Protection circuit for electrostatic discharge
First Claim
Patent Images
1. A protection circuit comprising:
- a semiconductor substrate;
an n-type semiconductor region in the semiconductor substrate;
a first p+ region in the n-type semiconductor region;
a first n+ region only in the n-type semiconductor region;
a p-type semiconductor region in the semiconductor substrate and contacting the n-type semiconductor region;
a second p+ region in the p-type semiconductor region;
a second n+ region in the p-type semiconductor region; and
a voltage divider having a first portion coupled to a second portion at a node;
whereinthe node is further coupled to the first n+ region;
the first portion is coupled between the first p+ region and the node; and
the second portion is coupled between the node and both the second n+ region and the second p+ region.
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Abstract
A protection circuit protects an integrated circuit (“IC”) from peak voltages and includes a voltage divider coupled to a silicon controlled rectifier. The voltage divider allows for adjustment of the trigger voltage, trigger current, and holding voltage of the protection circuit so that the protection circuit can conduct current after a particular voltage level has been applied to the protection circuit without accidental triggering on by, for example, noise.
24 Citations
22 Claims
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1. A protection circuit comprising:
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a semiconductor substrate; an n-type semiconductor region in the semiconductor substrate; a first p+ region in the n-type semiconductor region; a first n+ region only in the n-type semiconductor region; a p-type semiconductor region in the semiconductor substrate and contacting the n-type semiconductor region; a second p+ region in the p-type semiconductor region; a second n+ region in the p-type semiconductor region; and a voltage divider having a first portion coupled to a second portion at a node;
whereinthe node is further coupled to the first n+ region; the first portion is coupled between the first p+ region and the node; and the second portion is coupled between the node and both the second n+ region and the second p+ region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A protection circuit comprising:
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a silicon controlled rectifier including;
an anode;
a cathode;
a first transistor having a first emitter, a first base, and a first collector; and
a second transistor having a second emitter, a second base, and a second collector; anda voltage divider including a first portion and a second portion coupled at a node, wherein the first portion is coupled to the anode and the first emitter, the second portion is coupled to the cathode and the second emitter, and the node is coupled directly to the first base; and the first portion comprises one of a resistor or a diode, and the second portion comprises at least one of a resistor, a diode, or a capacitor.
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16. A protection circuit comprising:
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a voltage divider having a first portion and a second portion coupled at a node, wherein the first portion comprises one of a resistor or a diode, and the second portion comprises at least one of a resistor, a diode, or a capacitor; a first transistor, the first portion coupled to a base and an emitter of the first transistor; a second transistor, the second portion coupled across a collector and an emitter of the second transistor; an anode terminal coupled to the first portion and the emitter of the first transistor; and a cathode coupled to the second portion and an emitter of the second transistor; a collector and the base of the first transistor being respectively coupled to a base and the collector of the second transistor.
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17. A protection circuit comprising:
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a voltage divider including a first portion and a second portion coupled at a node, wherein the first portion comprises one of a resistor or a diode, and the second portion comprises at least one of a resistor, a diode, or a capacitor; a pnp transistor including a pnp collector, a pnp base, and a pnp emitter; the pnp emitter being coupled to the first portion; and pnp base being coupled directly to the node; an anode coupled to the pnp transistor and the first portion; a cathode; and an npn transistor including an npn collector, an npn base, and an npn emitter; the npn emitter being coupled to the second portion and the cathode. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification