| 摘要 |
PURPOSE:To obtain a signal having a constant oscillating frequency independently of the variance in manufacture by providing the 2nd floating gate not connected to any other electrode between the 1st gate of an N-channel transistor (TR) and a gate oxide film. CONSTITUTION:In applying a voltage VPP higher than the threshold voltage VTN than the power voltage to a terminal 9, a P-channel TR 12 is turned on. That is, N-channel TRs 11', 11'' and a TR 12 are turned on. In this case, an input voltage VIN of an inverter 15 is expressed as VIN=R1XVPP/(R1+R2+ R3), where R1, R2, R3 are ON-resistances of the TRs 11', 11'' and 12, and the input to the inverter 15 rises up to 'H' by increasing the VPP sufficiently, the TRs 113, 114 are turned on and the source potential is a potential lowered by one threshold value from the VPP. In this state, the VTN of the TR 13 rises by electrons injected from the drain and the oscillation is stopped when the voltage reaches the VDD or over. |
