KR102430231B1 - System and method for measuring an electric current of current sensor - Google Patents

Abstract

Disclosed are a device and a method for measuring current of a DC sensor. According to an aspect of the present invention, the device for measuring current of a DC sensor, comprises: a DC sensor; a capacitor connected in parallel to the DC sensor; an application-specific integrated circuit (ASIC) module connected to the DC sensor and the capacitor, applying voltage to the DC sensor to measure sensing current flowing through the DC sensor, measuring the applied current by the applied voltage and charging voltage of the capacitor, and calculating the sensing current of the DC sensor on the basis of the applied current and the charging voltage; and a control unit for controlling whether the DC sensor is operated. Therefore, a measurement error of sensing current can be reduced.

Description

Current measuring device and method of DC sensor

The present invention relates to an apparatus and method for measuring a current of a DC sensor, and more particularly, to an apparatus and method for measuring a current of a DC sensor capable of accurately measuring a sensing current flowing through a DC sensor in consideration of a voltage change of an external capacitor. .

In general, a current sensor is a sensor that measures the current flowing through a conductor such as a wire electrically connected to a control object. Such a current sensor includes a resistance type current sensor, a current transformer (CT), a Hall effect current sensor, and the like.

Among them, the resistance type current sensor is widely applied because it has high accuracy compared to its low price. The resistance type current sensor is configured to insert a shunt resistor, a resistor with a low resistance value, in the middle of the circuit to measure the current, and measure the current value by using the voltage difference occurring at both ends of the resistor.

The resistance type current sensor consists of an input bus bar connected to the power supply side, an output bus bar connected to the load side, and a shunt resistor connected between the input bus bar and the output bus bar. do.

In this resistance type current sensor, the voltage generated by V=IR is read from the ADC (Analog/Digital Converter) of the ASIC (Application Specific Integrated Circuit). Here, if the resistance value is fixed, it is designed to measure the current flowing through the current sensor (hereinafter referred to as 'sensing current') using an equation in which voltage and current are proportional.

However, when a capacitor is connected in parallel to the current sensor, there is a problem in that a difference occurs between the sensing current flowing through the current sensor and the applied current due to the current flowing through the capacitor. There is a problem in that the measurement error of the current magnitude adversely affects the control of the load operating based on the sensing current.

Background art of the present invention is disclosed in Republic of Korea Patent Publication No. 10-1171557 (2012.08.09. Announcement).

The present invention has been devised to improve the above problems, and an object according to an aspect of the present invention is to measure the current of a DC sensor so that the sensing current flowing through the DC sensor can be accurately measured in consideration of the voltage change of the external capacitor. To provide an apparatus and method.

The problem to be solved by the present invention is not limited to the problem(s) mentioned above, and another problem(s) not mentioned will be clearly understood by those skilled in the art from the following description.

A current measuring device for a DC sensor according to an aspect of the present invention is connected to a DC sensor, a capacitor connected in parallel to the DC sensor, the DC sensor and the capacitor, and is configured to measure a sensing current flowing through the DC sensor. Application-specific (ASIC) that applies a voltage to a DC sensor, measures an applied current by the applied voltage and a charging voltage of the capacitor, and calculates a sensing current of the DC sensor based on the applied current and the charging voltage Integrated Circuit) module, and a control unit for controlling whether the DC sensor operates.

In the present invention, the ASIC module includes a current mirror unit that copies and outputs the applied current by the voltage, a charging voltage measurement unit that measures the charging voltage charged in the capacitor, and the current mirror using the charging voltage of the capacitor. It may include a noise compensator for calculating the sensing current of the DC sensor by removing power noise of the applied current output through the unit.

In the present invention, the noise compensator includes a delay unit synchronizing the applied current with the charging voltage of the capacitor, a capacitor current calculating unit calculating a capacitor current by differentiating the charging voltage of the capacitor, and the applied current from the delay unit and and a sensing current calculator configured to calculate the sensing current of the DC sensor by using a difference between the capacitor currents from the capacitor current calculator.

In the present invention, the control unit transmits a sensor-on signal for activating the DC sensor at a preset period to the ASIC module, and the ASIC module applies the voltage to the DC sensor when the sensor-on signal is received. can

In the present invention, the control unit may receive the sensing current of the DC sensor from the ASIC module, and compare the sensing current with a preset threshold value to determine whether the seat belt is fastened.

