IGBT Modules - Technologies, Driver and Application (Second Edition) - page 68

proportionate to the main emitter current. IGBTs with integrated current measurement
are calledCurrent Sense IGBTs.
The signal can be evaluated bymeans of an external circuit comprising, for example, a
low-impedance resistance R
, and if applicable, subsequent circuit amplification and
isolated signal transmission
shows an example of how the gate
can be turned off directly by a simple circuit (in this example no signal is sent to the
microcontroller). In a parallel connection, the current is usually measured in only one
IGBT chip, while the sense emitter is connected directly to themain emitter on the other
Integrated current measurement is frequently used in IPMs (chapter
, some of
which contain a microcontroller, so as to evaluate the signals of all the IGBTs and
transmit this via a common terminal as a serial signal.
It should be noted that integrated current measurement within the IGBT chip does not
take into account the currents of the freewheeling diodes (although it does pick up their
reverse recovery currents) andmore external current sensors may need to be included
in the design if theapplication so requires.
Fig. 1.49
Use of Current Sense IGBTs, illustratedby a half-bridge circuit
Integrated temperaturemeasurement is usually achieved with a pn-junction (diode), the
forward voltage of which is temperature-dependent and can be evaluated using an
external circuit. A good estimate for silicon is a dependence of the forward voltage on
the temperature of approximately 1.7
, i.e. a 1K increase in temperature increases
the forward voltage by about 1.7mV. Just as in a Current Sense IGBT, integrated
temperature measurement is frequently used in IPMs. It is worth remembering that, in
all commercially available IGBT modules so far, only the temperature of the IGBT is
picked up, not that of the freewheeling diodes, so that their temperature cannot be
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