Patent ID: 7956786
Filing Date: 2011-06-07
Classification: H03M

Abstract:
1. A digital-to-analogue converter (DAC) for converting an input code to an analogue output signal, the DAC comprising: a main DAC circuit configured in the form of a main impedance string circuit for producing an analogue signal corresponding to the value of the most significant bits (MSBs) of the input code, a sub-DAC circuit for producing an analogue signal corresponding to the value of the least significant bits (LSBs) of the input code, the sub-DAC circuit and the main DAC circuit co-operating for producing the analogue output signal on an output terminal of value corresponding to the input code, a level shifting circuit for selectively altering the voltage value of the analogue output signal by a predetermined voltage value, and a control circuit responsive to the input code for operating the level shifting circuit to alter the voltage value of the analogue output signal by the predetermined voltage value, and for altering the value of the LSBs of the input code applied to the sub-DAC circuit by a value corresponding to the predetermined voltage value to compensate for the alteration of the voltage value of the analogue output signal by the level shifting circuit.