KR20240001938A - Sensor and Operation Method Thereof - Google Patents

Abstract

The sensor device according to one embodiment forms a first offset capacitance in response to the initialization control signal, forms a second offset capacitance in response to the offset control signal, and adjusts the first offset capacitance by the second offset capacitance to create an offset. An offset removal unit that outputs a removal capacitance, an analog signal processor that generates digital level detection data from the adjusted sensing capacitance from which the offset removal capacitance has been removed from the sensing capacitance detected in the touch pad, and an offset by comparing the detection data with the threshold. It may be configured to include a digital signal processor that generates a control signal.

Description

Sensor device and operation method {Sensor and Operation Method Thereof}

This technology relates to an object sensing device, and more specifically, to a sensor device and its operating method.

A user interface is a device that receives user input to control an electronic device.

An example of a user interface is a touch recognition device.

Among various types of touch recognition devices, capacitance sensors that detect objects based on the capacitance formed by a dielectric such as the human body and a conductive touch pad are widely used.

The capacitance of the touch pad provided in the capacitive sensor changes not only due to proximity or contact with the dielectric, but also due to external environments such as temperature and humidity, so a sensor device that can detect input signals without being affected by changes in the external environment is required. .

Embodiments of the present technology can provide a sensor device and a method of operating the same that are adaptive to changes in the external environment.

A sensor device according to an embodiment of the present technology forms a first offset capacitance in response to an initialization control signal, forms a second offset capacitance in response to an offset control signal, and forms the first offset capacitance by the second offset capacitance. An offset removal unit that adjusts the capacitance and outputs an offset removal capacitance; an analog signal processor that generates digital level sensing data from the adjusted sensing capacitance in which the offset removal capacitance is removed from the sensing capacitance detected in the touch pad; and a digital signal processor that generates the offset control signal by comparing the sensed data with a threshold.

A method of operating a sensor device according to an embodiment of the present technology includes: setting a first offset capacitance in response to an initialization control signal as a sensor device for detecting a change in capacitance of a touch pad; setting a second offset capacitance in response to an offset control signal; outputting an offset removal capacitance by adjusting the first offset capacitance by the second offset capacitance; generating digital level sensing data from the adjusted sensing capacitance obtained by removing the offset removal capacitance from the sensing capacitance detected in the touch pad; and comparing the sensed data with a threshold to generate the offset control signal.

According to this technology, parasitic components of an input signal can be removed adaptively to changes in the external environment. Accordingly, it is possible to secure the resolution of the sensor device and sufficiently secure the detection range of the change in capacitance.

1 is a configuration diagram of a sensor device according to an embodiment.
Figure 2 is a configuration diagram of an analog signal processing unit according to an embodiment.
Figure 3 is a configuration diagram of a digital signal processing unit according to an embodiment.
Figure 4 is a conceptual diagram for explaining a method of detecting capacitance according to an embodiment.
Figure 5 is a conceptual diagram for explaining a sensing method according to an embodiment.
Figure 6 is a flowchart explaining a method of operating a sensor device according to an embodiment.

Hereinafter, embodiments of the present technology will be described in more detail with reference to the attached drawings.

1 is a configuration diagram of a sensor device according to an embodiment.

Referring to FIG. 1, the sensor device 10 according to one embodiment may include a touch pad 200 and a detection signal processor 100 electrically connected to the touch pad 200.

The detection signal processing unit 100 may include an analog signal processing unit 110, a digital signal processing unit 120, and a controller 130.

The analog signal processor 110 may apply an input voltage to one electrode of the touch pad 200 and receive a sensing capacitance, that is, a sensing signal Cs1. A ground voltage (GND) may be applied to the other electrode of the touch pad 200. The analog signal processor 110 may generate a sensing voltage from the sensing signal Cs1, digitally convert the sensing voltage, and output sense data (Sense Data, Dout).

The digital signal processor 120 may receive sensing data (Dout) and generate a sensor output signal (Sout). The sensor output signal (Sout) may be provided to a controller of a host device (not shown). The host device is an electronic device equipped with the sensor device 10 as a user interface, such as a television, refrigerator, air conditioner, vacuum cleaner, oven, microwave oven, washing machine, air purifier, set-top box, bidet, smart phone, or tablet PC. It can contain at least one.

