Abstract: An apparatus for developing a signal voltage that represents the angular position of the crankshaft of an internal combustion engine. The apparatus includes a variable reluctance sensor that has a pick-up coil. The sensor is associated with means driven by the crankshaft of the engine for causing an alternating voltage to be induced in the pick-up coil as the crankshaft rotates. The apparatus includes a negative voltage clamp which clamps the voltage of a junction of the clamp circuit to substantially ground potential during negative half-cycles of the alternating voltage induced in the pick-up coil. The clamp circuit is adapted to be connected to a control circuit that is an integrated circuit having a bulk substrate diode. The clamp circuit prevents forward biasing of the bulk substrate diode.

Abstract: A reference voltage developing circuit that develops a multiple slope reference voltage that is a function of temperature. The circuit has a plurality of base-emitter multipliers each of which includes a transistor and each of which develops an output voltage that is a function of the base-emitter voltage of the transistor of the multiplier. Since the base-emitter voltage varies with changes in temperature, each multiplier circuit develops a voltage that varies with changes in temperature. The multiplier circuits have different multiplier magnitudes to thereby provide temperature dependent output voltages that have different slopes. A voltage selector circuit is connected to the multiplier circuits and it provides an output voltage that corresponds to the higher of the output voltages developed by the multiplier circuits.

Abstract: A concentric collector PNP transistor is utilized in electrical circuits to determine when the voltages of different parts of a circuit are very close to each other. The transistor has an emitter zone, an inner collector zone that surrounds the emitter zone and an outer collector zone that surrounds both the emitter zone and the inner collector zone. When the voltage of the emitter is slightly higher than the voltage of the inner collector a signal is developed at the outer collector which is used as a trigger or control signal. An oscillator-voltage doubler circuit and a series pass voltage regulator circuit are disclosed that utilize the concentric collector transistor.

Abstract: A high gain voltage responsive current source supplies emitter current to a lateral input PNP transistor in a monolithic integrated circuit voltage responsive switch and, in conjunction with an impedance between the voltage signal input terminal and base region of the input PNP transistor, protects the voltage responsive switch from negative voltage transients at the signal input terminal.