One of the key trends in the automotive market these days is to make vehicles safer, more reliable and more comfortable via emerging applications like telematics (e.g., vehicle-tracking, satellite navigation, mobile communications, and television) and mechatronics (e.g., anti-lock braking systems, spin assist and airbag deployment). As automakers work hard to introduce new advances in these areas, the amount of in-vehicle electronics and, in turn, electronic components, has and will continue to rise. Likewise, the number of electronic control units (ECUs) required to control the new electronic components will increase. In contemporary automotive electronic systems, for example, it is common to have anywhere from six to 12 control ECUs. These ECUs, as well as the electronic components they control, function in an extremely harsh electrical environment. They are constantly subject to power system voltage transients and dropouts caused by high-current motors, solenoids and other components on the power system. In this mission-critical environment, any malfunction is simply not tolerated as it could severely erode the consumer's confidence in his or her vehicle, not to mention jeopardizing vehicle driver/passenger safety.

Successful operation of automotive electronics, therefore, depends on adequate power transient immunity, making thorough ECU and electronic component testing absolutely critical. A variety of test standards such as ISO-7637 and ISO-16750 document transient waveform profiles and can help automotive R&D engineers with power system transient testing, but those waveforms are difficult to create and therefore require expensive, specialized equipment. A new category of instrument has emerged — the DC power analyzer — which now offers automotive R&D engineers a flexible, cost-effective alternative. It allows the engineer to test the electrical components being used in a vehicle by simulating various power conditions. This ensures that the components will continue to work properly, regardless of the different power conditions from the vehicle's charging system such as the abrupt loading of the power system during starter crank, which causes voltage dips powering the electrical components.

Simulating the vehicle charging system is a crucial task for any automotive R&D engineer, but the process can be challenging. Consider the example of a voltage dip waveform (Figure 1). To ensure proper electrical component operation, the engineer must thoroughly test the components through a variety of charging scenarios similar to that of the voltage dip shown in Figure 1. These scenarios replicate cranking profiles, power disturbances or decay reflected on the vehicle's power system.

Simulating the various power waveforms is traditionally done using test systems that are custom in nature. These solutions are generally created by the engineers themselves and involve the use of specialized equipment, such as a power supply with fast response, a high-speed function generator, an industrial computer interface, and application software that has been specifically developed for recreating the necessary power waveforms. Often times, this specialized equipment must be ordered from outside vendors. And, because the test systems are custom-made for specific tests, they do not allow for much flexibility in terms of changing test settings. Furthermore, to actually test the electrical components, the engineer is forced to go to a local test station since the number of customized systems is low due to the high cost.

While these custom test systems are expensive, inflexible and require a lot of time and energy, not simulating the power waveforms is an option deemed too risky, often leading to problems that may not be found until vehicle production. Prime examples of the types of problems that can occur include a radio that goes mute after cranking the starter motor, or vehicle-integrated cell phones that temporarily cease to function. Today's automakers can hardly afford the risk and expense associated with finding these types of problems during production.