KR102369444B1 - Self ckeck circuit and touch sensing device having the same - Google Patents

Abstract

A touch sensing device according to an embodiment of the present invention is a touch sensing device applicable to an electronic device including a touch switch unit having at least one first touch member formed in a housing, wherein the first touch member is disposed inside the first touch member. a first sensing inductor disposed; a first capacitor electrically connected to the first sensing inductor; an oscillation circuit including the first sensing inductor and the first capacitor, the oscillation circuit generating an oscillation signal having a variable frequency according to a touch input (touch-contact or touch-force) through the touch switch unit; a reference signal generation circuit generating a reference signal corresponding to a reference clock and outputting the reference signal to the signal processing unit; a signal processing unit for detecting the presence or absence of a touch input using the oscillation signal and the reference signal and outputting a touch detection signal; and a self-check circuit for providing a check signal by checking whether at least one of the oscillation signal and the reference signal is normal. includes

Description

Self-check circuit, touch sensing device and electronic device having same

The present invention relates to a self-check circuit, a touch sensing device having the same, and an electronic device.

In general, thinner, simpler, and cleaner designs are preferred for wearable devices, and the conventional mechanical switches are disappearing accordingly. This is becoming possible with the implementation of dustproof and waterproof technology and the development of a model with a sense of unity with a smooth design.

Currently, ToM (touch on metal) technology that touches metal, capacitor sensing method using a touch panel, MEMS (Micro-Electro-Mechanical-System), and micro strain gauge technology are being developed. Furthermore, the force touch function is also being developed.

In the case of the existing mechanical switch, a large size and space are required internally to realize the switch function. The downside is that you need it.

In addition, there is a risk of electric shock due to direct contact of a mechanical switch that is electrically connected, and in particular, there is a disadvantage in that it is difficult to prevent dust and water from the structure of the mechanical switch.

In order to solve this disadvantage, an electronic touch switch device is being developed, and the electronic touch device may include a circuit for generating a reference signal or an oscillation signal, and can check whether an operation error for this circuit is performed by itself. A function or circuit that exists is required.

(Prior art literature)

(Patent Document 1) KR Patent Publication No. 10- 2013-0136358 A (2013.12.12)

(Patent Document 2) KR Patent Publication No. 10- 2013-0123068 A (2013.11.12)

An embodiment of the present invention proposes a self-check circuit capable of performing a self-check function for an internal circuit in an electronic switch device replacing a mechanical switch, a touch sensing device having the same, and an electronic device.

According to an embodiment of the present invention, there is provided an edge detector for outputting an edge detection signal having a short pulse generated when an edge of a pulse signal having a pulse train is detected; a charging/discharging circuit for generating a detection voltage by performing a charging operation and a discharging operation based on the edge detection signal; and a comparison circuit configured to output a check signal by checking whether the pulse signal is normal based on the detected voltage. A self-check circuit including

In addition, according to another embodiment of the present invention, in the touch sensing device applicable to an electronic device including a touch switch unit having at least one first touch member formed in a housing, disposed inside the first touch member a first sensing inductor; a first capacitor electrically connected to the first sensing inductor; an oscillation circuit including the first sensing inductor and the first capacitor, the oscillation circuit generating an oscillation signal having a variable frequency according to a touch input (touch-contact or touch-force) through the touch switch unit; a reference signal generation circuit generating a reference signal corresponding to a reference clock and outputting the reference signal to the signal processing unit; a signal processing unit for detecting the presence or absence of a touch input using the oscillation signal and the reference signal and outputting a touch detection signal; and a self-check circuit for providing a check signal by checking whether at least one of the oscillation signal and the reference signal is normal. A touch sensing device including

In addition, according to another embodiment of the present invention, the touch switch unit having at least one first touch member formed in the housing; a first sensing inductor disposed inside the first touch member; a first capacitor electrically connected to the first sensing inductor; an oscillation circuit including the first sensing inductor and the first capacitor, the oscillation circuit generating an oscillation signal having a variable frequency according to a touch input (touch-contact or touch-force) through the touch switch unit; a reference signal generation circuit generating a reference signal corresponding to a reference clock and outputting the reference signal to the signal processing unit; a signal processing unit for detecting the presence or absence of a touch input using the oscillation signal and the reference signal and outputting a touch detection signal; and a self-check circuit configured to provide a test result signal by checking whether the oscillation signal from the oscillation circuit and the reference signal from the reference signal generating circuit are normal. An electronic device including a

According to an embodiment of the present invention, in a touch sensing device that is an electronic switch device replacing a mechanical switch, it is possible to check whether a circuit generating a reference signal or an oscillation signal is operating normally.

Accordingly, there is an advantage in that it is possible to identify the cause of a malfunction or malfunction of the touch sensing device, and a prompt response is possible.

1 is an exemplary view illustrating the appearance of an electronic device and a touch sensing device according to an embodiment of the present invention.
FIG. 2 is an exemplary view of an electronic device and a touch sensing device having a cross-sectional structure taken along line II′ of FIG. 1 .
3 is an exemplary diagram of a touch sensing device according to an embodiment of the present invention.
4 is an exemplary diagram of an oscillation circuit having a variable capacitance when a touch-contact is applied.
5 is an exemplary diagram of an oscillation circuit having a variable inductance when a touch-force is applied.
6 is a block diagram of the self-check circuit of FIG. 2 .
FIG. 7 is a first exemplary diagram of the self-check circuit of FIG. 6 .
FIG. 8 is a second exemplary diagram of the self-check circuit of FIG. 6 .
FIG. 9 is a first exemplary diagram of the first inspection circuit of FIG. 3 .
FIG. 10 is a first exemplary diagram of the second inspection circuit of FIG. 3 .
11 is a second exemplary diagram of the first inspection circuit of FIG. 3 .
12 is a second exemplary diagram of the second inspection circuit of FIG. 3 .
13 is a waveform diagram of main signals and voltages of the first inspection circuit of FIG. 9 .
FIG. 14 is a waveform diagram of main signals and voltages of the second inspection circuit of FIG. 10 .

