with load current regulation

Abstract: In a DC power supply, a switching transistor and an inductor are connected in series between an unregulated DC supply and a DC output terminal. The output DC voltage is a function of the on to off ratio of the switching transistor. The switching period of the switching transistor is controlled by a load feedback circuit which compares the output voltage, as sensed by the voltage drop of the current through the switching transistor, with a sawtooth voltage from a synchronized oscillator. An overload detection circuit includes a diode and integrator coupled to a junction between the inductor and the switching transistor. When the switching transistor is turned off, the load current which was flowing through the switching transistor is diverted to the diode. The current through the diode is thus directly proportional to the load current. The load current is detected and causes disabling of the load feedback circuit when the load current rises above a predetermined level.

Circuit for maintaining operating point stability of an amplifier

Abstract: An amplifier for driving a color image reproducing device includes a first transistor the base of which is capacitively coupled to a source of color difference signals. The emitter of the first transistor is direct current coupled to the base of a second transistor. The collector of the second transistor is direct current coupled to the base of the first transistor. The emitter of the second transistor is coupled to a source of a predetermined voltage. The emitter of the first transistor is direct current coupled to the emitter of a third transistor of opposite conductivity type which serves as a luminance signal amplifier. The first and third transistors form a matrix amplifier operative to generate a color signal at the collector of the first transistor. The capacitive coupling device and the second transistor form a clamping circuit for maintaining the voltage developed at the emitter of the first transistor substantially independent of direct current conditions of the source of color difference signals and base-to-emitter voltage variations of the first transistor.

Arrangement for compensating the temperature drift of a power amplifier

Abstract: A bias arrangement makes it possible to automatically compensate the temperature drift occuring in an amplifier transistor. The bias arrangement formed by a first and a second transistor, supplies the bias voltage for an amplifier transistor, which voltage is variable by a variable resistor in the emitter lead of the first transistor. A third transistor identical to the first transistor assembled on the same radiator as the first transistor and the amplifier transistor supplies to the base of the amplifier transistor a voltage proportional to the temperature variations, with a coefficient which is chosen by means of a resistance bridge, in order to precisely compensate the variations the amplifier transistor.

Voltage sensitive isolation for static logic circuit

Abstract: A static logic circuit utilizing transistors of the MOSFET type includes a high resistance load transistor, a low resistance logic network having a large self-loading capacitance, and a gating transistor connected in series between the network and the load device. The logic network controls the output voltage across a load capacitor by grounding the load transistor output for selected input data, and the gating transistor is biased to turn OFF when the voltage across the large self-loading capacitance exceeds a predetermined level, thereafter isolating the input network from the load capacitor and speeding up the output transition by decreasing the time required to charge the load capacitor.

Overvoltage protection for an integrated circuit

Abstract: A pass transistor is coupled serially with an integrated circuit across a DC energy source. The DC source includes a battery coupled in parallel with a charging transformer output and a diode, the negative side being connected to ground. A resistor is coupled across the pass transistor collector and base to assure conduction by the pass transistor when the DC source is operative. A string of zener diodes is connected between the pass transistor base and ground to provide voltage limiting by clamping the transistor base during an overvoltage condition arising, for example, when the battery has a defective cell or an open connection to the remainder of the circuit. Such an arrangement allows reliable operation with monolithic transistors having about 27 volts collector to emitter breakdown voltage rating.

Active breakdown circuit for increasing the operating range of circuit elements

Abstract: An active circuit and method for increasing the operating range of circuit elements of the type connected between a power supply and a circuit element, the active circuit including a transistor having a base, emitter and a collector, the transistor having a breakdown voltage. The transistor is biased to provide a current path through it to the circuit element and to develop a voltage thereacross. The transistor and its biasing in combination are operative when the supply voltage exceeds a predetermined level to cause the transistor to breakdown. The breakdown voltage across the transistor opposes the supply voltage so that the operating range is increased and the actual voltage applied to the element does not exceed the breakdown voltage of the element.

Composite transistor circuit

Abstract: A circuit exhibiting the characteristics of a transistor suited for use in a quasi-complementary push-pull amplifier uses input and output transistors of the same conductivity type. The ''''base'''' electrode of the composite transistor is at the emitter electrode of the input transistor, operated as a common-base amplifier. The collector electrode of the input transistor is coupled by a current mirror amplifier to the base electrode of the output transistor. The ''''emitter'''' electrode of the composite transistor is at the joined base electrode of the input transistor and the collector electrode of the output transistor. The ''''collector'''' electrode of the composite transistor is at the emitter electrode of the output transistor. The current gain of the composite transistor can be made to be equal to that of the output transistor, although the apparent conductivity type of the composite device is opposite to that of the input and the output transistors.

