| 摘要 |
<p>PURPOSE:To prevent the occurrence of erroneous erasure, erroneous writing, and erroneous reading by making a driver to select and drive all word lines at a fixed voltage during the period of a reset signal outputted from a reset circuit when the power supply is turned on and a discharge circuit to discharge electricity from a control gate and bit lines. CONSTITUTION:When the power supply is turned on, a reset circuit 2 outputs a reset signal 201 for a fixed period of time (several mus) and a bias circuit 3 outputs a fixed voltage (2V) 301 upon receiving the signal 201. When the signal 201 is inputted, a driver 4 selects and drives all word lines by outputting a voltage which is equal to the voltage 301 to word lines 101 and 102. As a result, four memory cells 1 are turned on and a discharge circuit 5 starts discharging operations to discharge electricity from control lines 111 and 112 and bit lines 121 and 122. When the circuit 5 starts the discharging operations, the cells 1 are short-circuited with each other, but, since all word lines are not selected and driven with a power supply voltage at a logically high level, but with the voltage of 2V which is lower than the lowest programmable voltage, the occurrence of erroneous erasure, erroneous writing, and erroneous reading is prevented.</p> |