Hereinafter, it should be understood that the present invention is not limited to the described embodiments, and various changes may be made without departing from the spirit and scope of the present invention.

In addition, in each embodiment of the present invention, the structure, shape, and numerical value described as an example are only examples for helping the understanding of the technical matters of the present invention, and thus the spirit and scope of the present invention are not limited thereto. It should be understood that various changes may be made without departing from it. The embodiments of the present invention may be combined with each other to form various new embodiments.

In addition, in the drawings referenced in the present invention, components having substantially the same configuration and function will be denoted by the same reference numerals in light of the overall content of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily practice the present invention.

1 is an exemplary view illustrating the appearance of an electronic device and a touch sensing device according to an embodiment of the present invention.

Referring to FIG. 1 , an electronic device 10 to which the present invention can be applied may include a touch screen 11 , a housing 100 , and a touch switch unit TSW.

The touch switch unit TSW may include a first touch member TM1 and a second touch member TM2 formed in the housing to replace the mechanical button. Although the first touch member TM1 and the second touch member TM2 are illustrated in FIG. 1 , the present invention is not limited thereto, and the touch switch unit TSW may include at least one first touch member TM1 . can

For example, referring to FIG. 1 , the electronic device 10 may be a portable mobile device, such as a smart phone, or a wearable device, such as a smart watch, and is not limited to a specific device. It may be a portable or wearable electronic device, or an electronic device having a switch for operation control.

The housing 100 may be an outer case exposed to the outside of the electronic device. For example, when the touch sensing device is applied to a mobile device, the housing 100 may be a cover disposed on a side (side) of the electronic device 10 . For example, the housing 100 may be formed integrally with the cover disposed on the rear surface of the electronic device 10 , or may be separately manufactured and combined with the cover disposed on the rear surface of the electronic device 10 .

For example, referring to FIG. 1 , the touch switch unit TSW may be disposed on the cover of the electronic device. In this case, the cover is a cover other than the touch screen, for example, a side cover, a rear cover, It may be a cover that may be formed on a part of the front surface, and for convenience of description, a case in which the housing is disposed on a side cover of an electronic device will be described as an example of the housing, but the present invention is not limited thereto.

For each drawing of the present invention, unnecessary redundant descriptions of components having the same reference numerals and the same functions may be omitted, and possible differences may be described for each drawing.

FIG. 2 is an exemplary view of an electronic device and a touch sensing device having a cross-sectional structure taken along line II′ of FIG. 1 .

Referring to FIG. 2 , an electronic device according to an embodiment of the present invention may include a housing 100 , a touch switch unit TSW, and a touch sensing device.

The touch switch unit TSW may include a first touch member TM1 formed in the housing 100 of the electronic device. 2 and later, the touch switch unit TSW may be illustrated and described as including one first touch member TM1, but the present invention is not limited thereto. It may include a touch member.

The touch sensing device includes a first sensing inductor LE1 , a first capacitor CE1 , an oscillation circuit 500 , a reference signal generating circuit 600 , a signal processing unit 700 , and a self-check circuit 800 . can do.

The first sensing inductor LE1 may be disposed inside the first touch member TM1 (ie, inside the housing 100 ). For example, the first sensing inductor LE1 may be mounted on one surface of the substrate 200 disposed inside the housing 100 . The first sensing inductor LE1 may be in contact with the inner surface of the first touch member TM1 or may be disposed to be spaced apart from the inner surface of the first touch member TM1 by a predetermined distance.

The first capacitor CE1 may be electrically connected to the first sensing inductor LE1 and may be disposed on one surface or the other surface of the substrate 200 .

The oscillation circuit 500 includes the first sensing inductor LE1 and the first capacitor CE1, and according to a touch input (touch-contact or touch-force) through the touch switch unit TSW An oscillation signal Sosc having a variable frequency may be generated.

For example, the oscillation circuit 500 may include a capacitance circuit having an inductance that varies when a touch-contact is applied through the first touch member TM1 , and is variable when a touch-force is applied through the first touch member TM1 . It may include an inductance circuit having a corresponding capacitance. The first sensing inductor LE1 may be included in a capacitance circuit, and the first capacitor CE1 may be included in an inductance circuit.

The reference signal generation circuit 600 may generate a reference signal Sref corresponding to the reference clock CLK and output it to the signal processing unit 700 .

The signal processing unit 700 may detect the presence or absence of a touch input using the oscillation signal Sosc and the reference signal Sref and output a touch detection signal DF.

The self-check circuit 800 checks whether each of the oscillation signal Sosc from the oscillation circuit 500 and the reference signal Sref from the reference signal generation circuit 600 is normal, and the test result signal can provide

In this document, touch input refers to touch-contact, which means simply contacting the outer surface of the first touch member TM1 without force (force) such as pressure, and the outer surface of the first touch member. It may be a concept including all of the touch-force accompanying the force (force) to press with pressure. For example, the touch input may be a touch-contact application or a touch-force application.

For example, a part of the oscillation circuit 500 (eg, an amplifier circuit such as an inverter), a reference signal generating circuit 600 , a signal processing unit 700 , and a self-check circuit 800 may be included in the circuit unit CS. and the circuit unit CS may be an integrated circuit.

For example, the first sensing inductor LE1 may be disposed on one surface of the substrate 200 opposite to the inner surface of the first touch member TM1 . A circuit part CS and a first capacitor CE1 may be disposed on the other surface of the substrate 20 . Here, the circuit part CS, the first sensing inductor LE1, and the first capacitor CE1 may be electrically connected through the substrate 200 .

