Circuits, Systems and Methods to Detect and Accommodate Power Supply Voltage Droop

• US 20110241423A1
• Filed: 04/01/2010
• Published: 10/06/2011
• Est. Priority Date: 04/01/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Patel, Sanjay B., Bridges, Jeffrey Todd
• Granted Patent: US 9,483,098 B2
• Time in Patent Office: Days
• US Class Current: 307/31
• CPC Class Codes: G06F 1/305 in the event of power-supply fluctuations

Abstract

Circuits, systems, and methods for monitoring a power supply voltage and determining if the power supply voltage has drooped are disclosed. In one embodiment, a voltage monitoring circuit is provided and configured to determine if the power supply voltage supplied to a functional circuit has drooped. When no droop of the power supply voltage is detected, the voltage monitoring circuit is configured to provide an indication to the functional circuit to operate in a first mode. When droop of the power supply voltage is detected, the voltage monitoring circuit is configured to provide an indication to the functional circuit to operate in a second mode. In this manner, operating margin in the power supply may be reduced since the functional circuit may be configured to properly operate when a voltage droop of the power supply voltage occurs.

Claims

1. A voltage monitoring circuit configured to:

receive a signal indicative of a power supply voltage associated with supplying power to a functional circuit;

determine if the power supply voltage has drooped;

when no droop of the power supply voltage is detected, provide an indication to the functional circuit to operate in a first mode; and

when droop of the power supply voltage is detected, provide an indication to the functional circuit to operate in a second mode.

2. The voltage monitoring circuit of claim 1, wherein the indication to the functional circuit to operate in the second mode allows the functional circuit to operate when droop in the power supply voltage is detected.

3. The voltage monitoring circuit of claim 1, wherein the indication to the functional circuit to operate in the first mode comprises an indication to the functional circuit to operate without a reduction in a minimum voltage level for the functional circuit;

and

wherein the indication to the functional circuit to operate in the second mode comprises and indication to the functional circuit to operate with a reduced minimum voltage level for the functional circuit.

4. The voltage monitoring circuit of claim 1, further configured to:

select the first mode based on droop status information when no droop in the power supply voltage is detected; and

select the second mode based on the droop status information, wherein operating in the second mode allows operation of the functional circuit when droop in the power supply voltage is detected.

5. The voltage monitoring circuit of claim 1, further configured to:

receive the signal indicative of the power supply voltage;

determine if the power supply voltage has drooped; and

provide droop status information based on detecting if the power supply voltage has drooped.

6. The voltage monitoring circuit of claim 5, wherein the determination if the power supply voltage has drooped is based on performance of the droop detection circuitry.

7. The voltage monitoring circuit of claim 5, wherein the droop detection circuitry comprises a ring oscillator circuit,

wherein the determination if the power supply voltage has drooped is based on an at least one oscillation frequency of the ring oscillator circuit.

8. The voltage monitoring circuit of claim 5, wherein the droop of the power supply voltage is detected based on a magnitude of the power supply voltage.

9. The voltage monitoring circuit of claim 8, wherein detection of the droop of the power supply voltage is based on the magnitude of the power supply voltage being less than the magnitude of the power supply voltage during no droop of the power supply voltage.

10. The voltage monitoring circuit of claim 1 integrated in at least one semiconductor die.

11. The voltage monitoring circuit of claim 1, integrated into a device selected from the group consisting of a set top box, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile location data unit, a mobile phone, a cellular phone, a computer, a portable computer, a desktop computer, a monitor, a computer monitor, a television, a tuner, a radio, a satellite radio, a music player, a digital music player, a portable music player, a video player, a digital video player, a digital video disc (DVD) player, and a portable digital video player, into which the voltage monitoring circuit is integrated.

12. The voltage monitoring circuit of claim 1, wherein the functional circuit has a first minimum acceptable operating voltage in the first mode, and the functional circuit has a second minimum acceptable operating voltage less than the first minimum acceptable operating voltage in the second mode.

13. The voltage monitoring circuit of claim 1, wherein the functional circuit operates using a clock signal at a first frequency in the first mode, and the functional circuit operates using a clock signal at a second frequency less than the first frequency in the second mode.

14. The voltage monitoring circuit of claim 1, wherein the functional circuit comprises current limiting circuitry to limit a current demand of the functional circuit in the second mode.

15. A voltage monitoring circuit, comprising:

a means for receiving a signal indicative of a power supply voltage associated with supplying power to a functional circuit;

a means for determining if the power supply voltage has drooped;

when no droop in the power supply voltage is detected, a means for providing an indication to the functional circuit to operate in a first mode; and

when droop is detected in the power supply voltage, a means for providing an indication to the functional circuit to operate in a second mode.

16. The voltage monitoring circuit of claim 15, wherein the indication to the functional circuit to operate in the second mode allows the functional circuit to operate at the power supply voltage when droop in the power supply voltage is detected.

17. A method for limiting power supply voltage droop, comprising:

receiving a signal indicative of a power supply voltage associated with a power supply supplying power to a functional circuit;

determining if the power supply voltage has drooped;

when no droop is detected in the power supply voltage, providing an indication to the functional circuit to operate in a first mode; and

when droop is detected in the power supply voltage, providing an indication to the functional circuit to operate in a second mode.

18. The method of claim 17, wherein the indication to the functional circuit to operate in the second mode allows the functional circuit to operate at the power supply voltage when droop in the power supply voltage is detected.

19. The method of claim 17, wherein the indication to the functional circuit to operate in the first mode comprises an indication to the functional circuit to operate without a reduction in a minimum voltage level for the functional circuit;

and

wherein the indication to the functional circuit to operate in the second mode comprises and indication to the functional circuit to operate with a reduced minimum voltage level for the functional circuit.

20. The method of claim 17, wherein determining if the power supply voltage has drooped comprises:

operating a ring oscillator powered by the power supply;

estimating a frequency of the ring oscillator to provide a first estimated frequency; and

estimating the droop of the power supply voltage based on the first estimated frequency.

21. A system for detecting power supply voltage droop, comprising:

a functional circuit; and

a voltage monitoring circuit configured to;

receive a signal indicative of a power supply voltage associated with supplying power to a functional circuit;

determine if the power supply voltage has drooped;

when no droop of the power supply voltage is detected, provide an indication to the functional circuit to operate in a first mode; and

when droop of the power supply voltage is detected, provide an indication to the functional circuit to operate in a second mode.

22. The system of claim 21, wherein the functional circuit is configured to operate in the second mode when the droop in the power supply voltage is detected by the voltage monitoring circuit.

23. The system of claim 21, wherein the indication to the functional circuit to operate in the first mode comprises an indication to the functional circuit to operate without a reduction in a minimum voltage level for the functional circuit;

and

wherein the indication to the functional circuit to operate in the second mode comprises and indication to the functional circuit to operate with a reduced minimum voltage level for the functional circuit.

24. The system of claim 21, wherein the voltage monitoring circuit is integrated into at least one semiconductor die.

25. The system of claim 24, wherein the functional circuit is integrated into the at least one semiconductor die.

26. The system of claim 21, wherein the voltage monitoring circuit is further configured to:

select the first mode based on droop status information when no droop in the power supply voltage is detected; and

select the second mode based on the droop status information, wherein operating in the second mode allows operation of the functional circuit when droop in the power supply voltage is detected.

27. The system of claim 21, wherein the voltage monitoring circuit is further configured to:

receive the signal indicative of the power supply voltage;

determine if the power supply voltage has drooped; and

provide droop status information based on detecting if the power supply voltage has drooped.