E-fuses can be integrated into chip designs or added to a system to protect devices from multiple failure vectors, including overcurrent, overvoltage clamping, current-induced thermal protection, and short-circuit protection. (Image credit: Pixabay)
Industry demand has given rise to the use of e-fuses (electronic fuses) over the last decade as a way to better protect circuitry over traditional fuse counterparts. As BUS voltages climb ever higher with the latest technologies, better protection methods have become paramount to keep chips running efficiently without failure.
Traditionally, most systems are protected using sacrificial fuses, those that disconnect a power supply in the event of overcurrents; however in the process, they will shut down individual components or the entire device in those events. E-fuses, on the other hand, are integrated circuits or add-on modules that can provide options for maintaining functionality, even in the event of encountering a fault.
The simplest version of e-fuses makes use of transistors that sever a connection if the voltage is too high, which reacts faster than traditional fuses that require a certain amount of time to absorb enough thermal power to melt. With e-fuses, that disconnection happens a lot faster and is reversible, making it possible to reestablish a connection even after it’s been severed. As long as an electrical spike doesn’t happen after an event, some connections can be left up and running. If certain systems fail, take too long to respond, or consume too much power, a chip can change its behavior by blowing an e-fuse, thus saving the system.
E-fuses are also resettable, meaning after blowing the circuit, they can be reset and ready for protection, while traditional fuses need replacing. This saves more than just circuitry; it also shortens system downtime and is more cost-efficient as they don’t need to be replaced. This makes them ideal for any number of applications, including automotive electronics, power supplies, laptops and more.
Toshiba’s TCKE9 series of e-fuses have integrated overtemperature protection and feature adjustable current values. (Image credit: Toshiba)
Manufacturers have also designed e-fuses with features that go beyond simple current protection. Toshiba, for example, recently released its TCKE9 series of e-fuse ICs that feature overtemperature protection and have adjustable current set values with a range from 0.5 A to 4.0 A. Nexperia has followed suit with its latest NPS3102A and NPS3102B series of resettable e-fuses that operate at up to 21 V and offer a max current trip value of 13.5 A. Their current limit is adjusted from 2 A to 13.5 A via an external resistor and can operate in a current-limiting mode, which partially shuts off a MOSFET that only allows a pass-through current within a specific limit.
STMicroelectronics has also thrown its e-fuse hat in the ring with the recently released VNF9Q20F intelligent automotive circuit breaker. The e-fuse is a quad-channel monolithic IC that comes outfitted with four independent internal N-channel MOSFET switches for power control. Each can be independently controlled, while the MOSFETs allow the four outputs to drive resistive or inductive loads that connect to the ground directly. The e-fuse comes equipped with 64 programmable current limit values, has advanced diagnostic capabilities and includes a 10-bit analog-to-digital converter (ADC) and fault registers.
Of course, these new e-fuses are just some of the latest to hit the market. Additional manufacturers are following suit as the e-fuse market is expected to grow exponentially over the next decade. A recent report from Markets and Markets shows that the e-fuse market is set to grow from $538 million in 2023 to $703 million by 2030 and $881 million five years later. That growth is driven by the EV market, with applications in engine control units, infotainment systems and security systems, along with several additional electronics industries and applications. With that said, element14 is getting set to roadtest e-fuses to see what sets them apart from traditional fuses and their potential applications. Check back later for more information as it becomes available.
element14 is roadtesting an eFuse Eval Kit. Go here to enroll.
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