Integrated circuit with wireless freshness seal

• US 4,897,662 A
• Filed: 12/09/1988
• Issued: 01/30/1990
• Est. Priority Date: 12/09/1988
• Status: Expired due to Fees

• Current Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Original Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Inventors: Lee, Robert D., Mounger, Robert W.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): Le, Hoanganh
• Application Number:
  US07/282,410
• Time in Patent Office: 417 Days
• Field of Search: 343/701, 307/296.3, 307/296.1, 307/296.6, 307/290, 307/279, 365/229, 340/635, 340/636
• US Class Current: 343/701
• CPC Class Codes: H01Q 1/24 with receiving set

Abstract

A micropowered module containing an integrated circuit packaged with a battery. The module is originally in a state of zero power consumption. When the module is to be put into use, a very strong electromagnetic field is applied at a predetermined frequency. A preset pulse code at this frequency will activate logic elements to keep the integrated circuit turned on, in active or standby mode. In standby mode, the power from the battery will avoid data loss.

Claims

1. An integrated circuit, comprising:

input contacts connectable to an antenna;

a battery terminal, for connection to a battery;

enable logic, connected to said input contacts, comprising insulated gate field effect transistors which are connected to turn on only when the antenna provides a voltage greater than the threshold voltage of said transistors; and

other circuits, on a common integrated circuit with said enable logic, which have significant standby power consumption requirements and which are selectably connected to said battery terminal;

wherein said enable logic is connected to selectively disable said other circuits, and does not permit said other circuits to operate until said enable logic has detected a strong electromagnetically radiated signal at a predetermined low frequency.

2. The integrated circuit of claim 1, wherein said other circuits include wireless interface circuits.

3. The integrated circuit of claim 1, wherein said enable logic does not permit said other circuits to operate until said enable logic has detected a strong electromagnetically radiated signal with a predetermined coded pattern at said predetermined low frequency.

4. The integrated circuit of claim 1, wherein said enable logic can also command said other circuits to cease operation if enable logic has detected a strong electromagnetically radiated signal with a predetermined coded pattern at said predetermined low frequency.

5. The integrated circuit of claim 1, wherein the output of said enable logic is connected to change the state of at least one bit of nonvolatile memory, and said nonvolatile memory bit controls logic gates in said other circuits.

6. The integrated circuit of claim 1, further comprising a filter circuit which blocks the output of said enable logic unless energy near said predetermined low frequency is much stronger than energy at other frequencies.

7. The integrated circuit of claim 1, wherein said predetermined low frequency is below 3000 Hz.

8. An integrated circuit module, comprising:

a battery;

an antenna, which can receive electromagnetic radiation at frequencies including a predetermined low frequency;

enable logic, connected to said antenna, comprising insulated gate field effect transistors which are connected to turn on only when the antenna provides a voltage greater than the threshold voltage of said transistors; and

other circuits, at least some of which are included on a common integrated circuit with said enable circuit, which have significant standby power consumption requirements and which are connected to be selectably powered by said battery;

wherein said enable logic is connected to selectively disable said other circuits, and does not permit said other circuits to operate until said enable logic has detected a strong electromagnetically radiated signal at a predetermined low frequency.

9. The module of claim 8, wherein said other circuits include wireless interface circuits.

10. The module of claim 8, wherein said enable logic is included in a first integrated circuit, and at least some of said other circuits are included in other integrated circuits.

11. The module of claim 8, wherein said enable logic does not permit said other circuits to operate until said enable logic has detected a strong electromagnetically radiated signal with a predetermined coded pattern at said predetermined low frequency.

12. The module of claim 8, wherein said enable logic can also command said other circuits to cease operation if enable logic has detected a strong electromagnetically radiated signal with a predetermined coded pattern at said predetermined low frequency.

13. The module of claim 8, wherein said antenna has a Q of less than 10.

14. The module of claim 8, wherein said antenna has a Q of less than 3 at frequencies near said predetermined low frequency.

15. The module of claim 8, wherein said antenna is not resonant at frequencies near said predetermined low frequency.

16. The module of claim 8, wherein the output of said enable logic is connected to change the state of at least one bit of nonvolatile memory, and said nonvolatile memory bit controls logic gates in said other circuits.

17. The module of claim 8, wherein said enable logic is included in a first integrated circuit, and at least some of said other circuits are included in other integrated circuits, and wherein the output of said enable logic is connected to change the state of at least one bit of nonvolatile memory which controls portions of said other circuits which are included in said first integrated circuit, and the output of said nonvolatile memory bit also controls a power supply output which is provided by said first integrated circuit to said other integrated circuits.

18. The module of claim 8, wherein said predetermined low frequency is below 3000 Hz.

19. The module of claim 8, wherein said predetermined low frequency is below 300 Hz.