Those skilled in the art are capable of implementing the circuit CTRL, in particular when the comparison of the voltage V_T with the thresholds Vth, Vth_l and possibly Vth_h is implemented with another circuit than the one described in relation with FIG. 6. For example, this comparison may be implemented by sampling the voltage V_T with an analog-to-digital converter and by comparing the binary codes provided at the converter output with binary codes representative of the thresholds Vth, Vth_l, and possibly Vth_h.

Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these embodiments can be combined and other variants will readily occur to those skilled in the art. In particular, the component 116 may be a switch rather than a diode, the switch 116 being then controlled by the circuit CTRL, opposite to that of the switch 112.

Finally, the practical implementation of the embodiments and variants described herein is within the capabilities of those skilled in the art based on the functional description provided hereinabove. In particular, those skilled in the art are capable of implementing the circuit CTRL and determining the value of the thresholds Vth, Vth_l, and Vth_h.