Theory of operation, Insulated gate bipolar transistor (igbt) operation – Lincoln Electric INVERTEC SVM161-A User Manual
Page 40
THEORY OF OPERATION
E-6
E-6
INVERTEC® V205-T AC/DC™
INSULATED GATE BIPOLAR
TRANSISTOR (IGBT)
OPERATION
An IGBT is a type of transistor. IGBT are semiconduc-
tors well suited for high frequency switching and high
current applications.
Example A in Figure E.6 shows an IGBT in passive
mode. There is no gate signal, zero volts relative to the
source, and therefore, no current flow. The drain termi-
nal of the IGBT may be connected to a voltage supply;
but since there is no conduction, the circuit will not sup-
ply current to components connected to the source.
The circuit is turned OFF like a light switch.
FIGURE E.6 - IGBT
Example B shows the IGBT in an active mode. When
the gate signal , a positive DC voltage relative to the
source, is applied to the gate terminal of the IGBT, it is
capable of conducting current. A voltage supply con-
nected to the drain terminal will allow the IGBT to con-
duct and supply current to the circuit components cou-
pled to the source. Current will flow through the con-
ducting IGBT to downstream components as long as
the positive gate signal is present. This is similar to
turning ON a light switch.
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
DRAIN
SOURCE
GATE
INJECTING LAYER
BUFFER LAYER
DRAIN DRIFT REGION
BODY REGION
p +
n +
n -
p
n +
n +
DRAIN
SOURCE
GATE
INJECTING LAYER
BUFFER LAYER
DRAIN DRIFT REGION
BODY REGION
p +
n +
n -
p
n +
n +
POSITIVE
VOLTAGE
APPLIED
B. ACTIVE
A. PASSIVE