lectures & resources - innovation fellows program · 2018-07-12 · combinations of boolean...

Innovation Fellows Program

Digital Circuits Prof. Steven S. Saliterman, http://saliterman.umn.edu/ Department of Biomedical Engineering, University of Minnesota

Prof. Steven S. Saliterman

Topics

CMOS Logic Designing with NI Multisim (SPICE) and Ultiboard Software Boolean Logic CMOS IC Packaging and Pinouts Various Devices and Circuits Schmitt triggers

Contact debouncing Simulation and elimination of noise; voltage summing Leading edge detection

Drivers for LEDs, lamps and relays AD and DA Converters


Microelectronics Revolution

Triode tube 1915 (Langmuir)

Point-contact transistor 1947, Bell Labs (Brattain and Bardeen).

Junction transistor 1948 (Shockley), IC 1958 (Kibly and Noyce),

& Intel Pentium Microprocessor 108 Transistors!


From Molten Silicon to IC Chips…

Single crystal silicon boule

Molten silicon - Czochralski puller technique

Silicon wafer diced into integrated circuits (DIP and SMD).


CMOS Logic

Complementary Metal Oxide Semiconductor Logic e.g. 4000B and 74HC00 series.

Inputs are open circuits and easy to drive. Almost no power supply current needed except during input logic

changes. Logic changes half-way up the power supply voltage, giving good

noise immunity (at least better than TTL). Wide range of power supply voltages, from 3 to 15 Vdc The unloaded output logic swings the full range of the power

supply. CMOS circuits create little noise of their own. CMOS circuits pass along less noise.


Design with NI Multisim


CMOS Packages & Pins

Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)


Inverter – 74HC04

Input Output High Low Low High

Notice the output is inverse to the input.


Available Logic Gates in the 74HC04…



If either or both inputs are low the output will be high.

NAND – 74HC00

Input 1 Input 2 Output

0 0 1 1 0 1 0 1 1 1 1 0




In addition to this NAND gate, there are many different types and combinations of Boolean logic gates to select from. These include AND, OR, NOR, Exclusive OR & NOR and others.


Flip-Flop – 74HC74

In this configuration, with each clock pulse, the output Q alternates between 1 and 0, effectively halving the clock frequency. (Ǭ is simply the complement – or opposite, of Q.)

𝑄𝑄

𝑄𝑄

Notice the divide by 2 of frequency.

Clock Output


4 Bit Binary Counter with Buffer Drivers …

20=1 21=2 22=4 23=8 “Place”




In addition to this D-Flip-Flop, there are also JK Flip-Flops


Counter on Breadboard…


Tri-State Logic – 74HC126


Schmitt Trigger – 74C14


Switch Contact Noise…

Thresholds are ~ 1.35 V for Low and 3.15 V for High

Mechanical contact noise can cause multiple pulses to occur the first 100 µS or so. In this example, three pulses would be generated.


Contact Debouncer – Schmitt Trigger…

Output

Input – Switch Off & On


Creating Noise with Voltage Summing…

Voltage Summing

Voltage Inverter


Noise Eliminator – Schmitt Trigger 4093B…

Input

Output

Input

Output

Voltage Follower

Summer


Leading Edge Detector – Schmitt Trigger…

Debounced button pushes

Single pulse with each positive edge


Available Logic Gates in the 74HC14 & 4093B …



One-and-only One Synchronized Pulse

Clock

Button

Output is a synchronized pulse with the clock, while the button push is not.


Driving LEDs – 4049B

The 4049 Inverter- Buffer can source or sink sufficient current to light the LED directly. For other CMOS logic you need to have a transistor. Certain devices, like counters, may have built in LED drivers.

Current sourcing.

Current sinking.

Push Button Debounce

𝑅𝑅1 𝑜𝑜𝑜𝑜 2 =𝑉𝑉𝐹𝐹𝐼𝐼𝐹𝐹


Available Logic Gates in the 4049B…



Lamp Driver with Transistor

Lamp is rated 5 V and power of 200 mW. Required current: 𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑊𝑊 = 𝐼𝐼2𝑅𝑅 = 𝑉𝑉𝐼𝐼 𝐼𝐼 = 𝑃𝑃𝑜𝑜𝑃𝑃𝑃𝑃𝑜𝑜𝑊𝑊

𝑉𝑉= 200 𝑚𝑚𝑊𝑊

5= 40 𝑚𝑚𝑚𝑚

The 2N2222 is a general purpose medium power amplifier and switch, for IC of up to 500 mA (max. 1 A).


MOSFET Relay Driver with Transient Suppression…

MOSFET is a transconductance device (base current is negligible, base voltage controls collector current). The MOSFET allows for higher collector current than the BJT.


Analog to Digital Converters

Analog to Digital Converters (ADC) Convert an analog signal – such as voltage, into a digital

signal. Resolution is the number of discrete values the

converter can produce over the range of the analog signal. For example, an 8-bit encoder can decode an analog value to 28, or 256 different values.

Sampling rate is subject to the Nyquist-Shannon sampling theorem. In simple terms, you must sample minimally at a rate twice that of the frequency in order to reproduce the original analog signal.


Digital to Analog Converters…

Digital to Analog Converters (DAC) Convert digital data into an analog signal, such

as voltage or current. Commonly used to reproduce music from CD to

amplifiers, speakers and headphones. The Arduino pins can be configured for

ADC and DAC. Dedicated ADC/DAC chips are available

from a number of manufacturers.


Summary

CMOS Logic Designing with NI Multisim (SPICE) and Ultiboard Software Boolean Logic CMOS IC Packaging and Pinouts Various Devices and Circuits Schmitt triggers

Contact debouncing Simulation and elimination of noise; voltage summing Leading edge detection

Drivers for LEDs, lamps and relays AD and DA Converters

lectures & resources - innovation fellows program · 2018-07-12 · combinations of boolean...

Documents