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With the exception of the ixd408 the enable pin is

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Unformatted text preview: corporate a unique facility to disable output by using the ENABLE pin. With the exception of the IXD_408, the ENABLE pin is tied high internally. When this pin is driven LOW in response to detecting an abnormal load current, the Driver output enters its Tristate (High Impedance State) mode and a soft turn-off of MOSFET/IGBT can be achieved. This helps prevent damage that could occur to the MOSFET/IGBT due to Ldi/dt over voltage transient, if it were to be switched off abruptly, “L” representing total inductance in series with Drain or Collector. A suggested circuit to accomplish this soft turn off upon detecting overload or short circuit is shown in Fig. (2). It is also possible to do this by an independent short circuit/overload detect circuit, which could be a part of the PWM or other controller IC. All one needs to do is to take IXAN0009 output signal (FAULT) from such a circuit and feed it into the ENABLE pin of Driver. A resistor R P connected across Gate and Source or Gate and Emitter (as the case may be) would ensure soft turn-off of the MOSFET/IGBT, turn-off time being equal to RP(C GS + CGD) 4.2.1 LOW CURRENT DUAL IC DRIVERS Fig. (11) shows an interesting application for a 4 Amp Dual driver IC in a Phase Shift PWM Controller application, in which galvanic isolation is obtained by using Gate Drive Transformers. Note that this Controller operates at a fixed frequency. Turn-off enhancement is achieved by using local PNP transistors in secondary of gate drive transformer. For a vast number of low and medium current MOSFETs and IGBTs, 2 Amp to 4 Amp dual IC drivers provide a convenient tool and circuit simplicity, coupled with performance. 4.2.2 HIGH CURRENT IC DRIVERS These are eminently suitable for driving higher current MOSFETs and IGBTs and larger size MOSFET/IGBT Modules. Many circuit schematics applying these in various topologies are possible and some of these are shown in different figures. The 5 pin TO -263 surface mount version of some IC drivers can be soldered directly...
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