1 / 13

Bipolar Junction Transistor Analysis and Ebers-Moll Model

This announcement discusses the analysis of Bipolar Junction Transistors and introduces the Ebers-Moll model. Topics include diffusion equations, terminal currents, simplifications, BJT performance parameters, and the Ebers-Moll model in both active and saturation regions. Lecture slides are provided.

steil
Download Presentation

Bipolar Junction Transistor Analysis and Ebers-Moll Model

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. HW#8 ANNOUNCEMENTS Start Problem 4 early! Note that Problem 3f has been revised OUTLINE The Bipolar Junction Transistor Ideal Transistor Analysis Ebers-Moll model Reading: Chapter 11.1 Lecture #24 EE130 Lecture 24, Slide 1

  2. Diffusion equation: General solution: Boundary conditions: Solution: Emitter Region Solution EE130 Lecture 24, Slide 2

  3. Collector Region Solution • Diffusion equation: • General solution: • Boundary conditions: • Solution: EE130 Lecture 24, Slide 3

  4. Base Region Solution • Diffusion equation: • General solution: • Boundary conditions: • Solution: EE130 Lecture 24, Slide 4

  5. Since we can write as EE130 Lecture 24, Slide 5

  6. EE130 Lecture 24, Slide 6

  7. We know: Therefore: Terminal Currents EE130 Lecture 24, Slide 7

  8. In real BJTs, we make W << LB to achieve high current gain. Then, since we have: Simplification EE130 Lecture 24, Slide 8

  9. BJT Performance Parameters • Assumptions: • emitter junction forward biased, collector junction reverse biased • W << LB EE130 Lecture 24, Slide 9

  10. BJT with Narrow Emitter Replace with WE’ if short emitter EE130 Lecture 24, Slide 10

  11. Ebers-Moll Model increasing The Ebers-Moll model is a large-signal equivalent circuit which describes both the active and saturation regions of BJT operation. EE130 Lecture 24, Slide 11

  12. V V EB CB I B E B C I C If only VEB is applied (VCB = 0): aR : reverse common base gain aF : forward common base gain If only VCBis applied (VEB = 0): : Reciprocity relationship: EE130 Lecture 24, Slide 12

  13. In the general case, both VEB and VCB are non-zero: IC: C-B diode current + fraction of E-B diode current that makes it to the C-B junction IE: E-B diode current + fraction of C-B diode current that makes it to the E-B junction Large-signal equivalent circuit for a pnp BJT EE130 Lecture 24, Slide 13

More Related