Abstract: A semiconductor structure having a temperature sensor placed in close proximity to gate and source and/or drain electrodes. The sensor is compatible with conventional semiconductor processing and is typically made from doped polysilicon having a large temperature coefficient of resistivity. At least one sensor may be placed under, but insulated from, source or drain electrodes to protect against high electric fields. The sensor is also compatible with bipolar semiconductor structures.

Abstract: A power-conserving, linear and broad band RF amplifier, suitable for use at more than one band in the ultra-high frequency regions allotted to radiotelephone transceivers, employs an emitter-follower output transistor to deliver the nominal 1.0 milliwatt RF power to a single-ended load from a low voltage battery, typically 2.7 v. dc, without the use of output coupling transformers. The amplifier receives only a small differential input signal from the preceding mixer or multiplier stage having a typical peak-to-peak magnitude of 0.3 v. The differential input signal is applied to the emitters of a pair of transistors whose bases are interconnected, one transistor of which (B6) is diode-connected in a current-mirror configuration and the other (B5) of which is configured in a common-base connection with emitter degeneration. The signals are summed at the collector of the common-base transistor to deliver a substantial voltage swing, illustratively 1.

Abstract: Embodiments of the invention include an amplifier having an enhanced feedforward arrangement. In a typical operational amplifier output stage of this type, conventional feedforward arrangements comprise one or more active electrical components coupled between the second stage amplifying transistor and the negative output driver. The enhanced feedforward arrangement includes a resistor connected between the second stage amplifying transistor and the negative voltage source and a second resistor connected between the second stage amplifying transistor and the negative output driver. Alternatively, a capacitor is connected in parallel with the second resistor. In this manner, feedforward arrangements according to embodiments of the invention advantageously provide stable, enhanced frequency response, including high frequency response, e.g., above approximately 10 kHz, using economically advantageous passive rather than active electrical components.

Abstract: The specification relates to a thermal shutdown circuit for an integrated circuit. Two matching thermal sensing resistors are used to develop a voltage representing the relative differential temperature between the two resistors. One resistor is fabricated within the integrated circuit dissipating device dielectric isolation tub and therefore its temperature closely follows the temperature of the dissipating device. The second thermal sensing resistor reflects the ambient temperature of the integrated circuit. A third thermal sensing device is used to obtain actual absolute temperature at the location of the second thermal sensing resistor. By algebraically adding a voltage representing actual absolute temperature at an ambient temperature location with a voltage representing the relative differential temperature between thermal sensing resistors, a voltage representing the actual absolute temperature of the dissipating device is produced.

Abstract: The invention is an amplifier such as an operational amplifier having an output stage with a reduced quiescent current control transistor device area that provides sufficient quiescent current control for proper operation thereof. The output stage includes a current diverter or diverting arrangement whereby current flowing to the quiescent current control transistor area is reduced by diversion without jeopardizing the proper operation of the operational amplifier. In this manner, the relative size of the quiescent current control transistors can be significantly reduced without sacrificing any of the overall performance of the amplifier.

Abstract: The invention is an operational amplifier having an output stage for enhancing the output driver capability near the negative source voltage. The output stage of the invention includes a voltage detector in combination with a current redirector or redirecting arrangement. The voltage detector converts the voltage difference between the amplifier output and the input to the output stage of the amplifier to a control current, which is redirected at the positive source voltage and applied to the negative output driver. The current redirector, which is operably connected to the voltage detector, allows the amplifier output to be driven at full rated current (e.g., approximately 40 mA) close to the negative source voltage (e.g., within approximately 1.5 volts) while maintaining an output configuration appropriate for stability.

Abstract: A local battery feed circuit for telephone station sets comprises two half circuit portions substantially symmetric about an imaginary line midway between the TIP and RING telephone lines. Each half circuit includes a current drive amplifier including a pair of up-down emitter follower transistors and a driver transistor. A coupling capacitor and matched resistors provide common mode interference reduction without degrading differential mode signals. Power supply noise is substantially eliminated by transistors in each half circuit arranged to produce an a.c. current equal and opposite to that generated from the power source.

Abstract: A line transformer circuit in which the DC component of magnetization produced in the tip and ring windings by the battery supplying loop current to the telephone set microphone may be neutralized by an oppositely-poled, serially-connected balancing winding is disclosed. One end of the balancing winding is connected to the supply battery and is, therefore, at AC ground. The other end is kept at a point of high AC impedance to ground by the collector of a transistor so that audio frequency voltages induced in the balancing winding cannot load the transformer. The AC currents in the tip and ring windings are provided with a virtual ground return path by means of a differential amplifier controlled Darlington pair in circuit between the tip and ring windings and the balancing winding. The AC components of the Darlington pair collector current are bypassed to ground by a shunt capacitor at the junction of the Darlington pair collector terminal and the third winding.

Abstract: An electronic switch is disclosed comprising a transistor bridge having input and output signaling nodes and bias control nodes. A pair of matched current sources are selectively activated and deactivated in a series arrangement with symmetrical turn-on turn-off circuitry in response to a receipt of instruction signals. The instruction signals control the gating of a constant current to the turn-on/off circuitry for enabling the matched current sources to selectively apply and withdraw matched currents from bias control nodes. Switched turn-off circuitry is employed for reverse biasing the transistor bridge in response to a deactivation of the matched current sources. A pair of voltage reference and antisaturation circuits cooperate with bridge discharge circuits to effect the reverse biasing of the bridge and to discharge rapidly the effective electrical capacitance of that bridge shortly after the receipt of a bridge turn-off instruction.