Process monitor for monitoring an integrated circuit chip
View Patent ↗A system or apparatus for monitoring an Integrated Circuit (IC) chip includes: a sense circuit at least partially constructed on the IC chip and configured to produce one or more sense signals each indicative of a corresponding process-dependent circuit parameter of the IC chip; and a digitizer module configured to produce, responsive to the one or more sense signals, one or more digitized signals each representative of a corresponding one of the sense signals. A controller is configured to determine a value of one or more of the process-dependent circuit parameters based on one or more of the digitized signals.
1. An integrated circuit (IC) comprising:
a bias circuit configured to provide a bias current to measure an absolute value associated with a component on the IC;
a sense circuit configured to provide a sensed signal indicative of a parameter associated with the IC based on the measurement of the absolute value; and
an adjusting circuit configured to control operation of another component on the IC based on the sensed signal.
2. The IC of claim 1 , wherein the bias current includes a constant-to-absolute temperature (CTAT) current that is substantially constant as a temperature of the IC changes, or a proportional-to-absolute temperature (PTAT) current that is proportional to the temperature of the IC.
3. The IC of claim 2 , wherein when the bias current includes the CTAT current, the bias current comprises:
a first CTAT current provided by a first external resistor external to the IC;
a second CTAT current provided by a second external resistor external to the IC; and
at least one of a third CTAT current provided by a first polysilicon resistor of the IC and a first PTAT current provided by a second polysilicon resistor of the IC.
4. The IC of claim 1 , wherein the sense circuit comprises:
a plurality of process monitor circuits to monitor the parameter associated with the IC.
5. The IC of claim 4 , wherein the plurality of process monitor circuits comprise at least one of:
a first process monitor circuit to monitor a transconductance of the IC;
a second process monitor circuit to monitor a threshold voltage of a transistor of the IC;
a third process monitor circuit to monitor a resistivity per unit area of the IC; and
a fourth process monitor circuit to monitor a temperature of the IC.
6. The IC of claim 5 , wherein the first process monitor circuit is configured to select an NMOS transistor configured as a first diode-connected set-up or a PMOS transistor configured as a second diode-connected set-up to provide the sensed signal indicative of the transconductance of the IC.
7. The IC of claim 5 , wherein the first process monitor circuit is configured to receive a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
8. The IC of claim 5 , wherein the second process monitor circuit is configured to select an NMOS transistor configured as a first diode-connected set-up or a PMOS transistor configured as a second diode-connected set-up to provide the sensed signal indicative of the threshold voltage of a transistor of the IC.
9. The IC of claim 5 , wherein the second process monitor circuit is configured to receive a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
10. The IC of claim 5 , wherein the third process monitor circuit is configured to select a first polysilicon resistor having a first resistivity per unit area or a second polysilicon resistor having a second resistivity per unit area to provide the sensed signal indicative of the resistivity per unit area of the IC, the first resistivity per unit area being less than the second resistivity per unit area.
11. The IC of claim 5 , wherein the third process monitor circuit is configured to receive a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
12. The IC of claim 5 , wherein the fourth process monitor circuit comprises:
a polysilicon resistor to provide the temperature of the IC.
13. The IC of claim 5 , wherein the fourth process monitor circuit is configured to receive a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC or a proportional-to-absolute temperature (PTAT) current provided by a second polysilicon resistor of the IC, the CTAT current being substantially constant as the temperature of the IC changes, and the PTAT current being proportional to the temperature of the IC.
14. The IC of claim 5 , wherein at least one of the plurality of process monitor circuits further comprises:
a switch configured to provide the bias current to a predetermined process monitor circuit.
15. The IC of claim 1 , farther comprising:
a scaling amplifier configured to provide a scaled sensed signal based on the sensed signal;
a digital to analog converter (DAC) configured to provide an analog reference based on a digital reference; and
a comparator configured to compare the scaled sensed signal and the analog reference to provide a comparison result indicative of the parameter of the IC.
16. The IC of claim 15 , wherein the comparator uses a successive-approximation register (SAR) algorithm to determine a value of the scaled sensed signal by comparing the scaled sensed signal and the analog reference.
