CHAPTER 24 REGULATED POWER SUPPLIES

Example 24-1, Page 954

In [1]:
Rs=10                          #given source resistance Rs(Ohm)
RL=40                          #given load resistance RL(Ohm)
Vin=15                         #input voltage(V)
VBE=0.8                        #base-emitter voltage drop(V) 
Vz=9.1                         #voltage across diode(V)

Vout=Vz+VBE                         #output voltage(V) 
Is=1000*(Vin-Vout)/Rs               #input current(mA)  
IL=1000*Vout/RL                     #load current(mA)
IC=Is-IL                            #collector current(mA)

print 'Output voltage Vout = ',Vout,'V'
print 'input current Is = ',Is,'mA'
print 'load current IL = ',IL,'mA'
print 'collector current IC = ',IC,'mA'

Output voltage Vout =  9.9 V
input current Is =  510.0 mA
load current IL =  247.5 mA
collector current IC =  262.5 mA

Example 24-2, Page 954

In [1]:
Rs=10                          #given source resistance Rs(Ohm)
RL=40                          #given load resistance RL(Ohm)
Vin=15                         #input voltage(V)
VBE=0.81                       #base-emitter voltage drop(V) 
Vz=6.2                         #voltage across diode(V)
R1=750                         #base input resistance(Ohm)
R2=250                         #base input resistance(Ohm)

Vout=(Vz+VBE)*(R1+R2)/R1            #output voltage(V) 
Is=1000*(Vin-Vout)/Rs               #input current(mA)  
IL=1000*Vout/RL                     #load current(mA)
IC=Is-IL                            #collector current(mA)

print 'Output voltage Vout = ',round(Vout,2),'V'
print 'input current Is = ',round(Is,2),'mA'
print 'load current IL = ',round(IL,2),'mA'
print 'collector current IC = ',round(IC,2),'mA'

Output voltage Vout =  9.35 V
input current Is =  565.33 mA
load current IL =  233.67 mA
collector current IC =  331.67 mA

Example 24-3, Page 954

In [2]:
Vout=9.35                         #output voltage(V)
IL=234                            #load current(mA)
Is=565                            #input current(mA)
Vin=15.0                          #input voltage(V)

Pout=Vout*IL/1000                 #output power(W)
Pin=Vin*Is/1000                   #input power(W)
eff=Pout/Pin                      #efficiency
preg=Pin-Pout                     #power dissipated by regulator(W)

print 'input power Pin = ',Pin,'W'
print 'Output power Pout = ',round(Pout,2),'W'
print 'Effifciency = ',round((eff*100),2),'%'
print'power dissipated by regulator = ',round(preg,2),'W'

input power Pin =  8.475 W
Output power Pout =  2.19 W
Effifciency =  25.82 %
power dissipated by regulator =  6.29 W

Example 24-4, Page 955

In [3]:
Rs=10                          #given source resistance Rs(Ohm)
RL=40                          #given load resistance RL(Ohm)
Vin=15                         #input voltage(V)
Vz=6.8                         #voltage across diode(V)
R1=7.5*10**3                   #base input resistance(Ohm)
R2=2.5*10**3                   #base input resistance(Ohm)

Vout=Vz*(R1+R2)/R1                  #output voltage(V) 
Is=1000*(Vin-Vout)/Rs               #input current(mA)  
IL=1000*Vout/RL                     #load current(mA)
IC=Is-IL                            #collector current(mA)

print 'Output voltage Vout = ',round(Vout,2),'V'
print 'input current Is = ',round(Is,2),'mA'
print 'load current IL = ',round(IL,2),'mA'
print 'collector current IC = ',round(IC,2),'mA'

Output voltage Vout =  9.07 V
input current Is =  593.33 mA
load current IL =  226.67 mA
collector current IC =  366.67 mA

Example 24-5, Page 956

In [8]:
Is1=510                            #input current in ex. 24-1 (mA)
Is2=565                            #input current in ex. 24-2 (mA)
Is4=593                            #input current in ex. 24-4 (mA)

