KR20140092131A - Method for detecting validity of vehicular adc unit - Google Patents

Abstract

Disclosed is a method for testing validity of a vehicular analog-digital converter (ADC) unit to perform a reliable inspection of an A/D converter. The method for testing validity according to the present invention comprises the steps of: a) outputting a reference test voltage applied to the ADC unit based on a hardware circuit and monitoring an output voltage; b) monitoring a standard analog reference voltage applied to the ADC unit and a bit stuck of a result register storing a digital conversion result of an analog reference ground voltage; c) setting channel selection signals (S0 to S3) for selecting the standard analog reference voltage and the analog reference ground voltage to be mutually exclusive and monitoring whether the channel selection signals (S0 to S3) have an error; and d) performing, by a vehicular electronic control unit (ECU), an error notification if there is any error based on the determinations in the a) to c) steps and repeating the said steps if there is not any error. Therefore, it is possible to test the validity of the ADC unit by detecting an error in the ADC unit with ADC unit itself without an extra ADC unit or additional signal.

Description

TECHNICAL FIELD [0001] The present invention relates to an analog-to-

The present invention relates to a safety inspection method for a vehicle, and more particularly, to a safety inspection method for a vehicle, including a multiplexer for an ADC unit that converts an analog signal input, generated, (A / D converter), and a register for storing result information, thereby preventing errors in the conversion process of the input signal.

Recently, in order to improve the safety, comfort, and comfort of automobiles, the number of components to be controlled has been rapidly increasing. To this end, an electronic control unit (ECU) . The electronic control unit has been summarized to combine various control devices into one control unit. In order to ensure the quality and safety of the product due to the development of the product technology, a more effective inspection apparatus is required.

In the conventional inspection technique, a visual inspection or a manual inspection is performed by an operator in the process of assembling the overall parts of the electronic control unit, and furthermore, after the finished product is assembled, the quality inspection is performed by the operation inspection according to the operation. In particular, the stability check of an electronic control device for engine control is inevitable and very important.

An apparatus for checking the stability of such an electronic control apparatus will be described with reference to FIG.

The stability checking apparatus of the electronic control apparatus includes an amplifying unit 10, a signal converting unit 20, a timer 30 and a transistor 40 as shown in FIG. Amplifies the input signal according to the amplification ratio. The signal converting unit 20 inverts or re-inverts the amplified signal applied from the amplifying unit 10 to output the inverted signal or the same signal as the input signal.

The timer 30 modulates a signal applied from the signal converter 20 into a square wave and outputs an oscillation signal having a predetermined oscillation frequency. The FET transistor 40 is formed by a power transistor which is used for electric power by interrupting the set power which is switched at a predetermined cycle according to an input signal.

A signal oscillated according to the input signal is applied to the gate terminal of the FET transistor 40. An input power of 12V is input to the drain terminal and an external device is connected to the source terminal. Accordingly, in order to detect whether the electronic control device to be inspected normally operates in the intermittent input power interrupter, a PC (PERSONER COMPUTER) is connected to the input terminal of the stability testing device of the electronic control device, and an electronic control device And the driving power is 12 V by using the power supply terminal.

At this time, when the test signal set in the PC is applied to the input terminal, the amplification unit 10 of the stability checking apparatus of the electronic control unit amplifies the test signal applied from the PC according to the amplification ratio, To the signal converting apparatus 20. [ The signal converter 20 inverts the amplified signal according to a signal applied from the amplifier 10 and then inverts the amplified signal to output the same signal as the input signal to the timer 30.

The timer 30 outputs a rectangular wave oscillation signal to the gate terminal G of the FET transistor 40 in accordance with a signal applied to the signal converter 20. At this time, the gate stage (G) is controlled by the oscillation signal outputted from the timer (30) so that the FET transistor is on / off switched. Accordingly, the input power supplied to the electronic control device through the drain (D) terminal and the source (S) terminal is momentarily interrupted according to the on / off state of the FET transistor. At this time, the tester user checks whether a normal data signal according to basic characteristics is applied to the display unit while the input power is momentarily interrupted.