In the present invention, when the ASIC module and the control unit constitute an airbag system, and the airbag module is connected, the control unit periodically measures collision data to determine whether there is a collision, and fastens the seat belt based on the sensing current of the DC sensor It is determined whether or not the seat belt is fastened in a crash situation, the airbag module is deployed, and an alarm can be generated when the seat belt is not fastened in a crash situation.

A method for measuring a current of a DC sensor according to another aspect of the present invention comprises the steps of: a control unit transmitting a sensor-on signal to an ASIC module at a predetermined period in a method for measuring a current of a DC sensor connected in parallel with a capacitor; applying a voltage to the DC sensor by the ASIC module receiving and calculating the sensing current of the DC sensor.

In the present invention, in the measuring step, the ASIC module may measure the applied current through current mirroring and measure the charging voltage charged in the capacitor through the ADC.

In the present invention, calculating the sensing current includes, by the ASIC module, delaying, by the ASIC module, to synchronize the applied current with the charging voltage of the capacitor, and calculating the capacitor current by differentiating the charging voltage of the capacitor; and The method may include calculating, by the ASIC module, a sensing current of the DC sensor using a difference between the delayed applied current and the calculated capacitor current.

In the present invention, the control unit may further include the step of receiving the sensing current of the DC sensor from the ASIC module and determining whether the seat belt is fastened by comparing the sensing current with a preset threshold value.

In the present invention, when the ASIC module and the control unit constitute an airbag system, and the airbag module is connected, the control unit periodically measures collision data to determine whether there is a collision, and based on the sensing current of the DC sensor, the seat belt It is determined whether or not the seat belt is fastened, and an airbag module is deployed when the seat belt is fastened in a crash situation, and an alarm can be generated when the seat belt is not fastened in a crash situation.

The apparatus and method for measuring a current of a DC sensor according to an embodiment of the present invention can accurately measure the sensing current flowing through the DC sensor in consideration of a voltage change of an external capacitor.

The apparatus and method for measuring a current of a DC sensor according to an embodiment of the present invention measure an applied current and a charging voltage of a capacitor to remove power noise, thereby reducing a measurement error of a sensing current flowing through the DC sensor.

The apparatus and method for measuring a current of a DC sensor according to an embodiment of the present invention may check whether the seat belt is fastened through the sensing current of the DC sensor.

The apparatus and method for measuring a current of a DC sensor according to an embodiment of the present invention may deploy an airbag through a sensing current of the DC sensor.

On the other hand, the effects of the present invention are not limited to the above-mentioned effects, and various effects may be included within the range apparent to those skilled in the art from the description below.

1 is a view for explaining a current measuring apparatus of a DC sensor according to an embodiment of the present invention.
2 is a diagram illustrating an equivalent circuit of a DC sensor and a capacitor when an ASIC module applies a voltage according to an embodiment of the present invention.
3 is an exemplary diagram illustrating a case in which a DC sensor according to an embodiment of the present invention is used in an airbag system.
4 is a diagram for explaining the configuration of an ASIC module according to an embodiment of the present invention.
5 is a flowchart illustrating an operation of an ASIC module according to an embodiment of the present invention.
6 is a view for explaining a method of determining whether a seat belt is fastened based on a sensing current according to an embodiment of the present invention.

Hereinafter, an apparatus and method for measuring a current of a DC sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

Implementations described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Although discussed only in the context of a single form of implementation (eg, discussed only as a method), implementations of the discussed features may also be implemented in other forms (eg, as an apparatus or program). The apparatus may be implemented in suitable hardware, software and firmware, and the like. A method may be implemented in an apparatus such as, for example, a processor, which generally refers to a computer, a microprocessor, a processing device, including an integrated circuit or programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, portable/personal digital assistants ("PDA") and other devices that facilitate communication of information between end-users.

1 is a view for explaining a current measuring device of a DC sensor according to an embodiment of the present invention, Figure 2 is an equivalent circuit of a DC sensor and a capacitor when an ASIC module according to an embodiment of the present invention applies a voltage 3 is an exemplary view illustrating a case in which a DC sensor according to an embodiment of the present invention is used in an airbag system.

Referring to FIG. 1 , an apparatus for measuring a current of a DC sensor according to an embodiment of the present invention includes a DC sensor 100 , a capacitor 200 connected in parallel to the DC sensor 100 , and an Application-Specific Integrated (ASIC) Circuit) includes a module 300 and a control unit 400 .

The DC sensor 100 is a sensor for detecting a current, and may be, for example, a resistance type current sensor.

