Lecture 14. P-N Junction Diodes: Part 3 Quantitative Analysis (Math, math and more math) Reading: Pierret 6.1

Transcription

1 Lctur 4 - ucto ods art 3 Quattatv alyss Math, math ad mor math Radg rrt 6. Gorga Tch ECE r. la oolttl

2 Quattatv - od Soluto ssumtos stady stat codtos o- dgrat dog 3 o- dmsoal aalyss 4 low- lvl jcto 5 o lght G L 0 Quas-utral Rgos Currt quatos -ty -ty q µ E q d/d q µ E - q d/d lto Rgo V Gorga Tch ECE r. la oolttl

3 ECE r. la oolttl Gorga Tch -ty -ty Quattatv - od Soluto lto Rgo L G t τ τ L G t τ τ 0 Sc lctrc flds st th dlto rgo, th morty carrr dffuso quato dos ot aly hr. lcato of th Morty Carrr ffuso Equato 0 Codto Boudary? Codto Boudary? Codto Boudary 0 Codto Boudary E 0 0 E 0 E

4 ECE r. la oolttl Gorga Tch -ty -ty Quattatv - od Soluto lto Rgo - lcato of th Morty Carrr ffuso Equato? Codto Boudary? Codto Boudary E 0 0 E 0 E o E E at smlarly ad ad

5 ECE r. la oolttl Gorga Tch -ty -ty Quattatv - od Soluto lto Rgo - lcato of th Morty Carrr ffuso Equato? Codto Boudary? Codto Boudary E 0 0 E 0 E o E E at smlarly ad ad

6 Quattatv - od Soluto -ty lto Rgo - lcato of th Currt Cotuty Equato -ty E 0 E 0 E 0 q µ Ε d o q d d q d d d? d q µ Ε d d o q d d q d Gorga Tch ECE r. la oolttl

7 Quattatv - od Soluto Gorga Tch -ty lto Rgo -ty E 0 E 0 E 0 - lcato of th Currt Cotuty Equato lto Rgo t t q q t t RcombatoGrato 0 q 0 q o thrmal rcombato ad grato mls ad ar costat throughout th dlto rgo. Thus, th total currt ca b df trms of oly th currt at th dlto rgo dgs. RcombatoGrato 0 q 0 q t t ll othr rocsss such as lght, tc... ll othr rocsss such as lght, tc... ECE r. la oolttl

8 Quattatv - od Soluto -ty lto Rgo roach 0 -ty E 0 E 0 E 0 0 Solv morty carrr dffuso quato quas-utral rgos trm morty carrr currts from cotuty quato Evaluat currts at th dlto rgo dgs dd ths togthr ad multly by ara to dtrm th total currt through th dvc. Us traslatd as, ad - our soluto. Gorga Tch ECE r. la oolttl

9 Quattatv - od Soluto -ty lto Rgo -ty E 0 E 0 E ' ' '/ L ' / L 0 B τ whr L τ Boudary Codtos ' 0 ' 0 B 0 ad ' 0 ' '/ L for ' 0 Gorga Tch ECE r. la oolttl

10 Quattatv - od Soluto -ty lto Rgo -ty E 0 E 0 E ' '/ L for ' 0 q d d q L '/ L for ' 0 Gorga Tch ECE r. la oolttl

11 Quattatv - od Soluto -ty lto Rgo -ty E 0 E 0 E 0 0 Smlarly for lctros o th -sd 0 '' ''/ L for '' 0 q d d q L ''/ L for '' 0 Gorga Tch ECE r. la oolttl

12 Quattatv - od Soluto -ty lto Rgo -ty E 0 E 0 E Total o currt s costat throughout th dvc. Thus, w ca charactrz th currt flow comots as ''/ L Rcombato '/ L Rcombato Gorga Tch ECE r. la oolttl

13 Quattatv - od Soluto Thus, valuatg th currt comots at th dlto rgo dgs, w hav '' 0 ' 0 '' 0 '' 0 ' 0 ' 0 I I q L o I o L or for all whr Io q L L s th " rvrs saturato currt" ot Vrf from our rvous qualtatv aalyss quato s th thrmal voltag, /q Gorga Tch ECE r. la oolttl

14 Quattatv - od Soluto Eamls od a crcut I V IR R000 ohms V9V, 5V, V, -9V V Gorga Tch V I or 9V 9V I000 V 9V 9 V 0.059V 0.059V V 0.059V V 000 V 9V 5V V V -9V I rvrs bas V <0 th currt s ~costat saturato currt I Io whr Io Solutos V 0.59V 0.58V 0.55V -9.0V I 8.4 m 4.4 m.5 m - I forward bas V >0 th V s ~costat for larg dffrcs currt ECE r. la oolttl