Integrated circuit for logic purposes having transistors with different base thicknesses and method of manufacturing

Abstract: The invention relates to logic integrated circuits in which the collector of a multi-emitter transistor is connected to the base of a further transistor, as for example in TTL circuits. The base zone of the multi-emitter transistor is provided simultaneously with the isolation zones and strikes on a buried collector layer which separates such base zone from the substrate. Said multiemitter transistor has a low Beta inverse as a result of which the reaction to preceding parts of the logic circuit, particularly with small voltages, is comparatively small.

Two-dimensional carrier flow in a transistor structure under non-isothermal conditions

Abstract: Summary form only given, as follows. A two-dimensional mathematical model is developed to predict the internal behavior of power transistors operating under steady-state conditions. This model includes the internal self heating effects in power transistors and is applicable to predict the transistor behavior under high current and high voltage operating conditions. The complete set of partial differential equations governing the bipolar semiconductor device behavior under non-isothermal conditions is solved by numerical techniques without assuming internal junctions and other conventional approximations. No restrictions are made on the choice of the doping profile, mobility dependence, boundary conditions for external contacts, generation-recombination model and the injection level. Computed results of the analysis of a typical power transistor design are presented for various operating conditions. The current density, electrostatic potential, carrier charge density and temperature distribution plots within the transistor structure illustrate the combined effect of the electro-thermal interaction, base conductivity modulation, current crowding, base push-out, space charge layer widening and current spreading phenomena in power transistors.

Biasing circuit for multistage transistor amplifiers

Abstract: A novel circuit is disclosed for biasing the first transistor stage of a multistage transistor amplifier. The circuit comprises a semiconductor device, typically a transistor, connected to a feedback relationship between the output and input electrodes of the transistor amplifier for providing the requisite DC current bias to the base of the first transistor stage while maintaining the collector voltage at the output transistor stage substantially constant, independent of varying Beta characteristics of the transistor amplifier.

Transistor amplifier circuit

Abstract: In a transistor amplifier circuit comprising a common-emitter amplifier transistor, a collector load resistance has one end connected with the collector of the transistor, a constant-current circuit is connected with the collector of the transistor, and an output of the transistor amplifier circuit is derived from the collector. The constant-current circuit supplies a constant current which is substantially equal to the d.c. emitter current flowing through the transistor and a d.c. voltage which establishes a d.c. voltage level of the output is applied to the other end of the collector load resistance, whereby no d.c. current is permitted to flow through the resistance.

Electronic switches and switch networks

Abstract: In an electronic switching device for use as the switching component of a switching network in a telephone central office, the device being composed of a switching transistor connected in series in the signal conduction path for switched signals and a controllable impedance connected in a shunt branch, the switching transistor, in its conductive state, having a low series resistance and an associated high shunt resistance, and, in its blocking state, having a high series resistance and an associated low shunt resistance, the shunt branch is composed of a control transistor having a control voltage applied to its base, having its collector connected to the base of the switching transistor, and having its emitter connected to the switching transistor through a resistor to constitute a feedback path for the switching transistor, a voltage-dependent resistor connected to the base of the switching transistor, and suitable sources of operation voltages, the voltages and characteristics of the voltage-dependent resistor being selected to be such that when the switching transistor is conductive, the control transistor operates conductively in its active region and the voltage-dependent resistor presents a high resistance and when the switching transistor is blocking the control transistor is also blocking and the voltage-dependent resistor has a low resistance and supplies to the base of the switching transistor a voltage which maintains the switching transistor blocking.

Apparatus for non-destructively testing the voltage characteristics of a transistor

Abstract: A non-destructive test apparatus includes current limiting means whose current conducting level is set according to the transistor characteristics under test. The current limiting means is in series with the collector-emitter electrodes of the transistor under test. A test voltage is placed across the series-connected current limiting means and test transistor. The test transistor is rendered non-conductive in accordance with the characteristics being tested. If the transistor enters a voltage breakover region known as "snap-back," destructive failure of the transistor is imminent causing a change in voltage across the current limiting means. Upon this change in voltage being sensed, destructive power is directed away from the transistor under test.