Holding Device for a Sensor Signal, Method for Forwarding a Sensor Signal and Computer Program

• US 20070010967A1
• Filed: 06/30/2006
• Published: 01/11/2007
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Scherr, Wolfgang
• Granted Patent: US 7,369,969 B2
• Time in Patent Office: Days
• US Class Current: 702/182
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A holding device for a sensor signal comprises a signal input receiving a sensor signal, a signal output and a storage device coupled to the signal input and output. The storage device is designed to store a signal value in a first state and to update it based on the sensor signal in a second state. The storage device stores the signal value for a time period which is greater than a first predetermined time duration, independently of a supply voltage of the storage device. The holding device outputs the signal value present in the storage device. The holding device furthermore comprises a monitoring device, which is effectively coupled to the storage device and determines whether the sensor signal present at the signal input is valid. The monitoring device ensures that the storage device is in the second state only when the monitoring device identifies that the sensor signal is valid.

Claims

1. A holding device for a sensor signal from a sensor, comprising:

a signal input receiving the sensor signal from the sensor;

a signal output;

a memory, which is coupled to the signal input and the signal output, the memory being operable to store a signal value in a first state, to update the signal value based on the sensor signal in a second state, and to store the signal value for a time period that is greater than a first predetermined time duration, independently of a supply voltage of the memory; and

a monitor, which is effectively coupled to the memory, and operable to determine whether the sensor signal present at the signal input is valid, and to ensure that the memory is in the second state only when the monitor identifies that the sensor signal at the signal input is valid,

wherein the holding device is furthermore operable to output the signal value present in the memory at the signal output.

2. The holding device according to claim 1, wherein the monitor is operable to identify the sensor signal as invalid whenever a supply voltage of the sensor has a disturbance.

3. The holding device according to claim 1, wherein the monitor is operable to identify the sensor signal as invalid whenever a supply voltage of the sensor has a temporal change which is faster than a predetermined temporal change.

4. The holding device according to claim 1, wherein the memory is furthermore operable to set the signal value to a predetermined precharge value as a response to a precharge signal.

5. The holding device according to claim 1, wherein the memory is operable to store the signal value independently of an interference pulse on the supply voltage of the memory.

6. The holding device according to claim 1, wherein the monitor is operable to monitor whether the sensor has a disturbance, and to ensure that the memory is in the second state only when the sensor has no disturbance.

7. The holding device according to claim 1, wherein the monitor is operable to monitor an operating voltage of the sensor, and to ensure that the memory is in the second state only when the operating voltage of the sensor is in a permissible operating voltage range.

8. The holding device according to claim 1, wherein the monitor is operable to monitor an operating voltage of the sensor and to put the memory into the first state if a disturbance occurs on the operating voltage of the sensor, and to hold the memory in the first operating state for a second predetermined time after the end of the disturbance on the operating voltage of the sensor.

9. The holding device according to claim 8, wherein the second predetermined time is greater than a transient recovery time of the sensor, the transient recovery time of the sensor being a time duration required by the sensor until, after the end of a disturbance on the operating voltage of the sensor, the sensor signal attains a stable and reliable value.

10. The holding device according to claim 1, wherein the monitor comprises a first resetter, which is operable to monitor an operating voltage of an analogue circuit part of the sensor, and to reset the analogue circuit part if the operating voltage of the analogue circuit part meets a first disturbance condition, the monitor furthermore being operable to ensure that the memory is not in the second operating state while the first resetter resets the analogue circuit part of the sensor, the operating voltage of the analogue circuit part meeting the first disturbance condition if reliable operation of the analogue circuit part is not ensured on account of a disturbance on the operating voltage of the analogue circuit part.

11. The holding device according to claim 1, wherein the monitor comprises a second resetter, which is operable to monitor an operating voltage of a digital circuit part of the sensor, and to reset the digital circuit part if the operating voltage of the digital circuit part meets a second disturbance condition, the monitor furthermore being operable to ensure that the memory is not in the second operating state while the second resetter resets the digital circuit part of the sensor, the operating voltage of the digital circuit part meeting the second disturbance condition if reliable operation of the digital circuit part is not ensured on account of a disturbance on the operating voltage of the digital circuit part.

12. The holding device according to claim 10, wherein the first disturbance condition is met if the operating voltage of the analogue circuit part has at least one small deviation from a desired value over a long time period, and the second disturbance condition is met if the operating voltage of the digital circuit part has a large deviation from a desired value at least over a short time period.

13. The holding device according to claim 10, wherein the monitor is operable to hold the memory in the first state for a third predetermined time duration after an end of the resetting of the analogue circuit part and of the digital circuit part.

