Detection circuit and wearable device

Abstract

The embodiment of the invention provides a detection circuit and wearable equipment, the detection circuit comprises a voltage comparator, a capacitor plate and a main control chip, the first input end of the voltage comparator is connected with a power supply, the second input end of the voltage comparator is connected with the capacitor plate, and the output end of the voltage comparator is connected with the capacitor plate and the main control chip; the power supply module is used for receiving power supply voltage provided by a power supply, outputting first voltage under the condition that the voltage of the first input end is larger than that of the second input end, and outputting second voltage under the condition that the voltage of the first input end is smaller than that of the second input end. When a human body serving as a conductor approaches the capacitance plate, capacitance is formed, the capacitance continuously charges and discharges, the voltage comparator can continuously output first voltage and second voltage which are converted, and the main control chip can determine whether the human body approaches or not according to the voltage continuously output by the voltage comparator. The detection function can be realized through the circuit comprising the comparator, the capacitor plate and the main control chip, so that the device cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wearable devices, and particularly to a detection circuit and a wearable device. Background Art

[0002] At present, in the fields of consumer electronics and smart wearable devices, the mainstream technical solutions for object detection functions generally use infrared sensors to achieve. For traditional products such as beauty masks and beauty instruments, the detection and judgment of the wearing state are basically completed by integrating infrared sensor modules. However, adding an extra infrared sensor will significantly increase the cost. Summary of the Invention

[0003] In view of the above problems, embodiments of the present invention are proposed to provide a detection circuit and a wearable device that overcome the above problems or at least partially solve the above problems.

[0004] To solve the above problems, embodiments of the present invention disclose a detection circuit, which includes a voltage comparator, a capacitor plate, and a main control chip; The first input terminal of the voltage comparator is connected to a power supply, the second input terminal is connected to the capacitor plate, and the output terminal is respectively connected to the capacitor plate and the main control chip; the voltage comparator is configured to receive the power supply voltage provided by the power supply, and output a first voltage when the voltage at the first input terminal is greater than the voltage at the second input terminal; and output a second voltage when the voltage at the first input terminal is less than the voltage at the second input terminal; When the voltage comparator outputs the first voltage, the capacitor formed by the proximity of the capacitor plate to the human body is charged based on the voltage output by the voltage comparator until the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the second voltage, the capacitor discharges until the voltage at the first input terminal is greater than the voltage at the second input terminal; The main control chip is configured to determine whether it is close to a human body according to the voltage continuously output by the voltage comparator.

[0005] Optionally, the first voltage is a high level, and the second voltage is a low level.

[0006] Optionally, the main control chip is configured to determine that it is close to a human body when detecting that the voltage continuously output by the voltage comparator is an oscillating waveform.

[0007] Optionally, the detection circuit further includes a light-emitting device; One end of the light-emitting device is disposed between the output end of the voltage comparator and the main control chip, and the other end is grounded; the light-emitting device is configured to emit light when the voltage comparator outputs a high level and turn off when the voltage comparator outputs a low level.

[0008] Optionally, the detection circuit further includes a first resistor and a second resistor; The first resistor is disposed between the power supply and the first input terminal; One end of the second resistor is connected to the first input terminal of the voltage comparator, and the other end is grounded.

[0009] Optionally, the detection circuit further includes a third resistor; One end of the third resistor is connected to the first input terminal of the voltage comparator, and the other end is connected to the output end of the voltage comparator.

[0010] Optionally, the detection circuit further includes a fourth resistor; One end of the fourth resistor is connected to the output end of the voltage comparator, and the other end is connected to the capacitor plate.

[0011] Optionally, the detection circuit further includes a fifth resistor; The fifth resistor is disposed between the output end of the voltage comparator and the light-emitting device.

[0012] Optionally, the main control chip includes an analog-to-digital conversion interface, and the main control chip is configured to determine whether a human body is approaching according to the voltage output by the voltage comparator through the analog-to-digital conversion interface.

[0013] Correspondingly, an embodiment of the present invention discloses a wearable device including the detection circuit described in any one of the above.

[0014] The embodiments of the present invention have the following advantages: A detection circuit disclosed in an embodiment of the present invention includes a voltage comparator, a capacitor plate, and a main control chip. The first input terminal of the voltage comparator is connected to a power supply, the second input terminal is connected to the capacitor plate, and the output terminal is respectively connected to the capacitor plate and the main control chip. The voltage comparator is configured to receive the power supply voltage provided by the power supply, and output a first voltage when the voltage at the first input terminal is greater than the voltage at the second input terminal, and output a second voltage when the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the first voltage, the capacitor formed by the proximity of the capacitor plate and the human body is charged based on the voltage output by the voltage comparator until the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the second voltage, the capacitor discharges until the voltage at the first input terminal is greater than the voltage at the second input terminal; the main control chip is configured to determine whether it is close to the human body according to the voltage continuously output by the voltage comparator. Since a capacitor is formed when the human body as a conductor approaches the capacitor plate, and the capacitor continuously charges and discharges, the voltage comparator can continuously output the alternating first voltage and second voltage. The main control chip can determine whether it is close to the human body according to the voltage continuously output by the voltage comparator, and the detection function can be realized through a circuit including a comparator, a capacitor plate, and a main control chip, thereby reducing the device cost. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of a detection circuit according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of another detection circuit according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of an equivalent circuit according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of another equivalent circuit according to an embodiment of the present invention.

