KR101936381B1 - Method for testing back-EMF detection function of a vibration motor driving IC and device for the same - Google Patents

Abstract

A driving chip testing device is disclosed. The driving chip testing device provides a driving current to an actuator which generates a back EMF during operation through two current output terminals, detects the natural frequency of the actuator, and tests whether a driving chip for changing the waveform of the driving current according to the natural frequency operates normally.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of testing a back EMF detection function of a vibration motor IC,

The present invention relates to a testing apparatus for an IC, and more particularly to an apparatus for detecting whether an IC driving a vibration motor detects a Back EMF of a vibration motor and operates accordingly.

Electronic devices have a variety of interfaces for users. Some interfaces may provide vibration feedback to the user.

In order to generate a vibration effect, an LRA (linear resonance actuator) can be used. The LRA includes a spring, a mass portion attached to the spring, a magnetic body integrally formed with the mass portion or moving together with the mass portion, and an inductor coil for transferring drive energy. The mass portion may be driven to move back and forth. The LRA has its own resonance frequency.

According to one embodiment, in order to create a vibration effect, the electronic device may provide a driving cycle that includes a driving period and a monitoring period. During the driving period, the electronic device applies a plurality of driving pulses to the LRA, and during the monitoring interval, a signal corresponding to a back EMF formed by the position of the mass portion or the motion of the magnetic body may be received from the LRA.

1 schematically illustrates a structure of a driving chip 16 used in an embodiment of the present invention and a user equipment 10 including the same. Hereinafter, the driving chip may be referred to as a vibration motor IC.

The driving chip 16 according to an embodiment of the present invention is connected to the processor 12 so that its operation can be controlled by the processor. A memory 20 is connected to the processor 12. The driving chip 16 is connected to an actuator 18 for generating a Back EMF like the LRA. According to an embodiment of the present invention, a user equipment 10 including the above devices and screens and other user interfaces may be provided.

The processor 12 may be a general purpose processor or an ASIC. The processor may determine, based on the upper parameters, what vibration effect should be generated. In general, the upper parameters may define a particular vibration effect, including magnitude, frequency and duration. Lower parameters such as streaming commands may be used to produce a particular vibration effect. The vibrational effect may be considered dynamic when such vibrational effects include some variations in these parameters as they are created, or variations are included in these parameters based on user interaction.

The processor 12 provides a control signal to the drive chip 16. The drive chip 16 includes electronic components and circuitry used to provide the actuator 18 with the necessary current and voltage to produce the required vibrational effect.

The memory 20 may be any type of storage device such as RAM, ROM, or the like, and may be a computer-readable medium. The memory 20 may include executable code executed by the processor 12. The memory 20 may be included in the processor 12, or may be external to the processor 12.

Among the execution codes are a code for causing the processor 12 to generate a drive signal for the actuator 18 and a code for determining the resonance frequency of the actuator 18 and for modifying the period of the drive signal to match the resonance frequency Code may be included.

The user device 10 may be an electronic device for a user, such as a smart phone, a PDA, a tablet, or an electronic device for a portable user. The user device 10 may include a user interface such as a mouse, a touch screen 11, a keyboard, a joystick, a scroll wheel, and a trackball.

The user device 10 may include one or more actuators, and the unique resonance frequencies of the actuators may be different from each other.

Only one actuator may be included in the user device 10, and the natural resonance frequency of the actuator may slightly differ from one user device to another.

2 is a cross-sectional view of an LRA that can be used as an actuator included in the user equipment 10 used in an embodiment of the present invention.

The LRA 18 may include a housing 25, a magnetic body / mass 27, a spring 26, and a coil 28 having an inductance. The magnetic body / mass body 27 is installed in the housing 25 by a spring 26. [ The coil 28 may be installed directly below the bottom of the housing 25 below the magnet / mass 27. When a current flows through the coil 28, a magnetic field is formed around the coil 28 and the magnetic field interacts with the magnetic field from the magnetic body / mass 27 to push or pull the magnetic body / mass 27. The magnetic body / mass body 27 is pushed when the current direction is the first direction, and the magnetic body / mass body 27 is pulled when the current direction is the second direction. The spring 26 controls the movement of the magnetic body / mass 27. When the current does not flow through the coil 28, the magnetic body / mass 27 is in the zero-crossing position or the neutral position.

