Online monitoring of NBTI and HCD in beta-multiplier circuits

An Integrated DC/DC Converter with Online Monitoring of Hot-Carrier Degradation

“…The sensitivity of the alert signal is substantially dependent on the sensitivity of the circuit which compares the sampled voltage with the reference one, and on the maximum current IMAX. Indeed, it's worth noting that a positive effect of sampling the drain voltage when current is at its maximum is that the voltage difference due to degradation is maximum too, since (6) The designed comparator has a simulated sensitivity of ≈ 3mV (Vref_degrad = 0.5 V), so if we consider a IMAX current of 50 mA as an example, the maximum detectable increase of Ron is about 60 mΩ. However, the sampled voltage is also available outside the chip through a dedicated pin, so it is exploitable for further elaboration on-board.…”

“…Finally, a growing interest is evinced in finding solutions able to monitor the degradation level of MOSFETs, in order to predict an imminent failure or possibly to compensate the negative effects from the increased on-resistance on the behavior of the converter. More precisely, various approaches are currently studied in this direction, either at circuit level by developing dedicated testing structures [5] or in combination with common conversion architectures [6], or by using advanced passive techniques like the measurement of the luminescent emission [7]. In this varied scenario, new improved transistor layouts as well as advanced passive measurements offer an interesting solution to the HCD prevention and monitoring problem, although they require specific equipment at very high costs.…”