me 6405 introduction to mechatronics operational amplifiers chris nygren matt livianu brad schwagler
TRANSCRIPT
![Page 1: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/1.jpg)
ME 6405 Introduction to Mechatronics
Operational Amplifiers
Chris Nygren
Matt Livianu
Brad Schwagler
![Page 2: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/2.jpg)
ME 6405 Introduction to Mechatronics
Agenda• Introduction• Background• Amplifier Introduction• Basic Circuits Review• Characteristics of an Ideal Op Amp• Types of Op Amps• Practical Applications• Conclusion• Quiz
![Page 3: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/3.jpg)
ME 6405 Introduction to Mechatronics
Purpose
To introduce the Operational Amplifier by
providing background, functionality,
applications, and relevance to Mechatronics
class projects.
![Page 4: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/4.jpg)
ME 6405 Introduction to Mechatronics
Introduction
• Operational Amplifiers are represented both schematically and realistically below:– Active component!
![Page 5: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/5.jpg)
ME 6405 Introduction to Mechatronics
Background
• Originally invented in early 1940s using vacuum tube technology– Initial purpose was to execute math operations in analog
electronic calculating machines
• Shrunk in size with invention of transistor• Most now made on integrated circuit (IC)
– Only most demanding applications use discrete components
• Huge variety of applications, low cost, and ease of mass production make them extremely popular
![Page 6: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/6.jpg)
ME 6405 Introduction to Mechatronics
Amplifiers
• Differential Amplifier– Amplifies difference
between inputs
Single-ended Amplifier
![Page 7: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/7.jpg)
ME 6405 Introduction to Mechatronics
Operational Amplifier• Output gain high
– A ~= 106
• Tiny difference in the input voltages result in a very large output voltage– Output limited by supply
voltages
• Comparator– If V+>V-, Vout = HVS– If V+<V-, Vout = LVS– If V+=V-, Vout = 0V
![Page 8: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/8.jpg)
ME 6405 Introduction to Mechatronics
3-stage Op-Amp
![Page 9: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/9.jpg)
ME 6405 Introduction to Mechatronics
• Sensor signals are often too weak or too noisy– Op Amps ideally increase the signal amplitude
without affecting its other properties
Why are they useful?
![Page 10: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/10.jpg)
ME 6405 Introduction to Mechatronics
• Negative feedback leads to stable equilibrium
• Voltage follower (direct feedback)– If Vout = V- , then Vout ~ V+
Closed Loop Transfer Function
H(s) = A / (1 + AF)
When AF >> 1…
H(s) = 1 / F
Why are they useful?
Where: A = Op Amp Open Loop Gain
F = Feedback Loop Gain
![Page 11: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/11.jpg)
ME 6405 Introduction to Mechatronics
1. The output attempts to do whatever is necessary to make the voltage difference between the inputs zero.
2. The inputs draw no current.
![Page 12: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/12.jpg)
ME 6405 Introduction to Mechatronics
Basic Circuits Review
• Kirchoff’s Law– Voltage Law: The sum
of all the voltage drops around the loop = Vin
• Resistance (Ohms – Ω)– Series
– Parallel
V1 + V2 + V3 = Vin
![Page 13: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/13.jpg)
ME 6405 Introduction to Mechatronics
Basic Circuits Review
• Capacitance (Farad – F)– Series
– Parallel
• Inductance (Henry – H)– Series
– Parallel
![Page 14: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/14.jpg)
ME 6405 Introduction to Mechatronics
Ideal Op Amp
• Zin is infinite
• Zout is zero
• Amplification (Gain) Vout / Vin = ∞
• Unlimited bandwidth
• Vout = 0 when Voltage inputs = 0
![Page 15: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/15.jpg)
ME 6405 Introduction to Mechatronics
Ideal Op Amp
Ideal Op-Amp Typical Op-Amp
Input Resistance infinity 106 (bipolar)
109 - 1012 (FET)
Input Current 0 10-12 – 10-8 A
Output Resistance 0 100 – 1000
Operational Gain infinity 105 - 109
Common Mode Gain 0 10-5
Bandwidth infinity Attenuates and phases at high frequencies (depends on slew
rate)
Temperature independent Bandwidth and gain
![Page 16: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/16.jpg)
ME 6405 Introduction to Mechatronics
How are Op-Amps used?
