CONTROLLED RELIABILITY IN AN INTEGRATED CIRCUIT

• US 20080091990A1
• Filed: 09/28/2006
• Published: 04/17/2008
• Est. Priority Date: 09/28/2006
• Status: Active Grant

• Current Assignee: North Star Innovations Inc. (Wi-LAN Inc.)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Russell, Andrew C., Zhang, Shayan, Hunter, Bradford L., Bruce, Klas M.
• Granted Patent: US 7,793,172 B2
• Time in Patent Office: Days
• US Class Current: 714/721
• CPC Class Codes: G11C 29/02 Detection or location of defective auxiliary circuits, e.g. defective refresh counters
• CPC Class Codes: G11C 29/021 in voltage or current generators
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check
• CPC Class Codes: G11C 5/147 Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops G11C5/141 takes precedence

Abstract

Methods and systems for configuring characteristics associated with at least one portion of a memory array comprising addressable units are provided. In one aspect, a method for controlling a power supply voltage for a memory array comprises detecting whether an error occurred in performing a read operation on an addressable unit of the memory array using a first power supply voltage coupled to the memory array. The method further comprises incrementing an error counter for tracking an error count associated with the memory array and switching the memory array to a second power supply voltage if the error count is equal to or exceeds an error threshold for the memory array. The method further comprises, based on at least one condition, switching the memory array to the first power supply voltage and resetting the error counter to an initial value.

Claims

1. A method for controlling a power supply voltage for a memory array comprising addressable units, the method comprising:

detecting whether an error occurred in performing a read operation on at least one addressable unit of the memory array using a first power supply voltage coupled to at least one portion of the memory array;

if an error is detected, then incrementing an error counter for tracking an error count associated with the at least one portion of the memory array;

switching the at least one portion of the memory array to a second power supply voltage if the error count is equal to or exceeds an error threshold for the at least one portion of the memory array; and

based on at least one condition, switching the at least one portion of the memory array to the first power supply voltage and resetting the error counter to an initial value.

2. The method of claim 1 further comprising generating the first power supply voltage using a core voltage generator, wherein the core voltage generator generates a core voltage for a processor coupled to the memory array.

3. The method of claim 2 further comprising the processor communicating at least one voltage identifier to the core voltage generator, wherein the at least one voltage identifier corresponds to a specific value of the core voltage.

4. The method of claim 2, wherein the second power supply voltage is a fixed power supply voltage and wherein the fixed power supply voltage is greater than or equal to the core voltage.

5. The method of claim 1, wherein the at least one condition is evaluated by a memory configuration controller and the at least one condition relates to:

a signal from a user requesting a change in the power supply voltage;

a signal from a dynamic voltage and frequency scaling unit indicating a change in a value of the first supply voltage;

an elapse of a predetermined time from a time at which the memory array is switched from the first power supply voltage to the second power supply voltage;

a signal from CPU 12 or memory configuration controller 18 requesting a change in memory latency;

or

an error-free counter exceeding an error-free count threshold, wherein the error-free counter is incremented based on when a read operation on the memory array does not result in an error.

6. The method of claim 1, wherein detecting whether the error occurred in performing the read operation on the at least one addressable unit of the memory array further comprises determining whether the error is a single-bit error or a double-bit error.

7. The method of claim 6 further comprising incrementing the error counter for tracking the error count associated with the at least one portion of the memory array only when the single-bit error is detected.

8. The method of claim 6 further comprising generating an interrupt for a processing core coupled to the memory array when the double-bit error is detected.

9. A method for configuring characteristics associated with at least one portion of a memory array comprising addressable units, the method comprising:

detecting whether an error occurred in performing a read operation on at least one addressable unit of the memory array, wherein the at least one portion of the memory array is configured to operate based on a first set of characteristics;

if an error is detected, then incrementing an error counter for tracking an error count associated with at least one portion of the memory array;

if the error count is equal to or exceeds an error threshold for the at least one portion of the memory array, re-configuring the at least one portion of the memory array to operate based on a second set of characteristics, wherein the second set of characteristics differs from the first set of characteristics in terms of a value of at least one of the characteristics; and

based on at least one condition re-configuring the at least one portion of the memory array to operate based on the first set of characteristics and resetting the error counter to an initial value.

