A fault check circuit, including a first channel comparator to output a first channel comparator output signal indicating whether a first channel digital signal is outside of a first channel threshold range, wherein the first channel digital signal is A/D converted from a first channel analog signal; a second channel comparator to output a second channel comparator output signal indicating whether a second channel digital signal is outside of a second channel threshold range, wherein the second channel digital signal is A/D converted from a second channel analog signal; and an alarm generator circuit to combine the first and second channel comparator output signals, and output a fault check signal, wherein the first and second channel comparators and the alarm generator circuit are implemented in hardware, and the fault check circuit performs a fault check without software intervention.