Rca Inc.

Harris Corporation

Intersil Americas Inc.

Other

Intersil Corporation

Raymond L Giordano

Harold Allen Wittlinger

Salomon Vulih

William Brandes Shearon

Thomas R Deshazo, Jr

Sumer Can

Robert H Isham

Arthur J Leidich

Donald R Preslar

James E Gillberg

Stephen J Glica

Donald Ray Preslar

Thomas R DeShazo, Jr

A power supply switching circuit arrangement is configured to provide a relatively smooth (low noise) power supply switch-over during the transition between active and quiescent modes. Complementary inputs of an operational amplifier are selective coupled to feedback paths to the amplifier and the power supply switching circuit arrangement, so as to bias a switching transistor during system active mode at a value that is just slightly below the turn-on voltage of the transistor. This means that turning on the switching transistor for the purpose of providing quiescent mode powering of the utility device requires only a small transition in control voltage from an active mode 'almost turned-on' level.

Smooth voltage regulation transition circuit having fast recovery

A tracking soft start circuit architecture contains a plurality of soft start circuits for generating a plurality of soft start voltages during startup for application to associated power supply terminals of a power supply system. The soft start circuits are interconnected in such a manner that prevents any soft start circuit from generating a soft start voltage waveform until all of the controlled power output devices have been brought to the same prescribed state of operation, that is, all power FET gates are precharged and their source voltages match each other.

Tracking soft start circuit for generating a plurality of soft start voltages where all soft start voltages are prevented until all have been brought to the same prescribed state of operation

The current limiting circuit of the present invention includes a transconductance amplifier having two outputs and forming a conventional feedback loop. A first output connects to an output transistor and a second output is a replica output used to form a rapid response feedforward path to control the gate of the output transistor, for example, an external MOSFET.

Current limiting circuit with rapid response feedback loop

A thermally protected power device is disclosed and includes a semiconductor package having at least five pins. One of the pins comprises a ground pin for connecting to a ground connection, and another one of the five pins comprises a power pin for connecting to a source of a temperature stable reference voltage. A field effect transistor is formed within the semiconductor package and has a source, drain and gate connected to three of the output pins and forms respective source, drain and gate pins. A parasitic bipolar transistor is formed within the package and has a base, collector and emitter. The collector is connected to the gate of the field effect transistor. A voltage divider circuit is formed within the semiconductor package and connected to the power pin, the ground pin and the base of the thermal limiting bipolar transistor for receiving a temperature stable reference voltage obtained from a temperature stable voltage source connected to the power pin, and dividing the voltage down close to the Vbe of the thermal limiting bipolar transistor. As the temperature rises within the semiconductor package, the Vbe of the thermal limiting bipolar transistor drops and switches on to pull gate voltage down and limit current passing through the field effect transistor.

Current limited, thermally protected, power device

A transconductance amplifier suitable for the input stage of a comparator with the capability of amplifying input signals with common mode voltage components in a range including the entirety of its operating voltage. Operation at one voltage extreme is accomplished by use of a long tailed pair connection of a pair of bulk modulated FETs with gates at the input terminals of the amplifier. Operation at the other voltage extreme is accomplished by the use of a pair of FETs in a source follower mode to drive common gate transistors of opposite polarity, the gates of the FETs also being connected to the input terminals of the amplifier. A common high impedance load for the comparator is connected to current mirrors of the drains of both pairs of FETs in the amplifier. The circuit may be implemented with bipolar transistors and additional amplification provided. Methods of comparing voltages are also disclosed.

Wide common mode range comparator and method

An automatic fault monitoring system prevents the detection of fault conditions during operating modes or conditions that can produce false fault conditions. A motor control system that utilizes an H-bridge circuit having active devices, preferably field effect transistors, in each arm of the bridge. The motor is connected in the leg of the bridge. Currents and voltages are sensed in each arm as different operating conditions represented by input control signals, which may be computer generated, drive the bridge and place the transistors in different states (on or off). Such operating conditions include rotation of the motor in opposite directions and reversal of direction. Fault detection logic is responsive to currents and voltages in the arms and leg of the bridge and provides outputs indicative of over-current fault conditions in the arm and open circuit fault conditions in the leg. Fault detection control logic analyzes the input control signals and also applies them to change the state of the transistors in the H-bridge. When the control signal inputs and the sequence in which they occur represents a command to the H-bridge to reverse the direction of rotation of the motor, the fault detection logic is inhibited thereby preventing false detection of over-current conditions that can occur in response to the back EMF generated by the motor as it stalls and stops briefly while reversing direction of rotation. The fault detection control logic also enables the detection of open load fault condition during states where the motor is being driven in either direction of rotation, but not when a reversal of rotation is occurring or the motor is started from a stopped position and the current in the motor must build exponentially.

