SCALE™-2+ 2SC0435T
Preliminary Description & Application Manual
www.power.com/igbt-driver
Page 9
VDC terminal
The driver has one VDC terminal on the interface connector to supply the DC-DC converters for the secondary
sides.
VDC should be supplied with 15V. It is recommended to connect the VCC and VDC terminals to a common 15V
power supply. In this case the driver limits the inrush current at startup and no external current limitation of
the voltage source for VDC is needed.
MOD (mode selection)
The MOD input allows the operating mode to be selected with a resistor connected to GND.
Direct mode
If the MOD input is connected to GND, direct mode is selected. In this mode, there is no interdependence
between the two channels. Input INA directly influences channel 1 while INB influences channel 2. High level
at an input (INA or INB) always results in turn-on of the corresponding IGBT. In a half-bridge topology, this
mode should be selected only when the dead times are generated by the control circuitry so that each IGBT
receives its own drive signal.
Caution:
Synchronous or overlapping timing of both switches of a half-bridge basically shorts the DC-link.
Half-bridge mode
If the MOD input is connected to GND with a resistor 72k<R
m
<181k, half-bridge mode is selected. In this
mode, the inputs INA and INB have the following functions: INA is the drive signal input while INB acts as the
enable input (Fig. 6). It is recommended to place a capacitor C
m
=22nF in parallel to R
m
in order to reduce the
deviation between the dead times at the rising and falling edges of INA respectively.
When input INB is low level, both channels are blocked. If it goes high, both channels are enabled and follow
the signal on the input INA. At the transition of INA from low to high, channel 2 turns off immediately and
channel 1 turns on after a dead time T
d
.
Fig. 6 Signals in half-bridge mode
