| 摘要 |
PURPOSE:To improve an error of absolute accuracy of an output, which is caused by the variations in resistance, by constituting a D/A converter by symmetrically providing two circuits which have connected resistances R of 2(n-1) pieces and resistances 2R of 2(n+1) pieces in the form of a ladder. CONSTITUTION:Circuits 11, 12 which have connected resistances R of 2(n-1) pieces (integer of n<=2) and resistances 2R of 2(n+1) pieces in the form of a ladder are provided symmetrically. To one terminal of the resistance 2R of the respective first stages of the circuits 11, 12, electric power sources V1, V2 are connected, respectively, corresponding digital input terminals a1-a3 of the 2 circuits are connected in common, and the resistances R of the last stages are connected in common and are connected to an analog output terminal VOUT. In this circuit, for instance, when the resistance groups are concentrated to a prescribed area so that a resistance of a maximum weight bit of the circuit 11 and a resistance of a minimum weight bit of the circuit 12 are approached to each other, and a resistance of a minimum weight bit of the circuit 11 and a resistance of a maximum weight bit of the circuit 12 are approached to each other, an analog signal of a mean value of the circuits 11, 12 is outputted to the terminal VOUT, and an error of absolute accuracy of an output, which is caused by the variations in resistance is greatly improved. |
