Fast-enable current source
First Claim
1. A fast-enable current source comprising:
- a bias chain configured to generate a mirror reference voltage on a bias rail;
a first branch comprising a first transistor having a first drain connected to a first node, a first source connected to a first switch, and a first gate connected to the bias rail, the first switch configured to short the first source to a second node in response to an enable signal;
a first capacitance between the first gate and the first source;
a second branch comprising a second transistor having a second drain connected to a second switch, a second source connected to the second node, and a second gate connected to the bias rail, the second switch configured to short the second drain to the first node in response to the enable signal; and
a second capacitance between the second drain and the second gate, wherein in response to the enable signal, a first charge removed from the bias rail by the first capacitor is offset by a second charge added to the bias rail by the second capacitor.
1 Assignment
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Accused Products
Abstract
A method for fast-enabling a current source includes conducting a first current through a first branch including a first transistor connected in series with a first switch, in response to enabling the first switch with an enable signal. A first charge is removed from a bias rail with a first capacitance between a first gate and a first source of the first transistor. A second current is conducted through a second branch including a second switch connected in series with a second transistor, in response to enabling the second switch with the enable signal. A second charge is added to the bias rail with a second capacitance between a second drain and a second gate of the second transistor, wherein the first gate and the second gate are connected to the bias rail and biased by the mirror reference voltage.
7 Citations
20 Claims
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1. A fast-enable current source comprising:
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a bias chain configured to generate a mirror reference voltage on a bias rail; a first branch comprising a first transistor having a first drain connected to a first node, a first source connected to a first switch, and a first gate connected to the bias rail, the first switch configured to short the first source to a second node in response to an enable signal; a first capacitance between the first gate and the first source; a second branch comprising a second transistor having a second drain connected to a second switch, a second source connected to the second node, and a second gate connected to the bias rail, the second switch configured to short the second drain to the first node in response to the enable signal; and a second capacitance between the second drain and the second gate, wherein in response to the enable signal, a first charge removed from the bias rail by the first capacitor is offset by a second charge added to the bias rail by the second capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for fast-enabling a current source comprising:
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generating a mirror reference voltage on a bias rail; conducting a first current through a first branch between a first node and a second node, the first branch comprising a first transistor connected in series with a first switch, in response to enabling the first switch with an enable signal; removing a first charge from the bias rail with a first capacitance between a first gate and a first source of the first transistor, wherein the first gate is biased by the mirror reference voltage; conducting a second current through a second branch between the first node and the second node, the second branch comprising a second switch connected in series with a second transistor, in response to enabling the second switch with the enable signal; and adding a second charge to the bias rail with a second capacitance between a second drain and a second gate of the second transistor, wherein the second gate is biased by the mirror reference voltage. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A fast-enable current source comprising:
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a first branch comprising a first transistor having a first drain connected to a protection device, a first source connected to a first switch, and a first gate connected to a bias rail, the protection device connected to a first node, the first switch configured to short the first source to a second node in response to an enable signal; a first parasitic capacitance between the first gate and the first source; a second branch comprising a second transistor having a second drain connected to a second switch, a second source connected to a compensation device, and a second gate connected to the bias rail, the compensation device connected to the second node, the second switch configured to short the second drain to the first node in response to the enable signal; and a second parasitic capacitance between the second drain and the second gate, wherein in response to the enable signal, a first charge removed from the bias rail by the first capacitor is offset by a second charge added to the bias rail by the second capacitor. - View Dependent Claims (19, 20)
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Specification