IGBT Modules - Technologies, Driver and Application (Second Edition) - page 234

6 I
Fig. 6.19
IGBTgatedrivewithemitter follower in theemitter path MOSFETpush-pull gatedrives
The push-pull gate drive with MOSFETs is widely used and allows the digital turn-on
and turn-off of the gate-emitter voltage of the IGBT. Operation in the linear region,
similar to theBJT emitter follower, however, is not possible. The IGBT is switched on by
the p-channel MOSFET T
, which is connectedwith its source pin to the positive supply
voltage. If the voltage at the gate of T
becomesmore negative than the source voltage,
turns on. The current I
, limited only by the gate resistor R
, charges the input and
reverse transfer capacitances of the IGBT. The turn-off of the IGBT is done by the n-
channel MOSFET T
. In this case, the gate current I
is limited by R
. The n-channel
MOSFET is connected with its source pin to the normally negative supply voltage. To
turn-on T
, the gate-source voltage needs to be 10V (depending on the specific type of
MOSFET) and 0V to turn-off the MOSFET.
hows an example of a MOSFET
push-pull gate driver with a control voltageof 5V.
Fig. 6.20
Exampleof aMOSFETpush-pull gatedrive
The MOSFET gate drive has the advantage that it can switch high gate currents with
very low control currents compared to gate drives using BJTs. Additionally, aMOSFET
1...,224,225,226,227,228,229,230,231,232,233 235,236,237,238,239,240,241,242,243,244,...548
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