開關(guān)電源各種拓樸結(jié)構(gòu)2

1、Power Supply Topologies電源拓?fù)浣Y(jié)構(gòu)安安 森森 美美 半半 導(dǎo)導(dǎo) 體體 The Most Popular Topologies最常見的拓?fù)浣Y(jié)構(gòu)Buck降壓降壓Boost升壓升壓Buck-Boost降壓降壓-升壓升壓Flyback反激反激Forward正激正激Two-Transistor Forward雙晶體管正激雙晶體管正激Push-Pull推挽推挽Half Bridge半橋半橋Full Bridge全橋全橋SEPICCukDetails of the Circuit Operatio電路工作的細(xì)節(jié)電路工作的細(xì)節(jié)The Basic Pulse-Width Modulate

2、d Waveform基本的脈沖寬度調(diào)制波形These topologies all relate to switched-mode circuits.這些拓?fù)浣Y(jié)構(gòu)都與開關(guān)式電路有關(guān)。Definition of the basic pulse-width modulated waveform is as follows:基本的脈沖寬度調(diào)制波形定義如下：TSTONTOFFD = 1 - D =TONTOFFTOFFTOFFTS=Duty Cycle = Duty Ratio = D =TONTSTONTONTOFF=占空比占空比=負(fù)荷比負(fù)荷比Buck降壓Bucks the input down t

3、o a lower voltage.把輸入降至一個較低的電壓把輸入降至一個較低的電壓。Perhaps the simplest of all.可能是最簡單的電路。The inductor/capacitor filter averages the rectangular wave from the switch.電感/電容濾波器濾平開關(guān)后的方波。Output is always less than or equal to the input.輸出總是小于或等于輸入。Input current is discontinuous (chopped).輸入電流不連續(xù) (斬波)。Output curr

4、ent is smooth.輸出電流平滑。Load(R)VinVoutVout =VinD負(fù)載負(fù)載Boost升壓Boosts the input to a higher voltage.把輸入升至一個較高的電壓把輸入升至一個較高的電壓。Like the buck, but inductor, switch and diode are rearranged.與降壓一樣，但重新安排了電感、開關(guān)和二極管。Output is always greater than or equal to the input.輸出總是比大于或等于輸入。 (neglecting the forward voltage d

5、rop of the diode).(忽略二極管的正向壓降)。Input current is smooth.輸入電流平滑。Output current is discontinuous (chopped).輸出電流不連續(xù) (斬波)。Load(R)VinVout1Vout =VinD負(fù)載負(fù)載Buck-Boost 降壓-升壓Another arrangement of the inductor, switch and diode.電感、開關(guān)和二極管的另一種安排方法。Combines negative characteristics of both the buck and the boost.結(jié)

6、合了降壓和升壓電路的缺點(diǎn)。 Input current is discontinuous (chopped).輸入電流不連續(xù) (斬波)。 Output current is also discontinuous (chopped).輸出電流也不連續(xù) (斬波)。Output is always inverted from the input (note capacitor polarity), but can be of less or greater magnitude.輸出總是與輸入反向 (注意電容的極性)，但是幅度可以小于或大于輸入。The “flyback” converter is a

7、ctually an isolated (transformer coupled) version of the buck-boost. “反激”變換器實(shí)際是降壓-升壓電路隔離（變壓器耦合）形式。Load(R)VinVoutVout =VinD- D負(fù)載負(fù)載Flyback 反激Operates like the buck-boost, but the inductor has two windings and performs both as a transformer and inductor.如降壓-升壓電路一樣工作，但是電感有兩個繞組，而且同時作為變壓器和電感。Output can be

8、 either positive or negative, depending on the polarity of the winding and diode.輸出可以為正或?yàn)樨?fù)，由線圈和二極管的極性決定。Output voltage can be either less than or greater than the input voltage, depending on the turns ratio of the transformer.輸出電壓可以大于或小于輸入電壓，由變壓器的匝數(shù)比決定。This is the simplest of the isolated topologies

9、.這是隔離拓?fù)浣Y(jié)構(gòu)中最簡單的。Multiple outputs are possible with additional secondary windings and circuits.增加次級繞組和電路可以得到多個輸出。Load (R)VinVoutVout =VinDn Dn1負(fù)載負(fù)載Forward正激The transformer-coupled version of the buck.降壓電路的變壓器耦合形式。Discontinuous input current; smooth output current.不連續(xù)的輸入電流，平滑的輸出電流。Because of the transf

10、ormer, the output can be less or greater than the input and of either polarity. 因?yàn)椴捎米儔浩鳎敵隹梢源笥诨蛐∮谳斎?，可以是任何極性。Multiple outputs are possible be adding secondary windings and circuits.增加次級繞組和電路可以獲得多個輸出。The transformer core must be reset during each switching cycle. A popular way to do this is to add ano

11、ther winding with the same number of turns as the primary.在每個開關(guān)周期中必須對變壓器磁芯去磁。常用的做法是增加一個與初級繞組匝數(shù)相同的繞組。Energy stored in the primary inductance during the “on” time of the switch is discharged through the extra winding and diode during the “off” time.在開關(guān)接通階段存儲在初級電感中的能量，在開關(guān)斷開階段通過另外的繞組和二極管釋放。i1Load (R)Vin

