Electronic circuitry protected against transient disturbances and method for simulating disturbances
AssigneeiROC Technologies
InventorMichel Nicolaidis
Life of this patent
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Abstract
The circuitry comprises successive stages, each comprising a combinatory logic circuit connected to the input of a first latch. Staggered clock signals are respectively associated with the first latches of the odd and even stages. Means for detecting a transient disturbance affecting the first latch of a stage and liable to propagate downstream, compare, in each stage, a value present on the output of the first latch of the stage considered at an observation time with a value present on the input of said first latch at a predetermined observation time taking account of the various propagation times.
Claims23
Electronic circuitry comprising a plurality of successive stages, alternately odd and even stages, each stage comprising at least one combinatory logic circuit having at least one output connected to the input of an associated first latch, a clock signal being applied to a clock input of each first latch, the clock signal successively taking, during a clock cycle, a high level between a rising front and a descending front, and a low level from said descending front until the rising front of the next clock cycle, first and second clock signals being respectively applied to the clock input of the first latches of the odd stages and of the first latches of the even stages, the first and second clock signals being offset without overlapping of their high levels, and the circuitry comprising means for detecting a transient disturbance affecting the first latch of a stage and liable to propagate downstream, the means for detecting comprising, in each stage, monitoring means which compare:
- an output value, present on the output of the first latch of the stage considered at an observation time comprised between the descending front of each cycle of the corresponding clock signal and the rising front of the next cycle of said clock signal,
- with an input value, present on the input of said first latch at an observation time comprised between
- a first time, that follows the previous descending front of the other clock signal by a first time interval that corresponds to a maximum propagation time of the combinatory logic circuit of said stage
- and a second time, that follows the next rising front of said other clock signal by a second time interval, that is equal to the sum of a minimum propagation time of the first latch of the previous stage and of a minimum propagation time of the combinatory logic circuit of the stage considered.
Method for simulating disturbances affecting the latches of electronic circuits comprising a plurality of successive stages, each stage comprising at least one combinatory logic circuit having at least one output connected to the input of an associated first latch, a clock signal being applied to a clock input of each first latch and taking a high level and a low level during a clock cycle, the value present on the input of a latch during a leading or descending front of its clock, constituting the beginning of the clock cycle, being captured by the cell, said method determining whether a disturbance modifying the value of a disturbed first latch from any time produces an error captured by a first latch of the next stage at the beginning of the next cycle of its clock, and using:
- the time at which the disturbance occurs on said disturbed first latch,
- the correct logic state of the circuit, and
- the time periods of sensitized paths connecting the output of said disturbed first latch to the input of said first latch of the next stage to determine whether an error is captured by the latter latch.
Dependencies are inferred from the claim text.