Digital circuit monitoring device
AssigneeSTMicroelectronics S.r.l.
InventorsRicardo GOMEZ GOMEZ, Sylvain CLERC
Life of this patent
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Abstract
A ring oscillator includes a chain of logic components. A storage element is associated with each logic component and configured to store a state of an output of the logic component to which the storage element is associated. A first circuit counts state transitions of an output of a given logic component of the chain. A second circuit synchronizes each storage with a clock signal. A third circuit determines a number of logic components crossed by a state transition between two edges of the clock signal. This determination is made based on the counted number of state transitions and on the stored states of the outputs.
Claims30
A device, comprising:
- a ring oscillator comprising a chain of logic components;
- a first assembly of storage elements, wherein each storage element is associated with a different logic component of said chain and is configured to store a state of an output of said logic component to which said storage element is associated;
- a first circuit configured to count a number of state transitions of an output of a given logic component of said chain;
- a second circuit configured to synchronize each storing of the state with a clock signal;
- and
- a third circuit configured to determine a number of logic components of said chain crossed by a state transition between two edges of the clock signal, wherein said determined number of logic components is based on the counted number of state transitions and on the stored states of said outputs from said first assembly;
- wherein one of the logic components of said chain is configured to prevent a propagation of an oscillation in the oscillator in response to a control signal in a first state, and to allow the propagation of the oscillation in response to the control signal in a second state;
- and
- wherein the second circuit is configured to generate said control signal and deliver the control signal in the second state between said two edges of the clock signal.
A device, comprising:
- a ring oscillator comprising a chain of logic components;
- a first assembly of first storage elements, wherein each first storage element is associated with a different logic component of said chain and is configured to store a state of an output of said logic component to which said storage element is associated;
- a second assembly of second storage elements, wherein each second storage element is associated with a different logic component of said chain and configured to store a state of the output of said logic component, said first assembly and said second assembly being configured so that each logic component associated with one first storage element of said first assembly is further associated with one second storage element of said second assembly;
- a first circuit configured to count a number of state transitions of a logical combination of outputs of at least two logic components of said chain;
- a second circuit configured to synchronize each storing of the state with a clock signal;
- and
- a third circuit configured to determine a number of logic components of said chain crossed by a state transition between two edges of the clock signal, wherein said determined number of logic components is based on the counted number of state transitions and on the stored states of said outputs in the first and second assemblies.
The device according to claim 30, where said one of the logic components of said chain is said given logic component.
Dependencies are inferred from the claim text.