Significance of ISO7637 Pulse 2a to Integrated Circuits (ICs)
Creators: name: Kaschani, Karim T.
name: Jahn, Johannes
Publisher: name: Aachen : Apprimus
Year: 2022
Subjects: subject: EMV
subject: Verträglichkeit
subject: Elektromagnetik
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau::621 | Angewandte Physik::621,3 | Elektrotechnik, Elektronik

description: Year after year, an increasing number of electronic devices is introduced into vehicle designs. In order to address potential problems of these devices due to electrical transient disturbances, the standard ISO 7637 has been issued [1]. It deals with the emission of transients, transient transmission via electrical wiring and the potential susceptibility of electronic components to electrical transients. One of these transients is called “pulse 2a” [2]. It is supposed to simulate the voltage response of the partial load dump of a wiring harness. A corresponding schematic is shown in Figure 1. In this schematic, UA represents the power supply, SI is the ignition switch, LW models the inductive wiring harness, UDUT denotes the voltage drop across the device-under-test (DUT), RL represents the load and SL the load switch triggering a 2a pulse. The voltage waveform of UDUT with its characteristic parameters is depicted for two subsequent 2a pulses in Figure 2. The test pulses described in the different parts of ISO 7637 are stated to be characteristic of typical pulses [1]. Still, a device shall be subjected only to those tests in the relevant part of ISO 7637 which apply to that device. Only the tests necessary to replicate the use and mounting location of the device-under-test (DUT) shall be included in the test plan. In this way, ISO 7637 fosters a fit-for-use rather than a fit-for-standard qualification of devices as described in the Handbook of Robustness Validation [3]. Consequently, ISO 7637 points out the importance to know the correlation between laboratory tests and (the given) vehicle [1] and emphasizes the vehicle manufacturer's responsibility to define the test pulses (and failure criteria) required for a specific DUT [2]. EN 62215-3 [4] refers to ISO 7637-2 [2] and requires in chapter 4 and Annex D to apply pulse 2a directly to ICs, notwithstanding the application notes given in ISO 7637 [1] [2]. The only concession made to IC manufacturers is the allowance to demand an external protection. At the same time, it should be noted that 16 different pulse generators investigated in a round robin test in 2014 were found to give hardly reproducible results [5]. The reason for the poor reproducibility was attributed by the authors to the pulse shaping and decoupling networks of the pulse generators used as well as to loose or missing regulations in ISO 7637. Therefore, this paper investigates the applicability, usefulness and meaningfulness of pulse 2a as specified in ISO 7637 [1] [2] and its application to ICs as specified in EN 62215-3 [4]. The experimental set-ups are summarized in section 2. Two pulse 2a simulation models, their response to resistive and capacitive loads and their energy dissipation are introduced in section 3 and conclusions are drawn in section 4.