Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A comparator for sensing a small voltage differential at, or close to, the operating voltage rails includes first and second means for producing first and second currents and for producing a third current which is indicative of the difference between the first and second currents. The first current varies as a linear function of first (e.g. V.sub.IN) and second (e.g. V.sub.O) voltages, the amplitude of the first current being proportional to that one of said first and second voltage having the largest amplitude. The second current varies exponentially as a function of the difference between the first and second voltages. Comparator means embodying the invention are particularly useful in circuits where a transistor-switch couples an input voltage (V.sub.IN) to an output terminal and the transistor-switch is to be turned-off when V.sub.IN drops below the voltage (V.sub.O) at the output terminal.

Abstract: A circuit for limiting the load current through a transistor switch, where the load is connected between the collector of the transistor switch and a first power terminal and a resistive element, whose impedance is much less than that of the load, is connected between the emitter of the transistor switch and a second power terminal. The circuit includes first and second comparator transistors, with the emitter of the first transistor being connected to the emitter of the transistor switch and the emitter of the second transistor being connected to the second power terminal. The same potential is applied to the bases of the first and second comparator transistors whereby the difference between their base-to-emitter voltages is equal to the voltage drop across the resistive element. The collector currents of the first and second transistors are compared and the difference in the currents is used to control the conductivity of the transistor switch.

Abstract: A comparator for comparing a first current proportional to an input voltage against a relatively constant reference current produced by a bandgap reference circuit. The comparator includes hysteresis whereby the response of the comparator is sharpened at the switching points. The comparator is particularly useful in combination with a switch coupling an input voltage source to a load. When the input voltage exceeds a predetermined level the first current exceeds the reference current. The comparator responds sharply and produces a signal disabling the switch and maintaining it shut off until the input voltage decreases below the predetermined level.

Abstract: A switching circuit provides first and second output signals to respective first and second output load devices that are switched responsive to an input signal. The switching point of the first output signal is set relative to the switching point of the second output signal to achieve "make before break" or "break before make" switching of the first and second output load devices. In particular, the switching circuit uses an emitter coupled differential amplifier having first and second differential output signals. Each of the first and second differential output signals is received by a respective first and second current mirror amplifier for converting each differential output signal to the respective first and second output signal.

Abstract: Temperature compensation is provided in a switching circuit for the channel resistance of a MOS/FET transistor through which a voltage source is applied to an output terminal. The gate-source voltage of the transistor is varied directly with temperature changes to hold the channel resistance substantially constant within the switching circuit. In a particular embodiment, at least one output level of a pulse amplifier is controlled through the temperature compensated switching circuit of the invention. The other output level of this pulse amplifier is applied through a bipolar transistor of a second switching circuit in another embodiment. The base current of the bipolar transistor is varied inversely with temperature to hold the saturation voltage drop thereacross substantially constant within the second switching circuit.

Abstract: Temperature compensation is provided in a switching circuit for the saturation voltage drop across a bipolar transistor through which a voltage source is applied to an output terminal. The base current of the bipolar transistor is varied inversely with temperature to hold the saturation voltage drop thereacross substantially constant within the switching circuit. High temperature nonsaturating means for interrupting the base current to the bipolar transistor is combined with this temperature compensation to enhance the turn-on speed of the bipolar transistor in one of the described embodiments. In another embodiment a three state logic circuit (saturated, nonsaturation and nonconductive) is used to interrupt the base current to the bipolar transistor and thereby enhance both the turn on and turn off speed of the bipolar transistor.