An amplifier including: an output stage having two first power supply terminals capable of receiving a first voltage defined by first positive and negative variable potentials with respect to a reference potential; and a circuit for controlling the current in transistors of the output stage with a reference value, wherein the output stage includes a first and a second MOS transistors in series between the first two terminals, the junction point of this series association defining an output terminal of the amplifier; the control circuit includes two measurement MOS transistors having their respective sources and gates coupled to the respective sources and gates of the first and second transistors of the output stage; at least one control branch, comprising transistors in series between two terminals of application of a second voltage, defines nodes connected to the gates of the output transistors, said second voltage being greater than the first one.