COLLEGE OF ENGINEERING PUTRAJAYA CAMPUS FINAL EXAMINATION SEMESTER / 2014

Transcription

1 OLLEGE OF ENGNEERNG PUTRAJAYA AMPUS FNAL EXAMNATON SEMESTER 013 / 014 PROGRAMME SUBJET ODE SUBJET : Bachelor of Electrcal & Electrocs Egeerg (Hoours) Bachelor of Electrcal Power Egeerg (Hoours) : EEEB73 : ELETRON ANALYSS AND DESGN DATE : Jauary 014 TME : 3 hours NSTRUTONS TO ANDDATES: 1. Ths paper cotas Sx (6) questos Ne (9) pages.. Aswer ALL questos. 3. Wrte all aswers the aswer booklet proded. Use pe to wrte your aswer. 4. Wrte aswer to dfferet questo o a ew page. 5. For all calculatos, assume that T 6 m. THS QUESTON PAPER ONSSTS OF NNE (9) PRNTED PAGES NLUDNG THS OER PAGE. Page 1 of 9

2 Questo 1 [0 marks] You are requred to desg a dfferetal amplfer wth passe load usg NPN bpolar jucto trasstors (BJT) wth the followg specfcatos. You DO NOT eed to desg the basg crcut for the dfferetal amplfer. Two-trasstor NPN BJT curret source s basg a 1. ma costat curret. The crcut parameters are power supples of 10 ad 10. The oltages measured at 1 ad of the dfferetal amplfer are 4 olts. The trasstors parameters are matched NPN BJTs wth 50, BE (o) 0.7, ad A, ad arous resstors wth precse alues are made aalable. Desg the dfferetal amplfer descrbed aboe wth ts basg crcut. Draw ad label the crcut dagram of your desg clearly. Show all calculatos ad alues as accurate as possble wth regard to the desg. Based o your assumpto for the desg, calculate the alues for d, cm, ad E (.e. oltage at a pot where emtters for both trasstors the dfferetal amplfer are coected). [0 marks] Page of 9

3 Questo [15 marks] Fgure shows a basc dfferetal amplfer. A two-trasstor curret source s used to bas a costat curret source of 0.5 ma (Note: Q 0.5 ma). The dfferetal amplfer s usg a par of PNP trasstors as ts acte load. The output oltage, O, of the dfferetal amplfer s take as. The trasstors parameters are: 150, BE (o) EB (o) 0.7, AN 10, ad AP 100. Acte load s usg a par of PNP trasstors. Fgure (a) Draw a complete dfferetal amplfer crcut cludg the par of PNP trasstors as acte load ad the two-trasstor curret source as basg crcut. [5 marks] (b) Determe the dfferetal-mode oltage ga of the crcut, A d O / d. [6 marks] (c) alculate the dfferetal-mode oltage ga f the load resstace, R L, s 100 kω. [4 marks] Page 3 of 9

4 Questo 3 [10 marks] (a) (b) Descrbe the operato of a class-b output stage by meas of crossoer dstorto. [3 marks] A class-ab output stage wth BJTs s show Fgure 3. Reerse saturato curret for each trasstor s S A. () Fd BB whe 0, as such producg p 1 ma. [ marks] () alculate, p, ad to obta O 3.5. [3 marks] () alculate the power dsspated R L. [ marks] 5 0 Fgure 3 Page 4 of 9

5 Questo 4 [0 marks] A MOSFET op-amp crcut as show Fgure 4 s based wth Q 00 µa. The trasstor parameters are k 100 µa/, k p 40 µa/, TN 0.4, TP -0.4, ad λ λ p 0. The trasstor aspect ratos are (W/L) 1 (W/L) 0, (W/L) 3 50, ad (W/L) () Desg the crcut such that D3 150 µa, D4 00 µa, ad o 0 for 1 0. [9 marks] () Fd the dfferetal oltage ga (A d ) of the dfferetal amplfer the crcut. [4 marks] () Determe the oltage ga for the ga stage (A ), made up by trasstor M 3, the crcut. A ca be calculated usg A -g m3 R D. [3 marks] () alculate the oerall small-sgal oltage ga (A ) of the mult-stage amplfer crcut. You may assume alue for the oltage ga of the output stage (A 3 ) made up by trasstor M 4. [4 marks] Fgure 4 Page 5 of 9

6 Questo 5 [15 marks] osder a stadard 741 operatoal amplfer (op-amp) crcut as show Fgure 5a. Study Fgure 5a carefully ad obsere the alues for resstors the crcut. Load resstace coected to the Output of the 741 op-amp s R L kω. The op-amp s suppled by ±15 D oltages. The trasstors hae 00, p 50, AN AP 50, BE (o) EB (o) 0.6, ad the reerse saturato curret S 5x10-16 A. From D aalyss, bas currets for selected trasstors are 13A 0.18 ma, 13B 0.54 ma, µa, ma, ma, ad 0.18 ma. Fgure 5b shows the A equalet crcut for the ga stage of the 741 op-amp. Fgure 5c shows the A equalet crcut for the output stage of the 741 op-amp, whch s used to determe R 3 the Fgure 5b. Wth aalyss, the oltage ga for the ga stage (A ) of the 741 op-amp ca be calculated usg the followg formula: A o o1 R ( 1 ) R ( R R R ) 9 act π 17 { R [ r ( 1 ) R ]} 9 3 o17 8 Where: Ract r o 13B R r ( )[ R ] 3 π 1 p 19 R0 R19 R13 A r o 13A R 0 r 1 π 0 ( p ) R L alculate the oltage ga for the ga stage (A ) of the 741 op-amp. Neglect base curret your calculatos. [15 marks] Page 6 of 9

7 Fgure 5a Fgure 5b Fgure 5c Page 7 of 9

8 Questo 6 [0 marks] (a) EXEPT for stadard ertg ad o-ertg amplfer crcuts usg op-amp, state three (3) other applcatos usg the op-amp ad sketch those three (3) other op-amp based crcuts. You are requred to sketch the crcut to clude all exteral compoets coected to the op-amp, order for the oerall crcut to fucto ts teded applcato. [6 marks] (b) Wth a feedback resstor of 00 kω, desg a amplfer usg op-amp wth a closed-loop ga whch ca be ared betwee -10 to -5 usg a potetometer. Draw clearly your crcut desg. [6 marks] (c) For the strumetato amplfer show Fgure 6, the crcut parameters are R 1 0 kω, R 115 kω, R 3 50 kω, ad R 4 00 kω. For put sgals of s ωt () ad s ωt (), determe O1, O, ad O. [8 marks] Fgure 6 -END OF QUESTON PAPER- Page 8 of 9

9 Page 9 of 9 APPENDX BAS FORMULA BJT MOSFET Q A o T Q m Q T m B E E B S S r g r r g e e T EB T BE α α π π sgal ;Small 1 ;PNP ; NPN / / DQ o DQ m p ox p p TP SG p D TP SG SD ox TN GS D TN GS DS r g L W k L W L W k L W λ µ µ 1 ;Small sgal ] [ (sat) MOSFET ;P ] [ (sat) MOSFET N ;? ' '