| 摘要 |
PROBLEM TO BE SOLVED: To provide an A/D conversion device which can reduce the temperature characteristic of a detection resistance in converting an output voltage of a current detection circuit to a digital signal even if the output voltage of the current detection circuit is changed by the temperature characteristic of the detection resistance.SOLUTION: An A/D conversion device comprises: a current detection circuit 13 having a temperature characteristic, which converts a current flowing from a voltage source to a load into a voltage and detects it; another detection circuit 12 having no temperature characteristic; a selector 14 which selects one of an output voltage of the current detection circuit and an output voltage of the other detection circuit; a reference-voltage source 16 having a temperature characteristic, which produces a reference voltage; and an A/D converter 15 which compares the output voltage of the detection circuit selected by the selector with the reference voltage, thereby converting an analog signal into a digital signal. When the analog-to-digital conversion of the output voltage of the current detection circuit is performed, the reference-voltage source changes the temperature characteristic of the reference voltage so as to fit the temperature characteristic of the output voltage of the current detection circuit.SELECTED DRAWING: Figure 1 |
