Common pin voltage regulator

A voltage regulator for an automotive alternator battery charging system, said automotive alternator battery charging system further comprising a battery and an alternator coupled to the battery, and an operator-controlled switch connected between the battery and said voltage regulator for activating said voltage regulator upon closure of the operator-controlled switch, wherein the alternator is further drivingly coupled to a vehicle engine and provides a rectified output charging signal for charging the battery in accordance with an excitation signal provided by said voltage regulator to a field coil of the alternator, said voltage regulator comprising:

• a first module responsive to the battery voltage for providing a sensed signal representative of the battery voltage;
• a field terminal;
• a second module for providing an excitation signal to the alternator field coil in response to said sensed signal, wherein said excitation signal is provided at said field terminal;
• an input terminal;
• an I/F terminal connected via a unidirectional switch to said input terminal and further connected to said field terminal;
• and
• wherein said I/F terminal provides a signal representative of the excitation signal when said unidirectional switch is open and provides a bypass circuit around said input terminal when said unidirectional switch is closed.