POWER SUPPLY VOLTAGE PROPORTIONAL-TYPE CURRENT SOURCE CIRCUIT

PROBLEM TO BE SOLVED: To suppress as much as possible the number of MOS transistors in a power supply voltage proportional-type current source circuit to reduce an area of the entire circuit.SOLUTION: NMOS transistors 5 and 8 are cascode-connected to a current mirror circuit 1 composed of PMOS transistors 2 and 3, and a voltage divided from a voltage from a BGR circuit is inputted to a gate of the NMOS transistor 5. Also, the NMOS transistor 8 is operated within a linear region by a source voltage of the NMOS transistor 5. Further, a voltage divided from a power source voltage VDD is inputted to a gate of a PMOS transistor 10, and a source of the PMOS transistor 10 and a gate of the NMOS transistor 8 are connected. Then a threshold voltage of the PMOS transistor 10 and a threshold voltage of the NMOS transistor 5 are set so as to be substantially equal to each other.