Chapter 11 Advanced Operational Amplifier applications  Electronic Integration  Electronic...

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Transcript of Chapter 11 Advanced Operational Amplifier applications  Electronic Integration  Electronic...

  • Slide 1
  • Chapter 11 Advanced Operational Amplifier applications Electronic Integration Electronic Differentiation Active Filters o Basic Filter Concepts o Active Filter Design o Low-Pass and High-Pass Filters o Frequency and Impedance Scaling o Normalized Low-Pass and High-Pass Filters o Bandpass and Band-Stop Filters
  • Slide 2
  • Chapter 11 Advanced Operational Amplifier applications Electronic Integration Electronic Differentiation Active Filters o Basic Filter Concepts o Active Filter Design o Low-Pass and High-Pass Filters o Frequency and Impedance Scaling o Normalized Low-Pass and High-Pass Filters o Bandpass and Band-Stop Filters
  • Slide 3
  • FIGURE 11-1 The output of the integrator at t seconds is the area Et under the input waveform Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. When the input to an integrator is a dc level, the output will rise linearly with time.
  • Slide 4
  • FIGURE 11-2 An ideal electronic integrator Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. i1i1 iCiC
  • Slide 5
  • FIGURE 11-3 (Example 11-1) Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Example 11-1 1.Find the peak value of the output of the ideal integrator. The input is v i = 0.5 sin(100t)V. 2.Repeat, when v i = 0.5 sin(10 3 t)V
  • Slide 6
  • FIGURE 11-4 Bode plot of the gain of an ideal integrator for the R 1 C = 0.001 Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 7
  • FIGURE 11-5 Allowable region of operation for an op-amp integrator Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 8
  • FIGURE 11-6(a) A resistor R f connected in parallel with C causes the practical integrator to behave like an inverting amplifier to dc inputs and like an integrator to high-frequency ac inputs Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Practical Integrators
  • Slide 9
  • FIGURE 11-6(b) Bode plot for the practical or ac integrator, showing that integration occurs at frequencies well above 1 / (2 R f C) Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. X c = f c
  • Slide 10
  • FIGURE 11-7 (Example 11-2) Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Example 11-2 Design a practical integrator that 1.Integrates signals with frequencies down to 100 Hz, 2.Produces a peak output of 0.1 V when the input is a 10-V-Peak sine wave having frequency 10 kHz, and 3.Find the dc component in the output when there is a +50-mV dc input.
  • Slide 11
  • FIGURE 11-8 A three-input integrator Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 12
  • Chapter 11 Advanced Operational Amplifier applications Electronic Integration Electronic Differentiation Active Filters o Basic Filter Concepts o Active Filter Design o Low-Pass and High-Pass Filters o Frequency and Impedance Scaling o Normalized Low-Pass and High-Pass Filters o Bandpass and Band-Stop Filters
  • Slide 13
  • FIGURE 11-9 The ideal electronic differentiator produces an output equal to the rate of change of the input. Because the rate of change of a ramp is constant, the output in this example is a dc level. Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 14
  • FIGURE 11-10 An ideal electronic differentiator Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. ifif iCiC
  • Slide 15
  • FIGURE 11-11 A practical differentiator. Differentiation occurs at low frequencies, but resistor R 1 prevent high-frequency differentiation Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 16
  • FIGURE 11-12 Bode plots for the ideal and practical differentiators. f b is the break frequency due to the input R 1 - C combination and f 2 is the upper cutoff frequency of the (closed-loop) amplifier. Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 17
  • FIGURE 11-13 (Example 11-3) Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Example 11-3 1. Design a practical differentiator that will differentiator that will differentiate signals with frequencies up to 200 Hz. The gain at 10 Hz should be 0.1. 2. If the op-amp used in the design has a unity-gain frequency of 1 MHz, what is the upper cutoff frequency of the differentiator?
  • Slide 18
  • FIGURE 11-14 (Example 11-3) Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 19
  • Chapter 11 Advanced Operational Amplifier applications Electronic Integration Electronic Differentiation Active Filters o Basic Filter Concepts o Active Filter Design o Low-Pass and High-Pass Filters o Frequency and Impedance Scaling o Normalized Low-Pass and High-Pass Filters o Bandpass and Band-Stop Filters
  • Slide 20
  • FIGURE 11-29 Ideal and practical frequency responses of some commonly used filter types Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 21
  • FIGURE 11-30 Frequency response of low-pass and high-pass Butterworth filters with different orders Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Filters are classified by their order, an integer number n, also called the number of poles. In general, the higher the order of a filter, the more closely it approximates an ideal filter and the more complex the circuitry required to construct it. The frequency response outside the passband of a filter of order n has a slope that is asymptotic to 20n dB/decade. Filters are also classified as belonging to one of several specific design types that affect their response characteristics within and outside of their pass bands.
  • Slide 22
  • FIGURE 11-31 Chebyshev low-pass frequency response: f 2 = cutoff frequency; RW = ripple width Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 23
  • FIGURE 11-32 Comparison of the frequency responses of second- order, low-pass Butterworth and Chebyshev filters Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 24
  • FIGURE 11-33 Comparison of the frequency responses of low-Q and high-Q bandpass filters Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 25
  • FIGURE 11-34 Block diagram of a second-order, VCVS low-pass or high-pass filter. It is also called a Sallen-Key filter. Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. + - ZAZA ZDZD ZCZC ZBZB Low-Pass FilterRRCC High-Pass FilterCCRR
  • Slide 26
  • FIGURE 11-35 General low-pass filter structure; even-ordered filters do not use the first stage Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 27
  • FIGURE 11-36 General high-pass filter structure; even-ordered filters do not use the first stage Bogart/Beasley/Rico Electronic Devices and Circuits, 6e Copyright 2004 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved.
  • Slide 28
  • Example 11-9 Design a third-order, low-pass Butterworth filter for a cutoff frequency of 2.5 kHz. Select R = 10 k. Example 11-10 Design a unity-gain, fourth-order, high-pass Chebyshev filter with 2-dB ripple for a cutoff frequency of 800 kHz. Select C = 100 nF. Example 11-11 A certain normalized low-pass filter from a handbook