WEAK POWER SUPPLY OPERATION AND CONTROL

• US 20140143559A1
• Filed: 11/21/2012
• Published: 05/22/2014
• Est. Priority Date: 11/21/2012
• Status: Active Grant

• Current Assignee: Nano-Retina Inc.
• Original Assignee: Nano-Retina Inc.
• Inventors: Gefen, Ra'anan, Liran, Tuvia
• Granted Patent: US 9,720,477 B2
• Time in Patent Office: Days
• US Class Current: 713/300
• CPC Class Codes: A61F 2/14 Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
• CPC Class Codes: A61N 1/36046 of the eye
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: G06F 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: G11C 11/4125 Cells incorporating circuit means for protecting against loss of information
• 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: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Power monitoring circuitry is provided, comprising a capacitor configured to receive a current, so as to charge the capacitor and a switching device, connected to the capacitor. The switching device is configured to periodically discharge the capacitor in response to receipt of a clock signal from a circuit being monitored. The power monitoring circuitry also comprises a comparator, configured to perform a comparison of a voltage developed by the capacitor with a threshold voltage, and to output an indication of a change in power supplied to the circuit in response to the comparison. Other embodiments are also described.

Claims

1. Power monitoring circuitry, comprising:

a capacitor configured to receive a current, so as to charge the capacitor;

a switching device, connected to the capacitor, configured to periodically discharge the capacitor in response to receipt of a clock signal from a circuit being monitored; and

a comparator, configured to perform a comparison of a voltage developed by the capacitor with a threshold voltage, and to output an indication of a change in power supplied to the circuit in response to the comparison.

2. The circuitry according to claim 1, wherein the current comprises a fixed charging current, and wherein the circuitry comprises a constant current generator supplying the fixed charging current.

3. The circuitry according to claim 1, wherein the threshold voltage is determined in response to a level attained by the capacitor if the capacitor is not discharged.

4. The circuitry according to claim 1, wherein the indication is output in response to the switching device ceasing to periodically discharge the capacitor.

5. The circuitry according to claim 1, and comprising a power supply powering the circuit, wherein the comparator is configured to output the indication if a voltage of the power supply is less than a lower threshold.

6. The circuitry according to claim 5, wherein the comparator is configured to output the indication if the voltage of the power supply is less than the lower threshold, the lower threshold being less than 1.5 volts.

7. The circuitry according to claim 6, wherein the comparator is configured to output the indication if the voltage of the power supply is less than the lower threshold, the lower threshold being between 0.2 volts and 0.6 volts.

8. Circuitry, comprising:

a circuit comprising a volatile memory and an operating module configured to read from and write to the volatile memory; and

a power monitoring module, configured to detect a change in power supplied to the circuit, and, in response to the change, to reduce an operating module power level supplied to the operating module while maintaining a volatile memory power level supplied to the volatile memory.

9. The circuitry according to claim 8, wherein the circuit comprises a first switching circuit configured to supply power to the volatile memory and a second switching circuit configured to supply power to the operating module, and wherein the power monitoring module is configured to operate the first and second switching circuits so as to reduce the operating module power level while maintaining the volatile memory power level.

10. The circuitry according to claim 8, wherein reducing the operating module power level comprises reducing the operating module power level smoothly.

11. The circuitry according to claim 8, wherein reducing the operating module power level comprises reducing the operating module power level in a stepwise fashion.

12. The circuitry according to claim 8, and comprising a power supply powering the circuit, wherein the power monitoring module is configured to detect the change if a voltage of the power supply is less than a lower threshold.

13. The circuitry according to claim 12, wherein the power monitoring module is configured to detect the change if a voltage of the power supply is less than the lower threshold, the lower threshold being less than 1.5 volts.

14. The circuitry according to claim 13, wherein the power monitoring module is configured to detect the change if the voltage of the power supply is less than the lower threshold, the lower threshold being between 0.2 volts and 0.6 volts.

15. Circuitry, comprising:

a circuit comprising control logic and an operating module configured to read from and write to the control logic; and

a power monitoring module, configured to detect a change in power supplied to the circuit, and, in response to the change, to reduce an operating module power level supplied to the operating module while maintaining a control logic power level supplied to the control logic.

16. The circuitry according to claim 15, and comprising a power supply powering the circuit, wherein the power monitoring module is configured to detect the change if a voltage of the power supply is less than a lower threshold.

17. The circuitry according to claim 16, wherein the power monitoring module is configured to detect the change if the voltage of the power supply is less than the lower threshold, the lower threshold being less than 1.5 volts.

18. The circuitry according to claim 15, wherein the power monitoring module is configured to detect the change if the voltage of the power supply is less than the lower threshold, the lower threshold being between 0.2 volts and 0.6 volts.

19-119. -119. (canceled)