malvino ep 04 cac mach diode
TRANSCRIPT
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 1/70
Chng 4Các mch diode
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 2/70
T Vng (1) Bias = phân cc Capacitor-input filter = Mch lc ngõ vào
(dùng) t
Choke-input filter = Mch lc ngõ vào(dùng) cun dây Clamper = mch kp Clipper = mch xén
dc value of signal = giá tr DC ca tín hiu Filter = mch lc, b lc Half-wave signal = tín hiu bán k
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 3/70
T Vng (2) IC voltage regulator = Mch n áp IC Integrated circuit = IC = vi mch = mch
tích hp
Passive filter = mch lc th ng Peak detector = mch tách sóng nh Peak inverse voltage = in áp ngc
nh Polarized capacitor = t (in) hóa (hc) =
t có phân cc Power supply = ngun cp in
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 4/70
T Vng (3)
Rectifier = mch/b chnh lu Ripple = gn
Surge current = dòng in quá Surge resistor = in tr bo v quá Unidirectional local current = dòng in
cc b n hng
Volatge multiplier = mch nhân in áp Waveform = dng sóng
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 5/70
Ni dung chng 4
4-1 Mch chnh lu bán k4-2 Máy bin th4-3 Mch chnh lu toàn sóng4-4 Mch chnh lu cu4-5 Mch lc ngõ vào (dùng) cun dây4-6 Mch lc ngõ vào (dùng) t4-7 in áp ngc nh và dòng quá 4-8 Mt s vn khác v ngun cp in
4-9 Troubleshooting4-10 Mch xén và mch hn biên (limiter)4-11 Mch kp4-12 Mch nhân in áp
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 6/70
4-1 Mch chnh lu bán k
H. 4-1 (a) Mch chnh lu bán k lý tng;
(b) bán k dng (diode ON); (c) bán k âm (diode OFF)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 7/70
4-1 Mch chnh lu bán k (tt)Các dng sóng lý tng
Hình 4-2
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 8/70
4-1 Mch chnh lu bán k (tt)
in áp ra nh bng in áp vào nh:
Giá tr DC ca tín hiu bán k Vdc
:
Tn s ra:
f out = f in Xp x bc 2:
Vp(out) = Vp(in) ± 0.7V (diode Si)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 9/70
A simple Battery charger-Example of a
Rectifier Can be used to charge a car battery from the alternator
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 10/70
4-2 Máy bin th (Transformer)
Máy bin th là 1 cp cun dây có ghéph cm vi nhau ( truyn nng lng tcun này sang cun kia bng t trngbin thiên).
Vi s vòng dây khác nhau ta có máy binth tng áp (step up) hay gim áp (step
down).
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 11/70
4-2 Máy bin th (tt)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 12/70
4-2 Máy bin th (tt)
Ký hiu máy bin th The symbol for a transformer is a pair of thesame loopy lines used for inductors, but closetogether. If the inductor has a core of a
magnetic material, it is shown as a couple of lines between the coils.
The number of turns in the coils willBe written nearby.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 13/70
4-2 Máy bin th (tt)
Máy bin th lý tng in áp th cp (secondary) V2:
Vi:
± N1: s vòng dây s cp (primary) ± N2: s vòng dây th cp (primary)
± V1: in áp s cp
Chú ý ta ang nói n in áp AC
1
1
2
2 V N
N
V !