• Comparator (seen earlier)
• Voltage follower (seen earlier)
• Signal Modulation
• Mathematical Operations
• Filters
• Voltage-Current signal conversion
![Page 17: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/17.jpg)
ME 6405 Introduction to Mechatronics
Non-inverting Op-Amp
Uses: Amplify…straight up
www.wikipedia.org
![Page 18: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/18.jpg)
ME 6405 Introduction to Mechatronics
Inverting Op-Amp
Uses: Analog inverter
www.wikipedia.org
![Page 19: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/19.jpg)
ME 6405 Introduction to Mechatronics
Comparator
www.allaboutcircuits.com
Uses: Low-voltage alarms, night light controller
V2
V1Vout
![Page 20: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/20.jpg)
ME 6405 Introduction to Mechatronics
Pulse Width Modulator
• Output changes when – Vin ~= Vpot
• Potentiometer used to vary duty cycle
www.allaboutcircuits.com Uses: Motor controllers
![Page 21: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/21.jpg)
ME 6405 Introduction to Mechatronics
Summation
Uses: Add multiple sensors inputs until a threshold is reached.
www.wikipedia.org
![Page 22: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/22.jpg)
ME 6405 Introduction to Mechatronics
Difference
1
31
124
4132
)( R
RV
RRR
RRRVVout
12 VVVout
If all resistors are equal:
![Page 23: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/23.jpg)
ME 6405 Introduction to Mechatronics
Integrating Op-Amp
Uses: PID Controller
www.wikipedia.org
![Page 24: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/24.jpg)
ME 6405 Introduction to Mechatronics
Differentiating Op-Amp
(where Vin and Vout are functions of time)
www.wikipedia.org
![Page 25: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/25.jpg)
ME 6405 Introduction to Mechatronics
Filters
• Decouple the low-pass RC filter from the load.
Uses: Simple audio. Remove frequencies over 20kHz (audible)
![Page 26: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/26.jpg)
ME 6405 Introduction to Mechatronics
Low-pass Filter (active)
• Cutoff frequency
• This works because the capacitor needs time to charge.
www.wikipedia.org
![Page 27: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/27.jpg)
ME 6405 Introduction to Mechatronics
High pass filter (active)
Band-pass filter cascades both high-pass and low-pass!
www.wikipedia.org
![Page 28: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/28.jpg)
ME 6405 Introduction to Mechatronics
Measuring current
• Current (I) better than voltage (V) for measurement– Voltage suffers losses due to resistances in path– Low impedance is better for resisting noise
• So how do we generate a constant current source?– Transconductance Amplifier
![Page 29: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/29.jpg)
ME 6405 Introduction to Mechatronics
Transconductance Amp
• Precision 250Ω resistor
• 1V / 250 Ω = 4mA• 5V / 250 Ω = 20mA
• RLoad doesn’t matter, just as long as op-amp has high enough voltage rails
Uses: - In: Sensors (temp, pressure, etc),
- Out : Radios (Variable Freq Osc)
www.allaboutcircuits.com
![Page 30: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/30.jpg)
ME 6405 Introduction to Mechatronics
Conclusions
• Op-Amps are often used for– Sensor amplification– Mathematical operations (sums, difference,
inverse)– Filters (High/Low/Band pass)– Measurement devices
• Current in –> Voltage out
![Page 31: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/31.jpg)
ME 6405 Introduction to Mechatronics
Questions?
• Does an Op-Amp amplify current or voltage?• Can you use an Op-Amp as a buffer? If so,
How?• Why should you care about the device
bandwidth rating?• What is the most common Op Amp chip?• What is an ‘active’ component? Is an Op Amp
an active or a passive component?• What is the advantage of an active vs. passive
filter?
![Page 32: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/32.jpg)
ME 6405 Introduction to Mechatronics
Practical Tips
• Try to use single supply op-amps in order to minimize need for a 10V difference from power supply
• Good low resistance, twisted, and shielded wire should be used when a sensor is located far away from the op-amp circuit.
• Minimize current draw in sensor circuits to reduce thermal drift• Filter power into op-amp circuits using capacitors• Design op-amp circuits so output cannot be negative in order to
protect 68HC11 A/D port.• Isolate op-amp circuit output with unity gain op-amp if connected to
an actuator.• Make sure bandwidth of op-amp is adequate• Use trimmer potentiometers to balance resistors in differential op-amp
circuits• Samples of op-amps can be obtained from National Semiconductor
(http://www.national.com)
![Page 33: ME 6405 Introduction to Mechatronics Operational Amplifiers Chris Nygren Matt Livianu Brad Schwagler](https://reader030.vdocuments.site/reader030/viewer/2022033106/56649d845503460f94a6a3d5/html5/thumbnails/33.jpg)
ME 6405 Introduction to Mechatronics
Bibliography
• “Mechatronics”, Sabri Cetinkunt
• Wikipedia.org
• Allaboutelectronics.com