21
Components XXXI (1996) No. 3
APPLICATIONS
POWER SEMICONDUCTORS
components from the Semiconductor
Group’s range of single to four-channel
switches which are ideal for industrial
controls.
Four-channel driver IC with integrated
protection
The FZL 4146 is a driver IC in a standard
SO-20 package designed to drive four
p-channel MOSFET power transistors
(Fig.1). This component combines the ease
of direct driving by microcontroller with the
following features:
●
load current monitoring and limiting of
the driven transistors by external shunts,
●
short-circuit cutoff,
●
status feedback,
●
gate-discharge resistors for driven power
transistors,
●
gate-source zener diode for driven
power transistors, and
●
protection against line breaks.
Each of the four drivers has an active-high
input (DI1 to DI4). An enable input (ENA) is
also common to all stages. The load current
is measured via the RSC shunt (Fig. 2) and
limited by the respective output Q (1 to 4) if
required. If the load current exceeds the
set value, the connected power transistor
is protected by switching to pulsed opera-
tion. It is reactivated by the built-in clock
generator whose operation requires an
external capacitor C
E
at the CE terminal. If
C
E
is bridged by the normally closed contact
of a key, it is turned on again only when
the key is activated. The clock generator
has a pulse/pause ratio of 1:47. A short
circuit with respect to ground or excess
current is displayed at the status output SQ.
Smart power switches are
available for applications in
12 and 24 V DC systems.
Although they have been
predominantly used so far in
automotive electronics, they
also satisfy the requirements
of industrial automation.
Industrial controls in particular
open up a wide field of
applications for smart power
switches.
A
s microelectronics takes on more and
more applications, especially in auto-
mation and automotive technology,
higher performance is demanded from
power switches. In many cases, these re-
quirements can no longer be satisfied with
conventional electromechanical solutions.
Siemens offers a range of special compo-
nents for such applications. These include
an intelligent driver IC for power transistors
as well as a range of smart power switch-
es. In industrial electronics, smart power
switches must deliver a level of per-
formance similar to that required by auto-
motive electronics. As a rule, high-side
switches are required for loads connected
to ground. These switches should be pro-
tected, operate over a wide range of
temperatures and voltages, and, in certain
applications, generate a status feedback.
Whereas the driver IC was specially devel-
oped for industrial electronics, the smart
power switches represent a selection of
Peter Brauschke
Smart power switches
for industrial controls
Fig. 1 The FZL 4146 can drive four power transistors
IQ
&
IQ
&
IQ
&
IQ
&
BUV
ENA TS SQ
T
Q4
12 W4
11
Q3
14 W3
13
Q2
18 W2
17
Q1
20 W1
19
910 6
TS 16
SQ GND GND
ENA
DI4
DI3
DI2
2
8
7
4
DI1 3
CE 115
V
s
22
The inputs DI, ENA and W are safeguarded
against line breaks, i.e. open input DI or ENA
corresponds to input L, and open input W
corresponds to excess current. The maxi-
mum turn-on threshold is effective when
the TS input is open. Voltage monitoring
ensures that the outputs are disabled if the
supply voltage is too low.
Completely integrated in a minimum
space
Applications with compact modules and
extensive protection functions require
fully integrated components. A series of
fully protected power switches for loads
connected to ground (Table 1) satisfy the
requirements of automation technology.
They are divided into two performance
classes: Mini-PROFET (for currents up to
about 1.5 A) and PROFET (for currents of
approximately 1.5 to 9 A). These smart
power switches feature:
●
short-circuit protection,
●
input protection,
●
overtemperature shutdown with hystere-
sis,
●
overload protection,
●
limitation of the negative output voltage
when inductive loads are switched,
●
undervoltage shutdown, and
●
load current limitation.
Mini-PROFETs are available as current-
controlled or voltage-controlled switches.
The BSP350 is an example of a current-con-
trolled switch that is particularly suitable for
use as a signal transformer and amplifier for
Components XXXI (1996) No. 3
APPLICATIONS
POWER SEMICONDUCTORS
Fig. 2 Driver chip FZL 4146 with integrated protective functions for four power transistors
Fig. 3 The BSP 350 current-controlled switch is ideal as a signal transformer and amplifier for
long leads susceptible to short circuits
CE
C
E
Clock
Generator
Schmitt
Trigger
Schmitt
Trigger
Current
Regulator
RS
&
1
TS
ENA
DI
int.
V
S
GND
V
S
int.
