lectures & resources - innovation fellows program · 2018-07-12 · combinations of boolean...
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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
Prof. Steven S. Saliterman
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!
Prof. Steven S. Saliterman
From Molten Silicon to IC Chips…
Single crystal silicon boule
Molten silicon - Czochralski puller technique
Silicon wafer diced into integrated circuits (DIP and SMD).
Prof. Steven S. Saliterman
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.
Prof. Steven S. Saliterman
Design with NI Multisim
Prof. Steven S. Saliterman
CMOS Packages & Pins
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
Prof. Steven S. Saliterman
Inverter – 74HC04
Input Output High Low Low High
Notice the output is inverse to the input.
Prof. Steven S. Saliterman
Available Logic Gates in the 74HC04…
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
Prof. Steven S. Saliterman
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
Prof. Steven S. Saliterman
Available Logic Gates in the 74HC00…
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
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.
Prof. Steven S. Saliterman
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
Prof. Steven S. Saliterman
4 Bit Binary Counter with Buffer Drivers …
20=1 21=2 22=4 23=8 “Place”
Prof. Steven S. Saliterman
Available Logic Gates in the 74HC74…
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
In addition to this D-Flip-Flop, there are also JK Flip-Flops
Prof. Steven S. Saliterman
Counter on Breadboard…
Prof. Steven S. Saliterman
Tri-State Logic – 74HC126
Prof. Steven S. Saliterman
Available Logic Gates in the 74HC126…
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
Prof. Steven S. Saliterman
Schmitt Trigger – 74C14
Prof. Steven S. Saliterman
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.
Prof. Steven S. Saliterman
Contact Debouncer – Schmitt Trigger…
Output
Input – Switch Off & On
Prof. Steven S. Saliterman
Creating Noise with Voltage Summing…
Voltage Summing
Voltage Inverter
Prof. Steven S. Saliterman
Noise Eliminator – Schmitt Trigger 4093B…
Input
Output
Input
Output
Voltage Follower
Summer
Prof. Steven S. Saliterman
Leading Edge Detector – Schmitt Trigger…
Debounced button pushes
Single pulse with each positive edge
Prof. Steven S. Saliterman
Available Logic Gates in the 74HC14 & 4093B …
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
Prof. Steven S. Saliterman
One-and-only One Synchronized Pulse
Clock
Button
Output is a synchronized pulse with the clock, while the button push is not.
Prof. Steven S. Saliterman
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
Prof. Steven S. Saliterman
Available Logic Gates in the 4049B…
Lancaster, D. and Berlin, H.M. CMOS Cookbook. H.W. Sams, Indianapolis, IN (1988)
Prof. Steven S. Saliterman
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).
Prof. Steven S. Saliterman
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.
Prof. Steven S. Saliterman
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.
Prof. Steven S. Saliterman
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.
Prof. Steven S. Saliterman
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