Modern cars feature a host of safety-critical advanced driver assistance systems (ADAS) which must be designed for high availability and to meet fail operational requirements.
The impact on the primary power distribution is the introduction of safety elements to guarantee fast failure isolation in less than 100 µs. Since fuses cannot meet this requirement, partial or full electrification of the primary power distribution needs to be considered. In addition, modern cars have an increasing number of applications to improve driver and passenger comfort.
According to semiconductor and systems developer Infineon, its power distribution system supplies all of these applications by enabling energy to flow from a source to various loads in a secure and controlled manner. As the firm points out, one of the biggest challenges for designers currently is to reduce the cost, length, weight and complexity of the wire harness, which Infineon is aiming to address with its new EiceDriver 2ED2410-EM smart high-side Mosfet gate driver.
The EiceDriver is designed for 12V and 24V automotive applications with integrated wire protection and is an ideal partner to the company’s 40/60 V Optimos Mosfets.
The gate driver features two output channels for two different Mosfet structures, either back-to-back common source plus a pre-charging path or common drain. The enhanced driver capability to turn on and turn off allows it to easily scale up the amount of Mosfets to manage larger load currents. Even up to several hundred amps, the device ensures fast switch-off within microseconds while classical fuses only disconnect in the range of milliseconds, and it can be operated down to 3 V. Such low voltages can occur in a short circuit until the faulty load is disconnected.
The EiceDriver has three analogue measurement interfaces and four integrated comparators for protection purposes. This enables flexible and versatile solutions for various requirements including adjustable I-t wire protection, overcurrent protection, and over or under voltage protection. Currents can be measured in both directions and the drain-source-voltage is monitored to identify conditions such as an open load at the output.
The adjustable wire protection feature helps select the smallest possible wire cross section for the corresponding load behaviour. In the past, wires had to be designed with a diameter margin of up to 30% compared to the actual requirements, in order to consider the tolerance and aging effect of classical fuses. To minimize the discharge of the battery when the vehicle is parked, the device comes with a very low quiescent current consumption of only a few tenths of µA.
The EiceDriver is now in production and will come equipped with a safety application note to support evaluation of hardware elements according to ISO 26262.
