System for measuring response time of a circuit by determining the time difference between the earlier and the later clock pulses applied to the circuit
AssigneeSTMicroelectronics S.r.l.
InventorHenry Nurser
Life of this patent
Estimating the term…
Abstract
A method and device for measuring the response time of a circuit are described in which clocking pulses are applied to the circuit at input pads, the input pads being connected to the circuit by circuitry having substantially the same delays. By adjusting the timing of the later clock pulse relative to the earlier clock pulse until a valid output is just achieved, the response time of the circuit can be measured using a register circuit.
Claims14
A device for measuring the response time of a circuit, the circuit having an output for providing a response to a stimulus at an input node thereof, the device comprising first circuitry having a clock node and an output, said first circuitry being connected to store an output condition, said output condition corresponding to a state of said circuit output at the time of occurrence of a clock pulse at said clock node, the device further comprising second circuitry and third circuitry, said second circuitry being responsive to a second circuitry input signal at its input to provide said stimulus at said input node of said circuit, and said third circuitry being responsive to a third circuitry input signal at its input to provide a clock pulse at said clock node whereby said response time is determined by the time between said second circuitry input signal and said third circuitry input signal, wherein said second circuitry has an output connected to said input node, and said third circuitry has an output connected to said clock node, and a delay between the input to said second circuitry and its output is substantially the same as a delay between the input and output of the third circuitry.
The device of any one of the preceding claim wherein the first circuitry comprises flip-flop circuitry.
A device for measuring a response time of a circuit between an input node and a circuit output thereof, wherein said circuit output is connected via first connecting circuitry to an output pad, said device comprising a first timing signal source for providing a first timing signal to said input node via a first path having a first delay, clocked circuitry having a clock node and being connected at said circuit output, said clocked circuitry having an output to said first connecting circuitry, said clocked circuitry being responsive to a clock signal at said clock node to provide to said first connecting circuitry a signal existing at said circuit output immediately prior to the occurrence of said clock signal, the device further comprising a second timing signal source for providing a second timing signal as said clock signal to said clock node via a second path having a second delay substantially equal to said first delay, and means for determining a time period between said first and second timing signals.
A method of measuring the response time of a circuit having a circuit output for providing an output in response to a stimulus applied to a circuit input, the circuit input being connected to a first input pad via first circuitry having a predetermined delay, the method comprising:
- providing second circuitry having a clock node, said clock node being connected to a second input pad via third circuitry, said third circuitry having said predetermined delay, and said second circuitry having an output for storing an output condition, said output condition corresponding to the state of said circuit output at the time of occurrence of a clock pulse at said clock node;
- repeatedly applying a stimulus to said first input pad and at a variable delay after each application, providing a clock pulse to said second input pad;
- and determining, as said response time, a value of said variable delay corresponding to a desired output condition of said second circuitry.
Dependencies are inferred from the claim text.