슬라이드 1

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1 Chapter 3. Bipolar Junction Transistor

2 Golden ule : Bipolar Junction Transistor C mitter : 화살표표시, forward bias V C C V Near Zero : Large C Bias : F ~ infinite C = h F B = C + B V F V C - h F 값은많이변하기때문에, 정확성이필요한회로는 h F 값의영향을안받게디자인.

3 1. 진공관과트랜지스터소개

4 The invention of the incandescent lamp, "dison effect", sometime around 1883 n effect, what dison had stumbled upon was a diode! Unfortunately, he saw no practical use for such a device and proceeded with further refinements in his lamp design. J. A. Fleming experimented with its use in Fleming marketed his device as a "valve,".

5 n adding the grid to Fleming's "valve," De Forest had made the valve adjustable: it now functioned as an amplifying device, whereby a small electrical signal could take control over a larger electrical quantity. (1906)

Vacuum Tube as Amplifiers & Oscillators Calling his invention the "Audion," he vigorously applied it to the development of communications technology.

6 Vacuum Tube as Amplifiers & Oscillators Calling his invention the "Audion," he vigorously applied it to the development of communications technology. n 1912 he sold the rights to his Audion tube as a telephone signal amplifier to the American Telephone and Telegraph Company (AT& T), which made long-distance telephone communication practical. n the following year he demonstrated the use of an Audion tube for generating radio-frequency AC signals. n 1915 he achieved the remarkable feat of broadcasting voice signals via radio from Arlington, Virginia to Paris, and in 1916 inaugurated the first radio news broadcast. Such accomplishments earned De Forest the title "Father of adio" in America.

7 Vacuum Tube as Switches --> Digital Computers NAC

8 17,468 vacuum tubes 7,200 crystal diodes 1,500 relays 70,000 resistors 10,000 capacitors ~ 5 million hand-soldered joints. t weighed 27 t, was roughly 2.6 m by 0.9 m by 26 m, took up 67.6 m², and consumed 150 kw of power. Disadvantages of vacuum tubes -large -fragile -power-hungry

9 nvention of Transistor The transistor was invented in 1947 at Bell Telephone Laboratories by a team led by physicists John Bardeen, Walter Brattain, and William Shockley.

10 Advantages of Transistors -tiny -mechanically rugged -power-thrifty Transistor ushered in revolution in electronics. This revolution made possible the design and manufacture of lightweight, inexpensive electronic devices that we now take for granted. (C chips, cell phone, computer, Samsung, ) On the 25th anniversary of the invention, Brattain said: "The thing deplore most is the use of solidstate electronics by rock-and-roll musicians to raise the level of sound to where it is both painful and injurious" (The New York Times).

11 2. Bipolar Junction Transistor 회로해석연습

12 Bipolar Transistor (BJT) ( 참고자료 : The Art of lectronics by Horowitz) 1. 화살표있는부분이 mitter이고 forward bias 2. = C + B 3. V B ~ V + V F (diode voltage drop~0.6v for npn) if V B -V > V F 4. C =h F B (h F 또는 b : current gain.) 5. bers Moll quation ev cf.) ev C B C 0 exp 1 kt B B 0 exp 1 kt Note) 1. C, B, V C, power ( C V C ), temperature, V B, 등은모두최대값이있다. 2. nput 저항이작다. 3. 큰전류를흘릴수있다. B

13 Golden ule : Bipolar Junction Transistor C mitter : 화살표표시, forward bias V C C V Near Zero : Large C Bias : F ~ infinite C = h F B = C + B V F V C - h F 값은많이변하기때문에, 정확성이필요한회로는 h F 값의영향을안받게디자인.

14 Maximum C-to- voltage C-B 간의 capacitor ( 회로의 switching time 을결정 ) BJT 특성의예 Gain 이 1 로떨어지는주파수 다음슬라이드왼쪽그래프번호 (Figure 2.78) (at)

15 BJT 특성의예 DC current gain, h F Gain bandwidth product, f T collector current, c collector current, c - h F 값은많이변하기때문에, 정확성이필요한 analog 회로는그특성이 h F 값의영향을안받고, 상대적으로정확한조절이가능한저항 () 을이용해조절하도록디자인하는것이중요.

16 Current Source = (h F +1) x B V in = B = B, V B C C, V C V in = B x B + V F + x = ( B + x (h F +1)) x B + V F B = (V in V F )/( B + x (h F +1)) V F = 0.6V, V = C = h F x (V in V F )/( B + x (h F +1)) f h F >> 1, C ~ (V in V F )/ ( 많이변하는 h F 와별로상관없고, 주로 V in 으로조절 )

17 nverter 2 V F ~ 0.6 V i) f V in = 5, B = (V in -0.6)/ 1 C = h F x B = h F (V in -0.6)/ 1 V out = 5-2 x C = 5 2 x h F x (V in -0.6)/ 1 위의식으로계산하면 V out 이 0 보다작은작은값이나온다. 그러나, V out 의최저치는 0 이므로, V out ~0 if h F is very large 1 ii) f V in = 0 B = 0 C =0 V out = 5V

