Application Note #42 Conducted Transients in Road Vehicles

Application Note #42 Conducted Transients in Road Vehicles
Application Note #42
Conducted Transients in Road Vehicles’ Supply Lines
Over the last thirty years, the number of electrical/electronic modules used in road vehicles has increased
dramatically. The modules are used in many diverse functions, including engine and transmission control,
comfort and entertainment functions (radio, air conditioner and heater) and critical safety features (antilock brakes and air bag systems).
All of the electrical and electronic systems must operate without
interfering with each other and without reaction to outside interference signals. The road vehicle is
subjected to radiate RF signals as well as onboard radiating signals of its own. In addition, the vehicles
electrical system generates transients that are conducted via the power lines to the electrical/electronic
modules connected to it. This note explains the transients that are conducted via the vehicle power
system and the means by which the electrical/electronic modules are tested for immunity to the conducted
The ability of the road vehicles electrical/electronic system to operate in the vehicular electromagnetic
environment is called Electromagnetic Compatibility (EMC). The U.S. government does not regulate the
EMC of road vehicles in the sense that it regulates EMC of other equipment such as telephones and
medical devices. The major controlling documents for EMC in road vehicles are created by the vehicle
manufacturers themselves.
In the U.S., these are mainly the big three auto manufacturers,
DaimlerChrysler, Ford and General Motors. In addition, specifications outlining EMC performance for
road vehicles are written by the Society of Automotive Engineers (SAE) and the International
Organization for Standardization (ISO).
Standards Used in Road Vehicle Transients on Supply Line Testing
Automotive engineers want to insure that any electronic system used in the vehicle is able to function in
its automotive environment. One way to do this is to test the module to a pertinent standard during its
development and procurement. If all electronic modules pass the transient testing, then all modules
should work in the actual automobile environment if the standard and transient generator used for the
testing accurately resembles the vehicle electrical system in operation. Therefore, the transients and the
transient generators used to qualify the electronic modules are characterized in the standards used by the
manufacturers. A final functional test in the vehicle is performed to assure compatibility of all modules in
conjunction with each other.
As noted above, this application note applies to transients conducted along the vehicle DC supply lines.
The transients discussed pertain to 12 V and 24 V systems, although much discussion has been going on
about 42 V systems, an universal agreement by automotive engineers has not been reached on the
definition of 42 V system transients. In the past few years, most of the major automotive manufacturers
have migrated their transient definitions to match some or all of ISO 7637-2, which is the International
Standard most recently published in the Second Edition in June 2004 by ISO.
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Below are some of the common specifications encountered by module designers and test engineers:
ISO 7637-2
SAE J1113-11
SAE J1455
DC 10614/10615
GMW 3097
GMW 3172
JASO D001-94
Applicable to:
International standard for Supply Line Transients
USA Standard by the Society of Auto Engineers
USA Standard by the Society of Auto Engineers
DaimlerChrysler Standard
Ford Standard
General Motors Standard
General Motors Standard
Japanese Automotive Standard
Table 1: Vehicle Transient Standards.
Road Vehicle Transients Observed
As noted above, the International Standard, ISO 7637-2 is being used by many in the automotive industry
as the basis for transient specifications; we will review the characteristics of ISO 7637-2 pulses. The
International Organization for Standardization labels the transient characteristics as pulses 1 through 5.
The transients generated in the vehicle are created when systems are switched by relays or when solenoids
are activated and deactivated or the connected electronic modules perform some intended operation.
The switching operation causes changes of current flow along the vehicle wiring system. This creates
transients on the power system because of the inherent parasitic effects of the distributed vehicle wiring.