The ASIC module 300 is connected to the DC sensor 100 and the capacitor 200, and applies a voltage to the DC sensor 100 to measure the sensing current flowing through the DC sensor 100, and is applied by the applied voltage. The current and the charging voltage of the capacitor 200 are measured, and the sensing current of the DC sensor 100 is calculated based on the applied current and the charging voltage. In this case, the ASIC module 300 may apply a voltage to the DC sensor 100 when receiving a sensor on signal from the controller 400 .

The control unit 400 may be implemented as an MCU that controls whether the DC sensor 100 operates.

The control unit 400 may transmit a sensor on signal for activating the DC sensor 100 to the DC sensor 100 and the ASIC module 300 at a predetermined period.

Then, the DC sensor 100 is turned on, and the ASIC module 300 may measure the sensing current flowing through the DC sensor 100 by applying a voltage to the DC sensor 100 . At this time, since the capacitor 200 is connected in parallel to the DC sensor 100 , the ASIC module 300 needs to measure the sensing current flowing through the DC sensor 100 in consideration of the current flowing through the capacitor 200 .

If the DC sensor 100 and the capacitor 200 are connected in parallel and the ASIC module 300 applies a voltage to the DC sensor 100 as an equivalent circuit, it may be as shown in FIG. 2 . Referring to FIG. 2 , the sensing current of the DC sensor 100 may be calculated using a difference between an applied current and a capacitor current flowing through the capacitor 200 . Here, the capacitor current may be measured using a charging voltage charged in the capacitor 200 . Accordingly, the sensing current may be calculated using Equation 1 below.

[Equation 1]

는 t시간에 DC 센서(100)에 흐르는 센싱 전류,

는 t시간에 ASIC 모듈(300)이 인가한 전압에 의한 인가 전류,

는 t시간에 커패시터(200)에 흐르는 커패시터 전류, C는 커패시터, Vcap는 커패시터(200)에 충전되는 충전 전압을 의미할 수 있다. here,

is the sensing current flowing through the DC sensor 100 at time t,

is the applied current by the voltage applied by the ASIC module 300 at time t,

may denote a capacitor current flowing through the capacitor 200 at time t, C denotes a capacitor, and Vcap denotes a charging voltage charged in the capacitor 200 .

The ASIC module 300 may reduce a measurement error of a sensing current flowing through the DC sensor 100 by removing power noise by measuring an applied current and a capacitor charging voltage.

A detailed configuration of the ASIC module 300 for calculating the sensing current of the DC sensor 100 will be described with reference to FIG. 3 .

The control unit 400 may periodically activate the DC sensor 100 and check whether the seat belt is fastened through the sensing current of the DC sensor 100 . For example, when the sensing current is less than the threshold value, the controller 400 may determine that the seat belt is fastened. In addition, when the sensor current is equal to or greater than the threshold value, the control unit 400 may determine that the seat belt is not fastened.

For example, as shown in FIG. 3 , when the DC sensor 100 is used in the airbag system, a difference in resistance value may occur depending on whether the seat belt is fastened. That is, when the seat belt is fastened, the switch may be on and the resistance value may be R, and when the seat belt is not fastened, the switch may be off and the resistance value may be 2R. When the seat belt is fastened in this way, since the resistance value is R, the sensing current of the DC sensor 100 may increase compared to the case where the seat belt is not fastened. Therefore, it is possible to check whether the seat belt is fastened through the sensing current of the DC sensor 100 .

In addition, when the ASIC module 300 and the control unit 400 constitute an airbag system (not shown), and an airbag module (not shown) is connected, the control unit 400 periodically measures collision data to determine whether a collision exists, Determines whether the seat belt is fastened based on the sensing current of the DC sensor 100, deploys the airbag when the seat belt is fastened in a crash situation, and generates an alarm notifying that the seat belt is not fastened when the seat belt is not fastened. have. When the seat belt is not fastened, the controller 400 may not deploy the airbag. The control unit 400 may compare the collision data with a preset threshold value, and if the comparison result results in the collision data being equal to or greater than the threshold value, it may be determined that the collision situation exists.

4 is a diagram for explaining the configuration of an ASIC module according to an embodiment of the present invention.

Referring to FIG. 4 , the ASIC module 300 according to an embodiment of the present invention includes a signal receiving unit (not shown), a current mirror unit 310 , an applied voltage measuring unit 320 , a charging voltage measuring unit 330 and and a noise correction unit 340 .

The signal receiver may receive a sensor-on signal from the controller 400 . When the sensor-on signal is received, the signal receiver may apply a voltage to the DC sensor 100 to measure a sensing current flowing through the DC sensor 100 .

