Integrated circuit protected against electrostatic overvoltages
DCFirst Claim
1. A circuit for protecting a plurality of input/output pads of an integrated circuit associated with a plurality of power supply sources against electrostatic overvoltages, each power supply source being connected to a high voltage pad and a low voltage pad, comprising:
- a first conductive bus and a second conductive bus;
a plurality of first diodes coupled to the first conductive bus;
a plurality of second diodes coupled to the second conductive bus, wherein each of the plurality of input/output pads, at least one high voltage pad, and at least one low voltage pad is connected to an anode of a respective first diode having a cathode connected to the first conductive bus, and to a cathode of a respective second diode having an anode connected to the second conductive bus; and
a unidirectional clipping device having an anode connected to the second conductive bus, and a cathode connected to the first conductive bus.
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Accused Products
Abstract
A circuit protects pads of an integrated circuit having a plurality of power supply sources against electrostatic overvoltages. Each power supply is connected between a high voltage pad and a low voltage pad. Each pad of the circuit, as well as each power supply pad, is connected to the anode of a first diode having its cathode connected to a first conductive bus, and to the cathode of a second diode having its anode connected to a second conductive bus. A unidirectional clipping device is connected by its cathode to the first bus and by its anode to the second bus.
24 Citations
23 Claims
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1. A circuit for protecting a plurality of input/output pads of an integrated circuit associated with a plurality of power supply sources against electrostatic overvoltages, each power supply source being connected to a high voltage pad and a low voltage pad, comprising:
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a first conductive bus and a second conductive bus; a plurality of first diodes coupled to the first conductive bus; a plurality of second diodes coupled to the second conductive bus, wherein each of the plurality of input/output pads, at least one high voltage pad, and at least one low voltage pad is connected to an anode of a respective first diode having a cathode connected to the first conductive bus, and to a cathode of a respective second diode having an anode connected to the second conductive bus; and a unidirectional clipping device having an anode connected to the second conductive bus, and a cathode connected to the first conductive bus. - View Dependent Claims (2, 3, 4)
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5. A protection circuit for protecting an integrated circuit having a plurality of pads including a first circuit pad, a second circuit pad, a first voltage supply pad that connects to a first voltage supply and a second voltage supply pad that connects to the first voltage supply, the protection circuit comprising:
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a first conductive path and a second conductive path; a plurality of first diodes, a first diode being coupled between each pad and the first conductive path; a plurality of second diodes, a second diode being coupled between each pad and the second conductive path; and a clipping circuit coupled between the first and the second conductive paths.
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6. A protection circuit for protecting an integrated circuit having a plurality of pads including a first circuit pad, a second circuit pad, a first voltage supply pad that connects to a first voltage supply, and a second voltage supply pad that connects to the first voltage supply, the protection circuit comprising:
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a first conductive path and a second conductive path; a plurality of first diodes, a first diode being coupled between each pad and the first conductive path; a plurality of second diodes, a second diode being coupled between each pad and the second conductive path; and a clipping circuit coupled between the first and the second conductive paths, wherein each diode has an anode and a cathode, each pad is coupled to the anode of the first diode that is coupled between the pad and the first conductive path; each pad is coupled to the cathode of the second diode that is coupled between the pad and the second conductive path; the first conductive path is coupled to the cathode of each first diode; and the second conductive path is coupled to the anode of each second diode. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A protection circuit for protecting an integrated circuit having a plurality of external connecting means for establishing an external connection including first circuit means for establishing an external circuit connection, second circuit means for establishing an external circuit connection, first voltage supply means for establishing first external voltage connection to a first voltage supply and second voltage supply means for establishing a second external voltage connection to the first voltage supply, the protection circuit comprising:
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first conducting means for conducting current and second conducting means for conducting current; a plurality of first voltage controlling means for controlling voltage, a first voltage controlling means being coupled between each external connecting means and the first conducting means; a plurality of second voltage controlling means for controlling voltage, a second voltage controlling means being coupled between each external connecting means and the second conducting means; and clipping means for clipping voltage coupled between the first and a second conducting means. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A protection method for protecting an integrated circuit having a first circuit pad, a first voltage supply pad that connects to a first voltage supply, and a second voltage supply pad that connects to the first voltage supply, the method including:
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draining current from the first circuit pad through a first diode, a clipping device having a clipping voltage, and a second diode, each diode having a forward bias voltage, if a potential difference between the first circuit pad and the first voltage supply pad exceeds a sum of the forward bias voltages of the first and second diodes, and the clipping voltage; and providing current to the first circuit pad through third diode, the clipping device, and a fourth diode if a potential difference between the first circuit pad and the second voltage supply pad exceeds the sum. - View Dependent Claims (20, 21, 22, 23)
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Specification