In other words, the vehicle wiring is inductive and capacitive in nature which then generates transients in
the vehicular system. It is these transients that can cause unintended functions in electronic modules
connected to the system supply if the modules themselves are not impervious to the applied transients. At
some point in the past, the generated transients where observed in the vehicle after peculiar and
unintended electrical functions occurred. As a result, specifications were developed by the manufacturers
and other international organizations to require transient testing of electronic modules. Shown below in
Figures 1 through 11 are the depictions of the transients commonly encountered in the Road Vehicle
Pulse 1
Figure 1: ISO 7637-2 Pulse 1 wave shape and key parameters.
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Figure 1 above illustrates the ISO 7637-2 Pulse 1. Pulse 1 simulates a negative polarity transient caused
by the disconnection of the DC supply through an inductive load. This pulse applies to a device under
test (frequently called a DUT) as used in the vehicle and connected directly in parallel to an inductive
load. It is important to note that the vehicle DC power is first removed during the period t3 and the
negative pulse is then discharged into the DUT. If the DC power were not removed, the negative Pulse 1
would be absorbed by system battery or battery simulator and not by the DUT, rendering the test
pointless. Rise and fall times are specifically designated from 10% to 90% of maximum amplitude for all
pulses. Pulse duration (td) is also specified for each pulse. Long duration pulses can cause more stress on
the DUT as can faster rise times. Peak voltage, Us, varies according to the classification of the DUT.
DUT's with more critical functions are subjected to larger amplitude voltages. The repetition rate (t1)
and number of pulses applied to the DUT is usually controlled by the procurement agency and it varies
dependent upon the intended system function of the DUT.
12 V System
-75V to -100V
10 Ω
2 ms
1 +0/-0.5µs
0.5 to 5 s
200 ms
≤ 100 µs
24 V System
-450V to -600V
50 Ω
1 ms
3 +0/-1.5µs
0.5 to 5 s
200 ms
≤ 100 µs
Table 2: Pulse 1 Characteristics
Notice in Table 2 that the source impedance (Ri) is specified. This will be important during bench testing
of the DUT because it will influence the amount of energy delivered to the DUT. All the vehicle
transient testing specifications describe the transient generator as an ideal pulsed transient generator with
a series source resistor (Ri) that is purely resistive in nature.
Pulse 2a
Figure 2: Pulse 2a wave shape and key parameters.
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ISO 7637-2 Pulse 2a above simulates transients caused by sudden interruptions of current in an inductive
component connected in series with the DUT. The positive Pulse 2a is superimposed on the vehicle DC
supply voltage. This pulse usually occurs in the vehicle when the ignition is switched on.
Pulse 2a replaced Pulse 2 in the newest edition of ISO 7637. Pulse 2 was applied to the DUT with the DC
power to the DUT removed. This was the time t2 referenced in Table 3 below. This time was 200ms, the
time the power was removed from the DUT. Essentially, the old Pulse 2 test was merely a life test for the
DUT. With the change of specification to Pulse 2a, this test became a functional test and it is likely to
uncover more failures in the DUT. Also, the source resistance was reduced from 10 ohms to 2 ohms and
the amplitude of Pulse 2a has been reduced from a maximum of 100V to 50V.
12 V System
37 to 50V
50 µs
10 +0/-0.5µs
0.2 S to 5S
Not Applicable
24 V System
37 to 50V
50 µs
10 +0/-0.5µs
0.2 S to 5S
Not Applicable
Table 3: Pulse 2a Characteristics
Pulse 2b
Pulse 2b is newly incorporated in the latest versions of ISO 7637, but automotive engineers have long
known of its existence in the vehicle. This is frequently called the "PM motor rundown pulse" or the
"motor shutdown pulse". This name refers to a permanent magnet motor such as the cooling or heating
system blower motor, acting as a generator once the power to the motor has been removed. It was first
noticed in automotive radios as a "burring" noise through the radio speaker when the ignition key is first
turned off with the blower fan operating. It is a result of direct coupling of the radio speaker from the
audio output transistors of the radio instead of using a coupling transformer. This type of audio output
design was first utilized in the early 1970's. The blower motor supplies DC power to the audio system even
though the DC supply has been removed. As a result, the auto engineers required testing of the radio and
suppression of the phenomena. Subsequent specifications added testing of the motor shutdown pulse for
all electronic modules and as a result it has become a requirement in international test specifications as
well. The pulse waveshape is shown below in Figure 3.