18 Switch

19 mitter Follower - AC 신호의 nput 저항을높이고, output 저항을줄이는데이용 - Output terminal : emitter - Follow V B (diode 전압강하만큼 DC 차이 )

20 nput and Output esistances of mitter Follower source Source V B B VCC V Load V V F DV D V 0.6V 0.6 B DV B DV / Load DV / Load DV 0 Load D C ( h F B ( h F 1) D B 1) B nput 저항 - mitter follower 없이 source 와 load 를바로연결하면, source 가느끼는 input 저항은 Load - mitter follower 가있을경우, Source 에서전압신호 DV B 를줄때전류신호 D B 가생긴다고하면, Source 가느끼는 input 저항 in 은, Z in in DVB D ( h B F DV D /( h 1) 1) Z Load F Load ( h F 1) - AC 신호에대한 nput 저항이 (h F +1) 배로증가 (h F 에따라변하나, 정확한조절필요없이충분히크게또는작게만만들어주면됨.) Z out out Output 저항 - mitter follower 없이 source 와 load 를바로연결하면, Load 가느끼는 output 저항은 source - mitter follower 가있을경우 Load 가느끼는 output 저항은, Thevenin theorem 에의해서, emitter 를끊어놨을때의전압 DV -open 을, emitter 를 ground 에연결했을때의전압 D -short 로나눈값 ( thevenin =V open / short ). DV D Z ~ h open short source F 1 D B short DVo ( h F DVo ~ 1) ( DV / )( h o source - AC 신호에대한 output 저항이 1/(h F +1) 배로감소 F 1) h source F 1

21 Common mitter Amplifier V CC i v C C For small i B ~ i ~ i C v gain v v C out in v B v B AC voltage amplifier (gain 값이, 많이변하는 h F 영향을거의안받음 ) 주의 ) 소문자는작은 AC 신호를의미 ( 예, i C = D C ) V c V c ~ V CC - c c DV c =-D c c C C

22 v 1 V 1 C Differential Amplifier (long-tailed pair) -V 1 C +V CC =20V v out + - r V 0 1 r V 1 -V 2 v 2 i C ~ i v Common mode gain(v 1 =v 2 ) A c =v out /v 2 =-i C2 C /(i 2 ( +r )+2i 2 1 ) =- C /( +r +2 1 ) Differential gain (V 0 는고정, v 1 =-v 2 ) A d =v out /(v 1 -v 2 )=v out /(-2v 2 ) =-i C2 C /(-2(i 2 ( +r ))) = C /(2( +r )) Common mode ejection atio(cm) = A d /A c =( r )/2( +r ) ~ 1 /( +r ) (if 1 >> +r ) v B V 2 보통은 =0 A d = C /2r, A c =- C /2 1 CM= 1 /r - CM 이클수록두입력신호 (v1, v2) 의차이에의해서변하는 Vout 이크다. - gain 값들이, 많이변하는 h F 값의영향을거의안받음.

23 3. BJT 원리의이해 ( 대략적인원리만이해하며됨. 학기말시험에안나옴. 자세한식은, 4학년때고체물리또는반도체물리에서배울것 )

24 Two Types of BJT V B = V B -V (~ 0.6V) V CB = V C - V B V C = V C - V V C = V CB + V B *For an npn transistor, all the above potential differences are positive. C = current flowing into collector B = current flowing into base = current flowing out of emitter = C + B

25 Principles of BJT (Bipolar Junction Transistor) 1. collector/base: reverse biased 2. base/emitter: forward biased 3. quations for NPN BJT emitter collector base Amplification Current : e 1 e 1 e 1 e T BC T B T BC T B /V V 0 /V V 0 /V V 0 /V V 0 F F F F F F B C F F F C B F F C F h ) (~ 25 / mv e V T kt

26 BJT 원리의간단한이해 전압이걸렸을때전압이걸리지않았을때 B(+) B (-) n+ p n C n+ p n C(++) 전압이없으면, drift current와 diffusion current가평형을이뤄전류가안흐름. - 전압이걸리면, 에서 B쪽으로온전자중일부는 B로빠져나가고, 나머지는 B를지나 C로지나감 ev B B B 0 exp 1 - Base로부터홀이들어와서전류 B 를흘려준다. 이때, kt - B 증가 -> B의전압을증가 -> 부분의더많은전자들이접합면으로끌려옴, Potential Barrier 감도 -> 더많은전자들이 B를통과하여 C로가서 C 증가 + B 에서온 hole

Microsoft PowerPoint - ch03ysk2012.ppt [호환 모드]

Microsoft PowerPoint - ch03ysk2012.ppt [호환 모드] 전자회로 Ch3 iode Models and Circuits 김영석 충북대학교전자정보대학 2012.3.1 Email: kimys@cbu.ac.kr k Ch3-1 Ch3 iode Models and Circuits 3.1 Ideal iode 3.2 PN Junction as a iode 3.4 Large Signal and Small-Signal Operation