KR20150093498A - Circuit for correcting off-set and controlling method thereof - Google Patents

Circuit for correcting off-set and controlling method thereof Download PDF

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Publication number
KR20150093498A
KR20150093498A KR1020140014357A KR20140014357A KR20150093498A KR 20150093498 A KR20150093498 A KR 20150093498A KR 1020140014357 A KR1020140014357 A KR 1020140014357A KR 20140014357 A KR20140014357 A KR 20140014357A KR 20150093498 A KR20150093498 A KR 20150093498A
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South Korea
Prior art keywords
offset
sensing
digital
circuit
control value
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KR1020140014357A
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Korean (ko)
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최영길
표승철
나준경
김성태
김창현
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삼성전기주식회사
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Priority to KR1020140014357A priority Critical patent/KR20150093498A/en
Publication of KR20150093498A publication Critical patent/KR20150093498A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G01C19/5776—Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/14—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of gyroscopes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0228—Inertial sensors

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Signal Processing (AREA)
  • Gyroscopes (AREA)

Abstract

An offset correcting circuit comprises: an amplification unit which amplifies a sensing signal output from a sensing node of an inertial sensor by a predetermined gain; an offset detecting unit which detects whether a direct-current offset occurs in the sensing signal output from the amplification unit; a digital signal processing unit which outputs a digital control value for correcting the direct-current offset through a digital signal process based on the signal output from the offset detecting unit; and an offset correcting unit which controls the amount of a current flowing in the sensing node through a switching operation interlocked with the digital control value, to correct the direct-current offset.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an offset correction circuit,

The present invention relates to an offset correction circuit and a control method thereof.

Inertial sensors are widely used for various applications such as air bag, ESC (Electronic Stability Control), vehicle black box, anti-shake camcorder, mobile phone, game machine motion sensing, navigation for satellite, missile and unmanned aircraft. And is divided into an acceleration sensor capable of measuring linear motion and an angular velocity sensor capable of measuring rotational motion, and the acceleration can be obtained by Newton's law of motion "F = ma", where "m "Is the mass of the moving object," a "is the acceleration to be measured, and the angular velocity can be obtained by the expression" F = 2 mΩ · v "for the Coriolis Force. (where "m" is the mass of the moving object, "Ω" is the angular velocity to be measured, and "v" is the mass velocity).

Inertial sensors can be classified into ceramic sensors and MEMS (Micro Electro Mechanical Systems) sensors according to the manufacturing process. MEMS sensors are classified into capacitive type, piezoresistive type, (Piezoelectric Type). In particular, as the MEMS sensor is easily manufactured in a small size and light weight by using the MEMS technology, the function of the inertial sensor is also continuously evolving.

However, as more analogue elements are required to eliminate the offset that may be generated in the sensing signal output from the sensing node due to mismatching or degradation of the resistance component of the inertia sensor, etc., additional nonlinear components or noise And the like, and it has been difficult to increase the current consumption due to the analog devices, and to make the circuit configuration simple and lightweight.

KR2005-0030171 A1

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the conventional art, and it is an object of the present invention to provide a method and apparatus for detecting in real time whether or not a DC offset is generated in a sensing signal output from an inertial sensor, And to provide an offset correction circuit capable of correcting a DC offset.

The offset correction circuit includes an amplifier for amplifying a sensing signal output from the sensing node of the inertial sensor with a predetermined gain, an offset sensing unit for sensing whether a DC offset is generated in the sensing signal output from the amplifying unit, A digital signal processing unit for outputting a digital control value for correcting the DC offset through digital signal processing based on a signal output from the offset sensing unit and a digital signal processing unit connected to the sensing node through a switching operation interlocked with the digital control value And an offset correcting unit for controlling the amount of current flowing to correct the DC offset.

The sensing signal output from the sensing node may include a first sensing signal and a second sensing signal having mutually different phases of 180 °, and the offset sensing unit may sense the first sensing signal output from the amplifying unit as a non- +), And a first comparator configured to receive a predetermined reference voltage at an inverting terminal (-), and a second offset sensing circuit configured to receive the second sensing signal output from the amplifying unit at a non- And a second comparator for receiving the reference voltage input to the inverting terminal (-) and a second comparator (comparator) for inputting the reference voltage.

