What is dynamic random access memory, Computer Engineering

Assignment Help:

Q. What is Dynamic Random Access Memory?

RAM technology is divided into 2 technologies: Static and dynamic. A dynamic RAM (DRAM) is made with cells which store data as charge on capacitors. Absence or presence of charge on capacitor is interpreted as binary 1 or 0. Since capacitors have a natural tendency to discharge, dynamic RAM needs periodic charge refreshing to maintain data storage. Term dynamic corresponds to this tendency of stored charge to leak away even with power continuously applied.

Figure below is a typical DRAM structure for an individual cell which stores one bit. The address line is activated when bit value from this cell is to be read or written.  Transistor acts as a switch which is closed (allowing current to flow) if a voltage is applied to address line and open (no current flows) if no voltage is present on address line.

2157_What is Dynamic Random Access Memory.png

For write operation a voltage signal is applied to bit line; a high voltage represents 1 and a low voltage represents 0.  A signal is then applied to address line allowing a charge to be transferred to capacitor. 

For read operation when address line is selected transistor turns on and charge stored on capacitor is fed out onto a bit line and to the sense amplifier. Sense amplifier compares capacitor voltage to a reference value and decides if cell contains logic 1 or logic 0.  The read out from cell discharges the capacitor that should be restored to complete operation. 

Even though the DRAM cell is used to store a single bit (0 or 1) it is necessary an analog device. Capacitor can store any charge value within a range. A threshold value determines whether charge is interpreted as 1 or 0.


Related Discussions:- What is dynamic random access memory

What are invisible components, They are light weight components that do no ...

They are light weight components that do no painting, but can take space in the GUI. This is mainly used for layout management.

What do you mean by first fit, What do you mean by first fit? First fi...

What do you mean by first fit? First fit allocates the first hole that is big enough. Searching can either begin at the beginning of the set of holes or where the last first-f

How is the command suppress-dialog useful, How is the command Suppress-Dial...

How is the command Suppress-Dialog useful? Suppressing whole screens is possible using this command.  This command permits us to perform screen processing "in the background".

Define interrupt, Define interrupt. An interrupt is any exceptional eve...

Define interrupt. An interrupt is any exceptional event that causes a CPUU to temporarily transfer control from its present program to another program , an interrupt handler th

Explain in brief about the insert operation, INSERT OPERATION The inser...

INSERT OPERATION The insert operation inserts a new value into a set of bits. This is done by first masking bits and then O ring them with required value. For illustration, sup

What is flag, Flag is a flip-flop used to kept the information about the st...

Flag is a flip-flop used to kept the information about the status of a processor and the status of the instruction implemented most recently A software or hardware mark that si

Object orientation and uml, In this task you are supposed to create three U...

In this task you are supposed to create three UML diagrams. The conditions are given by the scenario in the document Theatre Case (on Blackboard). A theatre manager has ordered a s

What is digital switch, Digital switch It is a device that handles digi...

Digital switch It is a device that handles digital signals formed at or passed by a telephone company's central office and sends them across the company's backbone network.

State the approaches to organizing stored program control, Determine the ap...

Determine the approaches to organizing stored program control There are 2 approaches to organizing stored program control: 1.  Centralized: In this control, all control equi

Interfacing subroutines with parameter passing, Interfacing Subroutines wit...

Interfacing Subroutines with Parameter Passing Let's now write a C program which calls the assembly program for parameter passing. Let's extend the previous two programs such t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd