1. Power Semiconductor Diodes
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Power Semiconductor Diodes
Power diodes have large power-, voltage-, current-handling capabilities than that of ordinary signal diodes.
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

2. Power Diodes symbol and type of packaging
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Power Diodes symbol and type of packaging
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

3. Diode Characteristics
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Diode Characteristics
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

4. Forward-biased region Reverse biased region Breakdown region
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
V-I characteristics
Forward-biased region
Reverse biased region
Breakdown region
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

5. n=1, 2 ( Germanium, Silicon) practically 1.1—1.8
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Shockley’s equation
n=1, 2 ( Germanium, Silicon) practically 1.1—1.8
VT= Thermal voltage
IS= Saturation current
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

6. Shockley diode equation
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Shockley diode equation
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

7. Forward-bias VD>0 Islamic University of Gaza Faculty of Engineering
Electrical Engineering Department
Forward-bias VD>0
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

8. Reverse-bias VD<0 Islamic University of Gaza Faculty of Engineering
Electrical Engineering Department
Reverse-bias VD<0
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

9. Reverse Recovery Characteristics Tb/Ta is the softness factor (SF)
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Reverse Recovery Characteristics
Tb/Ta is the softness factor (SF)
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

10. The power diodes can be classified into three categories:
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Power Diode Types
Ideally, a diode should have no reverse recovery time.
The power diodes can be classified into three categories:
Standard or general-purpose diodes
Fast-recovery diodes
Schottky diodes
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

11. Standard or General-purpose diodes
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Standard or General-purpose diodes
Reverse recovery time= 25 us (relatively high).
Used in Low-speed applications.
Current rating : From less than 1 Ampere to several thousands of Amperes.
Voltage rating 50 v to 5 kV.
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

12. Reverse recovery time< 5 us ( Low).
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Fast-Recovery Diodes
Reverse recovery time< 5 us ( Low).
Used in DC-DC and DC-AC converter circuit (high speed applications).
Current rating : From less than 1 Ampere to several hundreds of Amperes.
Voltage rating 50 v to 3 kV.
Platinum or gold.
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

13. Used in high current and low voltage dc power supplies.
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
Schottky Diodes
No minority carriers .
Used in high current and low voltage dc power supplies.
Current rating : From 1 Ampere to 300 Amperes.
Voltage rating <100 V.
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3

14. (a) the storage charge Qrr (b) Peak reverse current 𝑰 𝒓𝒓
Islamic University of Gaza
Faculty of Engineering
Electrical Engineering Department
The reverse recovery time of a diode is 𝑻 𝒓𝒓 =3us and the rate of fall of the diode current is di/dt=30 A/us
Determine
(a) the storage charge Qrr
(b) Peak reverse current 𝑰 𝒓𝒓
Introduction to Power Electronics , Dr. Moayed Almobaied
Lecture 3