Imax1=Is1                           #maximum load current (mA) 
Imax2=Is2                           #maximum load current (mA) 
Imax4=Is4                           #maximum load current (mA) 

print 'maximum load current Imax1 = ',Imax1,'mA'
print 'maximum load current Imax2 = ',Imax2,'mA'
print 'maximum load current Imax4 = ',Imax4,'mA'

maximum load current Imax1 =  510 mA
maximum load current Imax2 =  565 mA
maximum load current Imax4 =  593 mA

Example 24-6, Page 956

In [4]:
VNL=9.91                              #given VNL(V)
VFL=9.81                              #given VFL(V)
VHL=9.94                              #given VHL(V) 
VLL=9.79                              #given VLL(V)

LoR=(VNL-VFL)*100/VFL                  #Load regulation(%)
LiR=(VHL-VLL)*100/VLL                  #Line regulation(%)

print 'Load regulation = ',round(LoR,2),'%'
print 'Line regulation = ',round(LiR,2),'%'

Load regulation =  1.02 %
Line regulation =  1.53 %

Example 24-7, Page 962

In [11]:
RL=40.0                         #given load resistance RL(Ohm)
VBE=0.7                         #base-emitter voltage drop(V) 
Vz=6.2                          #voltage across diode(V)
R1=3.0                          #base input resistance(KOhm)
R2=1.0                          #base input resistance(KOhm)
Vin=15                          #input voltage(V)

Vout=(Vz+VBE)*(R1+R2)/R1        #output voltage(V)
IC=Vout/RL                      #transistor current(A)
PD=(Vin-Vout)*IC                #power dissipation(W)

print 'Output voltage Vout = ',Vout,'V'
print 'transistor current = load current = IC = ',IC*1000,'mA'
print 'Power dissipation PD = ',PD,'W'

Output voltage Vout =  9.2 V
transistor current = load current = IC =  230.0 mA
Power dissipation PD =  1.334 W

Example 24-8, Page 963

In [5]:
Vout=9.2                          #output voltage(V)
IL=230                            #load current(mA)
Vin=15.0                          #input voltage(V)

Pout=Vout*IL/1000                 #output power(W)
Pin=Vin*IL/1000                   #input power(W)
eff1=Pout/Pin                     #efficiency
eff2=Vout/Vin                     #efficiency

print 'input power Pin = ',Pin,'W'
print 'Output power Pout = ',Pout,'W'
print 'Effifciency 1= ',round((eff1*100),2),'%'
print 'Effifciency 2= ',round((eff2*100),2),'%'

input power Pin =  3.45 W
Output power Pout =  2.116 W
Effifciency 1=  61.33 %
Effifciency 2=  61.33 %

Example 24-9, Page 963

In [6]:
RL=4.0                          #given load resistance RL(Ohm)
Vz=5.6                          #voltage across diode(V)
R1=2.7                          #base input resistance(KOhm)
R2=2.2                          #base input resistance(KOhm)
Vin=15                          #input voltage(V)
B=100                           #current gain

Vout=Vz*(R1+R2)/R1              #output voltage(V)
IL=Vout/RL                      #load current(A)
IB=IL/B                         #base current(A)

print 'Output voltage Vout = ',round(Vout,2),'V'
print 'Load current IL = ',round(IL,2),'A'
print 'base current IB = ',round((IB*1000),2),'mA'

Output voltage Vout =  10.16 V
Load current IL =  2.54 A
base current IB =  25.41 mA

Example 24-10, Page 964

In [9]:
VNL=10.16                              #given VNL(V)
VFL=10.15                              #given VFL(V)
VHL=10.16                              #given VHL(V) 
VLL=10.07                              #given VLL(V)

LoR=(VNL-VFL)*100/VFL                  #Load regulation(%)
LiR=(VHL-VLL)*100/VLL                  #Line regulation(%)

print 'Load regulation = ',round(LoR,3),'%'
print 'Line regulation = ',round(LiR,2),'%'

Load regulation =  0.099 %
Line regulation =  0.89 %

Example 24-11, Page 965

In [10]:
RL=3.0                          #given load resistance RL(Ohm)
Vz=4.7                          #voltage across diode(V)
R11=1750                        #base input resistance with max. potentiometer(Ohm)
R12=750                         #base input resistance with min. potentiometer(Ohm)
R2=750                          #base input resistance(Ohm)
Vin=22.5                        #max. input voltage(V)
B=100                           #current gain
Rs=820                          #input side resistance(Ohm)
Vcl=0.6                          #voltage across current limiting resistor(V)
Vcs=0.7                          #voltage across current sensing resistor(V)
Vo=12.5                         #regulated voltage given(V)

