Digital integrated circuit propagation delay regulator

Claim 2

A circuit for monitoring and controlling the propagation delay time of signals passing through an integrated circuit, the integrated circuit being of the type in which propagation delay time varies with variations in the temperature of the integrated circuit, comprising: a heater on the integrated circuit; means for controlling the heater to selectively heat the integrated circuit to control the propagation delay time.

Claim 3

A circuit according to claim 1 including: delay measuring means for measuring the signal propagation delay time of signals passing through at least a portion of the integrated circuit; and the means for controlling the heater comprising means responsive to the delay measuring means for controlling the heater to produce a first level of heating when the measured signal propagation delay time is of a first magnitude, to produce a second level of heating greater than the first level of heat when the measured signal propagation delay time is of a second magnitude which is less than the first magnitude, and to generate a third level of heating less than the first level of heating when the measured signal propagation delay time is at a third magnitude which is greater than the first magnitude.

Claim 4

A circuit according to claim 2 including means for adjusting the first level of heating.

Claim 5

A circuit according to claim 1 including: reference propagation delay signal means for providing a reference signal output corresponding to a reference propagation delay time; delay measuring means for measuring the signal propagation delay time of signals passing through at least a portion of the integrated circuit, the delay measuring means comprising means for producing a measured signal output corresponding to the measured propagation delay time; comparator means for comparing the reference signal output and the measured signal output and for producing a comparator output signal corresponding to the difference between the compared reference signal and measured signal outputs; and the means for controlling the heater comprising means responsive to the comparator output signal for controlling the heater to increase the heat provided by the heater when the measured propagation delay time is less than the reference propagation delay time and to decrease the heat provided by the heater when the measured propagation delay time is greater than the reference propagation delay time.

Claim 6

A circuit according to claim 4 including means for varying the reference signal output to vary the reference propagation delay time.

Claim 7

A circuit according to claim 1 in which the heater comprises plural integrated circuit heat generating elements which generate heat when energized, the means for controlling the heater comprising means for controlling the energization of the heat generating elements to control the heat from the heater.

Claim 8

A circuit according to claim 6 in which the heat generating elements comprise plural MOS transistors with different channel widths.

Claim 9

A circuit according to claim 2 including test signal source means for generating propagation time delay test signals; the delay measuring means comprising an oscillator having a gating input and N logic elements of the integrated circuit connected in series to form a ring with the output of each logic element being connected to the input of the succeeding logic element such that a pulse continuously circulates around the ring in response to a test signal from the test signal source means applied to the gating input, the oscillator logic elements having propagation delay characteristics typical of the other logic elements on the integrated circuit, the output of the oscillator being a delay measuring signal comprised of pulses of a frequency which is a function of the propagation delay of each logic element of the ring, the propagation delay of the logic elements being in part a function of the temperature of the integrated circuit; and the means for controlling the heater including frequency counter means for producing a frequency counter output signal corresponding to the frequency of the delay measuring signal and also including means responsive to the frequency counter output signal for controlling the heat from the heater means.

Claim 10

A circuit according to claim 8 in which the test signal source comprises means for generating a string of test signals which are not all of the same duration.

Claim 11

A circuit according to claim 8 in which the test signal source comprises means for generating a periodic string of test signals having first, second and third progressively increasing durations, the string comprising multiple test signals of the first and third durations to each test signal of the second duration.

Claim 12

A circuit according to claim 9 in which the test signal source comprises means for generating a string of alternating test signals of the first and third duration with periodic test signals of the second duration interspersed therebetween.

Claim 13

A circuit according to claim 8 including a first storage means for storing a reference frequency value corresponding to a reference propagation delay time, the frequency counter comprising means for receiving the reference frequency value from the first storage means at the start of each test signal and for decrementing the received reference frequency value in response to each pulse of the delay measuring signal, the frequency counter output signal corresponding to the value to which the reference frequency value is decremented at the end of each test signal.

Claim 14

A circuit according to claim 12 in which the means responsive to the frequency counter output signal comprises heater counter means for storing an initial heater value and for incrementing and decrementing the heater value between limits in response to the frequency counter output signal, the heater counter means comprising means for producing a heater control signal corresponding to the value to which the initial heater value is incremented and decremented in response to the frequency counter output signal, and the heater comprising means for generating heat which varies with the heater control signal.

Claim 15

A circuit according to claim 13 including means for varying the reference frequency value.

Claim 16

A circuit according to claim 14 including means for varying the initial heater value.

Claim 17

A circuit according to claim 13 in which the heater comprises plural integrated circuit heat generating elements which are selectively energized in response to the heater control signal and which generate heat when energized.

