This document discusses power diodes and their characteristics. It covers: 1) Power diodes are designed for larger power handling capabilities than standard diodes and have lightly doped regions for improved frequency response, though this response is still relatively low. They are used in rectifiers and free-wheeling applications. 2) The basic structure of a power diode includes a diode chip and connections for series or parallel configurations. 3) There are three types of power diodes: standard/general purpose, fast recovery, and Schottky diodes.

1. advance power electronics design
lecture 2

2. power diodes
• larger power handing
• additionally lightly dopped
region
• frequency response is
relatively low(sLoss)
• applications are rectifier and
free wheeling diode(provide
path to discharge inductor)

3. Power Diode
• diode spoils
•
BASIC STRUCTURE OF POWER
DIODE

4. power diode- switching characteristics

5. power diode - switching characteristic
• Types of recovery
1) soft recovery
2) hard recovery
ta/tb is soft factor

6. power diode - three types of diode
• standard or general
purpose diode
trr~25us, f<1kHz, IA to
several thousands amp, Vrb
50V to 5kV, diffusion and
alloyed
• fast recovery diode
trr< 5us, upto several amp
and 50V ~3kV
schottky diode

7. rating of PD and comparsion of SigD to PD
• peak breakdown voltage
• max avg forward current
• maximum surge current
• max junction temperacture
(silicon diode 150-200C)

8. silicon carbide diode
• low losses and high
reliability
• no temperature influence

9. connections in power diode
• Series
• =! v
• Parallel

10. transient voltage sharing in power diode
• parasatic capacitances

11. thyristor- common characteristics
• pulse triggered, mostly low
switching frequencies
• rev and forw blocking
voltages same
• except tiac forward
direction

12. thyristor SCR
• Three PN junctions 2
transistors
• J2 block forw and j1 j2
block reverse voltage
• cross section thyristor

13. I-V characteristics and switching
characteristic
• If IA< IH, the thyristor will
be in the blocking state

14. Methods to turn on thyristor
• basically they are pulse
controlled devices