DIAGNOSIS CIRCUIT, SEMICONDUCTOR DEVICE, ON-VEHICLE ELECTRONIC CONTROL UNIT, AND DIAGNOSIS METHOD BY DIAGNOSIS CIRCUIT

摘要

A diagnosis circuit includes a control unit configured to periodically switch one of a monitored voltage Vm corresponding to a power supply voltage VO1 when the power supply voltage VO1 is normal and a reference voltage for monitoring Vmref corresponding to a reference voltage Vref to one of first and second voltage values in such a way that a magnitude relationship between a voltage value of the monitored voltage Vm and a voltage value of the reference voltage for monitoring Vmref is periodically switched, a monitoring circuit configured to compare the monitored voltage Vm with the reference voltage for monitoring Vmref, and an evaluating circuit configured to evaluate as to whether or not the power supply voltage VO1 is normal and whether or not the monitoring circuit has a failure based on a monitoring result M1 by the monitoring circuit and information on the voltage value, which has been periodically switched by the control unit, of just one of the monitored voltage Vm and the reference voltage for monitoring Vmref.