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Feedback PowerPoint Presentation

Feedback

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  1. Feedback

  2. Feedback Concepts

  3. Expresion General de Circuitos Retroalimentados

  4. Efectos de la Retroalimentación Negativa

  5. Bandwidth with Feedback Effect of feedback on (a) the pole location and (b) the frequency response of an amplifier having a single-pole open-loop response.

  6. Gain Stability with Feedback Gain calculations with feedback are often based on external resistive elements in the circuit. By removing gain calculations away from internal variations of  and gm, the gain becomes more stable.

  7. Amplifier Types • Voltaje Amplifier • Current Amplifier • Transconductance Amplifier • Transresistance Amplifier

  8. Característica del Puerto de un Amplificador (Variable Voltaje)

  9. Característica del Puerto de un Amplificador (Variable Corriente)

  10. Feedback Connection Types 1. Voltaje Amplifier(series–shunt) voltage-mixing voltage-sampling topology. 2.Current Amplifier(shunt–series) current-mixing current-sampling topology 3.Transconductance Amplifier(series–series) voltage-mixing current-sampling topology 4. Transresistance Amplifier(shunt–shunt) current-mixing voltage-sampling topology

  11. The Four Basic Feedback Topologies • Voltage-mixing voltage-sampling (series–shunt) topology. • Current-mixing current-sampling (shunt–series) topology. • Voltage-mixing current-sampling (series–series) topology. • Current-mixing voltage-sampling (shunt–shunt) topology.

  12. Series-Shunt Feedback Voltaje Amplifier (b) Equivalent Circuit. (a) Ideal Structure

  13. 1. Series-Shunt Feedback Voltaje Amplifier Measuring the Output Resistance of the Series-Shunt Feedback Amplifier Rof : Vt/I.

  14. 1. Series-Shunt Feedback Voltaje Amplifier Derivation of the A circuit and b circuit for the series–shunt feedback amplifier. (a) Block diagram of a practical series–shunt feedback amplifier. (b) The circuit in (a) with the feedback network represented by its h parameters.

  15. Series-Shunt Feedback Voltaje Amplifier

  16. Summary of the rules for finding the A circuit and b for the voltage-mixing voltage-sampling case • Series-Shunt Feedback (Voltaje amplifier)

  17. Series-Shunt Feedback (Voltaje amplifier)

  18. Example 1 Series-Shunt Feedback -Voltaje Amplifier

  19. Example 1 Series-Shunt Feedback -Voltaje Amplifier

  20. Example 1Series-Shunt Feedback -Voltaje Amplifier

  21. Ganancia del Amplificador retroalimentado Af

  22. Resistencia de entrada real del amplificador

  23. Resistencia de salida real del amplificador

  24. Example 2Series-Shunt Feedback - Voltaje Amplifier

  25. 2. Series-Series FeedbackTransconductanceAmplifier (a) Ideal Structure (b) Equivalent Circuit.

  26. 2. Series-Series Feedback Transconductance Amplifier Measuring the Output Resistance of the Series-Series Feedback Amplifier Rof : Vt/I.

  27. 2. Series-Series Feedback Transconductance Amplifier Derivation of the A circuit and b circuit for the series–series feedback amplifier. (a) Block diagram of a practical series–series feedback amplifier. (b) The circuit in (a) with the feedback network represented by its h parameters.

  28. 2. Series-Series Feedback Transconductance Amplifier

  29. 2. Series-Series Feedback transconductance Amplifier Summary of the rules for finding the A circuit and b for the voltage-mixing current-sampling (series–series) case

  30. 2. Series-Series Feedback transconductance Amplifier

  31. Example 2Series-Series Feedback Transconductance Amplifier

  32. Example 1Series-Series Feedback Transconductance Amplifier

  33. Example 2Series-Series Feedback Transconductance Amplifier Some of the output current is directed back in series with the input. Example using a BJT: Feedback gain (Af):

  34. 3. Shunt-Shunt Feedback Transresistance Amplifier Ideal Structure

  35. 3. Shunt-Shunt Feedback Transresistance Amplifier Block diagram for a practical shunt–shunt feedback amplifier.

  36. 3. Shunt-Shunt Feedback Transresistance Amplifier Summary of the rules for finding the A circuit and b for the current-mixing voltage-sampling (Shunt-Shunt) case.

  37. Example 1Shunt-Shunt Feedback Transresistance Amplifier

  38. Example 1Shunt-Shunt Feedback Transresistance Amplifier

  39. Example 2Shunt-Shunt Feedback Transresistance Amplifier The output voltage is fed back in parallel with the input. Example of an op-Amp circuit: Feedback gain (Af):

  40. 4. Shunt-Series Feedback Current Amplifier Ideal Structure

  41. 4. Shunt-Series Feedback Current Amplifier Block diagram for a practical shunt–shunt feedback amplifier.

  42. 4. Shunt-Series Feedback Current Amplifier Summary of the rules for finding the A circuit and b for the current-mixing current-sampling (shunt–series) case.

  43. Example 1Shunt-Series Feedback - Current Amplifier

  44. Example 1Shunt-Series Feedback - Current Amplifier

  45. Example 1Shunt-Series Feedback - Current Amplifier

  46. Example 2Shunt-Series Feedback - Current Amplifier

  47. A. Voltage A. Transconductance A. Transresistance A. Current Summary of Each Type of Feedback and the Effects on Impedance

  48. A. Voltage A. Transconductance A. Transresistance A. Current Summary of Each Type of Feedback and the Effects on Gain