In figure 3, the time td is the amount of time voltage is being supplied by the PM motor after the DC
power to the vehicle modules has been removed. The DC power is off for 1 to 1.5 ms and then the PM
motor voltage is applied for a period of 0.2 to 2.0 seconds. All electronic modules used in the vehicle
must be impervious to this spuriously generated voltage.
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Figure 3: Pulse 2b wave shape
12 V System
10 V
0 to 0.05 Ω
0.2 to 2.0 S
1.0 +/-0.5 ms
1.0 +/-0.5 ms
1.0 +/-0.5 ms
24 V System
20 V
0 to 0.05 Ω
0.2 to 2.0 S
1.0 +/-0.5 ms
1.0 +/-0.5 ms
1.0 +/-0.5 ms
Table 4: Pulse 2b characteristics
Pulse 3a
Figure 4: Pulse 3a wave shape and key parameters
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12 V System
-112V to -150V
50 Ω
0.1 +0.1/-0µs
5 +/-1.5ns
100 µs
10 ms
90 ms
24 V System
-150V to -200V
50 Ω
0.1 +0.1/-0µs
5 +/-1.5ns
100 µs
10 ms
90 ms
Table 5: Pulse 3a characteristics
Pulse 3b
Figure 5: Pulse 3b wave shape and key parameters
12 V System
+75 to +100V
50 Ω
0.1 +0.1/-0 µs
5 +/-1.5ns
100 µs
10 ms
90 ms
24 V System
+150 to +200V
50 Ω
0.1 +0.1/-0 µs
5 +/-1.5ns
100 µs
10 ms
90 ms
Table 6: Pulse 3b characteristics
Pulse 3a and 3b are negative and positive pulses that are identical in characteristics except for their
polarity. They are similar to pulses identified in industrial and commercial EMC testing specifications as
high frequency switching transients that occur on AC power mains and are called Electrical Fast
Transients (EFT). In the vehicle their origins are similar in that these fast transients occur as arcing
across contact points in mechanical switches and relays. Distributed capacitance and inductance in the
wiring harness influence these transients, since the transients have rise and fall times (<5 ns) in the RF
frequency range (>200 MHz). As a result, these transients are coupled by conduction and via radiation
within the DUT. This can cause timing errors, memory losses and other functional errors within the
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DUT. DUT malfunctions caused by Pulse 3a and 3b are usually associated with wire placement problems,
system grounding problems and pc board layout problems.
Pulse 4
Figure 6: Pulse 4 Wave shape and key parameters
12 V System
-6 to -7 V
-2.5 V to -6V with |Ua| ≤ |Us|
0 to 0.02 Ω
15 ms to 40 ms
≤ 50 ms
0.5 to 20 S
5 ms
5 to 100 ms
24 V System
-12 to -16 V
-5 V to -12 V with |Ua| ≤ |Us|
0 to 0.02 Ω
50 ms to 100 ms
≤ 50 ms
0.5 to 20 S
10 ms
10 to 100 ms
Table 7: Pulse 4 characteristics
When the starter motor of the vehicle using an internal combustion engine is engaged, there is a very
large current drain on the vehicle battery (in the neighborhood of 400 amps). As a result of this large
current drain and the wiring resistance within the vehicle, the DC supply voltage to the vehicle electronic
systems is reduced. ISO 7637 Pulse 4, shown above in Figure 6, is a simulation by the vehicle standards of
this voltage reduction. Frequently known as the "crank pulse", the reduction in voltage to the electronic
modules can cause malfunctions if it is not properly accounted for. In the very recent past, there have
been cases where auto radios have lost their preset memory during this transient. This resulted in the
driver having to reset all his preselected station choices and radio time. Other vehicles have been known
to have ignition system problems during the crank cycle causing unprogrammed states to occur.
