| 摘要 |
<p>PURPOSE:To prevent a leakage current to a write circuit at readout by inserting plural diodes connected in cascade between a write circuit and a data terminal used in common for write/readout so as to bring the anode to a data terminal and the cathode to a write circuit side. CONSTITUTION:Two diodes D1, D2 connected in cascade are inserted between a data terminal 10 and a write circuit 1 while the anode is connected to the terminal 10 side and the cathode is connected to the circuit 1 side. When a power voltage VCC connected to a point A via a resistor R is lower than the applied voltage VOUT at the terminal 10, the diodes D1, D2 are not turned on. That is, no leakage current flows from the terminal 10 to the circuit 1 regardless of the quantity of the impedance in the circuit 1 and it is possible to apply normal readout. The number of diodes is not limited to two but the number has only to be determined in response to the level difference between the point A and the terminal 10.</p> |