Since such an arrangement structure is only an example, it is not limited thereto.

Meanwhile, referring to FIG. 2 , as an example, the housing 100 may be formed of a conductor such as metal. The first touch member TM1 may be formed on the housing 100 . As another example, the housing 100 may be a non-conductor such as plastic, and in this case, the first touch member TM1 may be a non-conductor or a conductor.

Also, the first sensing inductor LE1 , for example, the first sensing inductor LE1 may be an inductor including a PCB pattern, or may be an inductor component that is not a PCB pattern. Since the first sensing inductor LE1 is only an example, the present invention is not limited thereto.

3 is an exemplary diagram of a touch sensing device according to an embodiment of the present invention.

Referring to FIG. 3 , as described with reference to FIG. 2 , the touch sensing device includes an oscillation circuit 500 , a reference signal generation circuit 600 , a signal processing unit 700 , and a self-check circuit 800 . can do.

The oscillation circuit 500 may generate an oscillation signal Sosc having a variable frequency depending on whether or not a touch input is made through the touch switch unit TSW, and output the generated oscillation signal Sosc to the signal processing unit 700 . In an embodiment of the present invention, the oscillation circuit 500 may be, for example, an LC oscillation circuit, but is not limited thereto, and as an example, a capacitance variable according to a touch by a conductor such as a human hand Alternatively, it may be an LC oscillation circuit using a variable inductance.

The reference signal generating circuit 600 may generate a reference signal Sref and output it to the signal processing unit 700 . For example, the reference signal Sref may be a reference clock CLK having a preset frequency.

The signal processing unit 700 may detect the presence or absence of a touch input using the oscillation signal Sosc and the reference signal Sref to output a touch detection signal DF. For example, when there is a touch input, the touch detection signal DF may be a signal having a high level.

For example, the signal processing unit 700 generates a count value by counting the period of the reference signal Sref using the oscillation signal Sosc, and based on the count value, A touch detection signal DF may be output. Here, the frequency of the reference signal Sref may be lower than the frequency of the oscillation signal Sosc.

For example, the self-check circuit 800 includes a first inspection circuit 810 for inspecting the operation of the oscillation circuit 500 and an operation of the reference signal reference signal generating circuit 600 . A second inspection circuit 930 may be included.

The first check circuit 810 may provide a first check signal CHK1 by checking whether the oscillation signal Sosc is normal. For example, the first inspection circuit 810 may receive the oscillation signal Sosc and perform a charging operation and a discharging operation based on the oscillation signal Sosc to check whether the oscillation signal is normal.

The second check circuit 820 may provide a second check signal CHK2 by checking whether the reference signal Sref is normal. For example, the second inspection circuit 820 may receive the reference signal Sref and perform a charging operation and a discharging operation based on the reference signal Sref to check whether the reference signal Sref is normal. can

As an example, in FIG. 3 , the self-check circuit 800 includes the first inspection circuit 810 and the second inspection circuit 820 , but when a plurality of touch members are applied, a plurality of oscillation circuits are generated in response thereto. may be added, and in this case, a plurality of inspection circuits may be added.

The touch sensing device of the present invention described above senses a touch input through a change in a frequency output from an oscillation circuit using LC resonance according to the presence/absence of a touch input. The change in the frequency of the oscillation signal including the frequency of the LC resonance is configured to have high sensitivity through digital signal processing such as counting a reference signal using the oscillation signal.

On the other hand, when an oscillation signal or a reference signal is input to the signal processing unit, the signal processing unit may determine an error based on the input signal. However, if a problem occurs in the final detection signal, whether the cause of the problem is an internal problem , it may be difficult to accurately determine whether the problem is in the oscillation circuit or the reference signal generating circuit.

In consideration of this point, in the present invention, a separate self-check circuit is provided to check whether the analog circuits such as the oscillation circuit and the reference signal generation circuit operate normally based on the oscillation signal and the reference signal separately from the signal processing unit. implemented.

As described above, in the present invention, it is possible to check whether the outputs of the oscillation circuit using the LC resonance and the reference signal generating circuit are operating normally.

4 is an exemplary diagram of an oscillation circuit having a variable capacitance when a touch-contact is applied.

Referring to FIG. 4 , the oscillation circuit 500 may include an inductance circuit 510 , a capacitance circuit 520 , and an amplifier circuit 530 .

The inductance circuit 510 may include a first touch member TM 611 disposed on an inner surface of the touch member TM1 to include an inductance for resonance.

The capacitance circuit 520 may include a first capacitance element 621 connected to the inductance circuit 510 and include a capacitance that varies when the first touch member TM1 is touched.

The amplifier circuit 530 may generate an oscillation signal Sosc having a resonance frequency determined by the first inductance circuit 510 and the first capacitance circuit 520 . For example, the amplification circuit 530 may include at least one inverter, or may include a differential amplification circuit.

Referring to FIG. 4 , the operation of the first oscillation circuit 601 when there is no touch on the first touch member TM1 will be described.

Referring to FIG. 4 , the oscillation circuit 500 includes an inductance circuit 510 including an inductance Lind of the first sensing inductor LE1 and a capacitance Cext of the first capacitor CE1. It may be a parallel LC oscillation circuit including a capacitance circuit 520 .

In addition, the oscillation circuit 500 may further include an amplifier circuit 530 for maintaining or oscillating the LC resonance. As an example, the amplifying circuit 530 may include an inverter INT, but is not limited thereto.

As an example, the resonance frequency freq of the oscillation circuit 500 may be expressed as in Equation 1 below.

