Thanks to a new category of instrument that provides the flexibility and functionality needed to recreate some of the automotive power waveforms (e.g., slow decreasing/increasing of operating voltage, quick charges, cranking profiles and voltage dips) to power the electrical components in a vehicle, R&D engineers now can test their ECUs with many of the troublesome transients at the comfort of their lab bench. This saves both time and expense by giving the engineer the opportunity to fix ECU problems before traveling to the remote and expensive qualification lab. The DC power analyzer integrates multiple instrument functions such as an arbitrary waveform generator, multiple DC power supplies, digital multimeter (DMM), oscilloscope, and data logger into a single box. It is capable of producing several different voltage waveforms and features a configurable slew rate along with an intuitive front panel. With these capabilities, the DC power analyzer provides a cost-effective, easy, and highly productive way of sourcing, measuring and analyzing DC voltage and current in electrical components. This is accomplished in minutes — not hours — without having to write a single line of code.

To better understand how a DC power analyzer can be used to quickly and easily simulate transients in vehicle charging systems, consider the following example that uses the N6705A DC power analyzer with its programmable slew rates — as fast as 5 V in 160 µs, depending on the module (Figure 2). The solution's built-in arbitrary waveform controls allow the engineer to create nine different waveforms: sine, step, pulse, ramp, trapezoid, staircase, exponential, user-defined voltage and user-defined current waveforms. The waveforms are all configurable from the instruments front panel, thereby eliminating the need for the engineer to write any code.

To begin, the signal from Figure 1 is replicated using the N6705A DC power analyzer by creating a four-step user-defined voltage waveform (Figure 3a). The voltage waveform is described via the following parameters:

• begins at 14 V;
• drops to 9 V for 10 seconds;
• dips down to 4.5 V for a brief 100 milliseconds;
• rises to 9 V for 1 second; and
• finally, it returns to 14 V after the dip.

Once the waveform is created, it can be viewed in scope view (Figure 3b). Notice that in this example, the DC power analyzer is able to measure and display both voltage and current data at the device under test (DUT) in an oscilloscope-like display. It also allows users to save user-defined waveform setups and scope data either to an internal memory or external USB memory device.