SENSOR INTERFACE WITH VARIABLE CONTROL COEFFICIENTS

• US 20160018807A1
• Filed: 09/28/2015
• Published: 01/21/2016
• Est. Priority Date: 08/03/2011
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hammerschmidt, Dirk
• Granted Patent: US 9,817,381 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05B 19/0423 Input/output
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: H03M 1/56 Input signal compared with linear ramp
• CPC Class Codes: H04Q 2209/80 Arrangements in the sub-station, i.e. sensing device
• 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

The present disclosure is directed towards a sensor interface module that delivers a supply voltage to a plurality of sensors, and which exchanges data signals between the plurality of sensors and a control unit (e.g., an ECU). The sensor interface often employs a single-bit comparator (or a coarse analog to digital converter (ADC), e.g., a 2-bit or 3-bit ADC) to track signals to be exchanged between the sensors and controller over the sensor interface. Compared to power hungry ADC with more bits (e.g., 32 bit ADC), the single-bit comparator/coarse ADC limits hardware complexity and power consumption. In addition, in some embodiments the sensor interface module can include an estimator and assist comparators to speed up the tracking ability of the sensor interface module. In this way, techniques provided herein facilitate reliable, low-power communication between a control unit (e.g., an ECU) and its corresponding sensors.

Claims

1. A sensor interface module comprising;

a control unit interface configured to be coupled to a control unit;

a supply voltage module coupled to the control unit through the control unit interface;

a single-bit comparator or coarse analog to digital converter (ADC) having a first comparator input coupled to the supply voltage module and having a second comparator input coupled to an output node of the sensor interface module via a feedback path; and

a sensor interface coupled to the output node of the sensor interface module and configured to be coupled to a pair of wires which are coupled to a plurality of sensors.

2. The sensor interface module of claim 1, wherein to modulate the supply voltage based on an error signal output by the single bit comparator or coarse ADC.

3. The sensor interface module of claim 2, wherein the error signal is less than four bits in length.

4. The sensor interface module of claim 1, further comprising:

a proportional integral (PI) controller having an input coupled to an output of the single-bit comparator or coarse ADC; and

first and second controllable current sources having respective input terminals coupled to an output of the PEW controller and configured to cooperatively establish an output voltage on the output node of the sensor interface.

5. The sensor interface module of claim 4, further comprising:

an estimator coupled to the feedback path, wherein the estimator is configured to determine coefficients for the PEW controller based on a history of bits on the feedback path.

21. The sensor interface module of claim 2, wherein the error signal is a single bit in length.

6-20. -20. (canceled)

22. A sensor interface module for transmitting a control signal from an engine control unit (ECU) over a pair of wires to one or more of a plurality of vehicular sensors, the sensor interface module comprising:

first and second controllable current sources arranged in series on a current path and having an output node disposed between the first and second controllable current sources, wherein the output node provides an actual voltage level and is configured to be coupled to a pair of wires which is in turn coupled to a plurality of vehicular sensors;

a comparator configured to provide an error signal indicative of a difference between the actual voltage level and a target voltage-level, wherein the target voltage level is specified in the control signal from the ECU;

a proportional-integral (PI) controller configured to provide a current control signal to control terminals of the first and second controllable current sources based on the error signal and one or more PI coefficients; and

an estimator configured to determine the one or more PI coefficients based on a history of bits in the error signal.

23. The sensor interface module of claim 22 further comprising:

a plurality of assist comparators having different respective trigger points and configured to help set the PI coefficients based on the history of bits.

24. The sensor interface module of claim 22, wherein the comparator is a single-bit comparator or a coarse analog-to-digital converter (ADC).

25. The sensor interface module of claim 22, wherein the estimator comprises:

a shift register coupled to the comparator and configured to store successive values of the error signal in time.

26. The sensor interface module of claim 25, wherein the estimator further comprises:

a look up table configured to select a coefficient for the PI controller based on the successive values of the error signal stored in the shift register.

27. The sensor interface module of claim 22, wherein the error signal is less than four bits in length.

28. The sensor interface module of claim 22, wherein the error signal is a single bit in length.

29. A sensor interface module for transmitting a control signal from an engine control unit (ECU) to one or more of a plurality of vehicular sensors over a pair of wires, the sensor interface module comprising:

first and second controllable current sources arranged in series on a current path and having an output node disposed between the first and second controllable current sources; and

a voltage regulator configured to receive the control signal from the ECU and configured to monitor a voltage-level at the output node, the voltage regulator further configured to, based on the control signal and the monitored voltage-level, provide a current control signal to the first and second controllable current sources to adjust the voltage-level provided at the output node so as to track a target voltage-level indicated by the control signal and thereby transmit the control signal to the one or more of the plurality of vehicular sensors.

30. The sensor interface module of claim 29, further comprising:

a comparator configured to provide an error signal indicative of a difference between the target voltage-level and the voltage-level at the output node; and

a proportional-integral (PI) controller configured to provide the current control signal based on PI-coefficients that are set according to the error signal.

31. The sensor interface module of claim 30 further comprising:

an estimator configured to determine the PI coefficients based on a history of bits in the error signal; and

a plurality of assist comparators having different respective trigger points and configured to help set the PI coefficients based on the history of bits.

32. The sensor interface module of claim 31, wherein the estimator comprises:

a shift register coupled to the comparator and configured to store successive values of the error signal in time; and

a look up table configured to select a coefficient for the PI controller based on the successive values of the error signal stored in the shift register.

33. The sensor interface module of claim 31, wherein the error signal is less than four bits in length.

34. The sensor interface module of claim 31, wherein the error signal is a single bit in length.

35. The sensor interface module of claim 30, wherein the comparator is a single-bit comparator or a coarse analog-to-digital converter (ADC).