[Equation 1]

freq ≒ 1/2π sqrt (Lind * CT)

In Equation 1, ≒ means that it may be the same or that it is similar, where similar means that other values may be further included. In Equation 1, the capacitance may be the capacitance Cext of the first capacitor CE1.

In addition, as shown in FIG. 4 , in the capacitance circuit 520 , when there is a touch-contact of a conductor such as a human hand, the additionally generated variable capacitance ΔC is the first capacitor CE1 . It may be connected in parallel to the capacitance Cext.

As an example, the resonance frequency freq of the oscillation circuit 500 may be expressed as in Equation 2 below.

[Equation 2]

fres ≒ 1/{2π sqrt (Lind * CT(Cext +ΔC)])}

△C ≒ Ccase|Cfinger|Cgnd

In Equation 2, ≒ means that it may be the same or that it is similar, where similar means that other values may be further included. In Equation 2, the variable capacitance ΔC may be a capacitance corresponding to the parallel sum of Ccase, Cfinger, and Cgnd, where Ccase is a parasitic capacitance existing between the housing and the first sensing inductor LE1. (Parasitic Capacitance), Cfinger is the capacitance of the human body, and Cgnd is the ground return capacitance between the circuit ground and earth.

And, in Equation 2, if "|" is defined as follows, 'a' and 'b' are serially connected in a circuit, and the sum value is '(a*b) It is defined as being calculated as /(a+b)'. This definition can also be applied to other equations of the present invention. This description can also be applied to Equation 3 below.

Comparing Equation 1 (without touch-contact) and Equation 2 (with touch-contact), the capacitance (Cext) of Equation 1 can be increased to the capacitance (Cext+ΔC) of Equation 2, and , it can be seen that the resonant frequency without touch-contact is lowered to the resonant frequency with touch-contact.

5 is an exemplary diagram of an oscillation circuit having a variable inductance when a touch-force is applied.

Referring to FIG. 5 , the oscillation circuit 500 includes an inductance circuit 510 including an inductance Lind of the first sensing inductor LE1 and the first capacitor CE1 as described with reference to FIG. 4 . ) may be a parallel LC oscillation circuit including a capacitance circuit 520 including a capacitance Cext.

In addition, the oscillation circuit 500 may further include an amplifier circuit 530 for maintaining or oscillating the LC resonance. As an example, the amplifying circuit 530 may include an inverter INT, but is not limited thereto.

As an example, the resonance frequency freq of the oscillation circuit 500 may be expressed as in Equation 1 below. In this case, the inductance LT of FIG. 5 may be the inductance Lind of the first sensing inductor LE1.

In addition, as shown in FIG. 5 , in the inductance circuit 510 , when a touch-force is applied by a human hand or the like, an additionally generated variable inductance ΔC is applied to the first sensing inductor LE1 . It may be connected to an inductance (Lind).

For example, the resonance frequency freq of the oscillation circuit 500 may be expressed as in Equation 3 below.

[Equation 3]

fres ≒ 1/{2π sqrt (LT * CT)}

where LT = (Lind -ΔL)

In Equation 3, ≒ means that it may be the same or that it is similar, where similar means that other values may be further included.

In Equation 3, ΔL is a change in the distance between the housing 100 and the first sensing inductor LE1 according to the touch-force application, and the action of an eddy current generated by the change in the distance, The inductance of the first sensing inductor LE1 decreases (Lind -ΔL). Accordingly, it can be seen that the resonant frequency without the touch-force is increased to the resonant frequency with the touch-force applied.

6 is a block diagram of the self-check circuit of FIG. 2 .

2 and 6 , the self-check circuit 800 according to an embodiment of the present invention may be applied to a touch sensing device applied to an electronic device.

The self-check circuit 800 may include an edge detector 801 , a charge/discharge circuit 802 , and a comparison circuit 803 .

The edge detector 801 may output an edge detection signal Sedt having a short pulse generated when an edge of the pulse signal SPLS having a pulse train is detected. For example, the pulse signal SPLS may be an oscillation signal Sosc or a reference signal Sref. For example, a short pulse of the edge detection signal Sedt may be shorter than a width of a pulse of the pulse signal SPLS.

The charging/discharging circuit 802 may generate a detection voltage Vd by performing a charging operation and a discharging operation based on the edge detection signal Sedt. For example, the charging/discharging circuit 802 may repeatedly perform a charging operation and a discharging operation according to the edge detection signal Sedt, and the detection voltage Vd generated by the repeated charging and discharging operations. can be printed

The comparison circuit 803 may output a check signal CHK by checking whether the pulse signal SPLS is normal based on the detection voltage Vd. For example, the comparison circuit 803 includes a high level indicating normal when the detection voltage Vd is higher than the first reference voltage, and detects abnormality when the detection voltage Vd is lower than the second reference voltage. A check signal CHK (CHK1 or CHK2) including a low level may be output.

FIG. 7 is a first exemplary diagram of the self-check circuit of FIG. 6 .

The charge/discharge circuit 802 and the comparison circuit 803 shown in FIG. 6 may be implemented as shown in FIG. 7 .

Referring to FIG. 7 , for example, the charge/discharge circuit 802 may include a switch SW, a capacitor CT, and a resistor Rdis.

The switch SW is connected between the power supply voltage VDD terminal and the ground, and performs a switching operation such as an on-state or an off-state by the edge detection signal Sedt from the edge detector 801. can

The capacitor CT is connected between the switch SW and the ground, and can perform a charging operation when the switch SW is in an on state, and performs a discharging operation when the switch SW is in an off state. can do.

The resistor Rdis is connected between the connection node N1 of the first switch SW1 and the first capacitor CT1 and the ground, and is connected to the capacitor CT and the ground when the switch SW is in an off state. A discharge path may be provided between them.

