Method and apparatus for power supply aware memory access operations in an integrated circuit

• US 9,224,433 B1
• Filed: 04/09/2014
• Issued: 12/29/2015
• Est. Priority Date: 04/09/2014
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Altera Corporation (Intel Corporation)
• Inventors: Pedersen, Bruce B.
• Primary Examiner(s): Luu, Pho M
• Application Number:
  US14/248,583
• Time in Patent Office: 629 Days
• Field of Search: 365/226, 365/185.09, 365/228
• US Class Current: 1/1
• CPC Class Codes: G11C 11/40 using transistors
• CPC Class Codes: G11C 11/4074 Power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage generators, back-up power, power control circuits
• CPC Class Codes: G11C 16/225 Preventing erasure, programming or reading when power supply voltages are outside the required ranges
• CPC Class Codes: G11C 16/30 Power supply circuits
• CPC Class Codes: G11C 5/14 Power supply arrangements , e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels
• CPC Class Codes: G11C 5/143 Detection of memory cassette insertion or removal; Continuity checks of supply or ground lines; Detection of supply variations, interruptions or levels G11C5/148 takes precedence; Switching between alternative supplies G11C5/141 takes precedence
• 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

On-die variability noise or other variations in the power supply voltage to a storage circuit may cause the ability to perform memory access operations to be marginal. A control circuit may be coupled to the storage circuit and the power distribution network and monitor the actual power supply voltage. The control circuit may include a reference voltage generator that generates a nominal voltage. The control circuit may further include a comparator that generates a status signal based on a comparison between the actual power supply voltage and a nominal voltage. Based on the status signal, the control circuit may control memory access operations performed by the storage circuit. For example, the control circuit may enable and disable the execution of read and write operations on the storage circuit. If desired, the control circuit may also control the operation of predetermined portions of the integrated circuit.

Claims

1. An integrated circuit comprising:

a power supply rail that conveys a power supply voltage;

a storage circuit that performs memory access operations using the power supply voltage from the power supply rail;

a control circuit that controls the memory access operations performed by the storage circuit based at least in part on a comparison between the power supply voltage conveyed by the power supply rail and a nominal voltage; and

a reference voltage generator coupled to the control circuit that generates the nominal voltage and provides the nominal voltage to the control circuit, wherein the nominal voltage is the targeted operating voltage of the power supply rail.

2. The integrated circuit of claim 1, wherein the control circuit generates a status signal based at least in part on the comparison between the power supply voltage conveyed by the power supply rail and the nominal voltage.

3. The integrated circuit of claim 2, further comprising:

an input pin at which the integrated circuit receives the power supply voltage and propagates the received power supply voltage to the power supply rail; and

an output pin at which the integrated circuit produces the status signal for external circuitry.

4. The integrated circuit of claim 2, wherein the control circuit comprises:

a comparator that compares the actual voltage and a predetermined threshold voltage and wherein the status signal indicates whether the actual voltage is above the predetermined threshold voltage.

5. The integrated circuit of claim 2, wherein the control circuit comprises:

a comparator that compares the actual voltage and the nominal voltage and wherein the status signal indicates whether the actual voltage is within a predetermined range of the nominal voltage.

6. The integrated circuit of claim 5, wherein the control circuit directs the storage circuit to disable the memory access operations when the actual voltage is outside the predetermined range of the nominal voltage.

7. The integrated circuit of claim 5, wherein the control circuit directs the storage circuit to perform the memory access operations when the actual voltage is inside the predetermined range of the nominal voltage.

8. The integrated circuit of claim 1, wherein the storage circuit comprises:

an input port that receives data, wherein the memory access operations include write access operations that store the received data.

9. The integrated circuit of claim 1, wherein the storage circuit comprises:

an output port, wherein the memory access operations include read access operations that retrieve data and provide the retrieved data at the output port.

10. The integrated circuit of claim 1, wherein at least a portion of the storage circuit is implemented on a programmable logic device.

11. A method for operating an integrated circuit, the method comprising:

receiving a power supply voltage from an external power regulator;

with a power supply network, distributing the received power supply voltage;

with a storage circuit operated by the power supply voltage, initiating a memory access operation;

with a control circuit, monitoring variations of the power supply voltage;

with the control circuit, controlling the memory access operation based at least in part on the monitored power supply voltage variations;

with the control circuit, comparing an actual voltage of the power supply voltage to a nominal voltage to determine whether the actual voltage is within a predetermined range from the nominal voltage; and

with the control circuit, outputting a status signal to the external power regulator, wherein the status signal indicates whether the actual voltage is within the predetermined range from the nominal voltage.

12. The method of claim 11, further comprising:

in response to determining that the actual voltage is not within the predetermined range from the nominal voltage, disabling the memory access operation.

13. The method of claim 12, further comprising:

in response to determining that the actual voltage is within the predetermined range from the nominal voltage, enabling the memory access operation; and

with the storage circuit, completing the memory access operation.

14. The method of claim 11, wherein the integrated circuit comprises a programmable logic device, and wherein the storage circuit comprises configuration memory elements, the method further comprising:

with an input pin of the programmable logic device, receiving a bit stream that programs the configuration memory elements; and

with the control circuit, temporarily pausing the receipt of the bit stream based at least in part on the monitored power supply voltage variations.

15. A method for operating an integrated circuit including circuitry, the method comprising:

operating the circuitry at an actual voltage level;

with a reference voltage generator, generating a reference voltage level;

with a comparator, comparing the actual voltage level to the reference voltage level to generate a comparator output signal; and

with a control circuit, pausing the operation of the circuitry based at least in part on the comparator output signal.

16. The method of claim 15, wherein the comparator output signal indicates whether the actual voltage level has dropped below the reference voltage level.

17. The method of claim 15, further comprising:

with the comparator, generating a resume signal when the comparison between the actual voltage level and the reference voltage level indicates that the actual voltage level has risen above the reference voltage level.

18. The method of claim 17, further comprising:

with the control circuit, receiving the resume signal; and

with the control circuit, resuming the operation of the circuitry.

19. An integrated circuit comprising:

a power supply rail that conveys a power supply voltage;

a memory circuit that executes a read operation using the power supply voltage from the power supply rail;

a reference voltage generator that generates a nominal voltage;

a comparator that receives the power supply voltage from the power supply rail and the nominal voltage from the reference voltage generator, wherein the comparator compares the power supply voltage and the nominal voltage and provides a status signal that indicates whether the power supply voltage is within a predetermined range of the nominal voltage; and

an enable circuit coupled to the comparator and the memory circuit, wherein the enable circuit receives the status signal from the comparator and disables the read operation of the memory circuit when the received status signal indicates that the power supply voltage conveyed by the power supply rail is outside the predetermined range of the nominal voltage.