V
SW
1x/Channel
IED01123
SQ
QT2
T1
R
Q
R
L
X
R
I
R
SC
V
S
Unused W-inputs are to
be connected to
V
S
GND
Control
Circuit
Temperature
Sensor
1IN
R
IN
R
L
+
V
bb
OUT
3
2/4
3
12
4
Mini-PROFET
Type
V
bb (AZ)
V
bb (on)
R
on (max)
I
L (ISO)
I
L (SC)
Package
BSP 350 >50 V 4.9 to 45 V 5 V0.07 A 0.2 A SOT 223
BSP 450 >45 V 12 to 40 V 0.2 V1.7 A 0.7 A SOT 223
BSP 550 >45 V 12 to 40 V 0.2 V1.7 A 1.4 A SOT 223
PROFET
Type
V
bb (AZ)
V
bb (on)
R
on (max)
I
L (ISO)
I
non
I
L (SCr)
I
L (SCp)
Package
BTS 410H2 >60 V 4.7 to 12 V 220 mV1.8 A 1.5 A 5.5 A TO 220/5
BTS 432I2 >60 V 4.5 to 42 V 38 mV11 A 33 A 42 A TO 220/5
BTS 612N1 >60 V 5 to 34 V 2 u200 mV2 u2.3 A 2 u4 A 2 u7.5 A TO 220/7
BTS 712N1 >60 V 5 to 34 V 4 u200 mV4 u1.9 A 4 u4 A 4 u7.5 A Standard SO-20
Table 1 Selection of Mini-PROFET and PROFET types for automation applications
23
long feed lines susceptible to short circuits
(such as for sensors or remote-controlled
relays). T o turn the component on, a voltage
difference of at least 5V is required between
pin 2 and pin 1 (Fig. 3). The maximum oper-
ating current is only 1 mA. The current is
limited to this value, i.e. it rises no further
even at the maximum permissible supply
voltage of 45 V. The operating current
supplies the energy required for the charge
pump to switch loads connected to
ground. If the permissible chip temperature
is exceeded, the component turns off, in
which case the charge pump is also deacti-
vated. This causes a significant change in
the current level at pin1, a situation that may
be used for evaluating the status. If
V
bb
between pin 1 and pin 2 exceeds 55 V, the
component is protected by an integrated
zener diode. The negative voltage peak at
the output produced when inductive loads
are turned off is limited to
V
bb
–55 V, thus
allowing rapid demagnetization of the load.
The potentials of logic ground and load
ground may differ by any amount within the
data sheet limits without impairing the
function of the component.
BSP 450 (Fig. 4) is a low-resistance voltage-
controlled switch with a high-resistance
CMOS-compatible input in an SOT-223 pack-
age. It is turned on by a positive voltage at
pin 3, while the output transistor is turned
on with the aid of the integrated charge
pump. The other protective functions are
comparable to those of the BSP 350. As a
variant of the BSP 450, the BSP 550 offers
higher current limiting for loads with a
greater current requirement.
The functions of the PROFET switches are
comparable with those of the Mini-PROFET
components. All PROFETs are voltage-
controlled components with high-resistance
CMOS-compatible inputs (Fig. 5). They
additionally have a status output that pro-
vides information on the status of the switch
or the connected load. The PROFET compo-
nents BTS 410H2 (220 mV) and BTS 43212
(38 mV) are available both in TO-220/5 pack-
ages and as SMDs.
The integration and packaging density of
industrial controls can be increased even
further by using multiple switches in a
single package. Such switches are already
available and include the BTS 612N1, a
two-channel switch with 2 u200 mVin
a TO-220/7 package, and the BTS 712N1, a
four-channel switch with 4 u200 mVin a
standard SO-20 package.
h
Components XXXI (1996) No. 3
APPLICATIONS
POWER SEMICONDUCTORS
studied electrical engineering at Augsburg and
Giessen Polytechnics. In 1984 he joined Siemens
in product marketing for SIPMOS transistors.
From 1986 onward he helped to set up and
market the Smart-SIPMOS product spectrum
worldwide. Since 1995, Mr. Brauschke (39) has
been responsible for product marketing of smart
power switches.
Peter Brauschke,
Dipl.-Ing. (FH),
Fig. 4 The BSP 450 voltage-controlled switch offers low resistance and full protection within a
minimum space
Fig. 5 All PROFETs are fully protected low-resistance high-side switches with a status output
GND
Control
Circuit
Temperature
Sensor
2
R
L
+
V
bb
OUT
1
4
IN
3
V
bb
min/max
3
12
4
2
Signal GND
ESD Logic
Voltage
sensor
Voltage
source
Overvoltage
protection
Current
limit Gate
protection
IN
4
ST
Limit for
unclamped
ind. loads
Open load
detection
Short circuit
detection
Temperature
sensor
GND
1
Charge pump
Level shifter
Rectifier
V
Logic
+
V
bb
5
3
OUT
Load
Load GND
Standard1
5
Straight leads 1
55
SMD 1Standard
SO-20
TO-220AB/5
Check #3-96-6(HL) on Reader Service Card
