Critical view on the current sensor application for self-timing in VLSI systems

To solve the problem of global synchronization in massively parallel VLSI systems, it is necessary to organize asynchronous interaction between system blocks. The possibility of applying current sensors for detection of the end of signal transitions to construct asynchronous blocks in CMOS-technology is discussed. For known current sensors, their design principles and characteristics are analysed. Two ways of organizing the interaction between circuits with current sensors are suggested. Stubborn problems of using the known current sensors that appear due to the imperfection of their characteristics are formulated. A current sensor is suggested that removes the major of these problems but is capable of working only with a particular circuit class. However, simulation results indicated that using even such sensors is not efficient enough.