EVBUM2528/D
13
UVSET
The UVSET function is set by R2 and determines the
UVLO turn
−
on threshold. The EVB is preconfigured with
R2 = 113 k
W
which equates to UVLO turn
−
on (V
ON
) of
~17 V. The UVLO turn
−
on threshold can be changed by
selecting R2 according to a desired UVLO turn
−
on
threshold, V
ON
:
R
2
+
V
ON
6
25
m
A
(eq. 1)
DESAT
DESAT is a type of over
−
current protection dedicated to
monitoring the I
D
xR
DS
of the SiC MOSFET. The EVB is
preconfigured with R11 = 4.99 k
W
(DESAT resistor). The
internal DESAT threshold is fixed at V
DESAT(TH)
=7.5V and
the DESAT signal amplitude is adjustable by R11.
R11 = 4.99 k
W
may not be the correct resistor value for
some applications. If V
DESAT
> 7.5 V during normal
operation, decrease R11 to lower the signal amplitude. If
DESAT is active, the trailing edge of the OUT pulse is
terminated or reduced with respect to the input pulse (IN+).
The waveforms shown in Figure 16, show VDESAT < 7.5 V
during normal, 80 kHz, operation. Since DESAT is
operating with no load, the amplitude is varied by varying
the IN+ frequency. Figure 17 shows IN+ increased to
150 kHz and VDESAT = 7.5 V. The trailing edge of OUT is
clearly terminated compared to IN+ indicating that DESAT
is active.
