Sensor interface with variable control coefficients

• US 9,148,709 B2
• Filed: 08/03/2011
• Issued: 09/29/2015
• Est. Priority Date: 08/03/2011
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hammerschmidt, Dirk
• Primary Examiner(s): Balaoing, Ariel
• Assistant Examiner(s): Ma, Kam
• Application Number:
  US13/197,288
• Publication Number:
  US 20130033357A1
• Time in Patent Office: 1,518 Days
• Field of Search: 340/3.1, 340/534, 340/537, 340/538.11, 327/1, 327/50, 327/77, 327/87, 341/143, 341/155
• 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 and configured to output a target voltage signal;

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;

wherein the single-bit comparator or coarse ADC is configured to provide a single-bit error signal which has a voltage level based on a comparison between the target voltage signal and an output voltage on the output node;

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;

a proportional-integral-derivative (PID) controller having an input coupled to an output of the single-bit comparator or coarse ADC to receive the single-bit error signal;

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

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

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

2. The sensor interface module of claim 1, wherein the sensor interface is configured to provide a supply voltage to the sensors and to modulate the supply voltage based on the single-bit error signal output by the single-bit comparator or coarse ADC.

3. A sensor interface module comprising;

a control unit interface configured to receive a first control signal from a control unit,

wherein the first control signal corresponds to information to be transmitted to at least one of a plurality of sensors;

a supply voltage module coupled to the control unit interface and configured to output a target voltage signal based on the first control signal;

a single-bit comparator or a 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;

wherein the single-bit comparator or coarse ADC is configured to provide a single-bit error signal which has a voltage level based on a comparison between the target voltage signal and an output voltage on the output node; and

a sensor interface coupled to a pair of wires which are coupled to both the plurality of sensors and the single-bit comparator or the coarse ADC, wherein the sensor interface is configured to provide a supply voltage to the sensors and to modulate the supply voltage based on the single-bit error signal;

a PID controller configured to output a second control signal based on the single-bit error signal;

first and second controllable current sources configured to receive the second control signal and cooperatively establish the output voltage on the output node based on the second control signal;

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

wherein the estimator comprises;

a shift register coupled to the single-bit comparator or coarse ADC and configured to store successive values of the single-bit error signal from the single-bit comparator or coarse ADC in time; and

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

5. The sensor interface module of claim 3, wherein the estimator block comprises a logic unit configured to calculate a mathematical function to determine the PID coefficients.

7. The sensor interface module of claim 3, further comprising:

a demodulation unit coupled to the pair of wires;

wherein the demodulation unit is configured to receive a incoming signal from the at least one of the plurality of sensors by measuring current output onto the pair of wires by the at least one of the plurality of sensors.

4. A sensor interface module comprising:

a control unit interface configured to receive a first control signal from a control unit, wherein the first control signal corresponds to information to be transmitted to at least one of a plurality of sensors;

a supply voltage module coupled to the control unit interface and configured to output a target voltage signal based on the first control signal;

a single-bit comparator or a 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;

wherein the single-bit comparator or coarse ADC is configured to provide a single-bit error signal which has a voltage level based on a comparison between the target voltage signal and an output voltage on the output node; and

a sensor interface coupled to a pair of wires which are coupled to both the plurality of sensors and the single-bit comparator or the coarse ADC, wherein the sensor interface is configured to provide a supply voltage to the sensors and to modulate the supply voltage based on successive values of the single-bit error signal;

a PID controller configured to output a second control signal based on the single-bit error signal;

first and second controllable current sources configured to receive the second control signal and cooperatively establish the output voltage on the output node based on the second control signal;

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

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

6. A sensor interface module, comprising:

a control unit interface configured to receive a first control signal from a control unit, wherein the first control signal corresponds to information to be transmitted to at least one of a plurality of sensors;

a supply voltage module coupled to the control unit interface and configured to output a target voltage signal based on the first control signal;

a single-bit comparator or a 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;

wherein the single-bit comparator or coarse ADC is configured to provide a single-bit error signal which varies in time and which has a voltage level based on a comparison between the target voltage signal and an output voltage on the output node;

a sensor interface coupled to a pair of wires which are coupled to both the plurality of sensors and the single-bit comparator or the coarse ADC, wherein the sensor interface is configured to provide a supply voltage to the sensors and to modulate the supply voltage based on successive values of the single-bit error signal;

a PID controller configured to output a second control signal based on the single-bit error signal;

first and second controllable current sources configured to receive the second control signal and cooperatively establish the output voltage on the output node based on the second control signal; and

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

wherein the single-bit error signal and feedback path are each a single bit variable, and wherein the estimator is configured to determine the coefficients for the PID controller based on a number of single bits provided on the feedback path at different times.

8. 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 and configured to output a target voltage signal;

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;

wherein the single-bit comparator or coarse ADC is configured to provide a single-bit error signal which has a voltage level based on a comparison between the target voltage signal and an output voltage on the output node;

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;

a proportional-integral-derivative (PID) controller having an input coupled to an output of the single-bit comparator or coarse ADC to receive the single-bit error signal;

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

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

a shift register coupled to the single-bit comparator or coarse ADC and configured to store successive single-bit values from the single-bit comparator or coarse ADC in time; and

a look up table configured to select a coefficient for the PID controller based on the successive single-bit values stored in the shift register.