Accordingly, the stability check of the conventional electronic control device is to check whether the power is normally operated according to the basic characteristics set in the electronic control device when the supply power is instantaneously interrupted by momentarily interrupting the supplied electric power. However, it is pointed out that the reliability of the test is not high because it is only a hardware test. Especially, since the ADC unit of the vehicle ECU is widely used as an important input signal used in the electronic control unit, the validity of the ADC unit is inevitably checked, which is directly related to the stability of the electronic control unit. Therefore, in order to secure the stability of the vehicle, it is required to check the tread of the ADC unit.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and it is an object of the present invention to provide a method and apparatus for correcting an error of an ADC unit itself, such as a reference voltage of an ADC or a bit stuck of a register, To provide a method of validating a vehicle's analog-to-digital converter unit that can check the validity of the ADC unit with a separate ADC unit or with no additional signal.

It is another object of the present invention to provide a method and apparatus for testing a multiplexer error of an ADC unit, a standard analog reference voltage error check using a reference test voltage, a bit stuck test of a result register, The present invention provides a method for checking the validity of the analog-to-digital converter unit of a vehicle, which can secure the functionality and stability of the system without any additional hardware function by performing stable inspection of the A / D converter based on the A / D converter.

According to an aspect of the present invention, there is provided a method for checking the validity of an ADC unit of a vehicle, the method comprising the steps of: a) Outputting a reference test voltage based on a hardware circuit and monitoring an output voltage; b) monitoring a bit stuck of a result register storing a result of digitally converting a standard analog reference voltage and an analog reference ground voltage applied to the ADC unit; c) mutually exclusively sets the channel selection signals S0 to S3 of the multiplexer for selecting the standard analog reference and the analog reference ground, and the channel selection signals S0- S3); < / RTI > And d) if at least one error occurs as a result of the determination in steps a) to c), the electronic control unit (ECU) of the vehicle performs an error notification, and if no error occurs, the process is repeated periodically The method comprising the steps of:

According to a preferred embodiment of the present invention, step a) comprises the steps of: a-1) setting a normal range of the reference test voltage to a maximum and minimum threshold voltage according to a system configuration, ; And a-2) determining an error with respect to a reference test voltage when the difference is out of the range of the maximum and minimum threshold voltages.

The method of claim 1, wherein step b) comprises the steps of: b-1) if the maximum or minimum value of the standard analog reference voltage and the analog reference ground voltage is not output, ); And b-2) notifying an error when the bit stuck occurs in the step b-1).

The validity checking method of the analog-to-digital converter unit of the vehicle proposed in the present invention is based on the fact that the reference voltage of the ADC is not normal or the error of the ADC unit itself such as a bit stuck of a register By sensing, it is possible to check the validity of the ADC unit with a separate ADC unit or with the ADC unit itself without additional signal. In addition, A / D conversion is performed based on a multiplexer error check of the ADC unit, a standard analog reference voltage error check using a reference test voltage, and a bit stuck check of a result register. D converter can be performed in a stable manner.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram showing an apparatus for checking the stability of an electronic control unit of a conventional vehicle. FIG.
2 is a view for explaining a main configuration of an ADC unit of a vehicle according to the present invention.
3 is a flow chart for explaining the operation of the present invention.
4 is a graph for explaining a monitoring method for the reference test voltage of FIG.
5 is a diagram for explaining a result register monitoring method of FIG.
FIG. 6 is a diagram for explaining a multiplexer error monitoring method of FIG. 3. Referring to FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the ADC unit's validity can be verified using three channels of the ADC unit. In order to verify the validity of the ADC unit, the ADC unit includes a multiplexer for selecting one channel to be converted among the analog signals input to the plurality of channels, an A / D converter for converting the selected analog signal into a design signal, And a result register for storing the result register.

The A / D converter converts an analog signal into a digital signal by referring to a standard analog reference signal and an analog reference ground signal, which are reference values used for conversion. Here, the present invention examines the validity of the ADC unit by examining the mutiplexer, the A / D converter and the result register constituting the ADC, and the inspection method for inspecting the respective components is as follows.

