Voltage generator in a mos integrated circuit

A voltage generator comprising:

• a first circuit branch comprising a constant-current generator (Go), a first MOS transistor (Ml) having a channel with a first type of conductivity (n) and having its source-drain path in series with the constant-current generator (Go) between a first supply terminal (VDD) and a second supply terminal (ground),
• a second circuit branch comprising a second MOS transistor (M2) having a channel with a second type of conductivity (p), and a third MOS transistor (M3) having a channel with the first type of conductivity (n), the second and third MOS transistors (M2, M3) having their drain terminals in common and having their source terminals connected to the first supply terminal and to the second supply terminal, respectively, the second transistor (M2) having its gate terminal connected to a junction node (A) between the first transistor (M1) and the constant-current generator (Go), and the third transistor (M3) having its gate terminal connected to its own drain terminal,
• a third circuit branch comprising a fourth MOS transistor (M4) having a channel with the second type of conductivity (p), and a fifth MOS transistor (M5) having a channel with the first type of conductivity (n), the fourth and fifth MOS transistors (M4, M5) having their drain terminals connected to one another via two resistors (R1, R2) in series, the gate terminal of the fourth MOS transistor (M4) being connected to the junction node (A) between the first transistor (M1) and the constant-current generator, the gate terminal of the fifth MOS transistor (M5) being connected to the gate terminal of the third transistor (M3), and the drain terminal of the fifth MOS transistor (M5) being connected to the gate terminal of the first transistor (M1),
• a fourth circuit branch comprising a sixth MOS transistor (M6) having a channel with the second type of conductivity (p) and a seventh MOS transistor (M7) having a channel with the first type of conductivity (n), the sixth and seventh transistors (M6, M7) having their drain terminals connected together to a junction node (B) between the two resistors and their gate terminals connected to the drain terminal of the fourth MOS transistor (M4) and to the drain terminal of the fifth MOS transistor (M5), respectively,
• the gate terminals of the second transistor (M2), of the third transistor (M3), of the sixth transistor (M6), and of the seventh transistor (M7), and the junction node (B) between the two resistors (R1, R2) being output terminals of the voltage generator.