For example, the comparison circuit 803 may include a window comparison circuit 803 - 1 and an output selector 803 - 2 .

The window comparison circuit 803 - 1 compares the detection voltage Vd with a first reference voltage VHref and a second reference voltage VLef so that the detection voltage Vd is the first reference voltage The check signal CHK including a high level when it is higher than (VHref) and a low level when the detection voltage Vd is lower than the second reference voltage VLef may be output.

For example, in this document, the first reference voltage VHref is a high level determination reference voltage, the second reference voltage VLef is a low level determination reference voltage, and accordingly, the first reference voltage VHref is It is higher than the second reference voltage VLef.

The output selector 803 - 2 may perform an AND operation on the enable signal EN and the check signal CHK. For example, the output selector 803 - 2 may include an AND gate, and may output the check signal CHK when the enable signal EN is at a high level, and the enable signal EN ) is at a low level, the check signal CHK may not be output.

In this way, the output selector 803 - 2 may control the output of the check signal CHK based on the enable signal EN.

FIG. 8 is a second exemplary diagram of the self-check circuit of FIG. 6 .

The charging/discharging circuit 802 shown in FIG. 6 may be implemented as shown in FIG. 8 .

Referring to FIG. 7 , for example, the charging/discharging circuit 802 may include a first current source IS1 , a second current source IS2 , and a capacitor CT.

The first current source IS1 is connected between the power supply voltage VDD terminal and the ground, and is turned on based on the switching signals S1 and S2 included in the edge detection signal Sedt from the edge detector 801 . An operation or an off operation may be performed, and a current for charging the capacitor CT may be generated during an on operation. For example, in the switching signals S1 and S2, S1 may be a signal having the same phase as the edge detection signal Sedt, and S2 may be a signal having a phase opposite to that of the edge detection signal Sedt.

The second current source IS2 is connected between the first current source IS1 and the ground, and is turned off when the first current source IS1 is turned on, and turned on when the first current source IS1 is turned off. In the ON operation, a current for discharging the capacitor CT may be generated.

The capacitor CT is connected between the intermediate connection node N2 of the first current source IS1 and the second current source IS2 and the ground, and performs a charging operation when the first current source IS1 is turned on. and performing a discharging operation when the second current source IS2 is turned on to provide the detection voltage Vd.

FIG. 9 is a first exemplary diagram of the first inspection circuit of FIG. 3 .

Referring to FIG. 9 , the first inspection circuit 810 may include an edge detector 811 , a charge/discharge circuit 812 , and a comparison circuit 813 .

The edge detector 811 may output a first edge detection signal Sedt1 having a short pulse generated when an edge of the oscillation signal Sosc is detected. For example, the edge detector 811 may detect an edge of the oscillation signal Sosc and output a pulse signal having a high level having a pulse width shorter than a pulse width of the oscillation signal Sosc every time an edge is detected. .

The charging/discharging circuit 812 may generate a first detection voltage Vd1 by performing a charging operation and a discharging operation based on the first edge detection signal Sedt1 .

For example, the charging/discharging circuit 812 includes a switch SW1 and a capacitor CT1 connected in series between a power supply voltage (VDD) terminal and a ground, and a connection node of the switch SW1 and the capacitor CT1. It may include a resistor (Rdis1) connected between (N11) and the ground.

In the charging/discharging circuit 812 , the switch SW1 is turned on or off according to the pulse signal input from the edge detector 811 , and when the switch SW1 is in the on state, a voltage is applied to the capacitor CT1 . is charged, and when the switch SW1 is in an off state, the detection voltage Vd1 charged in the capacitor CT1 is discharged through the resistor Rdis1.

The first comparison circuit 813 may output a first check signal CHK1 by checking whether the oscillation signal Sosc is normal based on the first detection voltage Vd1 .

For example, the first comparison circuit 813 may include a window comparison circuit 813 - 1 and an output selector 813 - 2 .

The window comparison circuit 813 - 1 compares the detection voltage Vd1 with a first reference voltage VHref and a second reference voltage VLef so that the detection voltage Vd1 is the first reference voltage The check signal CHK1 including a high level when it is higher than (VHref) and a low level when the detection voltage Vd1 is lower than the second reference voltage VLef may be output. Here, the level of the check signal CHK1 is not limited to the above description and may be opposite to the above description.

The output selector 813 - 2 may perform an AND operation on the enable signal EN and the comparison circuit check signal CHK1 . For example, the output selector 813 - 2 may include an AND gate, and may output the check signal CHK1 when the enable signal EN is at a high level, and the enable signal EN ) is at a low level, the check signal CHK1 may not be output.

In this way, the output selector 813 - 2 may control the output of the check signal CHK1 based on the enable signal.

FIG. 10 is a first exemplary diagram of the second inspection circuit of FIG. 3 .

Referring to FIG. 10 , the second inspection circuit 920 may include a second edge detector 821 , a second charge/discharge circuit 822 , and a second comparison circuit 823 .

The second edge detector 821 may output a second edge detection signal Sedt2 having a short pulse generated when an edge of the reference signal Sref is detected. For example, the second edge detector 821 detects an edge of the reference signal Sref and outputs a pulse signal having a high level having a pulse width shorter than the pulse width of the reference signal Sref every time an edge is detected. can do.

Meanwhile, the first and second edge detectors 811 and 821 may detect a rising edge or a falling edge of an input signal, and may detect either a rising edge or a falling edge.

In addition, the short pulse of the first edge detection signal Sedt1 is shorter than the width of the pulse of the oscillation signal Sosc, and the short pulse of the second edge detection signal Sedt2 is of the reference signal Sref. It may be shorter than the width of the pulse.

