Method and apparatus for fail-safe start-up circuit for subthreshold current sources
First Claim
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1. An apparatus comprising counting means for controlling current to a current source during power up, wherein said counting means is operatively coupled to fully discharge a charge storage device when said current source is powered up.
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Abstract
A method and apparatus for fail-safe start-up circuit for subthreshold current sources have been disclosed.
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Citations
14 Claims
- 1. An apparatus comprising counting means for controlling current to a current source during power up, wherein said counting means is operatively coupled to fully discharge a charge storage device when said current source is powered up.
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6. A method comprising:
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increasing current to a current source during a power-up; counting pulses from an oscillator during said power-up; determining when said counted pulses reach a criteria; and decreasing current to said current source when said criteria is reached, wherein said criteria is substantially an equal number of positive and negative pulses. - View Dependent Claims (7, 8)
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9. A method comprising:
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increasing current to a current source during a power-up; counting pulses from an oscillator during said power-up; determining when said counted pulses reach a criteria; decreasing current to said current source when said criteria is reached; charging a capacitor coupled to an oscillator during said power-up; and discharging said capacitor when said criteria is reached.
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10. An apparatus comprising:
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a first switch operatively coupled shunting an existing current flow; a delay element having an input and an output, said delay element input operatively coupled to a charging circuit; a counter having an input and an output, said counter input operatively coupled to said delay element output; a logic circuit having an input and an output, said logic circuit input operatively coupled to said counter output; and said logic circuit output operatively coupled to said first switch. - View Dependent Claims (11, 12, 13, 14)
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Specification