Automatic fault monitoring system and motor control system incorporating

A transconductance amplifier suitable for the input stage of a comparator with the capability of amplifying input signal with common mode voltage components in a range including the entirety of its operating voltage. Operation at one voltage extreme is accomplished by use of a long tailed pair connection of a pair of bulk modulated FETs with gates at the input terminals of the amplifier. Operation at the other voltage extreme is accomplished by the use of a pair of FETs in a source follower mode to drive common gate transistors of opposite polarity, the gates of the FETs also being connected to the input terminals of the amplifier. A common high impedance load for the comparator is connected to current mirrors of the drains of both pairs of FETs in the amplifier. The circuit may be implemented with bipolar transistors and additional amplification provided. Methods of comparing voltages are also disclosed.

An IC is constructed with deep layers preventing current flow due to parasitic transistors formed within the IC. Reverse current in case of voltage source polarity reversal is prevented by means of the reverse bias diodes formed by the addition of a P+ ring, and N+ well, for the embodiment disclosed.

Reverse current flow prevention in a diffused resistor

A current source is selectively switched into the output circuit of a differential amplifier for producing hysteresis. In a circuit embodying the invention, a differential amplifier (diff-amp) stage operated at a first current level set by a first current source has first and second input terminals for the application therebetween of a differential input signal and first and second output nodes for the production of differential output signals. A second current source for inducing hysteresis is connected to one of the output nodes of the diff-amp and is selectively enabled. A differential input signal (VIN) is applied across the input terminals. When VIN varies in one direction and reaches a first threshold level, the second, hysteresis inducing, current source is enabled whereby a larger current can flow in the one node. VIN then has to vary in the opposite direction and reach a second threshold level to disable the second current source. When the first threshold level is reached the output of the amplifier stage switches from a first state to a second state and when the second threshold level is reached the output of the amplifier switches from the second state to the first state.

Differential amplifier with hysteresis

A normally non-conducting control device whose turn-on threshold decreases with increasing temperature is supplied with a control voltage which increases with temperature for causing a more rapid increase in the conduction of the control device when a predetermined temperature is exceeded.

Integrated circuit thermal sensor

A circuit in which the source-to-drain conduction path of a power switching transistor is connected in series with an inductive load between first and second power terminals includes a voltage transient clamping transistor having its source-to-drain conduction path connected between the drain and gate of the switching transistor. In response to a turn-off signal applied to the gate of the switching transistor, a transient voltage is generated at the drain of the switching transistor. When the transient voltage at the drain of the power switching transistor exceeds a predetermined value, the clamping transistor is turned-on. The conduction of the clamping transistor limits the voltage rise at the drain of the switching transistor and tends to maintain the switching transistor conducting temporarily to aid in the discharge of the energy stored in the inductive load. A unidirectional conducting element connected in series with the clamping transistor ensures that only current of a polarity to discharge the inductive load flows through the clamping transistor.

Inductive load dump circuit

A first IGFET and a first bipolar transistor are connected in series between a first power terminaland a first load terminal. A second IGFET and a second bipolar transistor are connected in series between a second load terminal and a second power terminal. the first and second IGFETs are biased to pass the same load current. The first and second bipolar transistors are selectively turned on at the same time to permit current flow via a load which may be connected between the first and second terminals. When the first and second bipolar transistors are turned-off, they prevent conduction (except for leakage) between the load terminals and the first and second power terminals, if and when the voltage at the load terminal goes positive and/or negative. The circuit also includes means for compensating for the base current of the first and second bipolar transistors.

BIMOS current driver circuit

The accuracy of a bandgap reference voltage generator that contains two n-p-n transistors, an operational amplifier and five resistors, is increased by the use of current compensation circuitry which includes a third n-p-n transistor with an emitter resistor and a current mirror circuit. A master leg of the current mirror circuit generates a first output current which is identical to base current needed by the two transistors of the bandgap voltage generator. A slave leg of the current mirror circuit generates a second output current which is identical to the first output current and which is coupled to bases of the two transistors of the bandgap reference voltage generator. Thus base current needed by the two transistors is supplied by the compensation circuitry. This improves the accuracy of the output voltage generated by the reference voltage bandgap generator.

Simplified transistor base current compensation circuitry

Each one of two switching transistors, driven by complementary input signals, has its conduction path connected between a different one of two output terminals and a first point of potential. Connected between each output terminal and a second point of potential are the conduction paths of a load transistor responsive to the signal at the other output terminal. A source follower transistor is connected to each output terminal. When the switching transistor connected to one output terminal is being turned-OFF, the source follower connected to that output terminal is turned-ON to enhance the voltage response at that terminal and to thereby accelerate the speed of response of the circuit and minimize its power dissipation.

Level shift circuit including source follower output

The collector-to-emitter voltage (V.sub.CE) of a transistor switch and its base drive are designed to have maximum specified values when the transistor switch conducts the highest specified load current. The base drive to the transistor switch is reduced when the load current is reduced, or when the beta of the transistor increases or is greater than a minimum specified value. The base drive to the transistor switch is regulated by sensing the V.sub.CE of the transistor switch and producing a control current which decreases with decreasing V.sub.CE and increases with increasing V.sub.CE. The control current is then used to supply a regulated base current to the transistor switch while maintaining the V.sub.CE of the transistor below, the maximum specified value, for values of load current below the maximum specified level.

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Flemington, NJ, United States of America

Raymond L Giordano