Means for compensating a data-dependent supply current in an electronic circuit

摘要

Electronic circuitry comprising a data processing circuit for processing a digital signal (DS), such as a digital to analog converter (DAC), and a current compensation circuit (CMP). Both the digital to analog converter (DAC) and the current compensation circuit (CMP) are powered by a single power supply (U1). The current taken from the power supply (U1) by the digital to analog converter (DAC) is normally dependent on the digital input signal (DS). This would lead to distortion since the loss-resistances (R11, R12) which are always present in series with the power supply (U1) then feed a data-dependent supply voltage (U2) to the digital to analog converter (DAC). This problem is overcome by the addition of the current compensation circuit (CMP) which is coupled for receiving the digital signal (DS). The current compensation circuit (CMP) is arranged in such a way that the sum of the data-dependent current drawn by the digital to analog converter (DAC) and the data-dependent current drawn by the compensation circuit (CMP) is substantially independent of the data.