| 摘要 |
An analog/digital converter has an integrator for integrating for a predetermined time a difference voltage (<VX) between a voltage equal to half a source voltage V1 and an input voltage VX supplied to the first input terminal after an initialization period, generating an output voltage increasing in proportion to the input voltage, and generating an output voltage decreasing at a predetermined rate after the predetermined time has elapsed, and a counter for generating count data until the output voltage from the integrator reaches a predetermined level. This converter also has a resistor-type voltage divider and a capacitor. The voltage divider is coupled between source terminals and generating from first and second output terminals first and second output voltages E1 and E2 which are lower than voltage V1/2. The capacitor has one terminal coupled to the first input terminal of the integrator and the other terminal coupled to the first and second output terminals of the resistor-type voltage divider through first and second switches. During initialization, the first switch closes and a voltage (E1-V1/2) is charged on the capacitor. After the predetermined period of time has elasped, the second switch is closed and a voltage (E1+E2-V1/2) is applied to the first input terminal of the integrator.
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