| 摘要 |
PURPOSE:To increase a range of conversion for a digital-analog converter, by providing a constant current source in parallel to the digital-analog converter. CONSTITUTION:A main D/A converter DAC2' of 14 bits is connected in parallel to a sub-D/A converter DAC4 of 2bits. The converters DAC2' and DAC4 absorb currents IM and IO respectively in response to the input digital signal. Therefore the sum of IM and IO flows to the feedback resistance R of an operational amplifier 6. The converter DAC4 absorbs a prescribed constant current in response to the input digital signal. As a result, the offset voltage of IOXR can be generated accurately at an output terminal 8. In such way, a range of conversion is increased, and furthermore the resolution can be maintained for the converter DAC2'. |
