Antifuse programming, protection, and sensing device

• US 7,236,043 B2
• Filed: 10/17/2005
• Issued: 06/26/2007
• Est. Priority Date: 10/17/2005
• Status: Expired due to Fees

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Wich, Mathew T., Gosmain, Vincent
• Primary Examiner(s): LE, DINH THANH
• Application Number:
  US11/252,180
• Publication Number:
  US 20070085593A1
• Time in Patent Office: 617 Days
• Field of Search: 327 50- 51, 327/525, 365/96, 365/225.7
• US Class Current: 327/525
• CPC Class Codes: G11C 17/18 Auxiliary circuits, e.g. for writing into memory

Abstract

An antifuse programming, protection, and sensing device incorporates a control circuit to program and protect an antifuse. The antifuse, which is initially constructed as a low conductivity path, is programmable to a high conductivity path by application of an elevated voltage across terminals of the antifuse. Application of 0 volts to the V_DD node of a conduction control portion of the antifuse programming, protection, and sensing device allows an elevated voltage for programming to be applied to the antifuse. Upon application of a nominal working voltage to the V_DD node of the conduction control circuitry, the antifuse and an adjoining sense amplifier circuit are protected from overvoltage and tampering. The sense amplifier supplies a sense current to the antifuse, measures a voltage at an input to the antifuse, and determines a programmed state if a measured voltage level is low.

Claims

1. An electrical conduction control and sending device comprising:

a control circuit coupled to an input of the electrical conduction control and sensing device;

an electrically configurable conduction device coupled to the control circuit, the electrically configurable conduction device having a low conductivity and capable of having a high conductivity;

a sense amplifier coupled to the electrically configurable conduction device, the sense amplifier capable of producing a sense current, detecting a magnitude of voltage produced by the sense current, and producing a blown signal at an output of the electrical conduction control and sensing device; and

a coupling circuit coupled to the electrically configurable conduction device and the sense amplifier, the coupling circuit having means for electrically communicating the sense current produced by the sense amplifier to the electrically configurable conduction device when the coupling circuit is enabled and for electrically protecting the sense amplifier when the coupling circuit is disabled.

2. The electrical conduction control and sensing device of claim 1, wherein the control circuit has means for programming the electrically configurable conduction device and protecting the electrically configurable conduction device from overvoltage.

3. The electrical conduction control and sensing device of claim 2, wherein the electrical conduction control and sensing device further comprises electrostatic protection devices and the control circuit further comprises protection devices for providing tampering prevention by preventing an excessive voltage applied to the input of the electrical conduction control and sensing device from raising a voltage across the electrically configurable conduction device and causing an erroneous measurement by the sense amplifier, the preventing of excessive voltage activated while a nominal voltage is applied to a supply node of the electrical conduction control and sensing device and the protection devices of the control circuit.

4. The electrical conduction control and sensing device of claim 1, further comprising a logic gating device coupled to the sense amplifier, the logic gating device capable of communicating a control signal applied to a control input of the logic gating device.

5. The electrical conduction control and sensing device of claim 1, wherein the means for electrically protecting the sense amplifier comprises an electrical isolation element.

6. The electrical conduction control and sensing device of claim 1, wherein the sense amplifier has both means for measuring a voltage across the electrically configurable conduction device due to the sense current applied and means f or determining a programmed or non-programmed state of the electrically configurable conduction device.

7. An electrical conduction control and sensing device comprising:

a control circuit coupled to an input of the electrical conduction control and sensing device;

an electrically configurable conduction device coupled to the control circuit, the electrically configurable conduction device having a low conductivity and capable of having a high conductivity;

a bias circuit coupled to the electrically configurable conduction device, the bias circuit capable of producing a sense current;

a level sensing device coupled to the bias circuit, the level sensing device capable of detecting a voltage level produced by the sense current and producing a blown signal at an output of the electrical conduction control and sensing device; and

a coupling circuit coupled between the electrically configurable conduction device, the level sensing device, and the bias circuit, the coupling circuit having both means for electrically communicating the sense current produced by the bias circuit to the electrically configurable conduction device when the coupling circuit is enabled and means for electrically protecting the level sensing device when the coupling circuit is disabled.