14. The holding device according to claim 1, wherein the monitor furthermore comprises a third resetter, which is operable to identify whether a lengthy disturbance of the operating voltage of the holding device or of the sensor with a duration longer than a fourth predetermined time duration was present, and to set the signal value of the memory to the predetermined precharge value if the lengthy disturbance of the operating voltage of the holding device or of the sensor was present.

15. The holding device according to claim 14, wherein the third resetter comprises an R-C element and a Schmitt trigger coupled to the R-C element, an output signal of the Schmitt trigger forming a precharge signal that is formed to precharge the signal value of the memory to the specific precharge value.

16. The holding device according to claim 1, wherein the memory is operable to store the signal value in a passive basic state, and to enable updating of the signal value based on the sensor signal in an active state.

17. The holding device according to claim 16, wherein the memory is operable to assume the passive basic state if a supply voltage of the memory falls below a predetermined minimum voltage.

18. The holding device according to claim 1, wherein the memory is an analogue holding element comprising a capacitor that is decoupled from the signal input in a passive basic state.

19. The holding device according to claim 1, wherein the memory is a digital holding element that is decoupled from the signal input in a passive basic state.

20. The holding device according to claim 1, wherein the memory comprises at least one electrical charge store that is decoupled from the signal input (120) in the passive basic state by means of at least one opened switch.

21. The holding device according to claim 1, wherein the memory is operable to update the signal value based on the sensor signal in the second state if the sensor indicates a presence of a new signal value of the sensor signal by means of an acceptance signal.

22. The holding device according to claim 1, wherein the monitor is operable, given the presence of an invalid sensor signal at the signal input, to bring the memory into the first state so rapidly that the invalid sensor signal is not accepted into the memory.

23. The holding device according to claim 1, wherein the holding device is furthermore operable to output the signal value to a signal conditioner of the sensor in order to enable an accelerated initialization of the sensor.

24. A method for forwarding a sensor signal using a memory operable to store a signal value for a time period which is longer than a predetermined first time duration, independently of a supply voltage of the memory, comprising the steps of:

receiving the sensor signal from a sensor;

checking whether the sensor signal is valid;

updating the signal value stored in the memory based on the sensor signal only if it is ensured that the received sensor signal is valid; and

outputting the signal value stored in the memory.

25. The method according to claim 24, furthermore comprising the step of:

storing the signal value in the memory as long as it is not ensured that the received sensor signal is valid.

26. The method according to claim 24, wherein checking whether the sensor signal is valid comprises monitoring an operating voltage of the sensor, it being assumed that the sensor signal is invalid if the operating voltage of the sensor has a disturbance.

27. The method according to claim 24, wherein checking whether the sensor signal is valid comprises monitoring an operating voltage of the sensor, it being assumed that the sensor signal is invalid for a predetermined time duration after an end of a disturbance of the operating voltage of the sensor.

28. The method according to claim 24, wherein checking whether the sensor signal is valid comprises monitoring whether a disturbance of the sensor is present, it being assumed that the sensor signal is invalid if a disturbance of the sensor is present.

29. The method according to claim 24, furthermore comprising resetting an analogue circuit part of the sensor if an operating voltage of the analogue circuit part meets a first disturbance condition, it being assumed that the sensor signal is invalid during the resetting of the analogue circuit part.

30. The method according to claim 24, furthermore comprising resetting a digital circuit part of the sensor if an operating voltage of the digital circuit part meets a second disturbance condition, it being assumed that the sensor signal is invalid during the resetting of the digital circuit part.

31. The method according to claim 29, wherein it is furthermore assumed that the sensor signal is invalid during the resetting of the analogue circuit part or of the digital circuit part and also for a predetermined second time duration after the conclusion of the resetting of the analogue circuit part or of the digital circuit part.

32. The method according to claim 24, furthermore comprising setting the signal value to a predetermined signal value if a disturbance of an operating voltage of the sensor which is longer than a predetermined third time duration is identified.

33. The method according to claim 24, wherein the signal value stored in the memory is updated in response to an activation of an acceptance signal supplied by the sensor.

34. The method according to claim 24, furthermore comprising the use of the stored signal value in an initialization of the sensor.

35. A computer program product comprising a computer usable storage medium having computer readable code for carrying out, when the computer program is executed on a computer, a method for forwarding a sensor signal using a memory operable to store a signal value for a time period which is longer than a predetermined first time duration, independently of a supply voltage of the memory, comprising the steps of:

receiving the sensor signal from a sensor;

checking whether the sensor signal is valid;

updating the signal value stored in the memory based on the sensor signal only if it is ensured that the received sensor signal is valid; and

outputting the signal value stored in the memory.