12、VoutiRESETVout =VinDnn1m負(fù)載負(fù)載復(fù)位復(fù)位Two-Transistor Forward雙晶體管正激The two switches operate simultaneously.兩個開關(guān)同時工作。When they turn off, the energy stored in the transformer reverses the polarity of the primary, causing the diodes to conduct.開關(guān)斷開時，存儲在變壓器中的能量使初級的極性反向，使二極管導(dǎo)通。Major advantages: 主要優(yōu)點(diǎn)：The voltage

13、 on each switch never exceeds the input voltage.每個開關(guān)上的電壓永遠(yuǎn)不會超過輸入電壓。No reset winding is needed.無需對繞組磁道復(fù)位。Load (R)VinVoutVout =VinDn負(fù)載Push-Pull推挽The switches (FETs) are driven out of phase and pulse-width modulated (PWM) to regulate the output voltage.開關(guān)（FET）的驅(qū)動不同相，進(jìn)行脈沖寬度調(diào)制（PWM）以調(diào)節(jié)輸出電壓。Good transforme

14、r core utilization-power is transferred on both half-cycles.良好的變壓器磁芯利用率-在兩個半周期中都傳輸功率。Full-wave topology, so output ripple frequency is twice the transformer frequency.全波拓?fù)浣Y(jié)構(gòu),所以輸出紋波頻率是變壓器頻率的兩倍。Voltage stress on the FETs is twice the input voltage.施加在FET上的電壓是輸入電壓的兩倍。Load(R)VinVoutVout =VinDnnn11負(fù)載Half

15、-Bridge半橋Very popular topology for higher-power converters.較高功率變換器極為常用的拓?fù)浣Y(jié)構(gòu)。The switches (FETs) are driven out of phase and pulse-width modulated (PWM) to regulate the output voltage.開關(guān)（FET）的驅(qū)動不同相，進(jìn)行脈沖寬度調(diào)制（PWM）以調(diào)節(jié)輸出電壓。Good transformer core utilization-power is transferred on both half-cycles. And-pr

16、imary winding utilization is better than push-pull.良好的變壓器磁芯利用率-在兩個半周期中都傳輸功率。而且初級繞組的利用率優(yōu)于推挽電路。Full-wave topology; output ripple frequency is twice the transformer frequency.全波拓?fù)浣Y(jié)構(gòu),所以輸出紋波頻率是變壓器頻率的兩倍。Voltage stress on the FETs is equal to the input voltage.施加在FET 上的電壓與輸入電壓相等。Load(R)VinVoutVout =VinD2 n

17、n11負(fù)載Most popular topology for high-power converters.較高功率變換器最為常用的拓?fù)浣Y(jié)構(gòu)。The switches (FETs) are driven in diagonal pairs and pulse-width modulated (PWM) to regulate the output voltage.開關(guān)（FET）以對角對的形式驅(qū)動，進(jìn)行脈沖寬度調(diào)制（PWM）以調(diào)節(jié)輸出電壓。Good transformer core utilization-power is transferred on both half-cycles.良好的變壓

18、器磁芯利用率-在兩個半周期中都傳輸功率。Full-wave topology; output ripple frequency is twice the transformer frequency.全波拓?fù)浣Y(jié)構(gòu)，所以輸出紋波頻率是變壓器頻率的兩倍。Voltage stress on the FETs is equal to the input voltage.施加在 FETs上的電壓與輸入電壓相等。For a given power, primary current is half that of the half-bridge.在給定的功率下，初級電流是半橋的一半。Load(R)VinVou

19、tVout =VinDn11n負(fù)載負(fù)載Full-Bridge全橋SEPIC (Single-Ended Primary Inductor Converter) （單端初級電感變換器）Output voltage can be either less than or greater than the input.輸出電壓可以大于或小于輸入電壓。Like the boost, the input current is smooth and output current is not.與升壓電路一樣，輸入電流平滑，但是輸出電流不連續(xù)。Energy is transferred from input

20、to output through a capacitor.能量通過電容從輸入傳輸至輸出。Requires two inductors.需要兩個電感。Load(R)VinVoutVout =VinD D負(fù)載負(fù)載Cuk (By Slobodan Cuk) (Slobodan Cuk的專利)Output is inverted.輸出反相。 Magnitude of output voltage can be less or greater than the input.輸出電壓的幅度可以大于或小于輸入。Input current and output current are both smooth

21、.輸入電流和輸出電流都是平滑的。Energy is transferred from input to output through a capacitor.能量通過電容從輸入傳輸至輸出。Requires two inductors.需要兩個電感。 Inductors can be coupled to achieve zero-ripple inductor current.電感可以耦合獲得零紋波電感電流。Load(R)VinVoutVout =VinD- D負(fù)載負(fù)載Details of the Circuit Operation電路工作的細(xì)節(jié)Buck regulator:降壓調(diào)整器： Co

