Infineon introduces family of intelligent load-guard switches
Power distribution in modern vehicles requires adjustable overcurrent limiting and capacitive load mode. For this purpose, Infineon has developed a family of smart load-guard switches.
The use of safety-critical systems in vehicles requires a reliable and intelligent on-board network architecture and, in combination with more comfort functions, causes an increasing number of loads in the power distribution. For this reason, modern E/E architectures need reliable and intelligent solutions that protect sensitive loads from overcurrent events and enable fast fault isolation from the on-board network.
For these requirements, Infineon introduces the intelligent high-side power switch portfolio PROFET Load Guard 12V. The combination of adjustable overcurrent limitation and a special mode for switching capacitive loads (CLS mode) offers a flexible solution for the diverse requirements of modern secondary power distribution. This creates a protection mechanism for the integration of safety-critical ADAS systems.
The two- and single-channel PROFET Load Guard 12V devices offer a wide current limitation range between 0.3 and 8.7 A, depending on the switch-on resistance R DS(ON). Without involving the microcontroller, this function allows the protection level to be set according to the system requirements. In this way, peak currents that could endanger sensitive loads are avoided. At the same time, fast fault isolation for power distribution is made possible if overload conditions occur due to faults in the loads, for example in the sensor fusion box. Loads with a large capacitive component, such as ADAS or display modules, can also be switched on quickly using the CLS mode of the components.
This CLS mode makes it possible to charge capacitances of several millifarads while remaining within the safe operating range of the automotive-qualified, intelligent high-side power switches. This increases the robustness of the overall system. Furthermore, by providing safety instructions, the PRO SIL ISO26262-compliant components simplify use in safety-related applications. In addition, the best-in-class current measurement accuracy in low current ranges allows precise module diagnostics and monitoring.
Hardware-based line protection
With a wide operating voltage range from 3 V (cranking: 2.7 V) to 28 V, combined with adjustable overcurrent limiting and CLS mode, the PROFET Load Guard 12V family offers maximum load flexibility. If the load or system requirements change, for example in variant handling, the analogue overcurrent limitation threshold can be adapted to the new conditions. This is done by simply switching to a different resistor connected to the OCT pin. The function not only provides flexibility, but also enables the implementation of hardware-based line protection cable protection for time-independent loads. The CLS mode further extends the load potential and takes into account the increasing number of capacitive loads such as modules.
The family is designed for rated currents of 2 to 3 A and consists of two 90 mΩ and two 50 mΩ devices – both available as single- and dual-channel intelligent high-side circuit breakers. The proven PG-TS-DSO-14 package offers high compatibility with other SMART7 devices, such as the PROFET +2 12V. Loads with large capacitive components can be controlled via the integrated CLS mode. It enables fast charging of large capacitors within the safe operating area (SOA) of the PROFET Load Guard 12V. The close-tolerance, best-in-class ratio (kILIS) of the actual current value in low-current ranges also allows precise diagnosis of the load conditions.
To support the design-in process of the PROFET Load Guard 12V devices, the family is integrated into the PROFET Guard tool, which is provided via the Infineon Developer Center. The tool supports the evaluation of the system protection capability of PROFET Load Guard devices with a given line and load profile. In addition, it calculates the correct resistor value for the adjustable overcurrent limitation.