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Páginas: 6 (1352 palabras)
Publicado: 27 de octubre de 2010
Diodos Di d
1
EL DIODO IDEAL
Símbolo Eléctrico
Curva Característica i-v
Circuitos Equivalentes
Directa
Microelectronic Circuits - Fifth Edition Sedra/Smith
Inversa
Copyright © 2004 by Oxford University Press, Inc. 2
MODOS DE OPERACIÓN DEL DIODO IDEAL
Usadas para limitar la corriente sobre el diodo p
Directa
Inversa
Figure 3.2 The two modes of operation of idealdiodes and the use of an external circuit to limit the forward current (a) and the reverse voltage (b).
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 3
EL DIODO COMO RECTIFICADOR
Circuito Entrada
Modelo Equivalente Salida
El circuito se comporta como un rectificador de media onda
Microelectronic Circuits - Fifth EditionSedra/Smith Copyright © 2004 by Oxford University Press, Inc. 4
EL DIODO COMO RECTIFICADOR
Por lo tanto, la función de transferencia característica v0 vs vi corresponde a: d
Voltaje a través del diodo (vD )
El diodo sólo conduce durante los ciclos positivos de vi, es decir,
vi > 0
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 5 Ejercicio
Para el circuito de carga de batería presentado, encuentre la fracción de cada ciclo en la cual el diodo conduce?
vs= 2 24sin ωt
Cuando vs= 12? vs= 24sin ωt = 12 ωt = 30º Entonces, θ = 90º- 30º = 60º Por lo tanto, la fracción en cada ciclo es 2θ = 120º.
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 6
EL DIODO COMODISPOSITIVO LÓGICO Compuerta OR Compuerta AND
Y=A+B+C
Y=A*B*C
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press, Inc.
7
ANÁLISIS DE CIRCUITOS CON DIODOS
Mecanismo Se supone el comportamiento (activa o inversa) del diodo y se verifica la consistencia de los resultados. Se pide calcular I y V para el siguiente circuito: Hay 4 opciones: 1. 1Ambos diodos conducen 2. Ningún diodo conduce 3. Solo conduce D1 4. Solo 4 S l conduce D2 d
Rta. I=0 y V=3.3 V.
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press, Inc.
8
Ejercicios
Encontrar I y V para los siguientes circuitos:
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press,Inc.
9
CURVA CARACTERÍSTICA DE UN DIODO Se distinguen tres regiones de operación:
• • • Forward (Activa) v>0 → Reverse (Inversa) v 0 v IS. The junction breaks down, and a voltage VZ , with the polarity indicated, develops across the junction.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 62
Figure 3.49 The pn junctionexcited by a constant-current source supplying a current I in the forward direction. The depletion layer narrows and the barrier voltage decreases by V volts, which appears as an external voltage in the forward direction.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 63
Figure 3.50 Minority-carrier distribution in aforward-biased pn junction. It is assumed that the p region is more heavily doped than the n region; NA @ ND.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 64
Figure 3.51 The SPICE diode model.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 65
Figure 3.52Equivalent-circuit model used to simulate the zener diode in SPICE. Diode D1 is ideal and can be approximated in SPICE by using a very small value for n (say n = 0.01).
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 66
Figure 3.53 Capture schematic of the 5-V dc power supply in Example 3.10.
Imágenes: Microelectronic Circuits - Fifth...
1
EL DIODO IDEAL
Símbolo Eléctrico
Curva Característica i-v
Circuitos Equivalentes
Directa
Microelectronic Circuits - Fifth Edition Sedra/Smith
Inversa
Copyright © 2004 by Oxford University Press, Inc. 2
MODOS DE OPERACIÓN DEL DIODO IDEAL
Usadas para limitar la corriente sobre el diodo p
Directa
Inversa
Figure 3.2 The two modes of operation of idealdiodes and the use of an external circuit to limit the forward current (a) and the reverse voltage (b).
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 3
EL DIODO COMO RECTIFICADOR
Circuito Entrada
Modelo Equivalente Salida
El circuito se comporta como un rectificador de media onda
Microelectronic Circuits - Fifth EditionSedra/Smith Copyright © 2004 by Oxford University Press, Inc. 4
EL DIODO COMO RECTIFICADOR
Por lo tanto, la función de transferencia característica v0 vs vi corresponde a: d
Voltaje a través del diodo (vD )
El diodo sólo conduce durante los ciclos positivos de vi, es decir,
vi > 0
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 5 Ejercicio
Para el circuito de carga de batería presentado, encuentre la fracción de cada ciclo en la cual el diodo conduce?
vs= 2 24sin ωt
Cuando vs= 12? vs= 24sin ωt = 12 ωt = 30º Entonces, θ = 90º- 30º = 60º Por lo tanto, la fracción en cada ciclo es 2θ = 120º.
Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 6
EL DIODO COMODISPOSITIVO LÓGICO Compuerta OR Compuerta AND
Y=A+B+C
Y=A*B*C
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press, Inc.
7
ANÁLISIS DE CIRCUITOS CON DIODOS
Mecanismo Se supone el comportamiento (activa o inversa) del diodo y se verifica la consistencia de los resultados. Se pide calcular I y V para el siguiente circuito: Hay 4 opciones: 1. 1Ambos diodos conducen 2. Ningún diodo conduce 3. Solo conduce D1 4. Solo 4 S l conduce D2 d
Rta. I=0 y V=3.3 V.
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press, Inc.
8
Ejercicios
Encontrar I y V para los siguientes circuitos:
Microelectronic Circuits - Fifth Edition
Sedra/Smith
Copyright © 2004 by Oxford University Press,Inc.
9
CURVA CARACTERÍSTICA DE UN DIODO Se distinguen tres regiones de operación:
• • • Forward (Activa) v>0 → Reverse (Inversa) v 0 v IS. The junction breaks down, and a voltage VZ , with the polarity indicated, develops across the junction.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 62
Figure 3.49 The pn junctionexcited by a constant-current source supplying a current I in the forward direction. The depletion layer narrows and the barrier voltage decreases by V volts, which appears as an external voltage in the forward direction.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 63
Figure 3.50 Minority-carrier distribution in aforward-biased pn junction. It is assumed that the p region is more heavily doped than the n region; NA @ ND.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 64
Figure 3.51 The SPICE diode model.
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 65
Figure 3.52Equivalent-circuit model used to simulate the zener diode in SPICE. Diode D1 is ideal and can be approximated in SPICE by using a very small value for n (say n = 0.01).
Imágenes: Microelectronic Circuits - Fifth Edition Sedra/Smith Copyright © 2004 by Oxford University Press, Inc. 66
Figure 3.53 Capture schematic of the 5-V dc power supply in Example 3.10.
Imágenes: Microelectronic Circuits - Fifth...
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