Welcome Seminar on MEMRISTOR 19 Sept. 2009 By:- Mangal Das Himanshu Ramchandani
Welcome Seminar on
MEMRISTOR
19 Sept. 2009
By:- Mangal Das
Himanshu Ramchandani
MEMRISTOR
Memristor
Memory Resistor+
Memristor
Definition of Memristor A memristor is a semiconductor whose
resistance varies as a function of flux and current. This allows it to “remember” what has passed through the circuit.
Characterized by Memristance
Memristance Memristance is simply charge-dependent
resistance. V(t) = M(q(t))*I(t)
Unit - ohm (Ω)
Symbol
Emergence Of Memristic Theory Theory was developed in 1971 by
Professor Leon Chua at University of California, Berkeley.
Found while exploring symmetry between the three fundamental passive linear circuit elements
In 2006, R.Stanley Williams developed practical model.
Fundamental Circuit Variables Voltage, V (V) – work done required to
bring charge from ∞ to a Electric field. Current, I (A) – flow of electric charge Flux, Φ(W) – rate of flow through an
area Charge, Q (C) – energy per electron
Symmetry Of Relationships
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
3 Fundamental Passive Linear Elements
Capacitor,C (F)
Resistor,R (Ω)
Inductor,L (H)
CAPACITORS
q = C v
Symmetry Of Relationships
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
q=CvCapacitors q=CvCapacitorsCapacitors
RESISTORS
Ohm’s Lawv = R i
Symmetry Of Relationships
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
Resistors v=Ri
Capacitors q=CvCapacitors
INDUCTORS
Φ = L i
Symmetry Of Relationships
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
Φ = Li Inductors
Resistors v=Ri
q=CvCapacitors
Fundamental Relationships
Current is the derivative of Charge
Q= ∫I dt
Voltage is the derivative of Flux
V= ∫ dΦ/dt
Symmetry Of Relationships
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
Φ = Li Inductors
The Missing Link
?
v=dΦ/dt i=dq/dt
Resistors v=Ri
q=CvCapacitors
Symmetry Of Relationships
Φ=Mq
Voltage (V)
Current(i)
Charge (q)
Flux (Φ)
Φ = Li Inductors
Memristor
v=dΦ/dt i=dq/dt
Resistors v=Ri
q=CvCapacitors
Relationship With Other Variables Φ = M q
dΦ/dt = M(q) dq/dt
V(t) = M(q) I
P = I² M(q)
Property Of Memristor
Retain its resistance level even after power had been shut down.
Output =F(present value + previous value of resistance.)
Pinched Hysteresis Loop
V(t) = M(q(t))*I(t)
* When I=0 , Then V becomes 0
The applied voltage (blue) and resulting current (green) as a function of time t for a typical memristor.
Pinched Hysteresis Loop
* For memristors, the Previous graph is reprented as a PINCHED HYSTERESIS LOOP
Memristic State Found when researching ways to overcome
nano-scale manufacturing issues. Memristivity has an inverse square
relationship with thickness of the material, so smaller = better!
Nonvolatile state can be accomplished by memristors because their state is encoded by impedance (physically), not by voltage.
WORKING
PT PTTiOv(2-x)
TiO2
3 nm
2 nm
OxidizedReduced
(-)ve (+)ve
Applied voltage makes the oxygen vacancies (+ve) to shift towards the cathode.
WORKING Shift between the layers in
permanent in nature. It exist even after the voltage has
been removed. Causes the permanent change in
resistance
Analogy Of Memristor
A RESISTOR WITH MEMORY BEHAVES LIKE A PIPE
The diameter of pipe remains same when the current is switched off, until it is switched on again.
The pipe, when the current is switched on again, remembers what current has flowed through it.
Delay In Discovery
As its effect depends on atomic-scale movements, it only poped up on the nanoscale of William’s devices.
Benefits Of Memristor Technology Would allow for a quicker boot up
since information is not lost when the device is turned off.
Hard Disk + RAM = MEMRISTOR
Benefits Of Memristor Technology
Uses less energy and produces less heat. Smaller, lower power consumption SSDs. Eliminates the need to write computer
programs that replicate small parts of the brain.
Benefits Of Memristor Technology Compatible with current CMOS
interfaces Power Consumption
As non-volatile memory, memristors do not consume power when idle.
Behaviour 3 Memristors to make a NAND gate 27 NAND gates to make a Memristor
Benefits Of Memristor Technology Creating a Analog Computer that
works much faster than Digital ones. Provides greater resiliency and reliability
when power is interrupted in data centers.
Density allows for more information to be stored.
Distinct Behaviour Of Memristor Conventional devices use only 0 and 1;
Memristor can use anything between 0 and 1.
Faster than Flash memory. Allow digital cameras to take pictures
with no delay in between Innovating nanotechnology due to the fact
that it performs better the smaller it becomes.
Not Perfect Yet ! Though hundreds of thousands of
memristor semiconductors have already been built, there is still much more to be perfected.
Needs more defect engineering. No design standards (rules). Fair endurance (overlookable e.g..
Transistors)
Thank You
QUESTIONS