Apparatus and methods for protection against inadvertent programming of fuse cells
First Claim
1. A fuse system for a semiconductor die, the fuse system comprising:
- a plurality of pads including a first pad and a second pad;
a fuse;
a fuse programming switch in series with the fuse;
a biasing circuit configured to bias a control input of the fuse programming switch with a fuse programming signal to thereby control a current through the fuse, the biasing circuit including a voltage regulator electrically connected between the first pad and the second pad and configured to generate a regulated voltage, and a level-shifter configured to control a voltage level of the fuse programming signal to be about equal to the regulated voltage in a first state of a control signal and to be about equal to the voltage of the first pad in a second state of the control signal; and
a fuse protection diode in series with the fuse programming switch and the fuse between the first pad and the second pad, the fuse protection diode configured to inhibit accidental programming of the fuse in response to a decrease in a voltage of the first pad relative to a voltage of the second pad, and to prevent accidental programming of the fuse arising from a delay of the voltage regulator in providing voltage regulation.
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Accused Products
Abstract
Apparatus and methods for protection against inadvertent programming of fuse cells are provided herein. In certain configurations, a fuse system includes a fuse protection diode, a fuse programming transistor, and a fuse cell electrically connected in series between a first pad and a second pad. The fuse system further includes a bias generator that biases a gate of the fuse programming transistor to control an amount of current provided to the fuse cell. The fuse protection diode helps prevent inadvertent programming of the fuse cell by blocking current from flowing through the fuse cell in response to a decrease in voltage of the first pad relative to the second pad.
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Citations
14 Claims
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1. A fuse system for a semiconductor die, the fuse system comprising:
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a plurality of pads including a first pad and a second pad; a fuse; a fuse programming switch in series with the fuse; a biasing circuit configured to bias a control input of the fuse programming switch with a fuse programming signal to thereby control a current through the fuse, the biasing circuit including a voltage regulator electrically connected between the first pad and the second pad and configured to generate a regulated voltage, and a level-shifter configured to control a voltage level of the fuse programming signal to be about equal to the regulated voltage in a first state of a control signal and to be about equal to the voltage of the first pad in a second state of the control signal; and a fuse protection diode in series with the fuse programming switch and the fuse between the first pad and the second pad, the fuse protection diode configured to inhibit accidental programming of the fuse in response to a decrease in a voltage of the first pad relative to a voltage of the second pad, and to prevent accidental programming of the fuse arising from a delay of the voltage regulator in providing voltage regulation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of protecting from accidental fuse programming, the method comprising:
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biasing a control input of a fuse programming switch with a fuse programming signal, including generating a regulated voltage using a voltage regulator that is electrically connected between a first pad and a second pad, and controlling a voltage level of the fuse programming signal to be about equal to the regulated voltage in a first state of a control signal using a level-shifter and to be about equal to the voltage of the first pad in a second state of the control signal; controlling a current through the fuse based on the fuse programming signal, the fuse electrically connected in series with the fuse programming switch and a fuse protection diode between the first pad and the second pad; inhibiting unintended programming of the fuse in response to a decrease in a voltage of the first pad relative to a voltage of the second pad using the fuse protection diode; and inhibiting unintended programming of the fuse arising from a delay of the voltage regulator in providing voltage regulation using the fuse protection diode. - View Dependent Claims (14)
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11. A packaged module comprising:
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a package substrate; and a semiconductor die attached to the package substrate, the semiconductor die including a fuse protection diode, a fuse programming switch, and a fuse electrically connected in series with one another between a first pad and a second pad, the semiconductor die further including a biasing circuit configured to bias a control input of the fuse programming switch with a fuse programming signal to thereby control a current through the fuse, the biasing circuit including a voltage regulator electrically connected between the first pad and the second pad and configured to generate a regulated voltage, and a level-shifter configured to control a voltage level of the fuse programming signal to be about equal to the regulated voltage in a first state of a control signal and to be about equal to the voltage of the first pad in a second state of the control signal, the fuse protection diode configured to inhibit accidental programming of the fuse in response to a decrease in a voltage of the first pad relative to a voltage of the second pad, and to prevent accidental programming of the fuse arising from a delay of the voltage regulator in providing voltage regulation. - View Dependent Claims (12, 13)
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Specification