Download presentation

Presentation is loading. Please wait.

Published byRicardo Jefferies Modified over 4 years ago

1
Transistors: Building blocks of electronic computing Lin Zhong ELEC101, Spring 2011

2
Key concepts Recap of PHY102 Ubiquity of resistance and capacitance Energy and power consumption Inverter: the simplest computing Transistor – Charge state 2

3
Electrons, charge, current Electron – Subatomic particle – ~9.109x10 -28 gram Carbon atom ~2X10 -23 grams – Elementary charge e - Charge – Q – Negative vs. positive – Coulomb: 6.25x10 18 e – Coulombs law Current – Flow of charge (electrons and electron holes) – I=dQ/dt 3

4
Field, potential and voltage Electric field – Force exerted on electric charge Electric potential Voltage: difference in potential – Ground (Gnd): 0 Volt – Supply voltage: 1.2-5 Volt for modern integrated circuits Current flows from high potential to low – How about electrons? 4

5
Resistance and Ohms Law Opposition to the passage of a steady current – Conductor (e.g. metal) has negligible resistance – Insulator (e.g. plastic) has negligible passage – Semiconductor (silicon) Ohms Law – I=V/R or R=V/I R=ρL/A 5

6
Resistance is everywhere 6

7
Resistor Axial lead resistors 7

8
Voltage divider 8 Vdd Gnd R2 R1 V=Vdd*R2/(R1+R2)

9
Capacitor Charge holder Capacitance (capability to hold charge) – Charge per volt 9 + - V C=Q/V

10
Capacitance is everywhere 10

11
Energy and power consumption 11 V Gnd R P=E/T =V*I =V 2 /R E=V*Q =V*I*T=V*(V/R)*T =V 2 *T/R

12
Energy and power consumption 12 V Gnd C Q=C*V + - Gnd C E=0.5*Q*V =0.5*C*V 2

13
13 Are resistors and capacitors enough? R=V/I C=Q/V Computing is about state Change Communication Storage

14
Think about a simple computer 14 Binary states for input and output: HIGH or LOW (1 or 0) How many different computers are there? 1)In=0 Out=0; In=1 Out=0 2)In=0 Out=1; In=1 Out=0 3)In=0 Out=0; In=1 Out=1 4)In=0 Out=1; In=1 Out=1 Can resistors and capacitors build them? How can we build 2)? In Out

15
How can we build an inverter? 15 In Out

16
16 Switch

17
Switch-based inverter 17 In Out Vdd Gnd

18
Lab: LED 18

19
What can one do with breadboard? 19 Breadboard prototype of the first IBM PC motherboard (1981) http://www.yourdictionary.com/computer/breadboard

20
Metal-Oxide-Semiconductor FET (MOSFET) Polysilicon Aluminum

21
MOSFET state 21

22
Controllable resistor 22 Gate control NMOS: resistance increases as gate voltage decreases Gate control PMOS: resistance increases as gate voltage increase Drain Source Drain

23
Controllable switch Change a state Communicate a state Store a state 23 Gate NMOS:ON with HIGH gate PMOS:ON with LOW gate

24
Change a state 24 Vdd Gnd Input Output Resistor LOW HIGH ?

25
Change a state (Contd.) 25 Vdd Gnd Input Output LOW HIGH Vdd Gnd Input Output Resistor LOW HIGH ? Resistor

26
Lab: NMOS and PMOS inverters 26

27
Whats wrong? 27 Vdd Gnd Input Output LOW HIGH Vdd Gnd Input Output Resistor LOW HIGH Resistor

28
Complementary MOS (CMOS) 28

29
Lab: CMOS inverter 29

30
Power consumption of Inverter Dynamic power – Remember capacitance is everywhere Static power 30

31
Delay of Inverter Capacitance and resistance are everywhere 31

32
A memory cell 32 Read/write Gnd Select

Similar presentations

Presentation is loading. Please wait....

OK

Introduction to CMOS VLSI Design Combinational Circuits

Introduction to CMOS VLSI Design Combinational Circuits

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google