The
circuit of figure circuit diagram shows the various parameters pertaining in
the IGBT characteristics.
Static
I-V or output characteristics of an IGBT (n channel type) show the plot of
conduct collector current IC versus collector-emitter voltage VCE for
various value of gate emitter voltages VGE1, VGE2 etc.
These characteristics are shown in figure static I-V characteristics.
In the forward directions, the shape of the output characteristics is similar to that of BJT. But here the controlling parameter is gate emitter voltage VGE because IGBT is a voltage-controlled device is when the device is of junction J2 to block the forward voltage and in case reverse voltage appears across collector and emitter junction J1 blocks it. In static I-V characteristics, VRM is the maximum reverse breakdown voltage.
The transfer characteristics of an IGBT is a plot of collector current IC vs gate emitter voltage VGE as shown in figure transfer characteristics. This characteristic is identical to that of power MOSFET when VGE is less than the threshold voltage VGET, IGBT is in the offset.
Output Characteristics :
- These connection are made as shown in the circuit
diagram.
- Now
increase the VCE voltage to the maximum position.
- When slowly increase the voltage across the VGE at certain voltage IGBT is turned on stop varying the voltage at that point.
- Then
reduce the voltage VCE to the minimum position.
- Now
vary VCE voltage slowly, correspondingly note down the VCE and
IC readings and plot the graph.
Transfer characteristic :
- These
connections are made as shown in the circuit diagram.
- In these characteristics when increase the
voltage VCE voltage to the maximum position.
- When
slowly increase increase the voltage across VGE and note
down the voltage VGE and current IC value
and plot graph.