| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an A/D converter which is not affected by the offset voltage of an amplifier, when utilizing a reference voltage by a BGR circuit in analog to digital conversion. Ž<P>SOLUTION: In the A/D converter, a band gap reference circuit includes: an operational amplifier for receiving a voltage, appearing in a temperature dependent element corresponding to the reference voltage, as an input voltage and outputting the reference voltage; a first switching circuit, capable of switching the state of replacing the inverted input and non-inverted input of the operational amplifier and the state of not replacing them; and a second switching circuit, capable of switching the state of outputting the output voltage of the operational amplifier by a positive phase and the state of outputting it by an opposite phase. An A/D conversion circuit, utilizing the reference voltage, sets the first and second switching circuits to a prescribed state to obtain a first digital value; sets the first and second switch circuits to a state which is reverse to that of the prescribed state, to obtain a second digital value; and obtains an A/D-converted result, as the average value of the first and second digital values. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
