Integrated voltage regulating circuit

摘要

A monolithically integrated voltage regulator is specified in which both the collector and the base electrode of a regulating transistor (13) is protected against excessive positive and negative interference voltages. The protection against positive interference voltages is achieved by a reversely polarised diode (22). The protection against negative interference voltages is achieved by a transistor (20) of a type of conductivity which is opposite to that of the regulating transistor (13), and by a resistor (21) connected in series therewith. The resistor (21) is a resistor of p-type of conductivity, which is diffused electrically insulated into a well of the n-type of conductivity, as a result of which negative interference voltages are kept away both from the transistor (20) and from the resistor (21). (Figure 1). <IMAGE>