The current mirror unit 310 measures the applied current by the applied voltage, and copies and outputs the measured applied current. That is, the current mirror unit 310 may perform mirroring so that a current copied from a current flowing in a node connected to the DC sensor 100 flows to another node. For example, the current mirror unit 320 may include semiconductor devices M1 and M2. Here, the output current mirrored from the current flowing through the semiconductor device M1 may flow through the semiconductor device M2.

The applied voltage measuring unit 320 may measure the applied current output through the current mirror unit 310 . In this case, the applied voltage measuring unit 320 may be implemented as an ADC.

The charging voltage measuring unit 330 may measure the charging voltage charged in the capacitor 200 . In this case, the charging voltage measuring unit 330 may be implemented as an ADC.

The noise compensator 340 removes power noise based on the applied current output through the current mirror unit 310 and the charging voltage of the capacitor 200 measured by the charging voltage measuring unit 330 to remove the power supply noise to the DC sensor 100 . of the sensing current can be calculated. The noise compensator 340 may include a delay unit 342 , a capacitor current calculator 344 , and a sensing current calculator 346 .

The delay unit 342 may synchronize the applied current measured by the applied voltage measuring unit 320 with the charging voltage of the capacitor 200 . That is, the delay unit 342 may delay the applied current to synchronize the applied current with the charging voltage of the capacitor 200 .

The capacitor current calculator 344 may calculate the capacitor current by differentiating the charging voltage of the capacitor 200 .

The sensing current calculator 346 may calculate the sensing current of the DC sensor 100 by using a difference between the applied current from the delay unit 342 and the capacitor current from the capacitor current calculator 344 . That is, the sensing current calculator 346 may calculate the sensing current of the DC sensor 100 using Equation 1 above.

5 is a flowchart illustrating an operation of an ASIC module according to an embodiment of the present invention.

Referring to FIG. 5 , the ASIC module 300 turns on the DC sensor 100 when receiving a sensor-on signal from the controller 400 ( S410 ). In this case, the ASIC module 300 may apply a voltage to the DC sensor 100 to measure the sensing current flowing through the DC sensor 100 .

When step S410 is performed, the ASIC module 300 measures the applied current and the charging voltage of the capacitor 200 by the applied voltage (S420). In this case, the ASIC module 300 may measure the applied current through current mirroring, and may measure the charging voltage of the capacitor 200 through the ADC.

When step S420 is performed, the ASIC module 300 calculates the sensing current of the DC sensor 100 based on the applied current and the charging voltage of the capacitor 200 ( S430 ). At this time, the ASIC module 300 delays the applied current to synchronize the charging voltage of the capacitor 200 , and calculates the capacitor current by differentiating the charging voltage of the capacitor 200 , between the delayed applied current and the calculated capacitor current. The sensing current of the DC sensor 100 may be calculated using the difference.

6 is a view for explaining a method of determining whether a seat belt is fastened based on a sensing current according to an embodiment of the present invention.

Referring to FIG. 6 , the control unit 400 transmits a sensor-on signal to the ASIC module 300 at a predetermined period ( S510 ).

The ASIC module 300 receiving the sensor-on signal turns on the DC sensor 100 ( S520 ), applies a voltage to the DC sensor 100 , and the applied current and the charging voltage of the capacitor 200 by the applied voltage is measured (S530).

When step S530 is performed, the ASIC module 300 calculates the sensing current of the DC sensor 100 based on the applied current and the charging voltage of the capacitor 200 ( S540 ), and transmits the calculated sensing current to the control unit 400 . transmit (S550).

Upon receiving the sensing current, the control unit 400 compares the sensing current with a preset threshold value (S560).

If the sensing current is less than the threshold as a result of comparison in step S560, the control unit 400 determines that the seat belt is fastened (S570).

If the comparison result in step S560 indicates that the sensing current is greater than or equal to the threshold, the control unit 400 determines that the seat belt is not fastened and generates an alarm for not fastening the seat belt (S580).

According to an embodiment of the present invention, the control unit 400 may periodically measure collision data to determine whether there is a collision, and when the seat belt is fastened in a collision situation, the control unit 400 may deploy the airbag. Also, when the seat belt is not fastened in a crash situation, the controller 400 may not deploy the airbag.

As described above, the current measuring apparatus and method of the DC sensor 100 according to an embodiment of the present invention can accurately measure the sensing current flowing through the DC sensor 100 in consideration of the voltage change of the external capacitor 200 . have.

