Abstract: A multiplexer output cell (FIG. 1, 15) controls the operation of multiplexer input cells (100, 105) in a multistage multiplexer according to the value of a signal select input (130), and a state control input (180). A signal driver (125) having a number of logical outputs comparable to the number of stages in the multiplexer is used in conjunction with the state control signal (170, 175, 180) to control the power ON/OFF state of each cell in the multiplexer. The multiplexer input and output cells (100, 105, 150) which are in the signal path are set to a power ON condition, while the multiplexer input and output cells (100, 105, 150) which are not in the signal path are set to a power OFF position. In this manner, only those cells which are in the signal path are powered ON, resulting in significant power savings.

Abstract: A single event upset (SEU) sensitivity control system (42) dynamically hardens a digital circuit (48) to single event upsets. The sensitivity control system (42) includes an upset rate sensor (66) for detecting a quantity of particles (38) that cause single event upsets. A noise margin control circuit (70) is configured to adjust a noise margin (46) of the digital circuit (48) in response to the quantity of particles (38). Noise margin (46) is increased when a particle density (34) is high to decrease the sensitivity of the digital circuit (48) to single event upsets. Additionally, noise margin (46) is decreased when a particle density (36) is low to decrease the power consumption level of digital circuit (48).