| 摘要 |
An offset compensator, a display device, a semiconductor device, an offset compensating method, a noise detector, and a noise detecting device are provided to improve high frequency characteristics of an operational amplifier by removing a phase compensating capacitor from the operational amplifier. An offset compensator includes an operational amplifier(1a) having a non-inverted input terminal and an inverted input terminal. A memory stores a first logic value, when an output voltage of the operational amplifier is greater than a reference value, and a second logic value, when the output voltage of the operational amplifier is smaller than the reference value. The output voltage is measured by short-circuiting the inverted input terminal to the non-inverted input terminal, while no feedback voltage is applied from an output terminal of the operational amplifier to the input terminals. The reference voltage is set as an ideal output voltage of the operational amplifier, when a differential input is zero. An offset of the output voltage of the operational amplifier with respect to the reference value is compensated by using the logic signals stored in the memory.
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