| 摘要 |
<p>PURPOSE:To make an elevated voltage constant without depending upon a source voltage by a method wherein a constant potential supply circuit which supplies a potential to an oscillation signal which is the output of an oscillating circuit is provided. CONSTITUTION:A high voltage generating circuit is composed of an oscillating circuit 2 which outputs an oscillation signal and a voltage elevating circuit 1 which is driven by the oscillation signal. A constant potential supply circuit 8 which supplies a potential to the oscillation signal which is the output of the oscillating circuit 2 is added to the high voltage generating circuit. For instance, a voltage V8 is supplied to the sources of the P-type channel transistors 6 and 7 of inverters 4 and 5 in the oscillating circuit 2 which output the oscillation signals CL and -CL by the constant potential supply circuit 8 composed of a P-type channel transistor 9 and N-type channel transistors 10-12. With this constitution, an elevated voltage does not depend upon a source voltage, so that the deterioration of the reliability on the high voltage source side caused by the high voltage application stress of a memory cell can be suppressed and, further, writing and erasing characteristics can be stabilized.</p> |
