Perturbation-immune radiation-hardened PLL with a switchable DMR structure

This paper proposes a perturbation-immune radiation-hardened PLL with a switchable dual modular redundancy (DMR) structure. By a radiation-strike, a PLL has clock-perturbation for a while. Conventional RHPLLs are proposed to reduce recovery-time which is the time to recover from perturbation. However, recovery still needs tens of clock cycles. Our proposal is `detecting´ and `switching´ instead of `recovering´ clock-perturbation. For robust perturbation-immunity, detecting speed is important. We identify types of clock-perturbation and - then propose a set of detectors to detect each type. With this, detectors guarantee high speed in detection.