Detector of noise peaks in the power supply of an integrated circuit

• US 7,839,182 B2
• Filed: 12/19/2006
• Issued: 11/23/2010
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: Stmicroelectronics France (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Duval, Benjamin, Malherbe, Alexandre
• Primary Examiner(s): NGUYEN, LONG T
• Application Number:
  US11/641,415
• Publication Number:
  US 20070139988A1
• Time in Patent Office: 1,435 Days
• Field of Search: 327/142, 327/143, 327/198, 327/391, 327/407, 327/408, 327/55, 327 58- 62, 327 72- 74, 327 77- 81
• US Class Current: 327/58
• CPC Class Codes: G06K 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• CPC Class Codes: G06K 19/07363 by preventing analysis of the circuit, e.g. dynamic or static power analysis or current analysis

Abstract

A circuit for detecting noise peaks on the power supply of an electronic circuit, including at least a first transistor having its control terminal connected to a terminal of application of a first potential of a supply voltage of the circuit and having a first conduction terminal connected to a terminal of application of a second potential via at least one first resistive element, the second conduction terminal of the first transistor providing the result of the detection.

Claims

1. A circuit for detecting noise peaks on a power supply of an electronic circuit, the power supply providing a first potential of a supply voltage, the circuit comprising:

a power terminal at which is applied the first potential of the supply voltage;

a low-pass filter receiving as input the first potential of the supply voltage and providing as output a second potential and a third potential of the supply voltage, the low-pass filter comprising at least one first resistive element; and

at least first and second transistors each having their control terminals connected to the power terminal of application of the first potential of the supply voltage of the circuit and each having first conduction terminals at which is applied one of the second and third potentials of the supply voltage, a second conduction terminal of each of the first and second transistors providing the result of the detection, wherein the first and second transistors are of opposite type and are connected in parallel to the low-pass filter.

2. The circuit of claim 1, wherein the low-pass filter comprises a first capacitive element connected to at least one of said first conduction terminals and to a terminal of application of a reference potential of the power supply voltage, and

wherein respective values of the first resistive element and of the first capacitive element are selected according to the minimum duration of the noise peaks to be detected.

3. The circuit of claim 2, wherein the first resistive element or the first capacitive element or the first resistive element and the first capacitive element are selected according to the amplitude and to the minimum duration of the peaks to be detected.

4. The circuit of claim 1, wherein the low-pass filter further comprises a second resistive element, and

wherein the second resistive element forms, with said first resistive element, a voltage-dividing bridge having an intermediate terminal connected to said first conduction terminal of the first transistor.

5. The circuit of claim 1, wherein said control terminal of the first transistor is directly connected to said power terminal of application of the first potential of the power supply voltage.

6. The circuit of claim 1, wherein the first and second transistors form a bi-directional noise peak detector.

7. The circuit of claim 6, wherein the low-pass filter comprises a capacitive element, and

wherein the first conduction terminal of the second transistor is connected to a first electrode of the capacitive element and another electrode of the capacitive element is connected to a terminal of application of a reference potential, and

wherein the at least one first resistive value comprises at least two first resistive elements each having a different value, each of the at least two first resistive elements forming at least a portion of a resistor network, the resistor network yielding the second and third potentials.

8. The circuit of claim 1, wherein said first transistor is a MOS transistor.

9. An electronic circuit comprising a detector of noise peaks on its power supply, wherein the detector is that of claim 1.

10. The circuit of claim 1, wherein the second conduction terminal of the first transistor is an output terminal of the first transistor.

11. A circuit for detecting noise in a power supply signal, the circuit comprising:

at least one circuit element that low-pass filters the power supply signal to produce at least one threshold signal; and

a comparison element comprising a control terminal and a conduction terminal, wherein the control terminal receives an unfiltered version of the power supply signal and the conduction terminal receives the at least one threshold signal, wherein the comparison element produces a binary noise detection signal in response to the at least one threshold signal and the unfiltered version of the power supply signal, the comparison element producing the binary noise detection signal based on whether the power supply signal rises above one of the at least one threshold signal or drops below one of the at least one threshold signal, the binary noise detection signal indicating a presence or absence of noise in the power supply signal as compared to the at least one threshold signal.

12. The circuit of claim 11, wherein the comparison element comprises first and second transistors of different types.

13. The circuit of claim 12, wherein the first and second transistors of different types are connected in parallel to the at least one circuit element that low-pass filters.

14. The circuit of claim 13, wherein each of the first and second transistors has a conduction terminal receiving one of the at least one threshold signal.

15. The circuit of claim 11, wherein the power supply signal is provided by first and second power supply terminals of the circuit, and

wherein the at least one circuit element that low-pass filters comprises a low-pass filter that low-pass filters the power supply signal, the low-pass filter comprising:

a voltage divider having a first end coupled to the first power supply terminal and a second end coupled to the second power supply terminal; and

a capacitor coupled to an intermediate terminal of the voltage divider.

16. The circuit of claim 15, wherein the voltage divider comprises resistors, and wherein the values of the capacitor and the resistors are selected based on a minimum duration of the noise to be detected.

17. The circuit of claim 15, wherein the control terminal is coupled to the first power supply terminal and the first conduction terminal is coupled to the intermediate terminal.

18. The circuit of claim 11, wherein the at least one threshold signal is produced by subtracting an offset from a low-pass-filtered version of the power supply signal.