1. MALVINO
Electronic
PRINCIPLES
SIXTH EDITION

2. Regulated Power Supplies
Chapter 24

3. Power supply regulation
Vout
Vline RL
Load regulation = x 100%
VNL - VFL
VFL
Line regulation = x 100%
VHL - VLL
VLL

4. A zener diode shunt voltage regulatorRS
Power
supply
Vin
Vout VZ RL
Vout = VZ
Vin - Vout
Vout
IS =
IL =
IZ = IS - IL RS RL

5. Improved shunt voltage regulatorRS
Power
supply
Vin
Vout VZ RL
Vout = VZ + VBE
Vin - Vout
Vout
IS =
IL =
IC  IS - IL RS RL

6. Power supply Zener follower is a series voltage regulator. RS Vin
PD  (Vin - Vout)IL
Vout = VZ + VBE VZ RL
Vout

7. Two-transistor voltage regulator
R3 + R4 R4
(VZ + VBE)
Vout =
+Vin
Vout Q2 R2 R1 R3 RL Q1 R4 VZ

8. Improved voltage regulator
R2 + R3 R3 VZ
Vout =
+Vin
Vout R2 R1 RL R3 VZ

9. Regulator with current limitingVZ
Vout = Q1
+Vin
Vout R4 R2 R1 RL R5 Q2 R3
ISL =
VBE R4 VZ

10. Simple current-limitingVL
Vreg
Constant current
region
VBE(Q2)  0.6 V IL
ISL

11. Foldback current limiting
ISL =
VBE
KR4
Foldback
current limiting Q1 R4
+Vin R6 R2 R1 R7 RL Q2 R5 R3
(1-K)Vout
KR4
Imax = ISL + VZ

12. Foldback current-limitingVL
Vreg
Foldback current
region IL
Imax
ISL

13. Monolithic regulator with current booster
Vin Q1 1 2
LM78XX
Vout R1 3 RL

14. Current booster with current limitingQ2
Vin Q1 1 2
Vout
LM78XX R1 3 RL

15. DC-to-DC converter
+Vin R1 Q2 T1
vin Q1 RL Q3 R2

16. Switching regulators
The pass transistor is switched between cutoff and saturation.
Better efficiency than linear.
Topologies:
Buck: steps the voltage down
Boost: steps the voltage up
Buck-boost: inverts the input voltage

17. Buck regulator Q L
+Vin D C RL R2
PWM R1
VREF
Vout = DVin

18. Boost regulator Vkick Vp L +Vin D Q C RL R2 PWM R1 VREF
Vp = Vin + Vkick

19. Buck-boost regulator Q
+Vin D L C RL R2
PWM R1
VREF

20. Monolithic buck regulator5 4 IN
OUT L
+Vin D C3 RL C1
LT1074 R2 1
COMP FB 2 3 R1 R3
Vout =
R1 + R2 R1
(2.21 V) C2

21. Using the charge pump of the MAX633 IC
+15 V IN
OUT 4 5
+Vin C3 CP 6
-12 V C1
MAX633 D2
1,3,7 C2 D1