Space-Saving Connectors for Automotive Electronics

Markus Breitenbücher, ERNI Electronics


Electromobility and autonomous driving entail increased requirements

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Figure 1: Connector solutions such as SMC, MiniBridge and MaxiBridge are installed in many inverters or battery management systems of hybrid vehicles

Particularly in the automotive industry, very high demands are placed on connections. In harsh and often near-engine environments, connector systems must not only be as compact as possible, but must also exhibit high vibration resistance, robustness, temperature resistance, high current carrying capacity and ease of handling. ERNI Electronics offers a wide range of connector solutions with high reliability, very compact designs, robust yet lightweight connectors, connectors for high data rates, very good EMC and high current carrying capacity.

Particularly in the automotive industry, customers benefit from comprehensive system expertise, which is based, among other things, on the company's high vertical range of manufacture. New and expanded product families such as miniaturized SMC connectors, compact, high-performance cable connectors (MiniBridge or MaxiBridge) and wire-to-board solutions address the demand for space and weight-saving connectivity solutions without compromising reliability.


The implementation of electromobility requires close cooperation between component manufacturers and OEMs. Many years of design and development experience make the component supplier a partner in the increasingly demanding automotive environment. In hybrid technology, optimum networking of electric motors and combustion engines plays a key role. For example, connector solutions such as SMC, MiniBridge and MaxiBridge are installed in many inverters or battery management systems of hybrid vehicles (Fig. 1).

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Figure 1: Connector solutions such as SMC, MiniBridge and MaxiBridge are installed in many inverters or battery management systems of hybrid vehicles

Parallel to electromobility, the trend towards self-driving cars is the second major challenge. For the various driver assistance systems, the data has to be collected and processed by many sensors and actuators have to be controlled accordingly. Only with a reliable, secure network or connection is a perfect interaction of the various systems possible.

Distributed control units with high computing power and high communication requirements are essential for automated vehicles. For example, shielded connector systems for high transmission rates and large data volumes for real-time networking of smart ESP systems and lane assist systems are required. Ultimately, the implementation of electromobility and autonomous driving requires unprecedented connectivity in cars and thus high-performance, space-saving and reliable connector solutions.

Modern connector solutions are also available for this range of applications. Applications range from highly sensitive front and rear camera solutions to sophisticated headlight systems with dynamic adaptive headlights and airbags that can precisely adjust to the weight of the occupants. Connectors available as robust and reliable Koshiri variants are used in electronically controlled steering systems and headlight range adjustment systems. Space-saving cable connectors can also be found in reversing cameras and parking assist sensors.

The products are manufactured to the highest quality standards on modern, largely automated production facilities. This is also reflected in the corresponding certifications such as IATF 16949 or the Koshiri specification. In many cases, the connectors also offer sufficient design margins to be able to handle higher currents or voltages with the small pitches. MiniBridge and MaxiBridge cable connectors also meet the applicable LV 214 specifications. In 29 test groups, this specification defines electrical, climatic, mechanical and corrosive stress scenarios that a contact system must withstand.

The most important criteria in automotive electronics include – in addition to the high-quality requirements mentioned above – compact and lightweight designs with high current carrying capacity and high reliability. These criteria are met in particular by the SMC connectors with a 1.27mm pitch, the MiniBridge cable connector system (1.27mm) with a current carrying capacity of 8 A/contact or the MaxiBridge cable connectors (2.54mm), which can handle up to 12 A/contact.

Confined spaces

MiniBridge connectors are ideal for a wide range of sensor, actuator, power supply or data applications in industrial electronics, computer technology, consumer electronics or medical technology.  Examples include valve connection technology, fans, LCD/TFT/LED displays, programming interfaces, handheld devices, motors, control panel elements, power supplies or the internal connections of white goods devices.  However, automotive electronics also offer ideal applications such as LED taillights, IR distance sensors, head-up displays or switch elements.

LED systems are often wired or modularly connectable with printed circuit boards. With appropriately assembled MiniBridge cable connectors, which can accommodate both ribbon cables and single wires, a particularly simple, flexible and cost-effective installation is possible. For such compact lighting tasks, the MiniBridge connectors are also available with "white" insulation (Fig. 2).Connectors with non-colored insulation prevent the shadowing effects in lighting applications, e.g. LED strips with transparent diffusing lens. This ensures uniform light distribution.

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Figure 2: MiniBridge cable connectors are ideal for applications such as LED taillights, IR distance sensors, head-up displays or switch elements.Versions with non-coloured "white" insulation prevent shadowing in lighting applications

The automotive industry in particular places high demands on the process reliability of plug connections. It must be ensured that no damage occurs to the male connector, especially if the male and female connectors are mated skewed. The MiniBridge connectors in the Koshiri version ensure that this requirement is met during the mating process.

The key features of the cable connector system are extreme compactness combined with high performance and reliability. With dimensions of only 10mm x 10mm x 3mm (4-pin version), a very high current carrying capacity (when using appropriate cables) is achieved over a wide temperature range of - 55°C to + 125°C due to a special contact material. Straight and angled male connectors and female connectors with angled and straight (90 degree and 180 degree) cable outlets can be used to address a wide range of applications.

MiniBridge connectors are available with 2, 3, 4, 6, 8, 10 and 12 pins. The male connectors have SMT terminals for economical processing, while the female variants are designed using insulation displacement contact termination (IDC). The female connectors are also available with various interlocking techniques for normal vibration/shock loads (black design) and for high vibration/shock loads (red design). With the more robust version (in red), the interlocking can only be released with a tool (screwdriver).

Doubly safe

The SMC family with a 1.27mm pitch is also recommended for demanding, often spatially confined applications in the automotive sector. And the development continues – as the SMC Secure Lock (Figure 3) shows. The SMC connector family has thus been extended to include versions with Secure Lock interlocking. The highly reliable electrical contact of the Secure Lock versions is provided when mated by the proven double-shank spring contact. The wire-to-board solution (connector system with IDC female connector and SMT male connector) was modified and optimized to meet, for example, the increased requirements of the automotive industry as well as modern automation technology for the safe mechanical connection of two assemblies. This means that even the most demanding applications, such as in inverters of electric/hybrid vehicles, can be addressed. Reliability in the locked state (e.g. under vibration and shock loads) is just as important as the precise and error-free mating process.

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Figure 3: SMC Secure Lock is a secure wire-to-board solution that also meets the high requirements of the automotive industry

The new geometry of the angled IDC female connector and the straight SMT male connector requires a defined force to lock the wire-to-board connection. The user thus receives a clear acknowledgement (audible, tactile) that the connection has been securely made. With additional guides and widened locking levers, contact damage when mating is ruled out. The connection is released using a cost-effective unlocking tool. With the 50-pin SMC Secure Lock connectors, compact and reliable ribbon cable assemblies can be realized.

ERNI Electronics