Abstract: The invention discloses an integrated high voltage generating system possessing a charge pump for boosting stepwise the potential of an output node sequentially from the value of a first supply voltage to the value of a second supply voltage in synchronism with the clock pulses applied through a capacitor, wherein the second supply voltage is supplied to the gate electrode of the output MOS transistor connected between the output node of the charge pump and the output terminal. In this constitution, since the gate potential of the output MOS transistor is fixed at the valve of the second supply voltage, the potential fluctuation due to clock pulses does not appear on the output voltage taken out of the output terminal.

Abstract: This invention relates to an integrated high voltage generating system provided with a charge pump for raising the input power supply voltage sequentially while transferring the electric charges of the capacitors on a stage by stage basis, by serially connecting unit circuits composed of diode elements and capacitors, and supplying clock signals of mutually opposite phases to adjacent capacitors. Source and drain electrodes of a MOS transistor are connected between the first power supply output terminal and a second power supply output terminal, and the gate electrode of this MOS transistor is connected to the input end of any one of the unit circuits of the charge pump, wherein the voltage of the first power supply output terminal is stepped down depending on the voltage applied to the gate electrode of the MOS transistor, and is delivered to the second power supply output terminal.

Abstract: In a voltage detection circuit, at least a portion of the gate insulation film of a voltage detecting transistor is formed thicker than the other portion of the gate insulation film. Such voltage detecting transistor can be fabricated on a semiconductor substrate in the same process as conventional MOS transistors, so that the extra mask or process is not required. And since the amount of trapped electron does not change due to the passing of time, aging effects for detection precision is small.

Abstract: An impedance conversion circuit wherein source-follower circuits are formed at the input side and at the output side, between the first source-follower circuit (input side) and the second source-follower circuit (output side), a signal transmission circuit is constructed by connecting two FETs. In this circuit the threshold voltages of the FETs and variation of the threshold voltages can be offset, whereby the output voltage becomes equal to the imput voltage regardless of fluctuations of the threshold voltage or temperature, thereby retaining the voltage constant during impedance conversion from a high input impedance to a low output impedance.