Pulse 5a and 5b
When electronic systems first appeared in vehicles during the early 1960's, mysterious failures occurred
periodically in the systems. The randomness and frequency of the failures led some auto manufacturer
managers to doubt the cost effectiveness of using electronic components in the largely mechanical auto
environment. In one case, early versions of electronic ignition systems were withdrawn from the vehicle
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design because of excessive failures. Since solid state devices were in the early stages of their use, this tack
seemed prudent. At the same time, alternators replaced generators as the battery charging source.
Alternators provided charging currents that were more consistent over all engine RPM ranges.
Failure analysis of the damaged electronic systems revealed that transistors directly connected to the DC
supply lines were completely "blown" or destroyed by high amounts of energy. The energy required to
blow the transistors was much higher than any known available energy in the vehicle DC supply system.
Investigation into the automotive charging system revealed that when the alternator is charging a fully or
nearly discharged battery, a large amount of current is flowing into the battery. When the battery cables
become corroded or frayed or otherwise disconnected from the charging battery, a very high energy pulse
is impressed upon the vehicle DC system. This high energy pulse is called "Load Dump". The load dump
pulse has the energy to destroy an unprotected electronic system. This is the reason for the failures in the
early electronic systems. As a result, auto manufacturers later added suppression zener diodes on the
output of alternators. The diodes clamped the load dump pulse to a maximum of about 32 volts, reducing
the damaging ability of the pulse. In an unsuppressed system, the load dump pulse can exceed 100 volts.
Also, the auto manufacturers added a load dump pulse testing requirement for the electronic modules.
The load dump pulse became known in most specifications as Pulse 5. In the latest versions of ISO 7637,
the load dump pulse is Pulse 5a and the zener diode suppressed pulse is Pulse 5b. The load dump pulse is
the highest energy pulse in the transient testing requirements of ISO 7637. Figure 7 below shows pulse 5a,
the unsuppressed pulse and Figure 8 shows the suppressed Pulse 5b. The pulse characteristics are shown
in Table 8 and Table 9.
Figure 7: Unsuppressed Pulse 5a wave shape and parameters
12 V System
65 to 87 V
0.5 to 4 Ω
40 to 400 ms
10 +0/-5 ms
24 V System
123 to 174 V
1 to 8 Ω
100 to 350 ms
10 +0/-5 ms
Table 8: Pulse 5a characteristics
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Figure 8: Diode Suppressed Pulse 5b wave shape and parameters
12 V System
65 to 87 V
As specified by the customer
Same as Unsuppressed Value
24 V System
123 to 174 V
As specified by the customer
Same as Unsuppressed Value
Table 9: Pulse 5b characteristics
Other Transients
Older versions of the ISO 7637 specifications included two additional pulses not discussed in this
application note: Pulse 6 and Pulse 7. Pulse 6 is a negative transient of 300 microseconds pulse width
associated with current interruption in a breaker point ignition system. Pulse 6 has been discontinued
because virtually all road vehicles now use electronic ignition systems and do not use breaker points.
Another discontinued pulse is Pulse 7. Pulse 7 also is a negative pulse of 100 milliseconds pulse width
called the "Field Decay Pulse". This pulse was associated with the decaying alternator field in systems
using mechanical voltage regulators. Pulse 7 was likewise discontinued because electronic voltage
regulators have long since replaced mechanical voltage regulators. Some off-road vehicles such as
tractors or snowmobiles may still include pulse 6 and 7 in their requirements.
Table 1 above lists the common specifications encountered by module designers and test engineers and we
have focused on ISO 7637-2 since most of the manufacturers use this standard as a basis for their
specifications. Car manufacturers test requirements are based on their own investigations of their vehicles
and hence include more test requirements that need to be fulfilled. Some of the more interesting ones are
shown below.