First, there is an error checking process for a standard anlog reference voltage using a reference test voltage. Then, a bit stuck of the result register is checked. And performs a muliplexer, which is the process of checking the error state of the multiplexer in the ADC unit.

As described above, according to the present invention, the stability of the ADC unit is checked through the three processes described above. As a precondition, the test signal is required to maintain a constant voltage at all times. For example, when a 5V voltage is used as a reference voltage, a reference test signal is required for a signal that always maintains a constant voltage even if the 5V voltage fluctuates by 5V or less.

2 is a hardware structure showing the ADC unit of the present invention. A multiplexer MUX for selecting an analog signal input from a 16-bit channel using four bits S0 to S3; an A / D converter for converting an output signal of the multiplexer MUX into a digital signal; D converter, and a result register for storing data converted by the A / D converter.

A reference test voltage is input to the input terminal of the ADC unit, including a standard analog reference signal and an analog reference ground signal. The reference test voltage is supplied by a separate hardware circuit (Fixed voltage generator). In addition, the A / D converter has a 12-bit decomposition capability, and accordingly, the result register also has a memory structure for storing 12-bit information.

The error checking method of the ADC unit according to the present invention will now be described with reference to FIG. 3 based on the above-described ADC unit. 3 is a flowchart for explaining an error checking method of the ADC unit.

As shown in the figure, in step S301, the reference test voltage is converted into a digital signal. To this end, the electronic control unit (ECU: not shown) of the vehicle selects the channel to which the reference test voltage is inputted by using the selection signals S0 to S3 of the multiplexer.

Thus, the multiplexer provides a reference test voltage to the A / D converter, which converts the reference test voltage into a digital signal and stores it in a result register. Here, the reference test voltage will be able to provide a fixed voltage regardless of the battery power level when an IC such as the above-described fixed voltage generator (e.g., NCV33161) is used.

That is, by implementing the above-described hardware circuit, when the standard test voltage is 5V and the reference test voltage is 2.5V as shown in FIG. 4A, The voltage level is fixed as shown in the graph.

In step S303, it is determined whether the reference test voltage of the currently inputted analog is in the normal range. This is done by setting the normal range of the reference test voltage to the maximum and minimum threshold voltages If the maximum and minimum threshold voltages are out of the range, it is determined that the reference test voltage is an error.

As a result of the determination in step S303, if the reference test voltage is not within the normal range, the maximum and minimum threshold voltages are out of the set range, and the error condition for the ADC unit is notified. Such an error condition is a variation of the reference test voltage, and may occur due to a voltage fluctuation of the battery if the battery does not have a hardware circuit for generating a reference test voltage.

As a result, if the standard analog reference voltage drops below 5V or increases above 5V, the ADC unit itself will change the signal value of the standard analog reference voltage even if it is operating normally. As shown in the graph of FIG. 4B, when the standard analog reference voltage is reduced below 5V, the reference test voltage is always read as a value of 2.5V or more without maintaining 2.5V.

Since the reference test voltage itself is constant at 2.5V but the standard analog reference voltage used to convert the input analog signal into a digital signal is smaller than the reference value, (reference test voltage) is read out larger than 2.5V. Conversely, when the standard analog reference voltage is increased by more than 5 V, the reference test voltage is fixed at 2.5 V, but the converted value is less than 2.5 V Value.

Therefore, when an error with respect to the reference test voltage is generated, the electronic control unit (ECU) notifies an error to the ADC unit in step S315.

On the other hand, if it is determined in step S303 that the reference test voltage is in the normal range, the process proceeds to step S305 and converts the currently input analog reference voltage into a digital signal.

In step S307, the electronic control unit ECU determines whether the currently input analog reference voltage is within the normal range. Here, the analog reference voltage refers to a standard analog reference voltage and an analog reference ground, and is implemented by sensing the stuck bit of each error state.

In step S307, an error determination process for an analog reference voltage first checks a bit stuck to an ADC result register. This is to check the bit stuck of the result register by repeatedly storing the minimum and maximum values that the result register may have.

Two analog signals are needed to check the bit stuck of the result register, one signal is a stadard analog reference and the other is an analog reference signal ground. Assuming a 12-bit result register, converting the channel of a standard analog reference will cause all bits in the result register to have a value of "1".