Claim 18

A circuit for monitoring and controlling the propagation delay time of signals passing through an integrated circuit composed of logic elements, the integrated circuit being of the type in which propagation delay time varies with variations in the temperature of the integrated circuit, comprising: test signal source means for generating propagation time delay test signals; delay measuring means for measuring the signal propagation delay time of signals passing through at least a portion of the integrated circuit, the delay measuring means comprising an oscillator having a gating input and N logic elements of the integrated circuit connected in series to form a ring with the output of each logic element being connected to the input of the succeeding logic element such that a pulse continuously circulates around the ring in response to a test signal from the test signal source means applied to the gating input, the oscillator logic elements having propagation delay characteristics typical of the other logic elements on the integrated circuit, the output of the oscillator being a delay measuring signal comprised of pulses of a frequency which is a function of the propagation delay of each logic element of the ring, the propagation delay of the logic elements being in part a function of the temperature of the integrated circuit; first storage means for storing a reference frequency value corresponding to a reference propagation delay time; means for varying the reference frequency value; a heater on the integrated circuit; means for controlling the heater to selectively heat the integrated crcuit to control the propagation delay time, the means for controlling the heater including frequency counter means for producing a frequency counter output signal corresponding to the frequency of the delay measuring signal, the frequency counter comprising means for receiving the reference frequency value from the first storage means at the start of each test signal and for decrementing the received reference frequency value in response to each pulse of the delay measuring signal, the frequency counter output signal corresponding to the value to which the reference frequency value is decremented at the end of each test signal; means responsive to the frequency counter output signal for controlling the heat from the heater means, the means responsive to the heater counter output signal comprising heater counter means for storing an initial heater value and for incrementing and decrementing the heater value between limits in response to the frequency counter output signal, the heater counter means comprising means for producing a heater control signal corresponding to the value to which the initial heater value is incremented and decremented in response to the frequency counter output signal; and the heater comprising means for generating heat which varies with the heater control signal.

Claim 19

A circuit for monitoring and controlling the propagation delay time of signals passing through an integrated circuit composed of logic elements, the integrated circuit being of the type in which propagation delay time varies with variations in the temperature of the integrated circuit, comprising: test signal source means for generating propagation time delay test signals; delay measuring means for measuring the signal propagation delay time of signals passing through at least a portion of the integrated circuit, the delay measuring means comprising an oscillator having a gating input and N logic elements of the integrated circuit connected in series to form a ring with the output of each logic element being connected to the input of the succeeding logic element such that a pulse continuously circulates around the ring in response to a test signal from the test signal source means applied to the gating input, the oscillator logic elements having propagation delay characteristics typical of the other logic elements on the integrated circuit, the output of the oscillator being a delay measuring signal comprised of pulses of a frequency which is a function of the propagation delay of each logic element of the ring, the propagation delay of the logic elements being in part a function of the temperature of the integrated circuit; first storage means for storing a reference frequency value corresponding to a reference propagation delay time; means for varying the reference frequency value; a heater on the integrated circuit; means for controlling the heater to selectively heat the integrated crcuit to control the propagation delay time, the means for controlling the heater including frequency counter means for producing a frequency counter output signal corresponding to the frequency of the delay measuring signal, the frequency counter comprising means for receiving the reference frequency value from the first storage means at the start of each test signal and for decrementing the received reference frequency value in response to each pulse of the delay measuring signal, the frequency counter output signal corresponding to the value to which the reference frequency value is decremented at the end of each test signal; means responsive to the frequency counter output signal for controlling the heat from the heater means, the means responsive to the heater counter output signal comprising heater counter means for storing an initial heater value and for incrementing and decrementing the heater value between limits in response to the frequency counter output signal, the heater counter means comprising means for producing a heater control signal corresponding to the value to which the initial heater value is incremented and decremented in response to the frequency counter output signal; and the heater comprising means for generating heat which varies with the heater control signal.

Claim 20

A circuit according to claim 17 in which the heater comprises plural integrated circuit heat generating elements which are selectively energized in response to the heater control signal and which generate heat when energized.

Claim 21

A circuit according to claim 18 in which the test signal source comprises means for generating a periodic string of test signals having first, second and third progressively increasing durations, the string comprising multiple test signals of the first and third durations to each test signal of the second duration, and the circuit also including means for varying the initial heater value.

Claim 22

A circuit for monitoring and controlling the propagation delay time of signals passing through an integrated circuit, the integrated circuit being of the type in which propagation delay time varies with variations in the temperature of the integrated circuit, comprising: means on the integrated circuit for varying the termperature of the integrated circuit; means for controlling the first named means to selectively vary the termperature of the integrated circuit to control the propagation delay time.

Claim 23

A circuit for monitoring and controlling the propagation delay time of signals passing through an integrated circuit, the integrated circuit being of the type in which propagation delay time varies with variations in the temperature of the integrated circuit, comprising: means on the integrated circuit for varying the termperature of the integrated circuit; means for controlling the first named means to selectively vary the termperature of the integrated circuit to control the propagation delay time.