Non-linear interpolation circuit, interpolation current generating circuit thereof and method for converting digital data into analog data

An interpolation current generating circuit, comprising:

• a first current interpolating unit for receiving a first reference voltage and an operating voltage corresponding to digital image data to generate a first operating current;
• and
• a second current interpolating unit coupled in parallel to the first current interpolating unit and configured for receiving the operating voltage and a second reference voltage to generate a second operating current, the second reference voltage being larger than the first reference voltage;
• wherein when the operating voltage starts to increase, the first current interpolating unit generates the first operating current corresponding to the operating voltage to be an interpolation current, and when the operating voltage is larger than the first reference voltage and continues increasing to a preset value, the second current interpolating unit generates the second operating current corresponding to the operating voltage and the second operating current is superimposed on the first operating current to be the interpolation current.