The controller 130 may control overall operations of the detection signal processing unit 100.

The detection signal processing unit 100 determines whether to approach or touch the touch pad 200 based on the capacitance when the dielectric is close to or not in contact with the touch pad 200 and the change in capacitance when the dielectric is close to or in contact with the touch pad 200. It can be determined.

When the dielectric is not in proximity or contact, the capacitance of the touch pad 200 itself acts as a parasitic component and may increase or decrease depending on external environments such as temperature and humidity. When the detection signal processor 100 is configured to detect a change in capacitance within a set detection range, changes in the capacitance of the touch pad 200 due to the external environment may result in limiting the detection range.

Therefore, this technology proposes a method for adaptively correcting parasitic components in response to changes in capacitance of the touch pad 200 due to the external environment.

Figure 2 is a configuration diagram of an analog signal processing unit according to an embodiment.

Referring to FIG. 2, the analog signal processing unit 110 according to one embodiment may include an offset removal unit 1110, a capacitance-to-voltage converter 1120, and an analog-to-digital converter (ADC, 1130).

The offset removal unit 1110 is configured to remove capacitance as a parasitic component present in the touch pad 200, and may include a first offset capacitor 1111 and a second offset capacitor 1113.

The first offset capacitor 1111 may be configured to remove parasitic components of the sensing signal Cs1 according to the first offset capacitance Cinit determined by the initialization control signal INIT provided from the controller 130. In one embodiment, the controller 130 determines the initialization control signal INIT based at least on the capacitance of the touch pad 200 and the capacitance-voltage converter 1120 when the sensor device 10 is powered on, thereby generating the first The offset capacitor 1111 can be driven.

The second offset capacitor 1113 may be configured to adjust the first offset capacitance (Cinit) according to the second offset capacitance (Cdelta) determined by the offset control signal (SW) provided from the digital signal processor 120. .

Accordingly, the offset removal capacitance may be determined by adjusting the first offset capacitance (Cinit) adjusted by the second offset capacitance (Cdelta), and the offset removal capacitance may be removed from the sensing signal (Cs1). Additionally, the offset removal unit 1110 may output an adjusted sensing signal (Cs2 = Cinit ± Cdelta).

The capacitance-voltage converter 1120 is configured to generate a sensing voltage (Vout) from the adjusted sensing signal (Cs2) and may include an amplifier (AMP) and a range capacitor (Crg).

The amplifier (AMP) can receive the input voltage (Vin) at the non-inverting input terminal (+), which is the first input terminal, and the adjusted sensing signal (C2s) at the inverting input terminal (-), which is the second input terminal. there is.

The range capacitor (Crg) may be connected between the inverting input terminal of the amplifier (AMP) and the sensing voltage (Vout) output terminal. Although not shown, the capacity-voltage converter 1120 may further include a switch for charging or discharging the range capacitor Crg.

The range capacitor (Crg) may be charged by the adjusted sensing signal (Cs2) and output as the sensing voltage (Vout).

The analog-to-digital converter (ADC, 1130) can digitally convert the sensing voltage (Vout) and output N-bit digital sense data (Sense Data, Dout).

Assuming that the second offset capacitor 1113 is not provided, the analog signal processor 110 subtracts the capacitance of the first offset capacitor 1111 from the sensing signal (Cs1) of the touch pad 200 and The corresponding capacitance (Cs1-Cinit) is converted to an analog voltage, that is, a sensing voltage (Vout) using a range capacitor (Crg).

In order to optimize the detectable range of the sensor device 100, the value of the first offset capacitor 1111 can be set according to [Equation 1] during the initialization operation.

[Equation 1]

Cinit = Cs1 - 0.5Crg

The sensing signal (Cs1) may increase or decrease due to changes in the external environment, but the range in which changes in capacitance of the touch pad 200 can be detected is the range capacitor (Cs1) that charges and outputs the sensing signal (Cs1). Depends on the capacity value of Crg).