The digital signal processor may further include a first digital control value for correcting the DC offset of the first sensing signal through filtering for integration and averaging of the first pulse signal output from the first comparator A second digital control module for correcting a DC offset of the second sensing signal through filtering for integration and averaging of a second pulse signal output from the second comparator, And a second digital circuit module outputting the second digital circuit module.

The first digital circuit module converts the first pulse signal into a digital value through filtering for integration and averaging of the first pulse signal output from the first offset detection circuit, A first digital signal conversion circuit for outputting a first digital control value and a first register for storing the first digital control value, and the second digital circuit module includes a second pulse signal output from the second offset detection circuit, A second digital signal conversion circuit for converting the second pulse signal to a digital value and outputting the second digital control value through filtering for integration and averaging for the second digital signal, And a second register for performing a second operation.

The offset correction unit may include a first offset correction module for controlling an amount of current flowing to the first sensing node through a switching operation interlocked with the first digital control value to correct the DC offset, And a second offset correction module for controlling the amount of current flowing to the second sensing node through a switching operation interlocked with the control value to correct the DC offset.

The first and second registers may each include at least one D flip-flop.

In addition, the first and second offset correction modules may include (n-1) correction units connected to the first and second registers, respectively, when the bits of the data stored in the first and second registers are n (bits) Circuit.

The correction circuit may further include a first switching circuit connected to each of the D flip-flops, the first switching circuit being controlled by a most significant bit (MSB) of data stored in the register, the first switching circuit being connected to the first switching circuit, A second switching circuit in which a switching operation is controlled by a D flip-flop, and a current source connected to upper and lower ends of the second switching circuit and outputting a current having a constant magnitude.

In addition, the first and second digital signal conversion modules may be a sigma delta analog-to-digital converter (&) ADC.

A method of controlling an offset correction circuit according to the present invention includes the steps of amplifying a sensing signal output from a sensing node of an inertial sensor in a gain unit with a constant gain, generating a DC offset in the sensing signal output from the amplifying unit in an offset sensing unit Outputting a digital control value for correcting the DC offset through a digital signal processing based on a signal output from the offset sensing unit in a digital signal processing unit, And controlling the amount of current flowing to the sensing node through a switching operation associated with the value to correct the DC offset.

The step of detecting whether or not the DC offset is generated may include detecting the presence of the DC offset by comparing the first sensing signal output from the amplifying unit, which is input to the non-inverting terminal (+) of the first comparator in the first offset detecting circuit, - detecting a DC offset of the first sensing signal through comparison of a preset reference voltage input to the non-inverting terminal (-) of the second comparator, And sensing a DC offset of the second sensing signal by comparing the second sensing signal output from the amplifying unit with a preset reference voltage input to the inverting terminal -.

Further, the step of outputting the digital control value for correcting the DC offset may include the step of outputting the digital control value to the first digital circuit module through filtering for integration and averaging of the first pulse signal output from the first comparator, Outputting a first digital control value for correcting the DC offset of the first sensing signal and filtering the second digital signal by integrating and averaging the second pulse signal output from the second comparator in the second digital circuit module And outputting a second digital control value for correcting a DC offset of the second sensing signal.

The step of correcting the direct current offset may include controlling the amount of current flowing to the first sensing node through a switching operation interlocked with the first digital control value in the first offset correction module to correct the direct current offset And correcting the direct current offset by controlling an amount of current flowing to the second sensing node through a switching operation interlocked with the second digital control value in the second offset correction module.

The offset correction circuit according to the present invention performs a process for correcting a DC offset that may be generated in a sensing signal output from an inertial sensor through a digital signal processing method, thereby correcting a nonlinear component It is possible to secure the reliability of the correction for the DC offset of the offset correction circuit.

