iC-DXC
DIGITAL SENSOR I/O DRIVER
nar y
limi
pre
Rev A0.8, Page 7/11
DESCRIPTION OF FUNCTIONS
iC-DXC is a current limited switching channel which
enables digital sensors to drive peripheral elements.
They are designed to cope with high driver currents.
The switches are reverse-polarity protected, feature a
free-wheeling circuit for inductive loads, and a current
limited output.
Reverse polarity protection
The pins VB, OUT an GND on the
line side
of the chip
are reverse polarity protected. As far as the maximum
voltage ratings are not exceeded, no possible supply
combination at the
line side
pins can damage the chip.
I(OUT)
Output characteristics of OUT
The switching channel is current limited to a value be-
tween 150mA and 450mA. (cf. Electrical Characteris-
tics Nos. 103, 104). The current limitation works only
for voltages higher than 3 V at OUT resp. lower than
VBO
−
3 V. For smaller output voltages the current lim-
itation is reduced in order to minimize the saturation
voltages without increasing the power dissipation. Fig-
ures 1 and 2 show the characteristic of the switching
channels when activated. Region "A" is the saturation
range, where the current limitation is not fully active yet
and region "B" is the current limited range. Region "C"
corresponds to the free-wheeling circuit activated. The
switching channel is designed so that the low side can
only sink current and high side can only source current
(no reverse current).
Free-wheeling circuit for inductive loads
The free-wheeling circuit is always present and does
not depend on the current output status. It is acti-
vated by voltages higher than 36 V at OUT referenced
to GND or lower than -36 V at OUT referenced to VB.
In that case the correspondent channel will switch on
without current limitation (see Figure 3).
I(OUT)
36V
Isc()lo
GND
3V
A
B
36V
VB
C
V(OUT)
Figure 1: OUT characteristic when Low side active
I(OUT)
VB-36V
C
Isc()hi
36V
GND
B
A
VB
V(OUT)
VB-36V
GND
VB
GND+36V
V(OUT)
36V
Figure 2: OUT characteristic when high side active
Figure 3: Free-wheeling characteristic
ICHAUS [ IC-HAUS GMBH ]
