Robert Boschgmbh

Karl Nagel

Gerhard Conzelmann

Walter Kohl

Hartmut Seiler

Klaus Streit

Gerhard Fiedler

Bernd W Kalkhof

Andreas Junger

Karl Staiger

Helmut Keller

Horst Gschwendtner

Uwe Gunther

In a semiconductor device including a semiconductor body, a continuous oxide layer, a continuous metallization layer, and a diffusion zone, the diffusion zone is located below a portion of the continuous oxide layer to reduce this portion in thickness, and the corresponding part of the metallization layer in the region of the oxide layer portion of reduced thickness forms an undulation which protects the metallization layer against thermal stresses.

Method of making metallization for semiconductor device

Precision reference voltage source

Power supply system

Voltage-regulator for generator

Voltage regulator for a generator

Device for protecting an electrical circuit against interference pulses

A power transistor monolithic integrated structure produced by a bipolar-epitaxial technology includes a plurality of parallel connected transistor cellular structures each containing at least one component transistor. The base of each component transistor is coupled to a common base control conductor via a protective resistor and a fuse link which melts in the event of a defect in the transistor cell. Another fuse link is incorporated in the branch conductors leading from the collectors of respective component transistor to a common conductor web mounted on the surface of the transistor chip. All transistor cellular structures are electrically isolated one from each other during the manufacturing process.

Power transistor monolithic integrated structure

Monolithic integrated semiconductor means to reduce power dissipation of

Multiple-cell transistor with base and emitter fuse links

A monolithically integrated, polarity-reversal protected switching circuit includes, in the output of a switching stage, a symmetrical thyristor instead of an otherwise customary diode. This thyristor is constituted by an npn transistor and a lateral pnp transistor. The control input of the thyristor is controlled by an additional control arrangement in such a manner that the thyristor is switched off at the occurrence of high voltage peaks. In this manner, there is obtained a relatively inexpensive monolithically integrated switching arrangement which is protected against polarity reversal and withstands voltage pulses of up to 150 volts.

Monolithically integrated, polarity-reversal protected circuit

The temperature sensing circuit includes a source of constant current I.sub.S, a voltage divider R.sub.1, R.sub.2 and an output transistor T.sub.1 whose base collector circuit is connected parallel to the first resistor and whose base emitter circuit is connected parallel to the second resistor. An auxiliary source of current having a positive temperature coefficient is connected in series with the first resistor of the voltage divider to cause a voltage drop thereon having an opposite temperature coefficient than the output voltage U.sub.S generated at the collector-emitter circuit of the output transistor.

Temperature sensing semiconductor circuit

To limit the current through the emitter-collector path of an output transistor, typically a Darlington transistor pair (T7, T8) to a load, in case of short circuit or malfunction of the load (L), in which a control circuit path resistor (R1) is serially connected with the emitter-collector path of the output transistor and the load, a reference current source is provided, connected to have current flow additionally through the resistor (R1) and providing control current to the output transistor at a control terminal (2) thereof, thereby permitting self-regulation of output current to a safe level regardless of reflected load resistance.

Transistor-controlled-load, short-circuit-protected current-supply

To improve the regulating response of an automotive-type, solid-state voltage regulator and render it essentially immune to ripple while additionally permitting complete integration of the entire voltage regulator without external discrete filter capacitors, a difference amplifier has the output voltage of the on-board vehicle network, for example from an alternator, applied thereto for comparison with a reference, the difference amplifier, respectively, controlling a capacitor charge current supply and a discharge current drain circuit, both connected to a small capacitor in the order of, for example, only 30 pF which, hence, can be integrated, the voltage across the capacitor being sensed in a high-low window or range-type discriminator which has a dual-state output to control conduction or non-conduction of a transistor in series with the field of the alternator in dependence upon whether the voltage across the capacitor, as it is being charged or drained, is above an upper threshold or below a lower threshold of the discriminator. Preferably, the circuit includes current mirror circuits in which currents in one branch are reflected in another to provide for balance, temperature compensation, and to render the circuit immune to variations in loading on the alternator.

Voltage regulator, particularly for automotive use

To provide for uniformity of power dissipation in the components of the switching system, regardless of the duty cycle upon repetitive, cyclical operation, the coupling resistors connected to the driver transistor and to the power transistor are so dimensioned relative to each other, and to the internal resistances of the driver transistor and the power transistor of the system that, in an initial approximation, the dissipation losses arising in the system are independent of the duty cycle of the switching transistor; this is obtained by selecting the sum of the resistance value of the collector resistor for the driver transistor and the base transistor of the power transistor such that (a) when the driver transistor is blocked, current flowing to the base of the power transistor holds the power transistor in full, saturated conduction and (b) the value of the collector resistor for the driver transistor is so selected that, when the driver transistor is conductive, the sum of the dissipated power in the collector-emitter path of the driver transistor, and in the collector-resistor of the driver transistor is approximately equal to the sum of the power which is dissipated in the collector resistor of the driver, the base resistor of the power transistor and the collector-emitter path of the power transistor, when the driver transistor is in blocked state. The entire system can be constructed on a monolithic chip and has a particular application as the switching circuit in automotive voltage regulators.

Cyclically operating transistorized power switching circuit system

A controlled main switch, typically a semiconductor switch, is connected in parallel to the load. In accordance with the invention, an auxiliary switch, typically also a semiconductor switch such as a switching transistor is directly connected across the terminals of the load, and with an impedance, for example a resistance, diode, or Zener diode to the main switch, and controlled to switch in synchronism with the main switch, so that the residual voltage across the load due to inherent voltage drop across the terminals of the switch becomes a minimum. Integrated technology may be used, combining preamplifiers and distribution networks in one monolithic chip.

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Gomaringen, Germany

Karl Nagel