VISHAY IGBT驱动光耦应用指导.pdf

VISHAY SEMICONDUCTORS

Optocouplers and Solid-State Relays Application Note 91
IGBT/MOSFET Gate Drive Optocoupler
INTRODUCTION TO IGBT voltage drive, which means that it is possible to have a less
The Insulated Gate Bipolar transistor (IGBT) is a plex circuit with lower power pared to
between a MOSFET (metal oxide semiconductor field effect a BJT. IGBTs are used for high current, high voltage
transistor) and a BJT (bipolar junction transistor) since it applications when switching speed is important (table 1).
combines the positive aspects of MOSFETs and BJTs.
The IGBT has the fast switching capability of the MOSFET TABLE 1- IGBTS VS. MOSFETS
and is capable of handling the high current values typical of
IGBTS POWER MOSFETS
a BJT. In addition, IGBTs have a lower on-state voltage drop
TYPE VOLTAGE DRIVEN VOLTAGE DRIVEN
and are capable of blocking higher voltages.
Very high, small
Current density per High at low voltage
The IGBT, as a first approximation, can be modeled as a trade-off with
voltage drop low at high voltage
PNP transistor driven by a power MOSFET, as shown in switching speed
figure 1. Switchung losses Low to medium Very low
C
IGBT SWITCHING BEHAVIOR
One of the important performance features of any switching
device is the switching (turn-on and turn-off) characteristic,
since significant power losses are incurred during these