1 / 41

ESE 232 Introduction to Electronic Circuits Professor Paul Min psm@wustl (314) 853-6200

ESE 232 Introduction to Electronic Circuits Professor Paul Min psm@wustl.edu (314) 853-6200 Bryan Hall 302A. Chapter 1. Signals and Amplifiers. Microelectronics Integrated circuit technology Billions of components Typically implement in silicon wafer < 100 mm 2

leigh-pratt
Download Presentation

ESE 232 Introduction to Electronic Circuits Professor Paul Min psm@wustl (314) 853-6200

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ESE 232 Introduction to Electronic Circuits Professor Paul Min psm@wustl.edu (314) 853-6200 Bryan Hall 302A

  2. Chapter 1. Signals and Amplifiers

  3. Microelectronics • Integrated circuit technology • Billions of components • Typically implement in silicon wafer < 100 mm2 • Examples: microprocessors, memories, logic chips • ESE 232 • Study of microelectronics • Analysis and design • Functional circuits

  4. Electrical circuits • Processes signals • Driven by power sources (voltage or current) • At every point in a circuit, voltage and current are defined. vs(t) = Rs is(t) Signal (or power) represented in voltage (Thevenin form) Signal (or power) represented in current (Norton form) Equivalent and translatable

  5. Signals • Contain time-varying information. • Exist in various forms (mechanical, electrical, chemical, acoustical, etc.) • Can be conveniently processed by electrical circuits. • Converting non-electrical signal to electrical signal is done by transducer (or sensor).

  6. Frequency Spectrum of Signals • Often difficult to express signals in time (in mathematical form). • Signals can be shown in frequency spectrum: Fourier series, Fourier transform, Z-transform, etc. → At what frequencies does the signal contain energy and by how much?

  7. Fourier Series • Example: • sine-wave va(t) = Va sin wt • va(t) has all its energy at the angular frequency of w = 2πf. • f is frequency in Hz. T = 1/f is period in seconds. • Magnitude of this sine-wave at the angular frequency w is Va.

  8. Example: square-wave Time expression w0= 2π/T Frequency expression

  9. Frequency Allocations in the U.S.A.

  10. Digital v. Analog • Analog signal: continuous value, continuous time • Digital signal: discrete value, discrete time Sample Quantize Analog Signal Digital Signal Continuous time Continuous value Discrete time Continuous value Discrete time Discrete value

  11. Less expensive circuits Privacy and security Small signals (less power) Converged multimedia Error correction and reduction Why Digital? Why Not Digital? • More bandwidth • Synchronization in electrical circuits • Approximated information

  12. Notation • Total instantaneous quantities: lowercase symbols with uppercase subscripts (e.g., iC) • dc quantities: uppercase symbols with upper case subscripts (e.g., IC) • Power supply voltages: uppercase V’s with double letter uppercase subscripts (e.g., VEE) • dc currents draw from power supply: uppercase I’s with double letter uppercase subscripts (e.g., ICC) • Incremental signal quantities: lowercase symbols with lower case subscripts (e.g., ic)

  13. Amplifiers • Amplification of input signal • Linear amplifier: vo(t) = Avi(t) (A: constant gain) • Voltage amplifier: changes input signal amplitude • Av= voltage gain = vo / vi • Preamplifier: shaping in frequency (i.e., amplifies different frequency components differently). • Power amplifier: gains in voltage and current symbols

  14. Transfer Characteristic

  15. Power Supplies

  16. Amplifier Saturation maximum output minimum output

  17. Nonlinear Transfer Characteristics and Biasing • To avoid saturation, input signal should be shifted. → Biasing • Input signals are biased to operate in the middle of linear region.

  18. Circuit Models for Voltage Amplifiers

  19. High Riwith gain 10 (Signal may be small.) Modest Riwith gain 100 (Provide gain.) Small Riwith gain 1 (Buffer output for next stage.)

  20. BJT

  21. Low pass RC circuit No distortion means constant amplitude gain and linear phase shift.

  22. High pass RC circuit No distortion means constant amplitude gain and linear phase shift.

  23. constant Function of s

  24. Logic Inverter Nonlinear (saturation) region for digital binary logic operation Linear region for ordinary amplifier operation (transition region) • Transfer function • high vi(> 0.690V) → low vo (≈ 0.3V) • low vi (≈ 0V)→ high vo (≈ VDD) • linear region for mid value of vi • Circuit symbol • input 1 (high) → out put 0 (low) • input 0 (low) → out put 1 (high)

  25. Noise Margin • For cascaded inverters • Noise margin for high input • NMH = VOH - VIH • Noise margin for low input • NML = VIL - VOL

  26. Ideal Inverter NMH = NML =VDD / 2

  27. Abstract Implementation of Inverter voltage controlled switch. When vI is low, switch is open, leaving the vertical path disconnected. → vo = VDD is an open circuit voltage. When vI is high, switch connects the vertical path. → vois a low level voltage determined largely by Voffset, a characteristic of the voltage controlled switch. (Ron is typically small.)

  28. Propagation Delay • Change of output after input change is not instantaneous. • Internal capacitance of devices causes the delay.

More Related