Patent ID: 7973694
Filing Date: 2011-07-05
Classification: H03K,H03M

Abstract:
1. An analog-digital converter comprising: an input polarity switching unit that switches polarity of an input signal; an integrator that integrates the input signal output from the input polarity switching unit; an integrator output adjusting circuit that adjusts an output voltage of the integrator; a window comparator that includes a high-voltage side comparator and a low-voltage side comparator, the high-voltage side comparator including a first reference voltage and a second reference voltage that is higher than the first reference voltage, the low-voltage side comparator including a third reference voltage and a fourth reference voltage that is lower than the third reference voltage, the window comparator further comparing the output voltage of the integrator with the first to fourth reference voltages; and a controller that controls the input polarity switching unit, the integrator output adjusting circuit, and the window comparator based on the comparison result in the window comparator, and generates a digital signal, wherein the controller resets the first reference voltage of the high-voltage side comparator to the second reference voltage when the output voltage of the integrator reaches the first reference voltage, and resets the third reference voltage of the low-voltage side comparator to the fourth reference voltage when the output voltage of the integrator reaches the third reference voltage, and the integrator output adjusting circuit adjusts the output voltage of the integrator so that the output voltage of the integrator becomes lower than the second reference voltage when the output voltage of the integrator reaches the second reference voltage, and adjusts the output voltage of the integrator so that the output voltage of the integrator becomes higher than the fourth reference voltage when the output voltage of the integrator reaches the fourth reference voltage.