The second charging/discharging circuit 822 performs a charging operation and a discharging operation based on a second edge detection signal Sedt2 input from the second edge detector 821 to generate a second detection voltage Vd2. can create

For example, the second charge/discharge circuit 822 includes a second switch SW2 and a second capacitor CT2 connected in series between a power supply voltage (VDD) terminal and a ground, and the second switch SW2 and a second resistor Rdis1 connected between the connection node N12 of the second capacitor CT2 and the ground.

In the second charge/discharge circuit 822 , a second switch SW2 is turned on or off according to a pulse signal input from the second edge detector 821 , and the second switch SW2 is turned on When the voltage is charged in the second capacitor CT1, when the second switch SW2 is in the off state, the voltage VCT2 charged in the second capacitor CT2 is discharged through the second resistor Rdis2. .

The second comparison circuit 823 may output a second check signal CHK2 by checking whether the reference signal Sref is normal based on the second detection voltage Vd2 .

For example, the second comparison circuit 823 may include a window comparison circuit 823 - 1 and an output selector 823 - 2 .

The window comparison circuit 823 - 1 compares the detection voltage Vd2 with a first reference voltage VHref and a second reference voltage VLef so that the detection voltage Vd2 is the first reference voltage The check signal CHK2 including a high level when it is higher than (VHref) and a low level when the detection voltage Vd2 is lower than the second reference voltage VLef may be output. Here, the level of the check signal CHK2 is not limited to the above description and may be opposite to the above description.

The output selector 823 - 2 may perform an AND operation on the enable signal EN and the comparison circuit check signal CHK2 . For example, the output selector 823 - 2 may include an AND gate, and may output the check signal CHK2 when the enable signal EN is at a high level, and the enable signal EN ) is at a low level, the check signal CHK2 may not be output.

In this way, the output selector 823 - 2 may control the output of the check signal CHK2 based on the enable signal.

In other words, in the self-check circuit 800 , the edge detector 811 or 821 detects an edge (at least one of a rising edge and a falling edge) of an oscillation signal or a reference signal, and a short pulse corresponding to the edge. ) to generate a switching signal with The charging/discharging circuit 812 or 822 charges the corresponding capacitor through a large current during the high-level section of the switching signal input from the edge detector, and discharges the charge with a very small current of about the leakage current during the low-level section. make it In this way, the detected voltage (Vd1 or Vd2) charged in the corresponding capacitor appears as a waveform as shown in FIG. 13 or 14 . In addition, the comparison circuit 813 or 823 recognizes the detection voltage Vd1 or Vd2 as a normal operation when the detection voltage Vd1 or Vd2 is equal to or greater than the first reference voltage using the window comparison circuit having hysteresis, and is less than or equal to the second reference voltage. It is recognized as an abnormal operation.

Accordingly, when the oscillation signal of the sending circuit or/and the reference signal of the reference signal generating circuit are normally output, a pulse signal with an edge detected is generated accordingly, and the charge of the capacitor is accumulated through this, and the detected voltage (Vd1 or Vd2) is As it continues to rise, it generates a signal that the output signal of the circuit to be inspected is normal.

Conversely, when the oscillation circuit or the reference signal generation circuit generates output and the signal output from the oscillation circuit and the reference signal generation circuit is maintained at a low level or a high level, an edge-detected pulse signal does not occur and the capacitor continues to be turned on. By discharging, the detection voltage Vd1 becomes lower than the second reference voltage for determining the low level of the comparison circuit, and the output of the inspection circuit 810 or 820 generates a signal indicating an abnormal operation.

11 is a second exemplary diagram of the first inspection circuit of FIG. 3 .

The first inspection circuit 810 shown in FIG. 11 differs from the first inspection circuit 810 shown in FIG. 9 in the first charging/discharging circuit 812 , so the first charging/discharging circuit 812 is Explain.

Referring to FIG. 11 , the first charging/discharging circuit 812 may include a first current source IS1 , a second current source IS2 , and a capacitor CT1 .

The first current source IS1 is connected between the power supply voltage (VDD) terminal and the ground, and may perform an on operation or an off operation based on the signals S1 and S2 from the edge detector 801, During the on operation, a current for charging the capacitor CT may be generated.

The second current source IS2 is connected between the first current source IS1 and the ground, and is turned off when the first current source IS1 is turned on, and turned on when the first current source IS1 is turned off. In the ON operation, a current for discharging the capacitor CT1 may be generated.

The capacitor CT1 is connected between the intermediate connection node N21 of the first current source IS1 and the second current source IS2 and the ground, and performs a charging operation when the first current source IS1 is turned on. and performing a discharging operation when the second current source IS2 is turned on to provide the detection voltage Vd1.

12 is a second exemplary diagram of the second inspection circuit of FIG. 3 .

The second test circuit 820 shown in FIG. 12 differs from the second test circuit 820 shown in FIG. 10 in the second charge/discharge circuit 822, so the second charge/discharge circuit 822 is Explain.

Referring to FIG. 12 , the second charge/discharge circuit 822 may include a first current source IS1 , a second current source IS2 , and a capacitor CT2 .

The first current source IS1 is connected between the power supply voltage (VDD) terminal and the ground, and may perform an on operation or an off operation based on the signals S1 and S2 from the edge detector 801, During the on operation, a current for charging the capacitor CT may be generated.

The second current source IS2 is connected between the first current source IS1 and the ground, and is turned off when the first current source IS1 is turned on, and turned on when the first current source IS1 is turned off. In the ON operation, a current for discharging the capacitor CT2 may be generated.

The capacitor CT2 is connected between the intermediate connection node N22 of the first current source IS1 and the second current source IS2 and the ground, and performs a charging operation when the first current source IS1 is turned on. and performing a discharging operation when the second current source IS2 is turned on to provide the detection voltage Vd2.

13 is a waveform diagram of main signals and voltages of the first inspection circuit of FIG. 9 .