The resonance frequency of the LRA 18 is determined mainly by the magnetic body / mass 27 and the spring 26, but is changed by the environment in which the LRA 18 is placed. That is, when the user equipment including the LRA 18 is placed on a soft cushion, the resonance frequency may change according to an environment such as being placed on a hard surface or being held tightly by a person.

The process of generating the vibration effect is efficient when executed depending on the resonance frequency on the premise that the intrinsic resonance frequency of the actuator is fixed. However, if the natural resonance frequency is not constant, the process of generating the vibration effect is preferably modified accordingly.

The driving chip 16 used in one embodiment of the present invention is adapted to determine the resonant frequency of the LRA 18 continuously and dynamically.

An example of a method for dynamically determining the resonant frequency of an LRA is disclosed in U.S. Patent No. 8,994,518.

US 8,994,518 discloses a method of using a sensor for detecting the position of a magnetic substance / mass 27 as a sensor installed separately in the LRA. However, the drive chip 16 according to the present invention is different from the magnetic substance / And the resonance frequency of the LRA is dynamically determined using the Back EMF generated by the coil 28 by the coil 28. [

Such a method of dynamically determining the resonant frequency of the LRA has already been demonstrated and there may be other methods other than those disclosed in US 8,994,518.

The present invention provides a technique for testing whether a driving chip adapted to operate at a resonance frequency of an actuator operates normally.

The present invention provides a technique for checking whether the driving chip can operate in accordance with the natural resonance frequency of the actuator by using a test apparatus that simulates a part of the operation of the actuator before connecting the actuator to the produced driving chip.

According to an aspect of the present invention, there is provided an actuator for generating a back EMF during operation, the actuator being provided with a driving current through two current output terminals, detecting a natural frequency of the actuator, It is possible to provide a driving chip inspection method in which the driving chip inspection apparatus inspects the driving chip which is adapted to change the waveform of the driving chip. At this time, the driving chip testing apparatus may include two input / output terminals (T1, T2) connected to the two current output terminals. In the driving chip testing method, the driving chip testing device outputs a test signal periodically generating zero-crossing according to a predetermined first period or a first frequency through the two input / output terminals (T1, T2) Wherein the driving chip testing apparatus determines a second period or a second frequency of the driving current outputted from the driving chip, and the driving chip testing apparatus further comprises: The driving chip is determined to be operating normally if the second frequency is substantially equal to the first frequency or the second period is equal to the first period within a predetermined time, And determining whether to do so.

According to an aspect of the present invention, there is provided an actuator for generating a back EMF during operation, the actuator being provided with a driving current through two current output terminals, detecting a natural frequency of the actuator, It is possible to provide a driving chip inspection apparatus for inspecting a driving chip which is adapted to change the waveform of the driving chip. The driving chip testing apparatus may include two input / output terminals T1 and T2 connected to the two current output terminals, respectively. The driving chip testing apparatus is configured to output a test signal through the two input / output terminals (T1, T2) periodically generating a zero crossing according to a predetermined first period or a first frequency, And the second frequency is substantially equal to the first frequency or within a predetermined time from the time when the generation of the test signal is started, Or if the second period is equal to the first period, it is determined that the driving chip operates normally, otherwise, the driving chip may be determined to malfunction.

According to another aspect of the present invention, there is provided an actuator for generating a back EMF during operation, the actuator being provided with a driving current through two current output terminals, detecting a natural frequency of the actuator, It is possible to provide a driving chip inspection apparatus for inspecting a driving chip which is adapted to change the waveform of the driving chip. At this time, the driving chip testing apparatus includes two input / output terminals T1 and T2 connected to the two current output terminals, a test signal periodically generating a zero crossing according to a predetermined first period or a first frequency, A pulse train driving unit 110 for outputting through the two input / output terminals T1 and T2, an impedance unit through which the drive current outputted from the driving chip passes, and a detection signal generated by detecting a voltage across the impedance unit And a second frequency detecting unit for detecting a second frequency or a second frequency of the driving current based on the detection signal and outputting the detected second frequency or the second frequency within a predetermined time from a time when the generation of the test signal is started, Or if the second period is equal to the first period, it is determined that the driving chip is normally operated, And may be configured to determine that the driving chip is malfunctioning.

