Abstract: Load driver system (10) preferably uses a microprocessor controller (20) to generate write/read signals and command signals received by a circuit at write/read and command/status input terminals (16, 17). The circuit (15) responds to the input signals and controls a semiconductor switch (11) that controls the operative state of a load (14). The circuit (15) includes a load shorted high detector (28), a load shorted low detector (29) and a load open detector (30) which are used to detect various faults and provide a predetermined sequence of logic states at the command/status input terminal (17) during read cycles implemented by the controller (20). Thus one input line (terminal 17) is used to both send commands to the semiconductor switch (11) and receive a sequence of logic states indicative of various fault modes. This permits the controller to determine which of several types of faults, if any, has occurred, while minimizing the number of controller-circuit interconnections.

Abstract: A dual tracking control device for use with a multiple voltage source system. The device provides a reference signal that may be used to control a voltage source, such that this voltage source will track another of the voltage sources, so long as the tracked voltage source maintains a predetermined relationship with respect to yet another voltage source. If this relationship is not maintained, then the tracking control device will cause the voltage source to track instead an alternative voltage source.