Dalington Circuit (=달링톤)Transistor

☆ Dalington 트랜지스터 회로는 매우큰 전류 이득을 갖는다. (출처, 학교전공서적 "전자회로")

 

두 바이폴라 접합 트랜지스터를 접속하여

하나의 'superbeta' 트랜지스터로 작동하는 Dalington회로이다.

Dalington회로 내부에 있는 두 트랜지스터의 전류이득을 각각 β1, β2 라고 한다면,

회로전체의 전류이득 βD는

 

βD = β1*β2

...가 된다.

 

 

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http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/emitfol.html

 

This emitter follower has a pair of transistors in the Darlington configuration.

이 에미터 팔로어는 갖고있다. 한쌍의 트랜지스터들을 in the 달링톤 구성에서.

In this arrangement, the emitter current of one transistor

                                           becomes the base current of the second.

이 배열에서, the 에미터 전류 of 한 트랜지스터의

                                   는 된다. the 베이스전류가 of the 두번째것의.

(빨간색 선 참고)

 

전류이득공식(=Current Gain)

키르히호프의 전류법칙(=KCL)에 의해 나가는전류는 들어온 전류들의 합과 같다는 뜻입니다.

뭐 먹은게 있어야 나오는게 있겠죠~~~

여기서 β는 Ie로 흘러들어가는 전류이득이 되겠다. (그래서 Ic/Ib)

α=Ic/Ie (Base없이 어떻게 적용되는가 의문을 갖는 분이 있는데, 그분이 지극히 정상입니다.)

(의구심 없이 공식만 외우는 분은 자격증은 딸수 있어도 실무가면 바보되니 항상 WHy?!? 를 외치세요~~~)

여기서 α는  Base를 GND에 물려서 Common-Base로 만들었을때의 Gain을 의미합니다.

α=Ic/Ie .....Ic=α*Ie

Ic=α*Ie 를 전류이득 공식 β에 적용해보면

β=Ic/Ib........α*ie / Ib

 

 

출처(▶LINK)

 

 

The Darlington configuration acts like one transistor with a beta which is the product of the betas of the two transistors.

달링톤 구성은 행동한다. like 하나의 트랜지스터같이

They are used where high output currents are needed.

그들은 사용된다. where 고출력 전류가 요구될때.

The input impedance of the Darlington configuration

                          is quite high.

입력 임피던스 of the 달링톤구성의

                          는 꽤 높다.

 

Switching of the second transistor

           may be slow,

so a resistor is commonly tied between the emitters

                                      to increase the speed switching.

스위칭 of the 두번째 트랜지스터의

      은 아마 느리게 될것이다.

so a 저항은 일반적으로 묶여있다. between the 에미터들사이에

                                      to 증가시키기위해 the 스피드 스위칭을.

 

Darlington pairs are available as single packages,

                           usually with the resistor included.

달링톤 패어는 이용가능한다. as 싱글 패키지로써,

                           보통 with the 레지스터와함께. 포함된상태로.

 

http://www.richardbrice.net/darlington.htm

Darlington Pair

Two transistors may be combined to form a configuration known as the Darlington pair

which behaves like a single transistor

                 with a current gain equivalent to the product of the current gain of the two transistors.

두 트랜지스터들은 아마 조합될것이다. to 형성하기위해 a 구성 알려진 as the 달링톤_페어라고

which 행동한다. like a 싱글 트랜지스터같이

              with a 전류 이득과함께 = 동등한 to the 제품 of the 전류이득 of the 두 트랜지스터들의.

 

This is especially useful where very high currents need to be controlled

                                                                        as in a power amplifier or power-regulator circuit.

Darlington transistors are available whereby two transistors are combined in one single package.

이건 특히 유용하다. where 매우 큰 전류가 필요할때 to be 제어되기위해

                                                                    as in 파워 증폭기에서 or 파워-레귤레이터 회로에서.

달링톤 트랜지스터들은 유용하다. whereby 두 트랜지스터들이 조합된곳에의해 in 하나의 싱클패키지안의.

(whereby : 무엇에 의하여)

 

The base-emitter volt-drop is twice that of a normal transistor.

 

In practical circuits

resistor R (shown dotted in the illustration) is often included to prevent leakage current

through the first transistor biasing the second into conduction.

실제 회로에서

저항 R (점선으로 보이는 in the 그림에서) 은 종종 포함된다. to 막기위해 누설전류를

through the 트랜지스터를 통한 바이어싱하는 the 두번째것을 into 컨덕터로.