The processor may include a pulse train frequency selector 131 for determining the first period or the first frequency and transmitting the determined first period or first frequency to the pulse train driving unit, A driving chip output signal frequency determining unit 133 for determining a second period or a second frequency of the driving current, and a driving chip output signal frequency determining unit 133 for determining whether the second frequency is higher than the first frequency (132) that determines that the driving chip normally operates if the first period becomes substantially the same as the first period, or determines that the driving chip malfunctions if the second period becomes equal to the first period .

At this time, the voltage detector may be configured to output a signal generated by low-pass filtering the voltage across the impedance section as the detection signal.

According to the present invention, there is provided a technique for checking whether or not the drive chip can operate in accordance with the natural resonance frequency of the actuator by using a test apparatus that simulates a part of the operation of the actuator before connecting the actuator to the produced drive chip Can be provided.

FIG. 1 briefly illustrates a structure of a driving chip and a user equipment including the driving chip used in an embodiment of the present invention.
2 is a cross-sectional view of an LRA that can be used as an actuator included in a user equipment used in an embodiment of the present invention.
FIG. 3 shows a state in which a driving chip and an actuator are connected according to an embodiment of the present invention.
FIG. 4 is a time chart depicting the shape of the driving current shown in FIG. 3 and the displacement of the magnetic body / mass body.
FIG. 5A shows a usage state of a driving chip inspection apparatus and a driving chip inspection apparatus provided according to an embodiment of the present invention, FIG. 5B shows a structure of a pulse train driving unit and a structure of a voltage detection unit in the circuit shown in FIG. .
6 shows a modification of the configuration of the pulse train driver in the circuit shown in FIG. 5A.
7 is a flowchart illustrating a driving chip testing method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein, but may be implemented in various other forms. The terminology used herein is for the purpose of understanding the embodiments and is not intended to limit the scope of the present invention. Also, the singular forms as used below include plural forms unless the phrases expressly have the opposite meaning.

FIG. 3 shows a state in which a driving chip and an actuator are connected according to an embodiment of the present invention.

The first output terminal OUTP and the second output terminal OUTN of the drive chip 16 are capable of providing a drive current I that is changed in direction with time to the coil 28 included in the actuator 18 have. The magnetic body / mass body 27 can reciprocate in the z-axis direction by the interaction between the magnetic field generated by the drive current I flowing through the coil 28 and the magnetic field generated by the magnetic body / mass body 27. Also, due to the interaction of the moving magnet / mass 27 with the coil 28, so-called Back EMFs known in the art can be generated, so that the voltage across the coil 28 is induced by the Back EMF The voltage can be reflected.

The PWM signals PWM1 and PWM2, which are control signals for generating the drive current I, may be input to the input terminal of the drive chip 16. [ The PWM signal may be generated and provided in the central processing unit 12 of the user equipment 10 on which the driving chip 16 is mounted.

The driving chip 16 may include four MOSFETs M1, M2, M3, and M4 operated by the PWM signal. The four MOSFETs may form an H-bridge circuit.

There are conventional techniques for controlling the H-bridge circuit using the PWM signal to cause the current to flow to the coil 28 connected to the bridge portion of the H-bridge circuit, and the present invention is not limited by the specific technology. The internal structure of the driving chip 16 shown in FIG. 3 is briefly described to facilitate understanding of the present invention, and the present invention is not limited by the embodiment of FIG.

 Fig. 4 is a time-depiction of the shape of the driving current I shown in Fig. 3 and the displacement of the magnet / mass body 27. Fig.

The horizontal axis in Fig. 4 represents time. Reference numeral 504 denotes the value of the drive current (I) in FIG. 3, and reference numeral 506 denotes the displacement of the magnetic body / mass 27. The displacement of the magnetic substance / mass body 27 is based on the assumption that a sensor capable of measuring the displacement of the magnetic substance / mass body 27 is provided in the actuator 18.

In an embodiment of the present invention, such a sensor may not be installed at the displacement of the magnetic body / mass 27. In this case, the waveforms shown in Fig. 4 can still be used to help understand the present invention.

Referring to Figure 4 (a), the actuator may be in either the oscillating state (Pd) or the dormant state (Pr). The idle state means that the actuator does not vibrate.

Referring to FIG. 4 (b), the vibration state Pd may be divided into a driving period Pd1 and a brake period Pd2.

The drive chip 16 feeds a drive current I to the actuator 18 for giving a desired vibration effect to the drive section Pd1 and the drive section 16 supplies the drive current I to the actuator section 18 after the drive of the desired vibration effect is completed in the brake section Pd2. / The mass (27) to the actuator (18).