17. A method to provide a sensed signal indicative of a parameter of an integrated circuit (IC), the method comprising:
(a) providing a bias current to measure an absolute value of a component on the IC;
(b) providing the sensed signal indicative of the parameter of the IC based on the measurement of the absolute value of the component; and
(c) controlling operation of another component of the IC based on the sensed signal.
18. The method of claim 17 , wherein step (a) includes (a)(i) providing a constant-to-absolute temperature (CTAT) current that is substantially constant as a temperature of the IC changes, or providing a proportional-to-absolute temperature (PTAT) current that is proportional to the temperature of the IC.
19. The method of claim 18 , wherein step (a)(i) comprises:
(a)(i)(A) providing the CTAT current using an external resistor external to the IC.
20. The method of claim 17 , wherein step (a) comprises:
(a)(i) providing a first constant-to-absolute temperature (CTAT) current using a first external resistor external to the IC, the CTAT current being substantially constant as a temperature of the IC changes;
(a)(ii) providing a second CTAT current provided using a second external resistor external to the IC; and
(a)(iii) providing at least one of a third CTAT current using a first polysilicon resistor of the IC and a first proportional-to-absolute temperature (PTAT) using a second polysilicon resistor of the IC, the PTAT current being proportional to the temperature of the IC.
21. The method of claim 17 , wherein step (b) comprises:
(b)(i) monitoring a transconductance of the IC;
(b)(ii) monitoring a threshold voltage of transistors of the IC;
(b)(iii) monitoring a resistivity per unit area of the IC; and
(b)(iv) monitoring a temperature of the IC.
22. The method of claim 21 , wherein step (b)(i) comprises:
(b)(i)(A) monitoring the transconductance of the IC by selecting an NMOS transistor configured as a first diode-connected set-up or a PMOS transistor configured as a second diode-connected set-up to provide the sensed signal indicative of the transconductance of the IC.
23. The method of claim 21 , wherein step (b)(i) comprises:
(b)(i)(A) monitoring the transconductance of the IC using a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
24. The method of claim 21 , wherein step (b)(ii) comprises:
(b)(ii)(A) monitoring the threshold voltage of a transistor of the IC by selecting an NMOS transistor configured as a first diode-connected set-up or a PMOS transistor configured as a second diode-connected set-up to provide the sensed signal indicative of the threshold voltage of the transistors of the IC.
25. The method of claim 21 , wherein step (b)(ii) comprises:
(b)(ii)(A) monitoring the threshold voltage of a transistor of the IC using a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
26. The method of claim 21 , wherein step (b)(iii) comprises:
(b)(iii)(A) monitoring the resistivity per unit area of the IC by selecting a first polysilicon resistor having a first resistivity per unit area or a second polysilicon resistor having a second resistivity per unit area to provide the sensed signal indicative of resistivity per unit area of the IC, the first resistivity per unit area being less than the second resistivity per unit area.
27. The method of claim 21 , wherein step (b)(iii) comprises:
(b)(iii)(A) monitoring the resistivity per unit area of the IC using a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC, the CTAT current being substantially constant as the temperature of the IC changes.
28. The method of claim 21 , wherein step (b)(iv) comprises:
(b)(iv)(A) monitoring the temperature of the IC by selecting a constant-to-absolute temperature (CTAT) current provided by an external resistor external to the IC or a proportional-to-absolute temperature (PTAT) current provided by a second polysilicon resistor of the IC, the CTAT current being substantially constant as the temperature of the IC changes, and the PTAT current being proportional to the temperature of the IC.
29. The method of claim 17 , further comprising:
(d) providing a scaled sensed signal based on the sensed signal;
(e) providing an analog reference based on a digital reference; and
(f) comparing the scaled sensed signal and the analog reference to provide a comparison result indicative of the parameter of the IC.
30. The method of claim 29 , wherein step (f) comprises:
(f)(i) comparing the scaled sensed signal and the analog reference using a successive-approximation register (SAR) algorithm to determine a value of the scaled sensed signal by comparing the scaled sensed signal and the analog reference.