also the secondary side (high-voltage side) of the optocoupler. Hence, in a full-bridge
inverter as shown in
for each upper IGBT a separate optocoupler and an
isolated power supply is needed. The bottom IGBTs can by operated, depending on the
application requirements, without isolation or with isolation provided by optocouplers.
Here then, at least one supply voltage (all bottom IGBTs are referenced to a common
ground) or a maximum of three supply voltages (each IGBT has its own ground as a
referencepoint) are required.
Example of propagation delay times andmismatches of the optocoupler driver