Glitch detection and method for detecting a glitch

• US 9,143,876 B2
• Filed: 11/17/2011
• Issued: 09/22/2015
• Est. Priority Date: 11/17/2011
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Kropfitsch, Michael, Ceballos, Jose Luis
• Primary Examiner(s): Mei, Xu
• Application Number:
  US13/299,098
• Publication Number:
  US 20130129116A1
• Time in Patent Office: 1,405 Days
• Field of Search: 327 33- 34, 327 77- 78, 381/107, 381111-115, 381/120, 381/123, 381/174, 381/58, 381/91, 381/92, 381/122, 330/199
• US Class Current: 1/1
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/016 for microphones
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005
• CPC Class Codes: H04R 29/004 for microphones H04R29/007 takes precedence
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 3/007 Protection circuits for transducers

Abstract

System and method for detecting a glitch is disclosed. An embodiment comprises increasing a bias voltage of a first capacitor, sampling an input signal of a first plate of the first capacitor with a time period, mixing the input signal with the sampled input signal, and comparing the mixed signal with a reference signal.

Claims

1. A method for generating signals, the method comprising:

receiving an input signal from a first plate of a first capacitor at a first input of a first signal path;

receiving the input signal from the first plate of the first capacitor at a second input of a second signal path, wherein the first signal path is separate from the second signal path;

in the first signal path, amplifying the input signal;

increasing a bias voltage of the first capacitor;

in the second signal path, generating a sampled input signal by sampling the input signal with a time period;

generating a subtracted signal by subtracting the sampled input signal from the input signal; and

comparing the subtracted signal with a reference signal.

2. The method according to claim 1, further comprising detecting a glitch if a value of the subtracted signal is larger than a predetermined value of the reference signal.

3. The method according to claim 1, wherein the sampled input signal is stored in a second capacitor.

4. The method according to claim 1, wherein sampling the input signal comprises sampling the input signal with a sampling time period (T_strobe), and wherein the sampling time period (T_strobe), is smaller than a glitch time period (T_glitch).

5. The method according to claim 4, wherein comparing the subtracted signal with the reference signal comprises comparing with a comparing time period (T_comp), and wherein the comparing time period (T_comp) is smaller than the sampling time period (T_strobe).

6. The method according to claim 1, further comprising increasing the bias voltage of the first capacitor until a glitch occurs.

7. A method for calibrating a microphone, the method comprising:

operating the microphone in a normal operation mode based on a first bias voltage;

activating a calibration mode by electrically connecting a calibration circuit to the microphone using a switch, wherein the switch is non-conducting during the normal operation mode; and

operating the calibration mode, wherein the calibration mode comprises

increasing a bias voltage of a first capacitor;

sampling an input signal of a first plate of the first capacitor with a time period;

calculating an output signal from the sampled input signal and the input signal; and

comparing the calculated output signal with a reference signal.

8. The method according to claim 7, further comprising deactivating the normal operation mode when activating the calibration mode.

9. The method according to claim 7, further comprising detecting a glitch if a value of the calculated output signal is larger than a predetermined value of the reference signal.

10. The method according to claim 9, further comprising adjusting the first bias voltage to a second bias voltage based on the detected glitch.

11. The method according to claim 10, further comprising operating the microphone in the normal operation mode based on the second bias voltage.

12. The method according to claim 7, wherein the calibration mode further comprises:

increasing the bias voltage of the first capacitor until a glitch occurs; and

detecting the glitch based on comparing the calculated output signal with the reference signal.

13. A circuit comprising:

an input terminal configured to receive an input signal;

a first summer configured to calculate an output signal, the first summer configured to receive the input signal and a sampled input signal, the sampled input signal being based on the input signal;

a comparator configured to generate a compared signal by comparing the calculated output signal with a reference signal;

an output terminal configured to provide the compared signal; and

a MEMS system electrically connected to the input terminal via a switch.

14. The circuit according to claim 13, wherein the reference signal is a difference between a first reference signal and a second reference signal.

15. The circuit according to claim 13, wherein the sampled input signal is sampled with a sample time period T_strobe, T_strobe being shorter than a glitch time period T_glitch.

16. The circuit according to claim 15, wherein the comparator compares the calculated output signal with the reference signal with a compare time period T_comp, T_comp being shorter than the T_strobe.