9 and 13 , when the oscillation signal Sosc includes a normal pulse, the first edge detector 811 outputs an edge detection signal Sedt1 having a repeated short pulse, and accordingly The detection voltage Vd1 charged in the first capacitor CT1 rises according to the charging and discharging operations of the first capacitor CT1, and eventually, when it is higher than the first reference voltage VHref, in the first comparison circuit 813 A check signal CHK1 having a high level indicating a normal operation may be output. As described above, in the normal state, the detection voltage Vd1 charged in the first capacitor CT1 rises up to the power supply voltage VDD and is maintained.

However, when the oscillation signal Sosc is abnormal and does not include a pulse, the pulse signal Sosc rising edge is not output from the first edge detector 811, and accordingly, the first capacitor CT1 is charged The detection voltage Vd1 continues to fall, and eventually, when it is lower than the second reference voltage VLref, a low-level signal CHK_OUT1 indicating an abnormal operation (abnormal operation) may be output from the first comparison circuit 813 . there is.

In other words, although FIG. 13 shows signal and voltage waveforms according to one operation example, the time it takes until the output of the inspection circuit is valid is determined by setting the length of the high-level section of the first edge detector, charging the first capacitor, and The amount of the discharging current may vary depending on the first and second reference voltages of the first comparison circuit, and these specific examples may be changed according to the environment of use of the applied system and product.

FIG. 14 is a waveform diagram of main signals and voltages of the second inspection circuit of FIG. 10 .

10 and 14 , when the reference signal Sref includes a normal pulse, the second edge detector 821 outputs an edge detection signal Sedt2 having a repeated short pulse, and accordingly The voltage VCT2 charged in the second capacitor CT2 rises according to the charging and discharging operations of the second capacitor CT2, and eventually, if it is higher than the second reference voltage VHref, the second comparator circuit 823 is normal. A check signal CHK2 having a high level indicating an operation may be output.

As described above, in the normal state, the voltage VCT2 charged in the second capacitor CT2 rises to the power supply voltage VDD and is maintained.

However, when the reference signal Sref is abnormal and does not include a pulse, the pulse signal Sref rising edge is not output from the second edge detector 821, and accordingly, the second capacitor CT2 is charged The voltage VCT2 continues to fall, and eventually, when it is lower than the second reference voltage VLref, a low-level signal CHK_OUT2 indicating an abnormal operation (abnormal operation) may be output from the second comparison circuit 823 . .

As described above, when the inspection circuit is included, it is possible to detect a state up to a normal state at the start of an operation for circuits that generate a frequency, such as an oscillation circuit and a reference signal reference signal generation circuit, and also a touch sensing operation Normal state or abnormal state can be monitored during operation.

In the above, the present invention has been described as an embodiment, but the present invention is not limited to the above embodiment, and without departing from the gist of the present invention as claimed in the claims, those of ordinary skill in the art to which the invention pertains Anyone can make various modifications.

10: electronic device
100: housing
200: substrate
500: oscillation circuit
600: reference signal generation circuit
700: signal processing unit
800: self-check circuit
CS: circuit
TSW: touch switch unit
TM1: first touch member

Claims (21)

