Semikron 4 Control pin IGBT

Question

Below is the datasheet of the IGBT https://www.semikron.com/dl/service-support/downloads/download/semikron-datasheet-skm75gb063d-22890050

It has 4 Control Pins , Number 4,5,6,7 . Generally a MOSFET has a single gate which is used to trigger the saturation mode (Short Circuit Collector and Emitter).

I'am confused here , can someone help me out on how to perform ON , OFF switching with these 4 pins available .

Thanks

Answer 1

From a drive point of view, an IGBT is very similar to a MOSFET

An IGBT,like a MOSFET is a 3 terminal device. It is controlled via the Gate-Emitter (gate-source for a MOSFET) voltage

To turn on a MOSFET you must raise the GATE voltage with respect to the SOURCE above the threshold voltage. Likewise to turn on an IGBT you must raise the GATE voltage with respect to the EMITTER above the threshold voltage

You are probably used to seeing the SOURCE of a MOSFET ground/earth/0V referenced and thus this key driving requirement appears as just a "gate voltage."

This particular IGBT module you are linking is an inverter leg made from 600V IGBT's. You will most certainly an isolated driver circuit that is capable of at least 600V+ between the primary & secondary which can also tolerate at 1500V/us dv/dt

When the voltage between pins4 & 5 (gate and emitter) exceeds 5.5V the left and IGBT will facilitate current flow from terminals 3 to 1

When the voltage between pins6 & 7 (gate and emitter) exceeds 5.5V the left and IGBT will facilitate current flow from terminals 1 to 2

Answer 2

The easy answer: An IGBT needs a gate-emitter voltage in order to turn on (that is, a voltage between the gate and the emitter) and having it set up this way makes it easy to access both of the important connections with a simple positive and negative wire. The SEMIKRON module you posted contains two IGBTs in a half-bridge configuration, which means you can switch the IGBTs alternately to get different output connections (connect the load to ground or connect it to a voltage source). You could also use two of them together to get an H-bridge, which can alternate the current through the Pin 1 connection. Either way, it makes it much easier to switch the IGBTs individually when you can access their own gates and emitters directly.

Answer 3

Short answer

It's a Half-Bridge IGBT with a Gnd routed to the low V side with tandem CE contacts for internal Kelvin current shunt conductors to pins 5&7 for external I_sense amplifiers .

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Long answer

**Why two active Drivers ** 2 IGBT's are better than 1

• Less power dissipated, faster switching times more modes of switching for different load types

Why so many pins? Ease of Kelvin current sensing from Low Voltage side with Rs of Emitter Current sense bond wires, which must be calibrated, as no specs are given.

How is used in industrial applications?

How flexible? What switching modes?

• Neutral Switch (NS), Zero Voltage Resonant Switch (ZVRS), Zero Current Resonant Switch (ZCRS), Zero Voltage Switch (ZVS), Zero current switch (ZCS), Hard switch (HS) (e.g. PWM)

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Since this was a newb question, I thought some may benefit from the reasons for this topology. ( and some may resent it)

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• Have you ever looked at TTL output stage? It has similarities.

• Although the name is fading out of favour, it was called a Totem Pole or Push-Pull driver. This is just for historical similarity in topology except 1,667x more current capacity.
• (joke) It looks like the pole came down in their schematic.
• the separate 100A Free Wheel Diodes have equal current capacity to the output stage and offer additional protection or flexibility in design.
• In MOSFET topology , it's also called a half-bridge that allows you keep impedance low for each half cycle rather an open drain topology with a T=L/Rs discharge time for value of Diode Rs similar to 20 mOhms of IGBT specs.
• For historical reference CMOS has reduced Vcc, 18Vmax down to 3.6Vmax with scaled outputs for Vgs, RdsOn now also down to 50 or 25 Ohms in different families.

• except for SMPS the impedance of charging low ESR caps must be driven by Rce values of equal or lower values which determines tradeoff between match impedance for low ripple or lower source impedance for high efficiency but higher peak ripple currents.

• so although this power half-bridge has very little resemblance with a Schottky gate or a CMOS gate they are all Push-pull drivers, yet the Transmission Line and Characteristic Impedance Rules still apply to both for well-controlled pulses with minimum ringing where ESR and ESL (inductance ) of cabling to load is also critical as well as Common Mode (CM) noise.