Abstract: A photodetector formed in an active area of a semiconductor substrate of a first conductivity type, including a MOS transistor and a photodiode formed of the junction between the substrate and a region of a second conductivity type also forming the source of the MOS transistor, a heavily-doped layer of the first conductivity type covering the source region and a portion of the substrate, said portion of the substrate being delimited by an opening of the source region extending in a centered manner from the side of the source region opposite to the channel region of the transistor, towards this channel region.

Abstract: A converter receiving an A.C. voltage between an input terminal and a reference terminal and providing two D.C. voltages of opposite polarities across a first and a second capacitor. The converter includes a first switch connected the input terminal and a node of the circuit; a third capacitor, connected in parallel with the first capacitor, between the node and the reference terminal; circuitry including a second switch for connecting, in series, the second capacitor and the third capacitor when the second switch is closed; and a control circuit for closing the first switch only at the beginning and at the end of halfwaves of given polarity, the first switch being open when the second switch is closed.