Abstract: A capacitor sensor circuit may be used in application such as touch screens. The capacitor sensor circuit includes a transimpedance amplifier, a filter module, a rectifier, an integrator and an analog to digital converter. Since a transmission signal fed into the capacitor sensor circuit has been preprocessed through the rectifier and the integrator, the analog to digital converter to be used can be a low speed analog to digital converter that has lower power consumption and a lower cost of manufacturing compared to a high speed analog to digital converter.

Abstract: A capacitance interface circuit is provided. An external inductive capacitor is divided into a variable portion and an invariable portion. The capacitance of an internal adjustable capacitor is designed to be equal or close to the fixed capacitance of the external inductive capacitor. The internal adjustable capacitor is used for storing charges having a polarity opposite to that of the invariable portion of the external inductive capacitor in order to neutralize the effect of the invariable portion of the external inductive capacitor. Thus, a charge converter composed of a fully-differential amplifier and feedback capacitors needs only work on the variable portion of the external inductive capacitor, and accordingly the accuracy in subsequent data processing is increased.

Abstract: A capacitor interface circuit is provided. A capacitor under test (CUT) is divided into a variable portion and an invariable portion, and the capacitance of an offset capacitor is designed to equal to or close to the fixed capacitance of the CUT. The offset capacitor is used to store the charges opposite to the invariable portion of the CUT for neutralizing the effect of the invariable portion of the CUT. Thereupon, the charge converter composed by the fully-differential amplifier and the feedback capacitors only responses for the variable portion of the CUT so as to increase the accuracy of the follow-up data processing.

Abstract: A capacitance interface circuit is provided. An external inductive capacitor is divided into a variable portion and an invariable portion. The capacitance of an internal adjustable capacitor is designed to be equal or close to the fixed capacitance of the external inductive capacitor. The internal adjustable capacitor is used for storing charges having a polarity opposite to that of the invariable portion of the external inductive capacitor in order to neutralize the effect of the invariable portion of the external inductive capacitor. Thus, a charge converter composed of a fully-differential amplifier and feedback capacitors needs only work on the variable portion of the external inductive capacitor, and accordingly the accuracy in subsequent data processing is increased.

Abstract: A capacitor interface circuit is provided. A capacitor under test (CUT) is divided into a variable portion and an invariable portion, and the capacitance of an offset capacitor is designed to equal to or close to the fixed capacitance of the CUT. The offset capacitor is used to store the charges opposite to the invariable portion of the CUT for neutralizing the effect of the invariable portion of the CUT. Thereupon, the charge converter composed by the fully-differential amplifier and the feedback capacitors only responses for the variable portion of the CUT so as to increase the accuracy of the follow-up data processing.

Abstract: A temperature measuring method and a temperature measuring apparatus using the same are provided. In the method, four different currents are provided to a temperature measuring device respectively so as to obtain four different voltages at two ends of the temperature measuring apparatus correspondingly. A ratio of two of the four different currents is equal to a ratio of the other two currents. Next, two voltage variation values are obtained according to mentioned four different voltages. One of the voltage variation values is converted to a first digital temperature code representing a first temperature, and the other voltage variation value is converted to a second digital temperature code representing a second temperature. Then, a real temperature code representing a real temperature is obtained according to the first digital temperature code and the second digital temperature code.

Abstract: A transistor circuit capable of eliminating influence of component parameter and a temperature sensing apparatus using the same are disclosed in the invention. The temperature sensing apparatus includes a current-producing unit, a switching unit, a current-duplicating unit and a transistor. The temperature sensing apparatus is used to measure ambient temperature utilizing the voltage difference of the base and the emitter of the transistor varied with temperature. The current-duplicating unit duplicates the base current of the transistor and applies the duplicated current to the emitter of the transistor so as to avoid the influence of a component parameter variation of the transistor at different temperatures and to eliminate the measurement error caused by a component parameter difference between different transistors. Therefore, the novel temperature sensing apparatus improves the precision and the accuracy of temperature measurement.