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 14/70
4-2 Máy bin th (tt)
Mch chnh lu bán k vi máy bin th
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 15/70
4-3 Mch chnh lu toàn sóng
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 16/70
4-3 Mch chnh lu toàn sóng (tt)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 17/70
4-3 Mch chnh lu toàn sóng (tt)
Các công thc Giá tr DC hay trung bình Vdc:
Vdc = 2Vp/T $ 0.636 Vp
Tn s ra:f out = 2f in
Xp x bc 2:
Vp(out) = Vp(in) ± 0.7V (diode Si)Chú ý: Vp(in) = 0.5 V2 (V2 là in áp th
cp vì ngõ ra có chu gia (center tap))
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 18/70
4-4 Mch chnh lu cu
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 19/70
4-4 Mch chnh lu cu (tt)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 20/70
4-4 Mch chnh lu cu (tt)
Các công thc Giá tr DC hay trung bình Vdc:
Vdc = 2Vp/T $ 0.636 Vp
Tn s ra:f out = 2f in Xp x bc 2:
Vp(out) = Vp(in) ± 1.4V (diode Si)
Chú ý: Chnh lu cu có u im hn loi bán klà ta có th s dng toàn b in áp th cp
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 21/70
4-5 Mch lc ngõ vào (dùng)
cun dây
Hình 4-10 (a) Mch lc ngõ vào (dùng) cundây; (b) mch tng ng AC
Ý tng c bn: Nu XL >> XC thì
Vout $ XCVin/XL
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 22/70
Lc ngõ ra ca mch chnh lu
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 23/70
Lc ngõ ra ca mch chnh lu (tt)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 24/70
4-6 Mch lc ngõ vào (dùng) t
Ý tng c bn (H.4-12, pp.108)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 25/70
4-6 Mch lc ngõ vào (dùng) t (tt)
Hiu ng ca in tr ti (H.4-13)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 26/70
4-6 Mch lc ngõ vào (dùng) t (tt)
Các công thc in áp gn nh-nh ngõ ra VR:
Vi: ± VR = in áp gn nh-nh
± f = tn s gn ( = f in vi bán k; = 2f in vi toàn sóng) ± C = in dung
fC
I V
R
!
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 27/70
4-7 in áp ngc nh PIV vàdòng quá (xét lc ngõ vào t)
H.4-18
(a) PIV = 2VP (b) PIV = VP (c) PIV = VP
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 28/70
Surge resistor
Hình 4-19 in tr bo v gii hn dòng quá
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 29/70
Half-wave Full-wave Full-wave
Bridge
# of diodes 1 2 4
DC output
voltage(**)
Vin (peak) Vin (peak) (*) Vin (peak)
DC diode
current
IL 0.5IL 0.5IL
PIV (***) 2Vin (peak) 2Vin (peak) Vin (peak)
Ripple
Frequency
f 2f 2f
Comparison of Rectifier Circuits
* With 1:2 transformer turns ratio; ** With Large C *** Peak Inverse Voltage (also with Large C)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 30/70
4-10 Mch xén và mch hn biên
Có 3 loi mch xén: ± Mch xén trên (mch xén dng)
± Mch xén di (mch xén dng) ± Mch xén 2 mc c lp (mch xén kt hp)
Mch hn biên hay kp diode
Chú ý: Tng quát các mch xén có phâncc
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 31/70
Các Mch xén và hn biên(Clippers and Limiters)
- Small Signal Diode
The positive clipper
or
* 1N914 : IF = 10mA for 1V
RB =mA
V
10
7.01 = 30 Ohm
* Stiff Clipper : 100 RB
< RS
< 0.01 RL
c tuyn truyn t
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 32/70
The Negative clipper
or
The Limiter or Diode clamp
protect sensitive circuits
c tuyn truyn t
c tuyn truyn t
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 33/70
Biased Clippers
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 34/70
Combination Clipper (slicer)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 35/70
Clipper Circuits using Zener Diodes
Zener diode provides a reference voltage of VZ
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 36/70
Clipper applications (1)
Transient-protection circuits
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 37/70
Clipper applications (2)
AM detector
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 38/70
4-11 Mch kp
Có 2 loi mch kp: ± Mch kp dng
± Mch kp âm
Mch tách sóng nh-nh: thng dùngcho diode tín hiu nh tn s cao
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 39/70
Clampers
Positive clamper
-
+ -
+ off
Vout = VP +
VP
Negative clamper
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 40/70
Biased clampers
Biased clampers.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 41/70
4-12 Mch nhân in áp
Thí d mt s mch nhân áp: ± Nhân ôi in áp (voltage doubler)
± Nhân 3 in áp (voltage tripler)
± Nhân 4 in áp (voltage quadrupler)
± Nhân ôi in áp toàn sóng (full-wave voltagedoubler)
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 42/70
Voltage multipliers (1)
Half-wave voltage doublers.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 43/70
Voltage multipliers (2)
Operation of half-wave voltage doublers.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 44/70
Full-wave voltage doubler
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 45/70
Cockcroft-Walton Circuit
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 46/70
S khi ca mt ngun DC
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 47/70
DC Power Supply Requirement
Since this circuit has a significant dc component,
with no dc component at the input, it can be usedto produce a dc power supply. A dc power supplymust be a nonlinear circuit.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 48/70
DC Power Supplies, PeakDetector
Power Supplies use a
rectifier with acapacitor at theoutput. We start witha half-wave rectifier,since it is simpler.Show Fig. 3.32 fromSedra and Smith.This is a half-waverectifier with a
capacitor, which holdsthe peak value of theinput source, v I (t).
