Clock determination for a sensor

• US 8,948,280 B2
• Filed: 10/01/2008
• Issued: 02/03/2015
• Est. Priority Date: 08/14/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hammerschmidt, Dirk, Rasbornig, Friedrich, Schaffer, Bernhard, Strasser, Michael, Scherr, Wolfgang
• Primary Examiner(s): Garcia, Santiago
• Application Number:
  US12/242,951
• Publication Number:
  US 20100002821A1
• Time in Patent Office: 2,316 Days
• Field of Search: 375/260
• US Class Current: 375/260
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 7/0278 Band edge detection
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

A method for determining a clock for a sensor signal which has a synchronization signal, which method involves a control unit measuring the period between a first edge and a second edge of the synchronization signal, wherein both edges are either rising or falling, and the control unit taking the period as a basis for determining a clock for sampling data in the sensor signal.

Claims

1. A method for determining a clock of a sensor, the method comprising:

transmitting a synchronization signal by a sensor in response to a trigger signal sent by a control unit;

receiving the synchronization signal by the control unit;

measuring, by the control unit, a period between a first edge and a second edge of the synchronization signal, wherein the edges are either rising or falling;

determining, by the control unit, a local clock of the sensor from the period; and

using, by the control unit, the local clock to sample data in a data signal received by the control unit from the sensor.

2. The method according to claim 1, further comprising storing the local clock as a clock value by the control unit.

3. The method according to claim 1, further comprising requesting data by sending a wake-up signal by the control unit.

4. The method according to claim 3, further comprising sending the synchronization signal by the sensor following reception of the wake-up signal.

5. The method according to claim 1, further comprising requesting data and selecting the sensor by sending an address signal by the control unit.

6. The method according to claim 5, wherein the address signal is pulse-width modulated.

7. The method according to claim 5, further comprising sending the synchronization signal by the sensor following reception of the address signal.

8. The method according to claim 5, further comprising selecting the sensor based on a duration of the address signal.

9. The method according to claim 1, further comprising sending a data signal by the sensor following transmission of the synchronization signal.

10. The method according to claim 9, wherein the data signal is pulse-width modulated.

11. The method according to claim 1, wherein the synchronization signal from the sensor comprises known data for identification as a synchronization signal by the control unit.

12. The method according to claim 1, further comprising:

interrupting transmission of a data signal from the sensor by the control unit; and

sending data signals to the sensor by the control unit, wherein the data signals are dependent on the local clock.

13. The method according to claim 12, further comprising applying a signal from the control unit and a signal from the sensor as OR signals on a bus line.

14. The method according to claim 1, further comprising:

determining the local clock from a stored clock value from a previous data transmission from a sensor;

interrupting transmission of the synchronization signal from the sensor by the control unit; and

sending data signals to the sensor by the control unit, wherein the data signals are dependent on the local clock.

15. The method according to claim 14, further comprising applying a signal from the control unit and a signal from the sensor as OR signals on a bus line.

16. The method according to claim 1, further comprising sending signals to a bus line.

23. The method of claim 1, wherein a length of the synchronization pulse is dependent on a frequency of the local clock.

24. The method of claim 23, wherein the length of the synchronization pulse is a single or a multiple of the period.

17. A control unit system comprising:

a transmitter configured to send signals including a trigger signal to a sensor to provide at synchronization signal;

a receiver configured to receive signals including the synchronization signal from the sensor;

a timing circuit configured to determine a local sensor clock based on a period of a synchronization signal received from the sensor, wherein the timing circuit is configured to measure the period between a first edge and a second edge of the synchronization signal, and wherein both edges are either rising or falling; and

a sampling circuit configured to sample, on the local sensor clock, a data signal to be received from the sensor.

18. The control unit according to claim 17, wherein the transmitter is configured to send signals dependent on the local sensor clock.

19. The control unit according to claim 17, wherein the transmitter comprises a transistor, and wherein one of a collector or a drain of the transistor is coupled to a bus line configured to send a signal.

20. A sensor system comprising:

a sensor;

a clock generator configured to generate a clock in the sensor system;

a receiver configured to receive a trigger signal from a control unit separate from the sensor system; and

a transmitter configured to send signals from the sensor system to the control unit in response to the trigger signal from the control unit, wherein the transmitter is configured to send a synchronization signal based on the dock, and wherein a period between a first edge and a second edge of the synchronization signal is dependent on the clock and both edges are either rising or falling.

21. The sensor according to claim 20, wherein the transmitter comprises a transistor having one of a collector or a drain coupled to a bus line configured to send a signal.

22. The sensor according to claim 20, wherein the receiver is configured to decode intervals of time between two received edges based on a receiver clock.