4 (b), the drive chip 16 drives the first output terminal OUTP and the second output terminal OUTN of the drive chip 16 to a floating state while the drive current I has a value of 0 It can be. At this time, a time period in which the drive current (I) has a value of 0 may be referred to as a floating period in this specification. It can be confirmed that a pulse of the driving current I having a positive value or a pulse of the driving current I having a negative value exists between the floating intervals.

As a technique for detecting the back EMF, techniques already disclosed before the present patent application can be used.

The driving chip 16 may measure the back EMF of the actuator 18 during the floating interval present between adjacent pulses to detect the natural frequency of the actuator 18. [

Alternatively, the driving chip 16 may measure the back EMF of the actuator 18 detected at the start of the idle state Pr to detect the natural frequency of the actuator 18. To this end, the brake section Pd2 may be terminated before the actuator 18 completely stops operating. Since the magnetic body / mass 27 still holds a weak vibration state for a while after the end of the brake section Pd2, the back EMF can still be detected even after the brake section Pd2 ends.

In FIG. 4 (b), the pulse waveform of the drive current I having a positive value between the floating intervals is shown as being close to the step waveform, but it may have a shape close to a sine wave in some embodiments .

FIG. 4C shows an example of the waveform of any one of the PWM signals PWM1 and PWM2 in the period of time when the current pulse is generated in FIG. 4B. 4 (c), the duty of the PWM signal changes.

FIG. 5A shows the use state of the driving chip testing apparatus 1 and the driving chip testing apparatus 1 provided according to an embodiment of the present invention.

The driving chip testing apparatus 1 may include two input / output terminals T1 and T2. The driving chip testing apparatus 1 may include a pulse train driving unit 110, a voltage detecting unit 120, and a processing unit 130. The two input / output terminals T1 and T2 can be connected to the two current output terminals OUTP and OUTN of the driving chip 16. [ An impedance portion Z such as a resistor may be provided between the two input / output terminals T1 and T2.

The pulse train driving unit 110 may generate a test voltage Vsb varying with time and output the same through two output terminals O_P and O_N. The two output terminals O_P and O_N are connected to the two input / output terminals T1 and T2. The test voltage Vsb may have a waveform having a waveform having a predetermined first period and having a shape periodically alternating between the first maximum level and the second minimum level.

In one embodiment, the test voltage Vsb may be a rectangular wave.

The voltage detector 120 includes two input terminals I_P and I_N and two input terminals I_P and I_N are connected to the two input and output terminals T1 and T2. The voltage detector 120 can receive a voltage between the two input / output terminals T1 and T2 via two input terminals I_P and I_N. The voltage detector 120 may include a low-pass filter (LPF) for leaving only the low frequency components of the voltage waveform detected by the two input / output terminals T1 and T2. The low pass filter (LPF) may be provided in an analog manner or may be provided in a digital manner. The voltage detector 120 may convert the low-pass filtered signal into a digital sequence and provide it to the driving chip output signal frequency detector 133 of the processor 130.

The processing unit 130 may include a pulse train frequency selection unit 131, a frequency comparison unit 132, and a driving chip output signal frequency detection unit 133. The processing unit 130 transmits a command to the pulse train driving unit 110 and performs a low pass filtering on a signal detected from the two input / output terminals T1 and T2 or a signal detected from the two input / output terminals T1 and T2 A signal can be received from the voltage detector 120. [

The pulse train frequency selection unit 131 may determine a first period of a signal to be generated by the pulse train driving unit 110 and may transmit the determined first period to the pulse train driving unit 110. [ Also, the determined first period may be used in the frequency comparator 132.

The driving chip output signal frequency detector 133 can detect the second period which is the period of the waveform of the current output from the two current output terminals OUTP and OUTN of the driving chip 16. [

The frequency comparator 132 compares the drive current I (I) output from the drive chip 16 within a predetermined period of time from when the pulse train driver 110 starts outputting the test signal (ex: test voltage, test current) Can be determined to be equal to the second period of the test voltage Vsb output from the pulse train driver 110. [ If it is determined that the driving chip 16 operates normally when the first period becomes equal to the second period within the predetermined period and if the first period does not become equal to the second period within the predetermined period It can be determined that the driving chip 16 malfunctions.

