What is the DRAM of Taiwan China state?

DRAM brief introduction

DRAM (Dynamic Random Access Memory) , namely DRAM, most common system memory.

DRAM can hold data very short time only. To carry data, DRAM uses capacitance memory, must lie between refresh of period of time so (Refresh) , if location is done not have by refresh, the information of memory can be lost. (close machine can lose data)

Working principle

The RAM of working principle trends of dynamic RAM also is by a lot of main memory yuan bring crural answer to use composition according to travel and row address.

The working principle of RAM of 3 tubes trends the main memory circuit of RAM of 3 tubes trends. In this circuit, read a selection line and writing choice line is departure, reading is mixed according to the line writing data line also is departure.

When keeping an operation, write choice line to be ” 1 ” , so Q1 guides, the data that should keep sends the grid of Q2 through Q1, pass grid capacitance to carry message inside proper time.

When reading an operation, pass first public fill fulgurite Q4 to make reading occupies CD of on-line distributinging capacitance to charge beforehand, should read choice line to be when tall n is effective, q3 is in can guide the position that open. If be put so,have ” 1 ” , criterion Q2 guides, the distributinging capacitance CD that reads data line passes Q3, Q2 to discharge, the news that reads right now is ” 0 ” , as it happens and Yuan Cunxin breath are contrary; If put information to be formerly ” 0 ” , criterion although Q3 is had guide a condition, but end because of Q2, so, the voltage on CD keeps changeless, consequently, reads news is ” 1 ” . Visible, to such memory circuit, reads news and the information just in time that stock so are contrary, want so through numerating amplifier undertakes turning over sending toward data bus line again.