Built-in self test using pulse generators

A circuit for measuring a first signal-propagation time required for a rising edge of a signal to traverse a test circuit from a data input node of the test circuit to a data output node of the test circuit, the circuit comprising:

• a. means for providing sequential, alternating falling and rising signal transitions on the test-circuit data input node, thereby producing a corresponding series of alternating falling and rising signal transitions on the test-circuit data output node;
• and
• b. means for instigating a subsequent rising signal transition and a subsequent falling signal transition on the test-circuit data input node in response to one rising signal transition on the test-circuit data output node.

A method of measuring a first signal-propagation time required for a rising edge of a signal to traverse a test circuit from a data input node of the test circuit to a data output node of the test circuit, the method comprising:

• a. providing sequential, alternating falling and rising signal transitions on the test-circuit data input node, thereby producing a corresponding series of alternating falling and rising signal transitions on the test circuit data output node;
• and
• b. developing a signal having a period proportional to the first signal propagation time, wherein the period is independent of a second signal propagation time required for a falling edge of the signal to traverse the test circuit from the data input node of the test circuit to the data output node of the test circuit.

A method of measuring a first signal-propagation time required for a falling edge of a signal to traverse a test circuit from a data input node of the test circuit to a data output node of the test circuit, the method comprising:

• a. providing sequential, alternating rising and falling signal transitions on the test-circuit data input node, thereby producing a corresponding series of alternating rising and falling signal transitions on the test circuit data output node;
• and
• b. developing a signal having a period proportional to the first signal propagation time, wherein the period is independent of a second signal propagation time required for a rising edge of the signal to traverse the test circuit from the data input node of the test circuit to the data output node of the test circuit.