The period of the driving current at the first time point at which the driving current I is output from the driving chip 16 can be independently determined irrespective of the first period of the test signal.

The voltage between the two input / output terminals T1 and T2 can be substantially determined by the driving current I in a time period in which the driving current I has a value other than zero.

The voltage between the two input / output terminals T1 and T2 can be determined by the test voltage Vsb outputted from the pulse train driving unit 110 in the time interval having the value of the drive current I being zero.

The driving chip 16 can output the driving current I such that the driving current I initially has a predetermined fundamental frequency at the start of the operation. The driving chip 16 is driven by a predetermined DC voltage at a voltage detected through the two current output terminals OUTP and OUTN in a time period having a value of the driving current I when the driving chip 16 is operated. It is possible to detect whether or not zero crossing based on the voltage is generated, and adjust the period of the drive current I based on the detected zero crossing. That is, the drive chip 16 can control the period of the drive current I to be equal to the determined generation period after determining the occurrence period of the zero crossing. It is not a simple assumption that the driving chip is adapted to perform such a function, but its implementation has already been proved by the prior art.

When the driving chip 16 supplies current to the actuator in a state where the driving chip 16 is mounted on the actual user equipment, the detection voltage detected through the two current output terminals OUTP and OUTN during a rest period in which the supply of the current is temporarily stopped is It is the back EMF signal of the actuator. In contrast, in the test method shown in FIG. 5A, the test voltage Vsb output from the pulse train driver 110 replaces the role of the back EMF signal.

5B shows an example of the structure of the pulse train driving unit 110 and the structure of the voltage detecting unit 120 in the circuit shown in FIG. 5A.

The pulse train driving unit 110 may include a first resistor R1 and a second resistor R2 connected to the output terminals O_P and O_N. The first resistor and the second resistor may have the same value and may have a value of several tens of ohms. A square wave voltage Vrect may be applied between the first resistor and the second resistor.

The voltage detector 120 includes a first low-pass filter including a third resistor R3 and a first capacitor C1 and a second low-pass filter including a fourth resistor R4 and a second capacitor C2 Can be. The differential voltage output from the two low-pass filters may be directly input to the driving chip output signal frequency detector 133, or a value obtained by converting the differential voltage to a single-ended voltage may be input.

FIG. 6 shows a modification of the configuration of the pulse train driving unit 110 in the circuit shown in FIG. 5A.

The pulse train driver 110 may include a current source that generates a test current It that is predetermined or generates a zero crossing according to a first fundamental frequency indicated by the processing unit 130. [ The test current It may preferably be a spherical file having a first period according to the first fundamental frequency. However, the test current It is not limited to a square wave, but may be any waveform that periodically generates a zero crossing according to the first fundamental frequency.

The voltage between the two current output terminals OUTP and OUTN in the time interval in which the value of the driving current I outputted from the driving chip 16 is 0 is smaller than the voltage between the two current output terminals OUTP and OUTN, Lt; / RTI >

The voltage sensed by the two current output terminals OUTP and OUTN in the time period when the driving current I is not 0 is a voltage generated when the driving current I is generated at both ends of the impedance Z The first voltage and the test current It are the sum of the second voltages generated at both ends of the impedance section Z. At this time, the average value of the absolute values of the driving current I can be designed to be significantly larger than the average value of the absolute values of the test current It. In this case, the voltage between the two input / output terminals T1 and T2 detected by the voltage detecting unit 28 is mostly driven by the driving current I, and may be hardly affected by the test current It. Nevertheless, even if the absolute value of the test current It is very small, the driving chip 16 can detect the second voltage generated at both ends of the impedance section Z by the test current It It can be designed.

Hereinafter, a method of testing the driving chip 16 according to an embodiment of the present invention will be described with reference to FIG.

7 is a flowchart illustrating a driving chip testing method according to an embodiment of the present invention.

The two current output terminals OUTP and OUTN of the driving chip 16 are connected to the two input and output terminals T1 and T2 of the driving chip testing apparatus 1 in step S110.

In step S120, the driving chip testing apparatus 1 applies power to the driving chip 18 and operates the driving chip 16 in the test mode.

In step S130, the driving chip testing apparatus 1 generates a test signal Vsb or It which periodically generates a zero crossing according to a predetermined first fundamental frequency through the two input / output terminals T1 and T2 Output continuously.