In addition, it is possible to detect whether or not a DC offset of the first and second sensing signals output from the inertial sensor is generated, and to detect the occurrence of the DC offset when the occurrence of the DC offset is detected, 2 digital control value and thereby corrects the DC offset of the first and second sensing signals together with the control of the amount of current flowing through the sensing node of the inertial sensor so as to secure the reliability of the output of the sensing signal .

Further, a DC offset that may occur in the sensing signal is detected through the offset sensing unit, a square-wave pulse signal reflecting the DC offset is output, and the square-wave pulse signal is subjected to digital signal processing of a sigma delta ADC to correct the DC offset It is possible to simplify the configuration of the offset correction circuit than the conventional analog processing method.

1 is a block diagram of an offset correction circuit according to the present invention.
2 is a circuit diagram of an offset correction circuit according to the present invention.
3 is a diagram illustrating a process of calculating a first digital control value for correcting a DC offset with respect to a first sensing signal P 1 according to the present invention.
FIG. 4 illustrates a process of correcting a DC offset for a first sensing signal P 1 in a first offset correction module using the first digital control value of FIG. 3. Referring to FIG.
5 is a diagram illustrating a process of calculating a second digital control value for correcting a DC offset for a second sensing signal N 1 according to the present invention.
6 is a diagram illustrating a process of correcting a DC offset for a second sensing signal N 1 in a second offset correction module using the second digital control value of FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "one side,"" first, ""first,"" second, "and the like are used to distinguish one element from another, no. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, embodiments of the offset correction circuit and the control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an offset correction circuit according to the present invention. FIG. 2 is a circuit diagram of an offset correction circuit according to the present invention. The offset correction circuit 10 according to the present invention includes an inertia sensor 100, An offset detection unit 130, a digital signal processing unit 120, and an offset correction unit 110, as shown in FIG.

The inertial sensor 100 detects an inertial input applied from the outside and performs an application function using the inertial input. The inertial sensor 100 generally includes an acceleration sensor for detecting an acceleration, a gyro sensor for detecting an angular velocity, a pressure sensor for detecting a pressure, . Here, the sensing node may include a first sensing node P for outputting a first sensing signal P 1 and a second sensing node N for outputting a second sensing signal N 1 , The first and second sensing signals (P 1 , N 1 ) are 180 ° out of phase with each other.

The amplifying unit 140 may be an amplifier OP-amp that amplifies the sensing signal output from the sensing node of the inertial sensor 100 with a predetermined gain and has a predetermined gain. Here, when a DC offset occurs in the first and second sensing signals P 1 and N 1 due to a mismatch of resistance components of the inertial sensor 100, due to the amplifier, the first and second sensing The difference in the DC offset between the signals (P 1 , N 1 ) can be increased.

The offset sensing unit 130 senses whether or not a DC offset is generated in the sensing signal output from the amplifying unit 140. When the first sensing signal output from the amplifying unit 140 is a non- A first offset detection circuit 131 composed of a first comparator which is inputted to the first reference voltage V CM and a first comparator whose reference voltage V CM is inputted to the inverting terminal - And a second comparator (comparator) in which the sensing signal N 1 is input to the non-inverting terminal (+) and the reference voltage (V CM ) is input to the inverting terminal (- 132 < / RTI >

The digital signal processing unit 120 outputs a digital control value for correcting the DC offset through digital signal processing based on the signal P 3 output from the offset sensing unit 130, And outputs a first digital control value for correcting the DC offset of the first sensing signal P 1 through filtering for integration and averaging of the first pulse signal P 3 output from the first sensing signal P 1 a first of the digital circuit module 121 and the second comparator through a filter for integrating and averaging (averaging) for the the second pulse signal (N 3), output from 133, and the second sensing signal (N 1) And a second digital circuit module 122 for outputting a second digital control value for correcting the DC offset.

Further, the first digital circuit module 121 outputs the first pulse signal (P 3 ) through filtering for integration and averaging of the first pulse signal P 3 output from the first offset detection circuit 131 P 3 ) to a digital value and outputs the first digital control value, and a first register 121 a for storing the first digital control value.

