Removable hard disk drive (HDD) that is hot-plug compatible with multiple external power supply voltages
First Claim
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1. A circuit for sensing an input supply voltage and providing a desired output voltage, the circuit comprising:
- a voltage sensing circuit, configured to sense, at least at a predetermined time, a value of the input supply voltage and provide a voltage indication signal based on the supply voltage, so sensed;
a control circuit, responsive to said voltage indication signal, that generates a control signal; and
a switching element having a control terminal that receives said control signal;
said control signal being different for different first and second values of said supply voltage, so sensed, whereinsaid first value of said supply voltage, so sensed, is different from said desired output voltage, andsaid control signal is in the form of a pulse train for switching said switching element for said first value of said supply voltage, so sensed, wherein said pulsed control signal has a duty cycle greater than 0% and less than 100%.
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Abstract
Circuitry in a hard disk drive (HDD) senses the supply voltage, normally at power-on, and applies appropriate DC-to-DC conversion (pass-through, step-down, or boost regulation) according to the design requirements of the HDD.
24 Citations
23 Claims
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1. A circuit for sensing an input supply voltage and providing a desired output voltage, the circuit comprising:
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a voltage sensing circuit, configured to sense, at least at a predetermined time, a value of the input supply voltage and provide a voltage indication signal based on the supply voltage, so sensed; a control circuit, responsive to said voltage indication signal, that generates a control signal; and a switching element having a control terminal that receives said control signal; said control signal being different for different first and second values of said supply voltage, so sensed, wherein said first value of said supply voltage, so sensed, is different from said desired output voltage, and said control signal is in the form of a pulse train for switching said switching element for said first value of said supply voltage, so sensed, wherein said pulsed control signal has a duty cycle greater than 0% and less than 100%. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A circuit for powering a hard disk drive, the circuit comprising:
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a voltage sensing circuit, configured to sense, at least at a predetermined time, a single supply voltage at one input node and provide a voltage indication signal based on the supply voltage, so sensed; at least one DC-DC conversion circuit, connected to said one input node and to an output node, for converting said single supply voltage, so sensed, to a different desired output voltage when said single supply voltage sensed at the one input node is not the desired output voltage and providing said different voltage on said output node; and a control circuit, coupled to said voltage sensing circuit and to said DC-DC conversion circuit for controlling said DC-DC conversion circuit depending on said supply voltage, so sensed, wherein when the sensed single supply voltage is the desired output voltage, said control circuit controls the DC-DC conversion circuit to not convert the sensed single supply voltage to a different voltage so that said sensed single supply voltage is provided on said output node.
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14. A circuit for powering a hard disk drive, the circuit comprising:
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a voltage sensing circuit, configured to sense, at least at a predetermined time, a single supply voltage at one input node and provide a voltage indication signal based on the supply voltage, so sensed; at least one DC-DC conversion circuit, connected to said input node and to an output node, for converting said single supply voltage, so sensed, to a different desired output voltage and providing said different voltage on said output node; a switchable pass-through path between said input node and said output node; and a control circuit, coupled to said voltage sensing circuit, said DC-DC conversion circuit, and said switchable pass-through path; said control circuit controlling said DC-DC conversion circuit and said switchable pass-through path so that; when said voltage indication signal indicates that said single supply voltage is different from said desired output voltage, said control circuit enables said DC-DC conversion circuit to supply said different voltage on said output node, and prevents said pass-through path from passing said supply voltage to said output node; and when said voltage indication signal indicates that said supply voltage is equal to said desired output voltage, said control circuit prevents said DC-DC conversion circuit from supplying said different voltage on said output node, and allows said pass-through path to pass said supply voltage to said output node. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A hard disk drive comprising:
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a magnetic disk; a spindle motor connected to said disk to rotate said disk upon the application of power; a head for reading and writing data from and to said disk; a head motor connected to move said head across said disk upon the application of power; and a motor control circuit coupled to said spindle motor and said head motor to control the application of power to said spindle motor and said head motor; power distribution circuitry for connection to a power source solely through a two-pin connection to the power source, said connection providing a supply voltage between a voltage supply node and a ground node, said power distribution circuitry including; a voltage sensing circuit, configured to sense, at least at a predetermined time, said supply voltage and provide a voltage indication signal based on the supply voltage, so sensed; at least one DC-DC conversion circuit, connected to said voltage supply node and to an output node, for converting said supply voltage, so sensed, to a different desired output voltage when said supply voltage sensed at the voltage supply node is not the desired output voltage and providing said different voltage on said output node; and a control circuit, coupled to said voltage sensing circuit and to said DC-DC conversion circuit for controlling said DC-DC conversion circuit depending on said supply voltage, so sensed, wherein when the sensed supply voltage is the desired output voltage, said control circuit controls the DC-DC conversion circuit to not convert the sensed supply voltage to a different voltage so that said sensed supply voltage is provided on said output node. - View Dependent Claims (21, 22, 23)
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Specification