The current measuring apparatus and method of the DC sensor 100 according to an embodiment of the present invention measure the applied current and the charging voltage of the capacitor 200 to remove power noise, thereby measuring the sensing current flowing through the DC sensor 100 . error can be reduced.

The current measuring apparatus and method of the DC sensor 100 according to an embodiment of the present invention may check whether the seat belt is fastened through the sensing current of the DC sensor 100 .

The current measuring apparatus and method of the DC sensor 100 according to an embodiment of the present invention may deploy the airbag through the sensing current of the DC sensor 100 .

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and those of ordinary skill in the art to which various modifications and equivalent other embodiments are possible. will understand

Therefore, the true technical protection scope of the present invention should be defined by the following claims.

100: DC sensor
200: capacitor
300: ASIC module
310: current mirror unit
320: applied voltage measuring unit
330: charging voltage measuring unit
340: noise correction unit
400: control unit

Claims (11)

DC sensor (Direct Current Sensor);
a capacitor connected in parallel to the DC sensor;
It is connected to the DC sensor and the capacitor, and applies a voltage to the DC sensor to measure a sensing current flowing through the DC sensor, measures an applied current by the applied voltage and a charging voltage of the capacitor, and the applied an application-specific integrated circuit (ASIC) module for calculating a sensing current of the DC sensor based on a current and the charging voltage; and
Including a control unit for controlling whether the DC sensor is operated,
The ASIC module is
a current mirror unit which copies and outputs the applied current by the voltage;
a charging voltage measuring unit measuring a charging voltage charged in the capacitor; and
and a noise compensator for calculating the sensing current of the DC sensor by removing power noise of the applied current output through the current mirror unit using the charging voltage of the capacitor;
The noise correction unit,
a delay unit delaying the applied current to synchronize with the charging voltage of the capacitor;
a capacitor current calculator configured to calculate a capacitor current by differentiating the charging voltage of the capacitor; and
and a sensing current calculator configured to calculate the sensing current of the DC sensor by using a difference between the current applied from the delay unit and the capacitor current from the capacitor current calculator.
delete delete According to claim 1,
The control unit transmits a sensor-on signal for activating the DC sensor to the ASIC module at a predetermined period,
The ASIC module, a DC sensor current measuring device, characterized in that for applying the voltage to the DC sensor when the sensor on signal is received.
According to claim 1,
The control unit is
A current measuring device of a DC sensor, characterized in that it receives the sensing current of the DC sensor from the ASIC module, and determines whether the seat belt is fastened by comparing the sensing current with a preset threshold value.
According to claim 1,
When the ASIC module and the control unit constitute an airbag system, and the airbag module is connected,
The control unit periodically measures collision data to determine whether there is a collision, determines whether the seat belt is fastened based on the sensing current of the DC sensor, and deploys the airbag module when the seat belt is fastened in a collision situation; Current measuring device of DC sensor, characterized in that generating an alarm when the seat belt is not fastened in a situation.
In the method of measuring the current of a DC sensor connected in parallel with a capacitor,
transmitting, by the control unit, a sensor-on signal to the ASIC module at regular intervals;
applying, by the ASIC module receiving the sensor-on signal, a voltage to the DC sensor, and measuring an applied current and a charging voltage of the capacitor by the applied voltage; and
Comprising the step of calculating, by the ASIC module, the sensing current of the DC sensor based on the applied current and the charging voltage,
Calculating the sensing current comprises:
delaying, by the ASIC module, to synchronize the applied current with the charging voltage of the capacitor, and differentiating the charging voltage of the capacitor to calculate a capacitor current; and
and calculating, by the ASIC module, a sensing current of the DC sensor using a difference between the delayed applied current and the calculated capacitor current.
8. The method of claim 7,
In the measuring step,
The ASIC module measures the applied current through current mirroring, and measures the charging voltage charged in the capacitor through the ADC.
delete 8. The method of claim 7,
The control unit receives the sensing current of the DC sensor from the ASIC module, and compares the sensing current with a preset threshold value to determine whether the seat belt is fastened. How to measure.
8. The method of claim 7,
When the ASIC module and the control unit constitute an airbag system, and the airbag module is connected,
The control unit periodically measures collision data to determine whether there is a collision, determines whether the seat belt is fastened based on the sensing current of the DC sensor, and deploys the airbag module when the seat belt is fastened in a collision situation, A current measuring method of a DC sensor, characterized in that generating an alarm when the seat belt is not fastened in a collision situation.

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