Signal treating circuit with a class A/B output stage connectable to a source of multiple supply voltages

摘要

An A/B class output stage of a signal treating circuit, such as for example a mobile telephone, a radio car kit, other portable equipment, etc. treats a signal. The A/B class output stage drives a load with the signal as treated by the signal treating circuit. The output stage can be connected to one of more than one supply voltages as a function of a voltage value of the signal. The signal treating circuit comprises a D/A converter circuit and a non-linear operating circuit between an input of the signal treating circuit and the D/A converter. Above a certain signal value a change in supply voltage is made. Distortions in an output signal resulting from such a change are prevented by having the non-linear operating circuit generate a jump in DC level at an output of the output stage or raise a value of the signal at a non-clipping one of two output terminals with an extra amount that compensates for the clipping at a clipping one of the two output terminals.