Patent ID: 8618970

Claim:
A digital-to-analog (DA) conversion device comprising: a current output type DA converter; an operational amplifier including a non-inverting input terminal connected to the DA converter and an inverting input terminal connected to an external output unit to output an output signal to outside, and being configured to generate a voltage at the external output unit, the voltage corresponding to an output current from the DA converter; a buffer amplifier connected to an output terminal of the operational amplifier; power supply devices configured to respectively supply positive and negative power supply voltages to the buffer amplifier; and floating power supplies configured to respectively supply positive and negative power supply voltages directly to the DA converter and the operational amplifier, wherein a voltage midpoint between the positive and negative power supplies is connected to an output terminal of the buffer amplifier, and wherein an absolute value of the power supply voltages from the power supply devices to the buffer amplifier is greater than an absolute value of the power supply voltages from the floating power supplies.