It is conceivable to increase the capacity of the range capacitor (Crg) in order to increase the detection range of the capacitance change of the touch pad 200, but the capacity of the range capacitor (Crg) is a sensor device defined as [Equation 2] Because it determines the resolution of (10), there is a limit to increasing the capacity of the range capacitor (Crg).

[Equation 2]

Detection capacitance resolution = Crg/2 ^N

(N: Number of bits of detection data (Dout) output from ADC)

The digital signal processor 120 of the present technology can monitor whether the sensing signal Cs1 changes by more than a set level and output an offset control signal SW. The second offset capacitor 1113 may be configured to adjust, for example, add or subtract the first offset capacitance (Cinit) according to the second offset capacitance (Cdelta) determined by the offset control signal (SW).

In one embodiment, the digital signal processor 120 increases the first offset capacitance (Cinit) when the digital detection data (Dout) generated from the sensing signal (Cs1) is greater than or equal to the first threshold (TH1), and the digital detection data When (Dout) is less than or equal to the second threshold (TH2), an offset control signal (SW) may be generated to reduce the first offset capacitance (Cinit).

Figure 3 is a configuration diagram of a digital signal processing unit according to an embodiment.

Referring to FIG. 3, the digital signal processor 120 according to one embodiment may include a detection signal generator 121, a comparison unit 123, and an offset control signal generator 125.

The detection signal generator 121 may output a sensor output signal (Sout) corresponding to the detection data (Dout).

The comparison unit 123 may generate a comparison signal (COMP) by comparing the sensed data (Dout) and the threshold values (TH1 and TH2).

In one embodiment, the comparator 123 generates a first level detection signal (COMP) when the detection data (Dout) is greater than or equal to the first threshold (TH1), and the detection data (Dout) is greater than or equal to the first threshold (TH1). If TH2) or less, a second level detection signal (COMP) can be generated.

The offset control signal generator 125 may generate an offset control signal (SW) based on the comparison signal (COMP).

In one embodiment, the offset control signal generator 125 generates an offset control signal (SW) such that a second offset capacitance (Cdelta) is added to the first offset capacitance (Cinit) in response to the first level comparison signal (COMP). can be created. The offset control signal generator 125 may generate an offset control signal (SW) in response to the second level comparison signal (COMP) so that the second offset capacitance (Cdelta) is removed from the first offset capacitance (Cinit). .

Figure 4 is a conceptual diagram for explaining a method of detecting capacitance according to an embodiment.

Figure 4(a) shows a method of detecting capacitance when the sensing signal Cs1 is not changed by the external environment.

The capacitance (Cs1-Cinit) corresponding to the remainder after subtracting the first offset capacitance (Cinit) from the sensing signal (Cs1) can be converted to the sensing voltage (Vout) using the range capacitor (Crg).

Figure 4(b) shows a method for detecting capacitance when the sensing signal Cs1 increases beyond the first threshold TH1 due to an external environment. In one embodiment, the first threshold TH1 may be determined to be 3/4 of the maximum value of the sensed data Dout, but is not limited thereto. When the detection data (Dout) is output as 2 ¹⁰ bits, the maximum value may be 1024 in decimal and the first threshold value (TH1) may be 768, which is 3/4 of the maximum value. As in ①, when the sensing signal (Cs1) increases (Cs1+Cs1_inc) due to the external environment and the sensed data (Dout) is detected above the first threshold (TH1), as in ②, the first offset capacitance (Cinit) If parasitic components are removed only by using the range capacitor (Crg), the capacitance detection range is limited. For example, even if the sensing signal Cs1 changes slightly due to an unintentional approach or contact, it may be mistakenly judged as a valid approach or contact.

However, according to the offset control signal (SW) generated by the digital signal processor 120, a sufficient capacitance detection range can be secured by adding the second offset capacitance (Cdelta) to the first offset capacitance (Cinit) as shown in ③. there is.