The second digital circuit module 122 also receives the second pulse signal N (N) through filtering for integration and averaging of the second pulse signal N 3 output from the second offset detection circuit 132, 3 ) to a digital value and outputs the second digital control value, and a second register 122a for storing the second digital control value.

Here, the first and second registers 121a and 122a may each include at least one D flip-flop (hereinafter referred to as a DFF), and the first and second digital signal conversion modules may include a sigma delta analog digital converter (Σ △ ADC) may be a sigma delta analog to digital converter (121b) is to include a first digital integrating circuit (121b 3), a first digital comparator (121b 2) and a first digital filter (121b 1) .

The offset correction unit 110 may correct the DC offset by controlling the amount of current flowing to the sensing node through a switching operation interlocked with the digital control value generated by the digital signal processing unit 120, A first offset correction module 111 for controlling the amount of current flowing to the first sensing node through a switching operation interlocked with the first digital control value to correct the DC offset, And a second offset correction module 112 for controlling the amount of current flowing to the second sensing node through the switching operation to correct the DC offset.

When the bits of the data stored in the first and second registers 121a and 122a are n (bits), the first and second offset correction modules 111 and 112 are provided for each of the first and second registers 121a and 122a (MSB) of the data stored in the register, and the correction circuits 111a to 111c may be connected individually to each of the flip-flops. The correction circuits 111a to 111c may include (n-1) First switching circuits 111a 1 to 111c 1 and first and second switching circuits 111a 1 to 111c 1 whose switching operations are controlled by the first and second switching circuits 111a 1 to 111c 1 , 111a 2 to 111c 2 and current sources 111a 3 to 111c 3 connected to the upper and lower ends of the second switching circuit and outputting a current having a constant magnitude.

Hereinafter, a process of correcting a DC offset occurring in each sensing signal output from each sensing node of the inertial sensor will be described in detail with reference to FIGS. 3 to 6. FIG.

3 is a diagram illustrating a process of calculating a first digital control value for correcting a DC offset with respect to a first sensing signal P 1 according to an embodiment of the present invention. , And correcting the DC offset for the first sensing signal (P 1 ) in the first offset correction module.

3, a DC offset (D) is applied to the first sensing signal P 1 output from the first sensing node P due to deterioration or mismatching of the resistance component of the inertial sensor 100, 1 ) occurs (FIG. 3A), 1) the DC offset D 2 of the first sensing signal P 2 is amplified to a predetermined gain (FIG. 3B) through the amplifying unit 140, 1 offset detection circuit 131 outputs a first pulse signal P 3 whose duty ratio is determined according to the DC offset D 2 through a comparator ) The first digital signal conversion circuit 121b uses the first pulse signal P 3 to generate a first digital control value (4 bits, MSB (most significant bit) for correcting the DC offset (D 2 ) 4) the first register 121a may be formed of at least one D flip-flop, stores the first digital control value, and outputs the first digital control value Use may control the first offset correction module 111.

4, 1) the most significant bit (MSB) value ('0') of the first digital control value 0101 stored in the fourth D flip flop DFF 4 of the first register 121a, according to a second switch (111a 12 in the first switching circuit (111a 1 to 111c 1) of the first to third correction circuit (111a to 111c) To 111c 12 are turned on, and the first switches 111a 11 111c 11 ) can be turned off, and 2) the second switches 111a 12 To 111c 12) has a second switching circuit (111a 2 To according to the fourth switch (111a 22 to a digital value (0 or 1) stored in the controls 111c 22), the third to first D flip-flop (DFF 3 to DFF 1) of 111c 2), the fourth switch (111a by having on (oN) of 22 to 111c 22), the current source (111a 4 to 111c 4) through, it is possible to reduce the amount of current flowing to the first sensing node (P), a smaller voltage to the first sensing node (P) is by making, it is possible to correct the first sensed signal (P 1) DC offset (D 1) by the DC component is controlled to be equal to the common-mode voltage (V CM), it has occurred on the first sensing signal (P 1) of the.

