Physical Quantity Detection Circuit, Physical Quantity Sensor, Electronic Apparatus, Vehicle, And Method For Malfunction Diagnosis On Physical Quantity Sensor

A physical quantity detection circuit includes: a detection signal generation circuit generating a detection signal, based on an output signal from a physical quantity detection element; an analog/digital converter circuit converting the detection signal into a first digital signal and converting a test signal into a second digital signal; a test signal generation circuit generating the test signal; and a malfunction diagnosis circuit diagnosing a malfunction of the analog/digital converter circuit, based on the second digital signal. A full-scale voltage of the analog/digital converter circuit is selected from among a plurality of voltages having different magnitudes, according to a power supply voltage. The test signal includes an upper limit value test signal, a lower limit value test signal, and a first intermediate value test signal. The test signal generation circuit performs resistive voltage division of the full-scale voltage and thus generates the first intermediate value test signal.