When converting a channel to which an analog reference ground is allocated, all the bits of the result register have a value of "0". Here, since there is a slight error in the process of converting the analog signal due to the characteristics of the hardware or the like, it is determined that the normal range of the signal is normal and the converted value falls within the range.

When determining the normal range, the error range should be less than the sampling of 1 bit of the ADC unit. For example, if you use a 12-bit result register with a 5V reference voltage, the error range should be less than 0.001V.

That is, since the error range is the reference voltage ÷ the result register maximum value, "0.001V = 5V ÷ 4095 (3FFh)" is obtained.

5A, when the analog reference voltage is 5V, the standard analog reference is 5V and the analog reference ground is 0V when the ADC unit is normal. . On the other hand, when a predetermined bit of the result register, for example, the seventh bit, is fixed to '0', the reference voltage is measured as 4.921 V as shown in FIG. 5B, You can do it.

When the predetermined bit of the result register, for example, the first bit is fixed to '1', the value of the analog reference ground is measured as 0.001 V as shown in FIG. 5C, (bit stuck) can be detected.

In this manner, the bitstack for a predetermined bit of the result register is detected to detect whether or not an error has occurred with respect to the analog reference voltage. When an error occurs, the electronic control unit (ECU) And outputs a warning message.

On the other hand, if it is determined in step S307 that there is no error with respect to the analog reference voltage, step S309 is performed to extract the selection signals S0 to S3 for error detection of the multiplexer.

In step S311, it is determined whether or not there is an error in the selection signal S0 to S3. As described above, the multiplexer selects 16 analog channels to be input using the four signals S0 to S3. The standard analog reference voltage and the analog reference ground It is to judge whether the selection is clear.

That is, as shown in FIG. 6, the selection signals S0 to S3 used when selecting two channels for the analog reference voltage are configured mutually exclusive so that a problem can be detected in the selection signal of the multiplexer .

For example, when a standard analog reference is assigned to channel 0, an analog reference ground signal is assigned to channel 15, which is mutually disjointed. Thus, when there are four selection signals, there are eight ways of configuring the two channels, and it is judged whether the multiplexer is erroneous from the inversion code for each selection signal.

If it is determined in step S311 that an error has occurred in the AD multiplexer, the electronic control unit (ECU) proceeds to step S315 to notify of an error. On the other hand, if it is determined in step S311 that the AD multiplexer is normal The electronic control unit ECU determines in step S313 that the ADC unit is in a normal state. Then, the ADC unit is continuously monitored for errors by inspecting the process in a predetermined period.

MUX: Multiplexer S0 to S3: Select signal
Result register: Result register

Claims (4)

A method for checking the validity of an ADC unit of a vehicle,
a) outputting a reference test voltage applied to the ADC unit based on a hardware circuit, and monitoring an output voltage;
b) monitoring a bit stuck of a result register storing a result of digitally converting a standard analog reference voltage and an analog reference ground voltage applied to the ADC unit;
c) mutually exclusively sets the channel selection signals S0 to S3 of the multiplexer for selecting the standard analog reference and the analog reference ground, and the channel selection signals S0- S3); < / RTI > And
d) if the ECU of the vehicle performs an error notification when any one or more errors occur as a result of the determination in steps a) to c), and if the error does not occur, repeating the process periodically The method of claim 1, wherein the analog-to-digital converter unit comprises: The method according to claim 1,
Wherein the hardware circuit of step a) is configured to output a fixed voltage regardless of a power level of the battery using an IC element that outputs a rated voltage. Feasibility check method. The method according to claim 1 or 2, wherein the step a)
a-1) setting a normal range of the reference test voltage to a maximum threshold and a minimum threshold according to a system configuration; And
a-2) determining an error with respect to a reference test voltage when the difference between the maximum and minimum threshold voltages is out of the range of the maximum and minimum threshold voltages. The method of claim 1, wherein the step b)
b-1) monitoring a bit stuck of the result register when the maximum or minimum value of the standard analog reference voltage and the analog reference ground voltage is not output; And
b-2) a step of notifying an error when a bit stuck occurs in the step b-1).

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