Iz=(Vin-Vz)/Rs                  #max. zener current(A)
Vout1=Vz*(R11+R2)/R11           #min. regulated output voltage(V)
Vout2=Vz*(R12+R2)/R12           #max. regulated output voltage(V)
IL=Vcl/RL                       #load current(A)
RL1=Vo/IL                       #load resistance(Ohm)
ISL=Vcs/RL                      #shorted-load current(A)

print 'maximum zener current Iz = ',round((Iz*1000),2),'mA'
print 'Load current IL = ',IL*1000,'mA'
print 'load resistance RL = ',RL1,'Ohm'
print 'shorted-load current ISL = ',round((ISL*1000),2),'mA'

maximum zener current Iz =  21.71 mA
Load current IL =  200.0 mA
load resistance RL =  62.5 Ohm
shorted-load current ISL =  233.33 mA

Example 24-12, Page 971

In [11]:
Vout=12.0                                #regulated output voltage(V)
RL=100.0                                 #given load resistance RL(Ohm)

C=1000*10**-6                            #given capacitance(F)
f=120                                    #frequency(Hz)
RR_dB=72.0                               #ripple rejection(dB)

IL=Vout/RL                               #load current(A)
VRi=IL/(f*C)                             #peak to peak input ripple (V)
RR=10**(RR_dB/20)                        #ripple rejection
VRo=VRi/RR                               #peak to peak output ripple (V)

print 'Load current IL = ',IL*1000,'mA'
print 'peak to peak input ripple = ',VRi,'V'
print 'peak to peak output ripple = ',round((VRo*1000),2),'mV'

Load current IL =  120.0 mA
peak to peak input ripple =  1.0 V
peak to peak output ripple =  0.25 mV

Example 24-13, Page 972

In [26]:
R1=2.0                          #given resistance(KOhm)
R2=22.0                         #given resistance(KOhm)
R21=46.0                        #given resistance increased(KOhm)

Vout1=1.25*(R1+R2)/R1              #output voltage(V)
Vout2=1.25*(R1+R21)/R1             #output voltage with increased R2(V)

print 'Output voltage Vout1 = ',Vout1,'V'
print 'output voltage with increased R2, Vout2 = ',Vout2,'V' 

Output voltage Vout1 =  15.0 V
output voltage with increased R2, Vout2 =  30.0 V

Example 24-14, Page 972

In [12]:
Vout=5.0                          #output voltage(V)
Vin_min=7.5                       #min. input voltage(V)
Vin_max=20.0                      #max. input voltage(V)

eff_max=Vout/Vin_min                     #maximum efficiency
eff_min=Vout/Vin_max                     #minimum efficiency

print 'Minimum Effifciency = ',eff_min*100,'%'
print 'Maximum Effifciency = ',round((eff_max*100),2),'%'

Minimum Effifciency =  25.0 %
Maximum Effifciency =  66.67 %

Example 24-15, Page 984

In [31]:
R1=2.21                          #given resistance(KOhm)
R2=2.8                           #given resistance(KOhm)
R21=46.0                         #given resistance increased(KOhm)
VREF=2.21                        #Reference voltage(V)

Vout=VREF*(R1+R2)/R1             #output voltage(V)

print 'Output voltage Vout = ',Vout,'V'
print 'Input voltage should be 2V greater than output voltage So, Vin = 7 V'

Output voltage Vout =  5.01 V
Input voltage should be 2V greater than output voltage So, Vin = 7 V

Example 24-16, Page 984

In [13]:
R1=1                              #given resistance(KOhm)
R2=5.79                           #given resistance(KOhm)
VREF=2.21                         #Reference voltage(V)

Vout=VREF*(R1+R2)/R1             #output voltage(V)

print 'Output voltage Vout = ',round(Vout,2),'V'

Output voltage Vout =  15.01 V
In [ ]: