Patent ID: 7923997

Claim:
A magneto-sensitive integrated circuit comprising: a Hall element which generates a magneto-sensitive output voltage corresponding to a magnetic flux density of an applied magnetic field; an amplifier which amplifies the magneto-sensitive output voltage to generate an amplified voltage; an A/D converter which converts an output voltage of said amplifier into a digital signal; and a controller which generates a reference voltage of magnitude corresponding to an indicated value, wherein said amplifier includes voltage superposition means for superposing a DC voltage corresponding to the reference voltage on the amplified voltage to generate the output voltage of said amplifier, and wherein said controller includes a resistor ladder circuit having a plurality of resistors connected in series, a power source for supplying a voltage across said resistor ladder circuit, a plurality of reference voltage output terminals, connected to each end of said resistors, for outputting a voltage divided by each of said resistors, a first memory which holds the indicated value, a plurality of switches corresponding to each of said reference voltage output terminals and provided between said reference voltage output terminals and an additional voltage input terminal of said amplifier, and a decoder which selectively drives said switches based on the indicated value held in said memory, said controller applies as the reference voltage one of a plurality of mutually different voltages to said voltage superposition means by connecting a reference voltage output terminal corresponding to the indicated value to said additional voltage input terminal of said amplifier.