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 49/70
DC Power Supplies, PeakDetector
This circuit will hold
the peak value onlybecause there isnothing connectedat the output.
When we connect aload, somethingdifferent happens.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 50/70
DC Power Supplies
Here we
have connected aload, R, at theoutput. Lookcarefully at the
diagram for theoutput voltage,vO(t). Note that itno longer holdsthe peak value,but decreasesexponentially.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 51/70
DC Power Supplies
There is a short
time period,which is referredto here as theConduction
interval (t , wherethe diode is on,and conducts.During this time,vO(t) = v I (t).
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 52/70
DC Power Supplies
There is a longer
time period, which isabout as long as theperiod of the inputwave, where thediode is off. Duringthis time, theresistor andcapacitor make anatural response
circuit, and
2
.t t
RC O p
v t V e
!
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 53/70
DC Power Supplies
The total waveform,
vO(t), is acomplicatedcombination of asinusoid, and adecayingexponential, evenfor a simple diodemodel. A moreaccurate diode
model makes for avery complicatedsolution.
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 54/70
DC Power Supplies, Approximations
The waveform,vO(t), is oftenapproximated asa simpler case,that is a dc
component equalto V p, and an accomponentwhose peak-to-peak value iscalled V r , theripple voltage.
C S
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 55/70
DC Power Supplies, Approximations
The dc
component of vO(t) is oftenapproximated bythe zero-to-peak
input sinusoid,perhapsdecreased by thethreshold voltageof the diode,and/or by half theripple voltage.
DC P S li A i i
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 56/70
DC Power Supplies, Approximations
The ac component
of vO(t) which wecalled the ripplevoltage, or V r , canalso beapproximated. The
following is aderivation of asimple estimate of the ripple voltage,Vr, which is defined
as the peak to peakvoltage on theoutput of the power supply.
Ri l V lt A i ti
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 57/70
Ripple Voltage Approximation
The ac component of vO(t) which we called the ripple
voltage, or V r , can also be approximated.1. Assume an ideal diode. (If the input amplitude
is much larger than V f , we make little error in
ignoring V f . If the input amplitude is not much
larger than V f , we can make a more accurate
estimate by using a better diode model.)
2. Assume that RC >> T , which we make possible
by picking C large.3. Since RC >> T , we can treat the exponentialdecay as a straight line.
Ri l V lt A i ti
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 58/70
Ripple Voltage Approximation
The ripple voltage, or V r , can be approximated.
4. The charge gained by capacitor during charging,Qacq, is
Qacq = C V r .
5. The charge lost during discharge,
Qlost , isQlost = i L
(T-(t) } i L
T .
6. Here, we have assumed that(T-(t) } T ,
since it discharges for almost the entire period.
Ri l V lt A i ti
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 59/70
Ripple Voltage Approximation
The ripple voltage, or V r , can be approximated.
7. The voltage is a straight line, with a slope we willcall m, and a peak equal to V p. So, the current is
just that voltage divided by R,
. p
L
V mt i
R
!
Ri l V lt A i ti
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 60/70
Ripple Voltage Approximation
The ripple voltage, or V r , can be approximated.
8. Now, since RC >> T , we assume that m = 0. Then, withQacq = Qlost , and plugging in we get
where I L
is the load current, which is almost constantwith time, and so is expressed as a dc quantity.
.
Solving, we get
,
p
r L
p p L
r
V C V i T T
R
V T V I V
RC f RC fC
! !
! ! !
Ri l V lt A i ti
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 61/70
Ripple Voltage Approximation
The ripple voltage, or V r , can be approximated.
9. With a full wave rectifier, the frequency iseffectively doubled, so
which is a very handy little equation. It issurprisingly accurate, considering the number of approximations used to get it.
,2 2 2
p p Lr
V T V I V
RC f RC fC ! ! !
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 62/70
Các ng dng c bn ca diode
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 63/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 64/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 65/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 66/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 67/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 68/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 69/70
8/3/2019 Malvino EP 04 Cac Mach Diode
http://slidepdf.com/reader/full/malvino-ep-04-cac-mach-diode 70/70