Figure 4 (c) shows a method of detecting capacitance when the sensing signal (Cs1) decreases below the second threshold (TH2) due to the external environment. In one embodiment, the second threshold TH2 may be determined to be 1/4 of the maximum value of the sensed data Dout, but is not limited thereto. When the sensed data (Dout) is output as 2 ¹⁰ bits, the maximum value may be 1024 in decimal and the second threshold value (TH2) may be 256, which is 1/4 of the maximum value. As in ①, when the sensing signal (Cs1) decreases (Cs1-Cs1_dec) due to the external environment and the sensing data (Dout) is detected below the second threshold (TH2), as in ②, the first offset capacitance (Cinit) If parasitic components are removed only by using the range capacitor (Crg), the capacitance detection range is limited. For example, even if the sensing signal Cs1 changes due to an intended approach or contact, it may not be recognized as a valid approach or contact.

However, according to the offset control signal (SW) generated by the digital signal processor 120, a sufficient capacitance detection range can be secured by subtracting the second offset capacitance (Cdelta) from the first offset capacitance (Cinit) as shown in ③. there is.

Figure 5 is a conceptual diagram for explaining a sensing method according to an embodiment.

In order to detect whether the sensor device 10 has a change in capacitance caused by contact with an external substance, a reference value (Reference Data) and a detection threshold (THS) must be defined.

The reference value is a value when there is no change in capacitance due to contact with an external substance in the sensor device 10, and is defined as the average value of sense data (Sense Data, Dout) measured multiple times in the absence of contact with an external substance.

The detection threshold (THS) refers to the minimum value of the change in sense data by which the sensor device 10 determines whether or not an external substance is in contact.

Referring to FIG. 5, when the current sense data becomes greater than the reference value by more than the threshold (THS), it is determined that the device has been touched (Touch On). Once the Touch On judgment is completed, the reference data is reset based on the current sense data value.

Meanwhile, when the current sense data becomes smaller than the reference data by less than the threshold (THS), it is determined that the touch is off. Once the Touch Off judgment is completed, the reference value is reset based on the current sense data value.

In this process, it is detected whether the capacitance of the touch pad 200 increases (a) or decreases (b) due to the external environment, and the offset capacitance can be added or subtracted according to each case.

Referring to (a) of FIG. 5, sense data (Sense Data, Dout) may be detected as more than 3/4 of the first threshold (TH1), for example, the maximum value of sense data (Dout) ( A). The digital signal processor 120 may generate an offset control signal (SW) to form a second offset capacitance (Cdelta) that can increase the first offset capacitance (Cinit). Accordingly, the parasitic component of the sensing signal Cs1 can be removed by the first offset capacitance Cinit and the second offset capacitance Cdelta, so that the output range of the sense data can be secured.

Referring to (b) of FIG. 5, the sense data (Sense Data, Dout) may be detected as a second threshold (TH2), for example, less than 1/4 of the maximum value of the sense data (Dout) ( B). The digital signal processor 12 may generate an offset control signal SW to form a second offset capacitance Cdelta that can reduce the first offset capacitance Cinit. Accordingly, the parasitic component of the sensing signal Cs1 can be removed by an amount excluding the second offset capacitance Cdelta from the first offset capacitance Cinit, so that the output range of the sense data can be secured.

That is, when the capacitance of the touch pad 200 increases due to the external environment, the sensing sensitivity can be improved by additionally removing parasitic components corresponding to the increase using the second offset capacitance. In addition, when the capacitance of the touch pad 200 decreases due to the external environment, sensing sensitivity can be improved by excluding parasitic components corresponding to the decrease from the first offset capacitance.

Figure 6 is a flowchart for explaining a method of operating a sensor device according to an embodiment.

As the sensor device 10 is powered on (S101), the detection signal processor 100 sends an initialization control signal (Dout) based on the detection data (Dout) generated from the detection signal (Cs1) provided from the touch pad 200. INIT) can be determined.

Accordingly, the first offset capacitor 1111 may be driven to set the first offset capacitance (Cinit) (S103).

The detection signal processor 100 may continuously monitor the detection signal Cs1 from the touch pad 200 (S105).

The detection signal processing unit 100 determines whether the detection data (Dout) generated from the sensing signal (Cs1) is outside a preset range, for example, is greater than the first threshold (TH1) or less than the second threshold (TH2). You can do it (S107).