Negative Pulse 2a
This pulse represents a negative version of Pulse 2a above and is created in some vehicles when the wiper
motor returns to the off position.
Battery System Transients
A large number of tests are required in automotive specifications involving transients associated with the
battery DC supply systems. Some are shown below:
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Figure 9: Cranking Pulse
The voltage drop on the automotive DC supply system in Figure 9 is similar to ISO 7637 Pulse 4 crank
pulse, with the addition of a low frequency signal of about 2 to 5 Hertz superimposed during the reduced
battery voltage period. In the case of Ford Motor Company, a cranking pulse similar to Figure 9 is applied
simultaneously to up to four inputs in the DUT. Ford calls this pulse CI 230. Some modules have more
than one DC input supply line. An example is the radio, which has a battery direct DC input and two
inputs from the ignition switch when the switch is in the accessory mode and in the run mode. The
battery direct input is always on to maintain preset selector memory positions and other memory
functions. This test insures that the module does not malfunction during the engine start routine.
Figure 10: DC system voltage dropouts
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Figure 11: DC system voltage dips
Figures 10 and 11 illustrate voltage dropouts and dips that can occur on the DC battery supply system
because of load variations on the battery caused by switching. Electronic modules must not malfunction
or cause unprogrammed actions to occur during these DC supply variations.
Other battery DC supply system conditions that are tested in various specifications include reverse voltage
tests that can occur when the battery cables are accidentally reversed; Overvoltage conditions in excess of
the normal DC supply range and chattering relay pulses on the DC system to name a few of the many tests
encountered by the electronic module suppliers.
Transient Simulation
For the automotive equipment suppliers who must test their electronic modules to the customer's
specification, it is not practical to have the end customer test every module in its vehicular environment.
Therefore, ISO 7637-2 and other international and auto manufacturer specifications define the test set up
to be used for bench testing the modules in addition to the test pulses that must be applied to the DUT.
The transient test pulses to be applied to the DUT must be generated by a Transient Simulator. The
Transient Simulator must be able to generate the specified transient pulses and meet the voltage
amplitude, pulse width and rise time, source impedance and waveshape characteristics of each pulse. In
addition, ISO 7637-2 outlines a pulse verification procedure in Annex D. This verification process
requires the test engineer to use an oscilloscope to verify the transient pulse characteristics in an open
circuit condition and under a matched load condition. Matched load conditions occur when the
simulator load resistance is equal to the source resistance (Ri) specified for each test pulse.
The test specification details the values of the voltage (Us), rise time (tr) and pulse width (td) and
tolerances for both the open circuit and loaded circuit conditions. As a result, the supplier must either
procure the Transient Simulator on his own or he must have his product tested by a qualified test
laboratory that has adequate transient test equipment to verify compliance with the required specification
AR’S Solution
When specifying immunity test equipment, the test engineer must consider the international standards
and car manufacturer’s specification requirements. Many of the car manufacturer’s specifications require
more sophisticated test equipment than is necessary to comply with the international standards only. In
addition, the specification requirements and their test pulse characteristics are frequently changed. As a
result, automotive suppliers and test laboratories need to carefully evaluate their transient test equipment
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in order to fulfil the various test requirements with a minimum of cost with a maximum of performance.
A summary of desirable Transient Simulator attributes are given as follows:
1. A compact, self contained and configurable broad-based testing solution to simulate the many
different pulses worldwide specifications require.
2. The simulator must be flexible to accommodate changes in the pulse characteristics as the
standards change.
3. The ability to make custom designed waveforms is a big plus to eliminate the necessity of
purchasing new test equipment on a regular basis.
4. An easy to use test solution that simplifies the test environment resulting in greater accuracy of the
test and the results.
5. A transient test system approach works best because the user can automate and integrate the test
procedure for efficiency, accuracy and cost effectiveness.
6. A pulse verification system that is built into the Transient Simulator will also greatly speed up the
test process improving the accuracy and documentation of the results.