5, due to deterioration or mismatching of the resistance component of the inertial sensor 100, a second sensing signal N 1 output from the second sensing node N is subjected to a DC offset (D 3) if the called out (Fig. 5a), 1) through the amplifying section 140, the second the DC offset of the sensed signal (N 2) (D 4) is amplified at a predetermined gain (Fig. 5b), 2 ) The second offset detection circuit 132 outputs a second pulse signal N 3 whose duty ratio is determined according to the DC offset D 4 through a comparator (FIG. 5C) , 3) the second digital signal conversion circuit 122b uses the second pulse signal N 3 to generate a second digital control value (4 bits, MSB (most significant bit)) for correcting the DC offset D 4 (FIG. 5D); 4) the second register 122a may be composed of at least one D flip-flop, and the second digital control value may be stored And, it is possible to control the second offset correction module 112, use it.

6, 1) the most significant bit (MSB) value ('1') of the first digital control value 1101 stored in the fourth D flip-flop (DFF 4 ) of the second register 122a, The first switches 112a 11 to 112c 1 in the first switching circuits 112a 1 to 112c 1 of the first to third correction circuits 112a to 112c, To 112c 11 are turned on and the second switches 112a 12 To 112c 12) may be turned off (off), 2) a first switch (112a 11 To 112c 11 control the third switches 112a 21 to 112c 21 of the second switching circuits 112a 2 to 112c 2 to output the digital value stored in the third to the first D flip flop DFF 3 to DFF 1 The amount of current flowing to the second sensing node N is increased through the current sources 112a 3 to 112c 3 by turning on the third switches 112a 21 to 112c 21 in accordance with the control signals the second by having a greater voltage on the sensing node (N) is applied, the second sensing signal is controlled so that the direct current component of (N 1) equal to the common-mode voltage (V CM), and this, the second sensing signal (N 1 through The DC offset (D 3 ) generated in the DC offset can be eliminated.

As described above, the offset correction circuit according to the present invention performs a process for correcting a DC offset that may be generated in a sensing signal output from an inertial sensor through a digital signal processing method, It is possible to minimize the occurrence of noise due to the nonlinear component that may be generated in the offset correction circuit and thereby to assure the reliability of correction of the DC offset of the offset correction circuit.

In addition, it is possible to detect whether or not a DC offset of the first and second sensing signals output from the inertial sensor is generated, and to detect the occurrence of the DC offset when the occurrence of the DC offset is detected, 2 digital control value and thereby corrects the DC offset of the first and second sensing signals together with the control of the amount of current flowing through the sensing node of the inertial sensor so as to secure the reliability of the output of the sensing signal .

While the present invention has been described in detail with reference to the specific embodiments thereof, it is to be understood that the present invention is not limited to the above-described embodiments, but the present invention is not limited thereto. It will be apparent that modifications and improvements can be made by those skilled in the art.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: offset correction circuit
100: inertia sensor 110: offset correction unit
111: first offset correction module 112: second offset correction module
120: digital signal processing unit 121: first digital circuit module
122: second digital circuit module 130: offset detection unit
131: first offset correction module 132: second offset correction module
140:

Claims (13)