10. The method of claim 9, wherein the first set of characteristics relates to at least one of a first power supply voltage coupled to the at least one portion of the memory array, a first latency value associated with the at least one portion of the memory array, a first refresh rate associated with the at least one portion of the memory array, and a first programmable delay value associated with the at least one portion of the memory array and the second set of characteristics relates to at least one of a second power supply voltage coupled to the at least one portion of the memory array, a second latency value associated with the at least one portion of the memory array, a second refresh rate associated with the at least one portion of the memory array, and a second programmable delay value associated with the at least one portion of the memory array.

11. The method of claim 9, wherein the at least one condition is evaluated by a memory configuration controller and the at least one condition relates to:

a signal from a user requesting a change from the first power supply voltage to the second power supply voltage;

a signal from a dynamic voltage and frequency scaling unit indicating a change in a value of the first supply voltage;

an elapse of a predetermined time from a time at which the at least one portion of the memory array is switched from the first power supply voltage to the second power supply voltage;

an error-free counter exceeding an error-free count threshold, wherein the error-free counter is incremented based on when a read operation on the at least one portion of the memory array does not result in an error;

a signal from a user requesting a change from the first latency value to the second latency value;

a signal from a user requesting a change from the first refresh rate to the second refresh rate; and

a signal from a user requesting a change from a first programmable delay value to a second programmable delay value.

12. The method of claim 10 further comprising generating the first power supply voltage using a core voltage generator, wherein the core voltage generator generates a core voltage for a processor coupled to the memory array.

13. The method of claim 12 further comprising the processor communicating at least one voltage identifier to the core voltage generator, wherein the at least one voltage identifier corresponds to a specific value of the core voltage.

14. The method of claim 9, wherein detecting whether the error occurred in performing a read operation on at least one addressable unit of the memory array further comprises determining whether the error is a single-bit error or a double-bit error and further comprising:

incrementing the error counter for tracking the error count associated with the at least one portion of the memory array only when the single-bit error is detected; and

if necessary, generating an interrupt for a processor coupled to the memory array when the double-bit error is detected.

15. The method of claim 9 further comprising dynamically changing the error threshold based on a signal from one of a user of the memory array or a signal from a processor coupled to the memory array.

16. A system for controlling a power supply voltage for a memory array comprising addressable units, the system comprising:

an error detector/corrector for detecting whether an error occurred in performing a read operation on at least one addressable unit of the memory array using a first power supply voltage coupled to at least one portion of the memory array and using a first timing characteristic for accessing the at least one portion of the memory array; and

a memory configuration controller;

for incrementing an error counter for tracking an error count associated with at least one portion of the memory array, in case an error is detected by the error detector,

for switching the at least one portion of the memory array to a second power supply voltage if the error count is equal to or exceeds an error threshold for the memory array,

for switching the at least one portion of the memory array to the first power supply voltage and resetting the error counter to an initial value based on at least one condition, and

for changing at least one timing characteristic for accessing the at least one portion of the memory array if the error count is equal to or exceeds the error threshold for the at least one portion of the memory array.

17. The system of claim 16, wherein the memory configuration controller is further configured to change a refresh rate associated with the at least one portion of the memory array if the error count is equal to or exceeds the error threshold for the at least one portion of the memory array.

18. The system of claim 16, wherein the at least one condition evaluated by the memory configuration controller relates to:

a signal from a user requesting a change from the first power supply voltage to the second power supply voltage;

a signal from a dynamic voltage and frequency scaling unit indicating a change in a value of the first supply voltage;

an elapse of a predetermined time from a time at which the memory array is switched from the first power supply voltage to the second power supply voltage;

an error-free counter exceeding an error-free count threshold, wherein the error-free counter is incremented based on when a read operation on the at least one portion of the memory array does not result in an error;

a signal from a user requesting a change from the first latency value to the second latency value;

a signal from a user requesting a change from the first programmable delay value to the second programmable delay value;

or a signal from a user requesting a change from the first refresh rate to the second refresh rate.

19. The system of claim 16 further comprising a switch coupled to the memory array, the first power supply voltage, and the second power supply voltage, such that the switch can be controlled by the memory configuration controller to couple either the first power supply voltage or the second power supply voltage to the at least one portion of the memory array.

20. The system of claim 16 further comprising a core voltage generator, wherein the core voltage generator generates a core voltage for a processor coupled to the memory array, wherein the core voltage corresponds to the first power supply voltage, wherein the second power supply voltage corresponds to a fixed voltage, and wherein the second power supply voltage is greater than or equal to the first power supply voltage.