7. Finally, the test pulses applied with their verification data and the test results will need to be
documented to the customer in a complete test report.
How the TGAR Fulfills the Above Attributes
To meet the challenge, AR designed the TGAR (Transient Generator AR) to make difficult testing
environments much simpler and easier for any level of user ability. The TGAR system is completely
software controlled and is packaged in a 19-inch rack and is available with a 32 or 100 amp DC supply
capability. Each rack system includes the following items:
1. A DC source that simulates the road vehicle battery system. This includes pulses 2b, 4 and
cranking pulses.
2. Pulse generators to produce pulses 1, 2a, 3a, 3b, 5a and 5b and similar automotive specification
requirements. The pulse generators include all required source resistances.
3. A complete computer system including the LCD monitor with software for pulse configuration,
pulse verification, system control and report writing.
4. A network for coupling the generated transients onto the DC line. The coupling network outputs
are conveniently located on the right side of the rack to mate with the test table.
5. Onboard oscilloscope for pulse verification.
6. A PXI box which also contains an embedded computer, data acquisition card and arbitrary
waveform generator.
For testing to the standard, the TGAR user can select the required pulse from a library of test standards.
These tests are set up with all of the default parameters required to run tests according to the selected
standard. In today’s harsh electronic environment, testing to the standard may not be sufficient to catch
immunity problems. The user may need to test beyond the standard envelope. The TGAR solution is
designed to give the user the flexibility of testing beyond the specification by simply changing the
necessary parameters to test the DUT to higher disturbance levels. This gives the user some confidence
that the product will operate in conditions beyond the specification.
For custom pulse creation, the operator can utilize the TGAR Labview-based software along with the
built-in arbitrary waveform generators. The software will provide the user with the tools to create
waveforms from defined waveshapes like sinusoidal, triangular, square wave, lines (horizontal, vertical or
sloping) and others.
The TGAR system is designed to comply with the ever-changing test standards encountered in the
automotive industry. To keep up with the standards, upgrades to existing transient simulators, including
changing hardware, firmware and software every year or two, can be quite expensive. An example of this
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process is a system that is designed with specific firmware for each stand-alone generator. This requires an
upgrade each time specifications change. This is a very costly process for the tester. It involves crating up
the entire transient generator system and sending it back to the manufacturer for upgrade. This upgrade
process (depending upon the complexity of the changes) can take around 2-4 weeks time. During this
time the customer is without a system and cannot perform any transient tests.
AR designed the TGAR to avoid the substantial costs involved in upgrading hardware and firmware.
Most specification changes can be simply updated by downloading a new version of the TGAR software
from the AR website.
As pointed out above, transient pulse verifications are required under both open circuit and loaded circuit
conditions. The pulse verifications then need to be incorporated into the test report for product
certification to the end customer. Most transient generator manufacturers require the use of external
oscilloscopes to perform this verification, commonly requiring the writing of software drivers to
communicate with the external verification equipment. TGAR is designed with an onboard oscilloscope
to greatly simplify the pulse verification process. The onboard oscilloscope allows the user to easily
capture the required waveforms and automatically include them into the test report. The captured pulses
contain the measured parameters such as the rise-time, pulse width and amplitude. For each pulse
verification, the required pulse parameters are compared to the specification to see if the pulse is within
the tolerance. A Pass/Fail indication is then given for the verified pulses.
The TGAR Configuration
System Layout
Two different configurations of TGAR are available. The TG6032 has a base DC output current rating of
32 amps and the TG6100 can supply DC currents up to 100 amps. The two versions contain the same
TG6000LD Load Dump generator, but due to the specific current rating of each system, the remaining
modules are unique to that particular version.
The TG6032 system contains 4 major modules:
TG6032BU, TG6032PS, TG6000LD and the auxiliary supply. All of the modules reside in a 19” rack
totaling 69” in height. Figure 12 below shows the layout of the TG6032.
