초록 ▼

An output current of a constant current source formed of a gate potential control circuit and a p channel MOSFET is determined only by the sub threshold swing value of a p channel MOSFET and a resistance of a resistor. A signal out 1 controlling the operation of a ring oscillator circuit is switched

An output current of a constant current source formed of a gate potential control circuit and a p channel MOSFET is determined only by the sub threshold swing value of a p channel MOSFET and a resistance of a resistor. A signal out 1 controlling the operation of a ring oscillator circuit is switched at a predetermined potential corresponding to the sum of the threshold value of n channel MOSFETs through which the output current flows. Since the output current has no power supply voltage dependency and increases in proportion to the temperature, the predetermined potential is independent of the power voltage. The temperature dependency is also small since the temperature dependency of the output current value and the threshold value cancel each other. Therefore, the substrate potential can be controlled at a stable level unsusceptible to variation in the external operating conditions.

대표청구항 ▼

[ What is claimed is:] [1.] A substrate potential generation circuit supplying a predetermined substrate potential to a semiconductor substrate, comprising:first substrate potential level detection means for providing a first control signal according to a comparison result of a substrate potential a

[ What is claimed is:] [1.] A substrate potential generation circuit supplying a predetermined substrate potential to a semiconductor substrate, comprising:first substrate potential level detection means for providing a first control signal according to a comparison result of a substrate potential and a first predetermined potential,wherein said first substrate potential level detection means comprisesa first output node for providing said first control signal,a first input node coupled to said substrate potential,a first MOSFET of a first conductivity type having its drain directly connected to said first output node, its gate coupled to a reference potential, and its source connected to said first input node, anda first constant current generation means includinga gate potential control circuit, said gate potential control circuit including a current mirror circuit having first to fourth input/output nodes, said first and second input/output nodes being connected to a first power source terminal, and for maintaining a first current flowing between said first and third input/output nodes and a second current flowing between said second and fourth input/output nodes at equal level,a second MOSFET of a second conductivity type having its source and drain connected to a second power source terminal and said third input/output node, respectively, and having its gate and drain connected,a third MOSFET of the second conductivity type having its drain connected to said fourth input/output node, and having a gate width/gate length ratio greater than that of said second MOSFET of the second conductivity type,a first internal node to which the gate of said second and third MOSFETs of the second conductivity type are connected in common,a resistor connected between the source of said third MOSFET of the second conductivity type and said second power source terminal, anda fourth MOSFET of the second conductivity type having its drain, source, and gate connected to said first output node, said second power source terminal, and said first internal node respectively,said substrate potential generation circuit further comprising:oscillator means for switching between and active state and an inactive state according to said first control signal, andcharge pump means receiving an output of said oscillator means for providing said substrate potential.