An amplifier for amplifying a sensing signal output from a sensing node of the inertial sensor with a constant gain;
An offset sensing unit for sensing whether a DC offset is generated in the sensing signal output from the amplifying unit;
A digital signal processing unit for outputting a digital control value for correcting the DC offset through digital signal processing based on the signal output from the offset sensing unit; And
And an offset correcting unit for controlling an amount of current flowing to the sensing node through a switching operation interlocked with the digital control value to correct the direct current offset.
The method according to claim 1,
The sensing signal output from the sensing node
And a first and a second sensing signal having a mutual phase difference of 180 degrees,
The offset sensing unit
A first offset sensing circuit having a first comparator whose first sensing signal output from the amplifying unit is input to a non-inverting terminal (+) and a predetermined reference voltage is input to an inverting terminal (-); And
And a second comparator (comparator) in which the second sensing signal output from the amplifying unit is input to the non-inverting terminal (+) and the reference voltage is input to the inverting terminal (-) Offset correction circuit.
The method of claim 2,
The digital signal processing unit
A first digital circuit module for outputting a first digital control value for correcting the DC offset of the first sensing signal through filtering for integration and averaging of the first pulse signal output from the first comparator, ; And
A second digital circuit module for outputting a second digital control value for correcting the DC offset of the second sensing signal through filtering for integrating and averaging the second pulse signal output from the second comparator; ≪ / RTI >
The method of claim 3,
The first digital circuit module
A first offset detection circuit for converting the first pulse signal into a digital value through filtering for integration and averaging of the first pulse signal output from the first offset detection circuit, A digital signal conversion circuit and a first register for storing the first digital control value,
The second digital circuit module
The second pulse signal is converted into a digital value through filtering for integration and averaging of the second pulse signal output from the second offset detection circuit, A digital signal conversion circuit and a second register for storing the second digital control value.
The method of claim 4,
The offset correcting unit
A first offset correction module for controlling the amount of current flowing through the first sensing node through a switching operation interlocked with the first digital control value to correct the DC offset;
And a second offset correction module for controlling the amount of current flowing to the second sensing node through a switching operation interlocked with the second digital control value to correct the DC offset.
The method of claim 5,
The first and second registers
Each of the at least one D flip-flop.
The method of claim 5,
The first and second offset correction modules
And (n-1) correction circuits respectively connected to the first and second registers when the bits of data to be stored in the first and second registers are n (bits).
The method of claim 7,
The correction circuit
A first switching circuit which is connected to each of the plurality of flip-flops and whose switching operation is controlled by the most significant bit (MSB) of data stored in the register;
A second switching circuit connected to the first switching circuit, the switching operation being controlled by the D flip-flop; And
And a current source connected to upper and lower ends of the second switching circuit and outputting a current having a predetermined magnitude.
The method of claim 8,
The first and second digital signal conversion modules
An offset correction circuit that is a sigma-delta analog-to-digital converter (ΣΔ ADC).
Amplifying a sensing signal output from the sensing node of the inertial sensor with a predetermined gain;
Detecting whether a DC offset is generated in the sensing signal output from the amplifying unit in the offset sensing unit;
Outputting a digital control value for correcting the DC offset through digital signal processing based on a signal output from the offset sensing unit in a digital signal processing unit; And
And correcting the DC offset by controlling an amount of current flowing to the sensing node through a switching operation interlocked with the digital control value in the offset correction unit.
The method of claim 10,
The step of detecting whether or not the DC offset has occurred
The first offset sensing circuit compares the first sensing signal, which is input to the non-inverting terminal (+) of the first comparator, with the predetermined reference voltage input to the inverting terminal (-), Sensing a DC offset of the first sensing signal; And
The second sensing signal is input to the non-inverting terminal (+) of the second comparator in the second offset sensing circuit and the second sensing signal outputted from the amplifying unit is compared with the predetermined reference voltage input to the inverting terminal And sensing a DC offset of the second sensing signal.
The method of claim 11,
The step of outputting the digital control value for correcting the DC offset
The first digital circuit module outputs a first digital control value for correcting the DC offset of the first sensing signal through filtering for integration and averaging of the first pulse signal output from the first comparator ; And
A second digital control module outputs a second digital control value for correcting the DC offset of the second sensing signal through filtering for integration and averaging of the second pulse signal output from the second comparator in the second digital circuit module The offset correction circuit comprising:
The method of claim 12,
The step of correcting the DC offset
Controlling an amount of current flowing to the first sensing node through a switching operation interlocked with the first digital control value in the first offset correction module to correct the DC offset;
And controlling the amount of current flowing to the second sensing node through a switching operation interlocked with the second digital control value in the second offset correction module to correct the DC offset. .
KR1020140014357A 2014-02-07 2014-02-07 Circuit for correcting off-set and controlling method thereof KR20150093498A (en)

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