an edge detector for outputting an edge detection signal having a short pulse generated when an edge of a pulse signal having a pulse train is detected;
a charging/discharging circuit for generating a detection voltage by performing a charging operation and a discharging operation based on the edge detection signal; and
a comparison circuit for outputting a check signal by checking whether the pulse signal is normal based on the detected voltage;
A self-check circuit comprising a.
According to claim 1, wherein the short pulse of the edge detection signal,
shorter than the pulse width of the pulse signal
self-check circuit.
The method according to claim 1, wherein the charging/discharging circuit comprises:
a switch connected between the power supply voltage terminal and the ground;
a capacitor connected between the switch and the ground to perform a charging operation when the switch is in an on state; and
a resistor connected between a connection node of the switch and the capacitor and a ground to provide a discharge path between the capacitor and the ground when the switch is in an off state;
A self-check circuit comprising a.
The method of claim 1, wherein the comparison circuit comprises:
Comparing the detection voltage with a first reference voltage and a second reference voltage, a high level is included when the detection voltage is higher than the first reference voltage, and a low level is obtained when the detection voltage is lower than the second reference voltage. a window comparison circuit for outputting a check signal including; and
an output selector for performing an AND operation on the enable signal and the check signal;
A self-check circuit comprising a.
The method according to claim 1, wherein the charging/discharging circuit comprises:
a first current source connected between the power supply voltage terminal and the ground;
a second current source connected between the first current source and the ground, the second current source being turned off when the first current source is on, and turned on when the first current source is turned off; and
It is connected between the intermediate connection node of the first current source and the second current source and the ground, and performs a charging operation when the first current source is on, and performs a discharge operation when the second current source is on, so that the detected voltage capacitors that provide;
A self-check circuit comprising a.
A touch sensing device applicable to an electronic device including a touch switch unit having at least one first touch member formed in a housing, the touch sensing device comprising:
a first sensing inductor disposed inside the first touch member;
a first capacitor electrically connected to the first sensing inductor;
an oscillation circuit including the first sensing inductor and the first capacitor, the oscillation circuit generating an oscillation signal having a frequency varying according to a touch input (touch-contact or touch-force) through the touch switch unit;
a reference signal generation circuit that generates a reference signal corresponding to the reference clock;
a signal processing unit for detecting the presence or absence of a touch input using the oscillation signal and the reference signal and outputting a touch detection signal; and
a self-check circuit for providing a check signal by checking whether at least one of the oscillation signal and the reference signal is normal;
A touch sensing device comprising a.
The method of claim 6, wherein the self-check circuit,
a first check circuit for providing a first check signal by checking whether the oscillation signal is normal; and
a second check circuit for providing a second check signal by checking whether the reference signal is normal;
A touch sensing device comprising a.
The method of claim 7, wherein the first inspection circuit,
a first edge detector for outputting a first edge detection signal having a short pulse generated when an edge of the oscillation signal is detected;
a first charge/discharge circuit configured to generate a first detection voltage by performing a charging operation and a discharging operation based on the first edge detection signal; and
a first comparison circuit for outputting a first check signal by checking whether the oscillation signal is normal based on the first detection voltage;
A touch sensing device comprising a.
The method of claim 8, wherein the second inspection circuit comprises:
a second edge detector for outputting a second edge detection signal having a short pulse generated when an edge of the reference signal is detected;
a second charging/discharging circuit configured to generate a second detection voltage by performing a charging operation and a discharging operation based on the second edge detection signal; and
a second comparison circuit for outputting a second check signal by checking whether the reference signal is normal based on the second detection voltage;
A touch sensing device comprising a.
10. The method of claim 9, wherein the short pulse of the first edge detection signal,
shorter than the width of the pulse of the oscillation signal,
The short pulse of the second edge detection signal is
shorter than the pulse width of the reference signal
Touch sensing device.
10. The method of claim 9, wherein each of the first and second charge and discharge circuit
a switch connected between the power supply voltage terminal and the ground;
a capacitor connected between the switch and the ground to perform a charging operation when the switch is in an on state; and
a resistor connected between a connection node of the switch and the capacitor and a ground to provide a discharge path between the capacitor and the ground when the switch is in an off state;
A touch sensing device comprising..
The method of claim 9, wherein each of the first and second comparison circuits,
Comparing the detection voltage with a first reference voltage and a second reference voltage, a high level is included when the detection voltage is higher than the first reference voltage, and a low level is included when the detection voltage is lower than the second reference voltage. a window comparison circuit for outputting a check signal; and
an output selector for performing an AND operation on the enable signal and the check signal;
A touch sensing device comprising..
The method of claim 9, wherein each of the first and second charging and discharging circuits,
a first current source connected between the power supply voltage terminal and the ground;
a second current source connected between the first current source and the ground, the second current source being turned off when the first current source is on, and turned on when the first current source is turned off; and
a capacitor connected between an intermediate connection node of the first current source and the second current source and a ground to perform a charging operation when the first current source is turned on, and a capacitor configured to perform a discharging operation when the second current source is turned on;
A touch sensing device comprising..
a touch switch unit having at least one first touch member formed in the housing;
a first sensing inductor disposed inside the first touch member;
a first capacitor electrically connected to the first sensing inductor;
an oscillation circuit including the first sensing inductor and the first capacitor, the oscillation circuit generating an oscillation signal having a frequency varying according to a touch input (touch-contact or touch-force) through the touch switch unit;
a reference signal generation circuit that generates a reference signal corresponding to the reference clock;
a signal processing unit for detecting the presence or absence of a touch input using the oscillation signal and the reference signal and outputting a touch detection signal; and
a self-check circuit that checks whether the oscillation signal from the oscillation circuit and the reference signal from the reference signal generation circuit are normal, and provides a test result signal;
An electronic device comprising a.
15. The method of claim 14, wherein the self-check circuit,
a first check circuit for providing a first check signal by checking whether the oscillation signal is normal; and
a second check circuit for providing a second check signal by checking whether the reference signal is normal;
An electronic device comprising a.
The method of claim 15, wherein the first inspection circuit,
a first edge detector for outputting a first edge detection signal having a short pulse generated when an edge of the oscillation signal is detected;
a first charge/discharge circuit configured to generate a first detection voltage by performing a charging operation and a discharging operation based on the first edge detection signal; and
a first comparison circuit for outputting a first check signal by checking whether the oscillation signal is normal based on the first detection voltage;
An electronic device comprising a.
The method of claim 16, wherein the second inspection circuit,
a second edge detector for outputting a second edge detection signal having a short pulse generated when an edge of the reference signal is detected;
a second charge/discharge circuit configured to generate a second detection voltage by performing a charging operation and a discharging operation based on the second edge detection signal; and
a second comparison circuit for outputting a second check signal by checking whether the reference signal is normal based on the second detection voltage;
An electronic device comprising a.
The method of claim 17, wherein the short pulse of the first edge detection signal,
shorter than the width of the pulse of the oscillation signal,
The short pulse of the second edge detection signal is
shorter than the pulse width of the reference signal
Electronics.
The method of claim 18, wherein each of the first and second charge and discharge circuits
a switch connected between the power supply voltage terminal and the ground;
a capacitor connected between the switch and the ground to perform a charging operation when the switch is in an on state; and
a resistor connected between a connection node of the switch and the capacitor and a ground to provide a discharge path between the capacitor and the ground when the switch is in an off state;
An electronic device comprising a.
18. The method of claim 17, wherein each of the first and second comparison circuits,
Comparing the detection voltage with a first reference voltage and a second reference voltage, a high level is included when the detection voltage is higher than the first reference voltage, and a low level is included when the detection voltage is lower than the second reference voltage. a window comparison circuit for outputting a check signal; and
an output selector for performing an AND operation on the enable signal and the check signal;
An electronic device comprising a.
The method of claim 17, wherein each of the first and second charging and discharging circuits,
a first current source connected between the power supply voltage terminal and the ground;
a second current source connected between the first current source and the ground, the second current source being turned off when the first current source is on, and turned on when the first current source is turned off; and
a capacitor connected between an intermediate connection node of the first current source and the second current source and a ground to perform a charging operation when the first current source is turned on, and a capacitor configured to perform a discharging operation when the second current source is turned on;
An electronic device comprising a.

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