8. The electrical conduction control and sensing device of claim 7, wherein the control circuit is configured to have a first plurality of configuring voltages applied and further has means for providing electrical protection of the electrically configurable conduction device.

9. The electrical conduction control and sensing device of claim 8, wherein the electrical conduction control and sensing device further comprises electrostatic protection devices and the control circuit further comprises protection devices for providing tampering prevention by preventing an excessive voltage applied to the input of the electrical conduction control and sensing device from raising a voltage across the electrically configurable conduction device and causing an erroneous measurement by the level sensing device, the preventing of excessive voltage activated while the first plurality of configuring voltages is applied to a supply node of the electrical conduction control and sensing device and the protection devices of the control circuit.

10. The electrical conduction control and sensing device of claim 7, wherein the control circuit is configured to have a second plurality of configuring voltages applied and further has means for providing programming of the electrically configurable conduction device.

11. The electrical conduction control and sensing device of claim 7, further comprising a logic gating device coupled to the level sensing device, the logic gating device capable of communicating a control signal applied to a control input of the logic gating device.

12. The electrical conduction control and sensing device of claim 7, wherein the means for electrically protecting the level sensing device comprises an electrical isolation element.

13. The electrical conduction control and sensing device of claim 7, further comprising a means for associating the voltage level produced by the sense current applied to the electrically configurable conduction device to determine either a non-programmed state or a programmed state with a resultant blown signal produced at the output of the electrical conduction control and sensing device.

14. A programming, protection, and sensing device comprising:

a programming device coupled to an input of the programming protection, and sensing device;

an antifuse coupled to the programming device, the antifuse having a low conductivity and capable of having a high conductivity;

a bias circuit coupled to the antifuse and capable of producing a sense current;

a voltage sensing circuit coupled to the bias circuit and capable of detecting a voltage level produced by the sense current and producing a blown signal at an output of programming, protection, and sensing device;

a coupling circuit coupled between the antifuse and the voltage sensing circuit, the coupling circuit capable of electrically communicating the sense current produced by the bias circuit to the antifuse when the coupling circuit is enabled and electrically protecting the voltage sensing circuit when the coupling circuit is disabled; and

a logic gating device coupled to the voltage sensing circuit and capable of communicating a control signal applied to a control of the logic gating device.

15. The programming, protection, and sensing device of claim 14, wherein the voltage sensing circuit is further capable of determining a programmed or non-programmed state front the detected voltage level across the antifuse and further producing the blown signal upon determination of a programmed state.

16. An electrical conduction control and sensing device comprising:

a programmable electronic storage device;

a means for controlling configuration and protection of the programmable electronic storage device, the controlling means coupled to an input of the electrical conduction control and sensing device and the programmable electronic storage device;

a means for protecting the electrical conduction control and sensing device, the protecting means coupled to the input of the electrical conduction control and sensing device;

a means for sensing a condition of electrical conductivity, the sensing means coupled to the programmable electronic device;

a means for coupling the sensing means, the coupling means coupled to the sensing means, the programmable electronic storage device, and the controlling means; and

a means for gating a sense voltage across the programmable electronic storage device, the gating means coupled to the sensing means and a control input to the gating means.

17. The electrical conduction control and sensing device of claim 16, wherein a first plurality of voltages applied to the controlling means programs the programmable electronic storage device and a second plurality of voltages applied to the controlling means protects the programmable electronic storage device.

18. The electrical conduction control and sensing device of claim 17, wherein the electrical conduction control and sensing device further comprises at least one electrostatic protection device and the controlling means further comprises at least one protection device for providing tampering prevention by preventing an excessive voltage applied to the input of the electrical conduction control and sensing device from raising a voltage across the electrically configurable conduction device and causing an erroneous measurement by the sensing means, the preventing of excessive voltage activated while the second plurality of voltages is applied to a supply node of the electrical conduction control and sensing device and the at least one protection device of the controlling means.

19. The electrical conduction control and sensing device of claim 16, wherein the sensing means further applies a current to the programmable electronic storage device and senses a resultant voltage across the programmable electronic storage device to determine a programmed state.