22、ntinuous conduction連續(xù)導(dǎo)電 Critical conduction臨界導(dǎo)電 Discontinuous conduction不連續(xù)導(dǎo)電Boost regulator (continuous conduction)升壓調(diào)整器 (連續(xù)導(dǎo)電)Transformer operation變壓器工作Flyback transformer反激變壓器Forward transformer正激變壓器Inductor current is continuous.電感電流連續(xù)。Vout is the average of the voltage at its input (V1).Vout 是其

23、輸入電壓 (V1)的均值。Output voltage is the input voltage times the duty ratio (D) of the switch.輸出電壓為輸入電壓乘以開關(guān)的負(fù)荷比 (D)。When switch in on, inductor current flows from the battery.接通時，電感電流從電池流出。When switch is off, it flows through the diode.開關(guān)斷開時電流流過二極管。Neglecting losses in the switches and inductor, D is inde

24、pendent of load current.忽略開關(guān)和電感中的損耗, D與負(fù)載電流無關(guān)。A characteristic of buck regulators and its derivatives: 降壓調(diào)整器和其派生電路的特征是：Input current is discontinuous (chopped), and output current is continuous (smooth).輸入電流不連續(xù) (斬波), 輸出電流連續(xù) (平滑)。time0i 200i 1i30v 1i 1Load(R)Vout = 5 Vi3i 2v 1Vin =15 VBuck Regulator降

25、壓調(diào)整器 (Continuous Conduction)(連續(xù)導(dǎo)電)負(fù)載時間Inductor current is still continuous, but just “touches” zero as the switch turns on again.電感電流仍然是連續(xù)的，只是當(dāng)開關(guān)再次接通時 “達(dá)到”零。This is called “critical conduction.”這被稱為 “臨界導(dǎo)電”。Output voltage is still equal to the input voltage times D.輸出電壓仍等于輸入電壓乘以D。i 1Load(R)Vout = 5 V

26、i3i 2v 1Vin =15 Vi 10i 2v 1i3time0Buck Regulator降壓調(diào)整器 (Critical Conduction)(臨界導(dǎo)電)負(fù)載時間Buck Regulator降壓調(diào)整器 (Discontinuous Conduction)（不連續(xù)導(dǎo)電）In this case, the current in the inductor is zero during part of each period.在這種情況下，電感中的電流在每個周期的一段時間中為零。Output voltage is still (as always) the average of v1.輸出電壓

27、仍然 (始終)是 v1的平均值。Output voltage is NOT the input voltage times the duty ratio (D) of the switch.輸出電壓不是輸入電壓乘以開關(guān)的負(fù)荷比 (D)。While the load current is below the critical value, D varies with load current (while Vout remains constant).當(dāng)負(fù)載電流低于臨界值時，D 隨著負(fù)載電流而變化 (而 Vout 保持不變)。i 1i 2i 1Load(R)Vout = 5 Vi3i 2v 1V

28、in =15 Vi 1v 10i3i 2time負(fù)載時間Boost Regulator升壓調(diào)整器Output voltage is always greater than (or equal to) the input voltage.輸出電壓始終大于（或等于）輸入電壓。Input current is continuous, and output current is discontinuous (the opposite of a buck regulator).輸入電流連續(xù)，輸出電流不連續(xù)（與降壓調(diào)整器相反）。Relationship of the output voltage to t

29、he duty ratio, D, is not as simple as in the buck regulator. In the continuous-conduction case, it is:輸出電壓與負(fù)荷比（D）之間的關(guān)系不如在降壓調(diào)整器中那么簡單。在連續(xù)導(dǎo)電的情況下：In this example, Vin = 5,在本例中，Vin = 5,Vout = 15, and D = 2/3.Vout = 15，D = 2/3.timei 200i 1i30v 1i 1Load(R)Vout = 15 Vi3i 2v 1Vin =5 VVin = 5 VVout = 15 V0D11

30、VinVo負(fù)載時間Transformer Operation變壓器工作 Including Effect of Primary Inductance包括初級電感的作用Transformer is shown as an ideal transformer, with its primary (magnetizing) inductance as an inductor in parallel with the primary.變壓器看作理想變壓器，它的初級（磁化）電感與初級并聯(lián)。Load (R)i1i2turns ratio:1 : 2v0time0ii0i10v sec.i sec. 00v

31、 sec.i sec.i2負(fù)載匝數(shù)比：匝數(shù)比：時間Flyback Transformer反激變壓器 (Really a Multi-Winding Inductor)（實(shí)際是多繞組電感）Here, the primary inductance is intentionally low, to determine the peak current and hence the stored energy. When the primary switch is turned off, the energy is delivered to the secondary.此處初級電感很低，用于確定峰值電流和存儲的能量。當(dāng)初級開關(guān)斷開時，能量傳送到次級。turns ratio:1 : 2v pri. 0i pri.0v sec.i sec. 00v sec.i sec.Load (R)timeVinv drain0VoutVouti pri.v pri.負(fù)載匝數(shù)比：匝數(shù)比：時間Forward Converter Transformer正激變換變壓器