 

 

The Darlington pair was invented by Sidney Darlington

who was a researcher at Bell Labs in the nineteen-fifties

                       and

                       who invented his eponymous pair

at the weekend in his home laboratory!

달링톤 패어는 발명됬다. by Sidney Darlington에 의해

who was a 연구원 at 벨 연구소에서 in the 1950년대에

                        and

                        who 발명했다 그의 이름을딴 패어를

at the 주말에 in 그의 집 실험실에서!

(eponymous /이파너머스/)

 

 

A similar configuration is termed the complementary Darlington,

the Sziklai pair, in which two transistors of different polarity

                                      are combined to form a composite transistor as illustrated.

비슷한 구성은 용어화되있다. the 컴플러맨터리 달링톤,

the Sziklai패어, in which 두 트랜지스터들 of 다른 극성의

                                                  이 조합된 to 형성하기위해 a 합성 트랜지스터를 as 묘사했듯이.

 

 

The advantage of this configuration is that

                                                   the base-emitter volt-drop is limited to that of a single transistor.

이점                                       은 that이다.

                                              바이어스-에미터 전압강하는 제한된다. to that of a 싱글 트랜지스터의 그것으로.

 

The complementary Darlington is very popular in audio power amplifiers.

컴플러맨터리 달링톤은 매우 유명하다. in 오디오 파워 증폭기에서. 

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http://www.electronics-radio.com/articles/analogue_circuits/transistor/darlington-pair.php

Darlington pair circuit calculations and design example

When designing a circuit using a Darlington pair, exactly the same rules are used as for designing a circuit using a standard transistor. The Darlington pair can be treated as a form of transistor with the differences of the very much higher current gain, and the higher base emitter voltage.

To illustrate how this can be done, the example of an emitter follower circuit is given below.

 

★ Ci를 통해 들어오는 입력임피던스 Zi에 대한 공식은

Zi = R1 || (ri + βD*Re)

(여기서 βD는 Dalington회로안의 두 트랜지스터의 전체 전류이득)

(ri : 교류등가회로로 변환했을때 발생되는 가상저항)

임피던스는 교류전류에서 발생하는 저항이다. Z=V/I

 

Step by step instructions:

These instructions in this Darlington pair transistor design example can only be taken as a guide because the actual circuit may differ, or the requirements for the circuit may be different.

1. Determine the emitter current:   This is usually the starting point for the design. It can be determined from a knowledge of what the output load is.
2. Determine the emitter voltage:   This would normally be approximately half the rail voltage as this will give the maximum voltage swing at the output.
3. Determine the emitter resistor:   This is simply the emitter voltage divided by the emitter current. Then choose the nearest available value.
   
   Note:   These last stages all depend on each other and it may be necessary to make the calculations in a different order dependent upon what is known.
4. Determine the base current:   This is simply the emitter current divided by the overall current gain, HFEtot
5. Choose the bias point for the Darlington base:   This is the emitter voltage plus the overall base-emitter voltage for the Darlington (normally 1.2 to 1.4 volts).
6. Choose bias current for the bias potential divide:   This is normally chosen to be approximately ten times the base current.
7. Calculate the voltage across each resistor in the bias chain:   The voltage across the lower resistor is simply the base voltage. The voltage across the upper resistor is the rail voltage less the base voltage.
8. Calculate the resistors in the bias chain:   The voltage each resistor can be calculated using the voltage in the previous step and is voltage / bias chain current. Then choose the nearest available values from the relevant resistor series.
9. Determine the input impedance:   This is the emitter resistor times the current gain, in parallel with the lower bias chain resistor, in parallel with the upper bias chain resistor.
10. Determine the input capacitor value:   The reactance of the input capacitor should be the same as the input impedance at the lowest frequency for a 3 dB roll off. Using the formula for the reactance of 2 pi x (Frequency, f in Hz) x (Capacitance C in farads) or 6 f C determine the value of the capacitor. Choose the next largest capacitance value available to ensure the frequency response is assured.
11. Calculate the output impedance:   The value of the output impedance can be assumed to be low, and the impedance of the load can be assumed to dominate for most applications.
12. Determine the output capacitor value:   The reactance of the output capacitor should be the same as the load impedance at the lowest frequency for a 3 dB roll off. Using the formula for the reactance of 2 pi x (Frequency, f in Hz) x (Capacitance C in farads) or 6 f C determine the value of the capacitor. Choose the next higher value of capacitor to ensure the frequency response is assured.

Some of the calculations are an approximation, but in view of the tolerances on the components, they give a good end result. It may be that some iteration of the calculations is required to obtain satisfactory overall results.