If the detection data (Dout) does not exceed the preset range (S107:N), the detection signal processor 100 continues monitoring (S105).

When the detection data (Dout) is outside the preset range (S107:Y), the detection signal processor 100 generates an offset control signal (SW) to adjust the first offset capacitance (Cinit) to adjust the second offset capacitance (Cdelta). can be formed (S109). And, the first offset capacitance (Cinit) can be adjusted by the second offset capacitance (Cdelta).

For example, when the sensed data Dout is detected to be greater than or equal to the first threshold TH1, the second offset capacitance Cdelta may be formed to increase the first offset capacitance Cinit.

For example, when the sensed data Dout is detected to be less than the second threshold TH2, the second offset capacitance Cdelta may be formed to reduce the first offset capacitance Cinit.

Accordingly, the adjusted sensing signal Cs2 can be detected within the range of the range capacitor Crg.

This monitoring operation is performed in real time while the sensor device 10 is operating, so that the maximum detectable amount of change in capacitance (Cinit + 0.5Crg) can be secured.

As such, a person skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

10: sensor device
100: detection signal processing unit
200: touch pad

Claims (12)

An offset that forms a first offset capacitance in response to an initialization control signal, forms a second offset capacitance in response to an offset control signal, and outputs an offset removal capacitance by adjusting the first offset capacitance by the second offset capacitance. removal part;
an analog signal processor that generates digital level sensing data from the adjusted sensing capacitance in which the offset removal capacitance is removed from the sensing capacitance detected in the touch pad; and
a digital signal processor that generates the offset control signal by comparing the sensed data with a threshold;
A sensor device configured to include. According to claim 1,
The digital signal processor,
A sensor device that generates the offset control signal to increase the first offset capacitance when the sensed data is greater than or equal to a first threshold. According to claim 2,
The sensor device wherein the first threshold is set to correspond to 3/4 of the detectable sense data. According to claim 1,
The digital signal processor,
A sensor device that generates the offset control signal to reduce the first offset capacitance when the sensed data is less than or equal to a second threshold. According to claim 4,
The second threshold is set to correspond to 1/4 of the detectable sensed data. According to claim 1,
The analog signal processing unit includes a capacitance-voltage converter including a range capacitor that charges the adjusted sensing capacitance and outputs it as a sensing voltage, and an analog-to-digital converter configured to digitally convert the sensing voltage and output the sensing data. Contains,
The sensor device includes: a controller that sets the first offset capacitance to a value obtained by subtracting 1/2 of the range capacitance capacitance from the sensing capacitance when power is turned on;
A sensor device configured to further include. A sensor device that detects changes in capacitance of a touch pad,
setting a first offset capacitance in response to an initialization control signal;
setting a second offset capacitance in response to an offset control signal;
outputting an offset removal capacitance by adjusting the first offset capacitance by the second offset capacitance;
generating digital level sensing data from the adjusted sensing capacitance obtained by removing the offset removal capacitance from the sensing capacitance detected in the touch pad; and
generating the offset control signal by comparing the sensed data with a threshold;
A method of operating a sensor device configured to include. According to claim 7,
Generating the offset control signal includes generating the offset control signal to increase the first offset capacitance when the sensed data is greater than or equal to a first threshold. According to claim 8,
The method of operating a sensor device wherein the first threshold is set to correspond to 3/4 of the detectable sensed data. According to claim 7,
Generating the offset control signal includes generating the offset control signal to reduce the first offset capacitance when the sensed data is less than or equal to a second threshold. According to claim 10,
The second threshold is set to correspond to 1/4 of the detectable sensed data. According to claim 7,
Generating the sensed data includes charging the adjusted sensing capacitance with a range capacitor and outputting it as a sensing voltage, and digitally converting the sensing voltage to output the sensed data,
Setting the first offset capacitance, setting the first offset capacitance to a value obtained by subtracting 1/2 of the range capacitance capacitance from the sensing capacitance when the sensor device is powered on;
A method of operating a sensor device configured to further include.

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