The TG6100 is housed in 2 separate racks, one rack for the 100 amp TG6100PS DC supply and the rest of
the equipment will reside in a rack next to the TG6100PS. The modules for the TG6032 are described in
detail below.
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Figure 12: TG6032 Layout
Figure 13: TG6100 Layout
TG6032 Model Specifications
TG6032BU Base Unit
The TG6032BU serves as the hub of the system and is the starting block that allows other modules to be
added to form a complete test system. This module as well as the system is controlled by an embedded
computer that provides the system control and report writing. The embedded computer is contained
within the PXI box along with an onboard oscilloscope, data acquisition card (DAQ) and arbitrary
waveform generator. The onboard oscilloscope allows the user to perform pulse verifications and
incorporate them directly into the test report. The DAQ card contains analog inputs as well as 8 digital
I/O lines for control of the entire system. The I/O lines trigger relays and control circuits located
throughout the TG6032 system. The arbitrary waveform generator card is used in conjunction with the
TG6000 software (supplied with the system) to generate various voltage profile pulses.
The TG6032BU can be used to generate the following ISO 7637-2 (2004) pulses: inductive switching
pulses 1 and 2a, Electrical Fast Transient (EFT) pulses 3a and 3b, and it includes a fast switch for voltage
dip/drop tests. Also included with this module is the main coupling/decoupling network used to couple
transients onto the DUT DC supply line. The decoupling network serves the purpose of blocking the
transient from going back into the system DC supply line. This coupling network is rated at 32 amps
continuous current. Also included on the front panel of the TG6032BU is an external impedance jumper,
allowing the user to add a resistor in series with the internal impedance to achieve the desired source
impedance. This impedance would only be necessary for unusual applications that require a source
impedance not contained within the system. The load dump pulse is also coupled onto the DC line
through the coupling network. The coupling network provides the +/- battery outputs, the multiple Ford
CI 230 pulse outputs, along with the 50-ohm coaxial port for connection to the Automotive Capacitive
Coupling Clamp for application of pulses 3a and 3b to DUT I/O data lines. All of these outputs are
located on the right hand side of the system to conveniently mate up with the test table in most
laboratories. The TG6000 software also allows the user to generate custom pulses via the inductive pulsegenerating module. Some of the technical specifications for the covered pulses listed in the table below.
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TG6032BU Base Unit Specifications
Pulse 1 and 2a Inductive pulses per ISO 7637Pulse 3a and 3b per ISO 76372(2004)
Test Level Output
Test Level Output
Open Circuit Voltage Vs= 20-600V +10% (The peak
20-1,000V +10%
voltage and polarity are
dependent upon the selected
standard.) 1100V pulse for
Volvo and ISO 7637-2 (1990)
version available with the
optional module.
ISO 7637-2 (2004) Pulse 1 (12 Volt system)
Waveshape 5/100 ns
Rise time tr (10-90%
1 μs +0/-50%
Verification As per Annex D of
of waveform)
ISO7637-2 with a 50 and
1000 Ω load
Pulse duration td (10- 2 ms + 10%
Z= 50Ω
10% of the
Internal Resistor
10 Ω + 10%
Positive and negative
ISO 7637-2 (2004) Pulse 1 (24 Volt system)
Rise time tr (10-90% of
3 μs +0/-50%
Via 50 Ω coaxial
Pulse duration td (101 ms + 10%
Coupling Mode
To the + battery
10% of the waveform)
Internal Resistor
50 Ω + 10%
ISO 7637-2 (2004) Pulse 2a (12/24 Volt system)
Rise time tr (10-90% of
1 μs +0/-50%
Pulse duration td (1050 μs + 10%
10% of the waveform)
Internal Resistor
2 Ω + 10%
+/- output
Central DUT output
To the + battery line
Via diode and battery supply
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TG6032PS DUT DC Power Supply
The TG6032 is a programmable power supply that provides the DUT with the operating voltage up to 60
Volts 32 amps. This simulator supplies the following pulses per ISO 7637-2 (2004): Pulse 2b and 4
(Cranking Pulse).