The driving chip inspecting device 1 determines the second fundamental frequency of the driving current I outputted through the two current output terminals OUTP and OUTN in the driving chip 18 in step S140. The second fundamental frequency may be updated and determined according to a predetermined period.

In step S150, the driving chip testing apparatus 1 determines whether or not the second fundamental frequency is substantially equal to the first fundamental frequency within a first predetermined time after the point in time when the test signal is generated .

In step S160, if the drive chip inspection apparatus 1 determines that the drive chip 18 normally operates when the second fundamental frequency is substantially equal to the first fundamental frequency within the predetermined first time period And otherwise determines that the driving chip 18 malfunctions.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the essential characteristics thereof. The contents of each claim in the claims may be combined with other claims without departing from the scope of the claims.

1: driving chip inspection device
16: driving chip
18: Actuator
110: Pulse train driving part
120: Voltage detector
130:
131: Pulse train frequency selector
132: Frequency comparator
133: driving chip output signal frequency determining unit
I: drive current
It: Test signal
OUTP, OUTN: Current output terminal
T1, T2: I / O terminal
Z: Impedance part

Claims (5)

Wherein the actuator is configured to provide a drive current through two current output terminals to an actuator that generates a back EMF during operation and to drive the actuator to change the waveform of the drive current according to the natural frequency of the actuator, A method for inspecting a chip by a driving chip inspection apparatus,
Wherein the driving chip testing apparatus includes two input / output terminals respectively connected to the two current output terminals,
Outputting a test signal through the two input / output terminals to periodically generate a zero crossing according to a predetermined first period or a first frequency;
Wherein the driving chip inspection apparatus comprises: a step of determining a second period or a second frequency of the driving current outputted from the driving chip; And
The driving chip inspection apparatus may further comprise a driving chip inspecting device which, when the second frequency becomes equal to the first frequency or the second period becomes equal to the first period within a predetermined time from the time when the generation of the test signal starts, Determining that the chip is operating normally, otherwise determining that the driving chip is malfunctioning
/ RTI >
Driving chip inspection method. Wherein the actuator is configured to provide a drive current through two current output terminals to an actuator that generates a back EMF during operation and to drive the actuator to change the waveform of the drive current according to the natural frequency of the actuator, A driving chip inspection apparatus for inspecting a chip,
And two input / output terminals respectively connected to the two current output terminals,
Outputting a test signal periodically generating a zero crossing according to a predetermined first period or a first frequency through the two input / output terminals,
A second period or a second frequency of the driving current outputted from the driving chip is detected and determined,
It is determined that the driving chip normally operates if the second frequency is equal to the first frequency or the second period becomes equal to the first period within a predetermined time from the time when the generation of the test signal starts Or otherwise determine that the drive chip is malfunctioning,
Driving chip inspection device. Wherein the actuator is configured to provide a drive current through two current output terminals to an actuator that generates a back EMF during operation and to drive the actuator to change the waveform of the drive current according to the natural frequency of the actuator, A driving chip inspection apparatus for inspecting a chip,
Two input / output terminals respectively connected to the two current output terminals;
A pulse train driver for outputting a test signal periodically generating a zero crossing according to a predetermined first period or a first frequency through the two input / output terminals;
An impedance unit through which the driving current outputted from the driving chip passes;
A voltage detection unit for detecting a voltage across the impedance unit and outputting a detection signal;
Determining whether the second frequency is equal to the first frequency or not within a predetermined time from the time when the generation of the test signal is started from the detection signal, A processor for determining that the driving chip normally operates if the period becomes equal to the first period, and otherwise determines that the driving chip malfunctions;
/ RTI >
Driving chip inspection device. The method of claim 3,
Wherein,
A pulse train frequency selection unit for determining the first period or the first frequency and delivering the determined first period or first frequency to the pulse train driving unit;
A driving chip output signal frequency determining unit for determining a second period or a second frequency of the driving current from the detected voltage; And
It is determined that the driving chip normally operates if the second frequency is equal to the first frequency or the second period becomes equal to the first period within a predetermined time from the time when the generation of the test signal starts And determines that the drive chip malfunctions,
/ RTI >
Driving chip inspection device. The driving chip inspection apparatus according to claim 3, wherein the voltage detecting section is configured to output a signal generated by low-pass filtering the voltage across the impedance section as the detection signal.

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