Circuit to indicate the status of a supply voltage
First Claim
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1. A system comprising:
- a processor to use a first supply voltage to furnish a first indication of a second supply voltage to be received by the processor;
a voltage regulator to furnish the second supply voltage in response to both the first indication and a second indication that the first supply voltage is valid; and
a circuit to provide the second indication and regulate a timing of the second indication to prevent the voltage regulator from furnishing the second supply voltage until a predefined interval of time has elapsed after the first supply voltage becomes valid.
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Abstract
A system includes a processor, a voltage regulator and a circuit. The processor uses a first supply voltage to furnish a first indication of a second supply voltage to be received by the processor. The voltage regulator furnishes the second supply voltage in response to both the first indication and a second indication that the first supply voltage is valid. The circuit provides the second indication and regulates a timing of the second indication to prevent the voltage regulator from furnishing the second supply voltage until a predefined interval of time has elapsed after the first supply voltage becomes valid.
62 Citations
22 Claims
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1. A system comprising:
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a processor to use a first supply voltage to furnish a first indication of a second supply voltage to be received by the processor;
a voltage regulator to furnish the second supply voltage in response to both the first indication and a second indication that the first supply voltage is valid; and
a circuit to provide the second indication and regulate a timing of the second indication to prevent the voltage regulator from furnishing the second supply voltage until a predefined interval of time has elapsed after the first supply voltage becomes valid. - View Dependent Claims (2, 3, 4, 5, 6, 7)
a comparator to compare the first supply voltage to a threshold level to detect when the first supply voltage is valid.
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6. The system of claim 1, wherein the circuit comprises:
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a resistor; and
a capacitor coupled to the resistor to introduce the predefined interval of time.
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7. The system of claim 1, wherein the first indication represents a voltage identification number.
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8. An apparatus comprising:
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a first circuit to indicate whether a supply voltage is valid; and
a second circuit to receive the indication from the first circuit, measure a delay interval from the time when the first circuit indicates the supply voltage is valid and provide a status signal that indicates the supply voltage is valid in response to the expiration of the delay interval. - View Dependent Claims (9, 10, 11, 12)
a comparator to compare the supply voltage to a predefined threshold to determine whether the supply voltage is valid.
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10. The apparatus of claim 8, wherein the signal comprises a power good signal.
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11. The apparatus of claim 8, wherein the second circuit comprises:
a level shifter to translate a level of the first supply voltage to produce the signal.
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12. The apparatus of claim 8, wherein the circuit comprises:
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a resistor; and
a capacitor coupled to the resistor to introduce the delay interval.
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13. A method comprising:
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in response to receiving a first supply voltage, providing an indication of a second supply voltage to be received by a processor;
furnishing the second supply voltage in response to the indication; and
preventing the furnishing until a predefined interval of time has elapsed after the first supply voltage becomes valid. - View Dependent Claims (14, 15, 16, 17)
comparing the first supply voltage to a predefined threshold to determine if the first supply voltage is valid.
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15. The method of claim 13, wherein the preventing comprises:
providing a time-delayed power good signal based on whether the first supply voltage is valid.
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16. The method of claim 15, wherein the preventing further comprises:
level shifting the first supply voltage to generate the power good signal.
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17. The method of claim 13, wherein the indication comprises a processor voltage identification number.
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18. A method comprising:
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detecting whether a supply voltage is valid;
measuring a delay interval in response to the supply voltage becoming valid;
generating a signal to indicate that the supply voltage is valid in response to the expiration of the delay interval; and
generating another supply voltage in response to the indication that the first supply voltage is valid. - View Dependent Claims (19, 20, 21, 22)
comparing the supply voltage to a predefined threshold to determine if the supply voltage is valid.
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20. The method of claim 18, wherein the signal comprises a power good signal.
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21. The method of claim 18, wherein the generating comprises:
level shifting the supply voltage to generate the signal.
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22. The method of claim 18, further comprising:
introducing the delay interval to prevent a voltage regulator from prematurely responding to a processor voltage identification signal.
Specification