Signal processing apparatus for wheel speed sensor

1. A signal processing apparatus for a wheel speed sensor, comprising:

a sensor input terminal unit to which a sensing signal of a wheel speed sensor is input; and

a normality determination block determining whether or not the sensing signal is normal,

wherein the sensor input terminal unit protects a circuit therein by detecting that the wheel speed sensor is erroneously connected to a battery, and

wherein the normality determination block determines a difference between a level detection time of a rising edge or a falling edge and a level detection time after detection of the rising edge or falling edge using at least one of a fixed timing synchronization algorithm, an adaptive timing synchronization algorithm, and a timing tracking circuit.

2. The signal processing apparatus according to claim 1 , wherein the sensor input terminal unit protects the circuit therein by detecting that the wheel speed sensor is erroneously connected to a ground portion.

3. The signal processing apparatus according to claim 1 , wherein the sensor input terminal unit protects the circuit therein by detecting that an overcurrent flows to the wheel speed sensor.

4. The signal processing apparatus according to claim 1 , wherein the sensor input terminal unit detects that connection of the wheel speed sensor is opened and transmits open information to the normality determination block such that the normality determination block is not erroneously operated.

5. The signal processing apparatus according to claim 1 , wherein the normality determination block comprises a sensing signal processing section which outputs the sensing signal to an external microcontroller (MCU).

6. The signal processing apparatus according to claim 1 , wherein the normality determination block identifies whether the sensing signal satisfies a predetermined upper limit current value and a predetermined lower limit current value.

7. The signal processing apparatus according to claim 1 , wherein the normality determination block further comprises a sensing signal processing section which has a falling/rising timing similar to the sensing signal and outputs a sensing voltage signal copied as a voltage signal having a high/low level required by an external MCU.

8. The signal processing apparatus according to claim 1 , wherein the normality determination block comprises:

an analog-to-digital converter (ADC) for converting the sensing signal transmitted from the sensor input terminal unit into an analog-digital signal; and

a normality determination section for analyzing result values of the ADC to determine a normal status thereof.

9. The signal processing apparatus according to claim 8 , wherein the ADC comprises:

a signal selection section which has a Built In Self Test (BIST) signal input terminal for instructing a BIST and at least one bandgap input terminal; and

an analog-digital conversion block which outputs a comparison result of levels of a predetermined reference threshold voltage and a voltage applied by the signal selection section as a binary value.

10. The signal processing apparatus according to claim 9 , wherein the normality determination section comprises:

an edge determination section which determines the rising edge and the falling edge;

a comparison section which compares a high level range and a low level range; and

a range monitoring section which monitors whether or not at least a level of the edge determination section and the comparison section is in a range between upper and lower limit values.

11. The signal processing apparatus according to claim 1 , wherein the normality determination block comprises:

an edge counter which determines and counts the rising edge and the falling edge of the sensing signal;

a data identification section which identifies a falling pattern and a rising pattern of the sensing signal; and

a comparison determination processing section which compares the number of counted edges output from the edge counter and the number of patterns output from the data identification section and determines a normal/abnormal status thereof.