TG6032PS Specifications
Programmable Power Supply for pulses 2b and 4 per ISO 7637-2(2004)
Test Level Output
Test voltage
0-60 Volts
Current rating
32 Amps Continuous
Peak Current (Inrush)
70 Amps Peak (500ms)
Coupling Mode
Thru the TG6032BU coupling network
Auxillary DC Supply
This Auxiliary Supply generates the voltage required to perform voltage dip tests. It is also utilized along
with an onboard arbitrary waveform generator (optional) to generate voltage supply variation tests such as
Ford CI 230.
Auxiliary Supply Specifications
Voltage dip testing per various manufacturer standards
Test Level Output
Test voltage
0-16 Volts
Current rating
0-31 Amps
Coupling Mode
Thru the TG6032 BU coupling network
TG6000LD Load Dump
The TG6000LD generator performs the Load Dump test per ISO 7637-2 pulse 5a/5b. This simulator also
generates high-energy load dump pulses for all the covered worldwide specifications. Open circuit
voltages up to 175 Volts are possible along with pulse durations up to 400 ms.
TG6000LD Load Dump Specifications
High energy pulse generator (Pulse 5a, 5b) per ISO 7637-2 (2004)
Test Level Output
Test voltage
20-175 Volts + 10%
Rise time tr (10-90% of waveform)
5-10 ms
Pulse duration td (10-10% of the waveform)
50-400 ms
Source Impedance
0.5, 1, 2, and 10 Ω
Repetition Rate
45 seconds
Coupling Mode
To the + battery line
Additional Features
Standard Onboard Oscilloscope
As mentioned above, the standard onboard oscilloscope is used within the system to provide verification
of the test pulses without the need of any external instrumentation. The process of pulse verification is
simplified with this oscilloscope, as it is setup and configured to capture pulses when the system is
manufactured. The technical specifications on the unit are shown in the following table:
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Oscilloscope Specifications
Bandwidth (50 Ω)
Bandwidth (1 MΩ)
Probe attenuation
Maximum input
Sample rate
Waveform memory
8 bit
500 MHz typical (400 MHz minimum)
300 MHz typical (250 MHz minimum)
AC or DC
0.9 to 1000:1
+250 VDC (1 MΩ)
+5 VDC (50Ω)
1 GS/s
32M samples/channel
Onboard Computer
As mentioned in the TG6032BU section, the onboard computer comes pre-loaded with the operational
software. The embedded computer resides in the PXI box along with the oscilloscope. The technical
specifications on the unit are shown in the table below:
Parallel Port
Hard Drive
Computer Specifications
2 GHz Pentium
10/100/1000 BaseTX, RJ-45 connector
Intel Graphics Media Accelerator
1 (RS232)
IEEE 1284
PCI-GPIB/TNT Micro D25 connector
IEEE 488
4 (USB 2.0)
512 MB standard
40 GB
Resistor Load Box
A resistor load box is supplied with the system for verification of the micropulse and load dump pulses in
conjunction with the Onboard Oscilloscope. The box simply plugs into the coupling network on the
output of the TGAR system. The following impedances are available in the load box: 0.5, 1, 2, 4, 10, 20,
and 50 ohms.
Keyboard and LCD Display
A keyboard and LCD display is mounted in a retractable drawer for interface with the embedded
Optional Items
1. Arbitrary Waveform Generator cards - Two additional cards are necessary if all four Ford CI 230 pulses
have to be performed simultaneously.
2. Two additional auxiliary supplies will be necessary to perform all four Ford CI 230 pulses
3. If the -1100 V pulse required in ISO 7637-2 (24V -1990) and Volvo (1998 EMC Requirements) is
requested, then an optional module will be necessary.
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