| 摘要 |
To determine an abnormality of a power supply voltage in an electronic control apparatus with less influence to a circuit mounting area and cost, and without reducing an operating voltage range. An electronic control unit (ECU) is provided with: a microcomputer (13), which has an input terminal (VCCin) and an input terminal (Vrin); a power supply IC (11), which supplies a power supply voltage (VCC) to the input terminal (VCCin); a voltage-dividing resistor (16) and a voltage-dividing resistor (17), which constitute, as a reference voltage generating circuit (12), a voltage-dividing circuit, which outputs a divided voltage (Vc) obtained by dividing the power supply voltage (VCC); a capacitor (19), which has one end thereof connected to the input terminal (Vrin), and the other end thereof grounded; and a voltage isolation element (18), which is connected to between the voltage-dividing circuit, and the input terminal (Vrin), and which outputs a reference voltage (Vr) to the input terminal (Vrin) in cooperation with the capacitor (19), said reference voltage having been separated from the power supply voltage (VCC) and the divided voltage (Vc). The microcomputer (13) detects an abnormality of the power supply voltage (VCC) using the reference voltage (Vr) inputted to the input terminal (Vrin). |