[0016] Reference numerals: voltage comparator 10, capacitor plate 20, human body 21, capacitor 23, main control chip 30, light-emitting device 40, first resistor 50, second resistor 51, third resistor 52, fourth resistor 53, fifth resistor 54. Detailed Embodiments

[0017] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0018] Currently, in the fields of consumer electronics and smart wearable devices, the mainstream technical solutions for object detection functions generally use infrared sensors to achieve. For traditional products such as beauty masks and beauty instruments, the detection and judgment of the wearing state are basically completed by integrating an infrared sensor module. However, adding an infrared sensor will significantly increase the cost.

[0019] One of the core concepts of the embodiments of the present invention is that when the human body as a conductor approaches the capacitor plate, a capacitor will be formed. The capacitor continuously charges and discharges, enabling the voltage comparator to continuously output a changing first voltage and second voltage. The main control chip can determine whether the human body is approaching based on the voltage continuously output by the voltage comparator. The detection function can be achieved through a circuit including a comparator, a capacitor plate, and a main control chip, avoiding the additional addition of an infrared sensor for detection and not requiring a detection chip, thereby reducing the device cost.

[0020] Referring to Figure 1 , a schematic structural diagram of a detection circuit according to an embodiment of the present invention is shown. The detection circuit includes a voltage comparator 10, a capacitor plate 20, and a main control chip 30.

[0021] The first input terminal of the voltage comparator 10 is connected to the power supply VCC, the second input terminal is connected to the capacitor plate 20, and the output terminal is respectively connected to the capacitor plate 20 and the main control chip 30. The voltage comparator 10 is configured to receive the power supply voltage provided by the power supply VCC, and output a first voltage when the voltage at the first input terminal is greater than the voltage at the second input terminal; and output a second voltage when the voltage at the first input terminal is less than the voltage at the second input terminal.

[0022] Exemplarily, the first input terminal may be the positive input terminal, the second input terminal may be the negative input terminal. The positive input terminal of the voltage comparator 10 is connected to the positive power supply voltage VCC, the negative input terminal of the voltage comparator 10 is connected to the capacitor plate 20, and the output terminal of the voltage comparator 10 is respectively connected to the capacitor plate 20 and the main control chip 30. The voltage comparator 10 outputs a first voltage when the voltage at the positive input terminal is greater than the voltage at the negative input terminal, and outputs a second voltage when the voltage at the positive input terminal is less than the voltage at the negative input terminal.

[0023] When the voltage comparator 10 outputs the first voltage, the capacitor formed by the proximity of the capacitor plate 20 to the human body (not shown in the figure) is charged based on the voltage output by the voltage comparator 10 until the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator 10 outputs the second voltage, the capacitor discharges until the voltage at the first input terminal is greater than the voltage at the second input terminal.

[0024] The capacitor plate is a key conductive component that constitutes a capacitor. It is usually made of metal or other conductive materials and is used to store electric charges and establish an electric field. A capacitor consists of two mutually insulated conductors (plates) with a dielectric (such as air, insulating material) filled in between. The role of the plates is to store electric charges. When there is a voltage between the plates, one plate accumulates positive charges and the other accumulates negative charges, forming an electric field.

[0025] The number of capacitor plates 20 in the embodiments of the present invention can be one. When a human body approaches the capacitor plate 20, a capacitor is formed between the human body and the capacitor plate 20. One plate of this capacitor is the capacitor plate 20, and the other plate is the human body as a conductor, with the medium being air or an insulating layer. The insulating layer can be a coating on the surface of the capacitor plate 20. Since the human body contains moisture and electrolytes, it can be regarded as a conductor and can form an electric field with the metal plate. The human body can be the palm or face of the human body. The capacitor plate 20 forms a similar capacitance effect through the palm or face. The capacitance effect is based on the principle of storing charges due to the potential difference between two conductors. When the palm of the human body approaches the capacitor plate, the human body as a conductor changes the surrounding electric field, resulting in a change in capacitance.

[0026] When the human body approaches the capacitor plate 20, a capacitor is formed between the capacitor plate 20 and the human body as a conductor. When the voltage comparator 10 outputs a first voltage, the capacitor is charged based on the first voltage output by the voltage comparator 10 until the voltage at the first input terminal of the voltage comparator 10 is less than the voltage at the second input terminal. Since the voltage comparator 10 outputs a second voltage when the voltage at the first input terminal of the voltage comparator 10 is less than the voltage at the second input terminal, that is to say, when the voltage comparator 10 outputs a first voltage, the capacitor will be charged until the voltage comparator 10 outputs a second voltage; when the voltage comparator 10 outputs a second voltage, the capacitor discharges until the voltage at the first input terminal of the voltage comparator 10 is greater than the voltage at the second input terminal. Since the voltage comparator 10 outputs a first voltage when the voltage at the first input terminal of the voltage comparator 10 is greater than the voltage at the second input terminal, that is to say, when the voltage comparator 10 outputs a second voltage, the capacitor will discharge until the voltage comparator 10 outputs a first voltage. When a capacitor is formed by the human body approaching the capacitor plate 20, the capacitor will continuously charge and discharge, thereby controlling the voltage comparator 10 to continuously alternate the output of the first voltage and the second voltage.

[0027] The main control chip 30 is used to determine whether the human body is approaching based on the voltage continuously output by the voltage comparator 10.

[0028] The main control chip 30 is connected to the output terminal of the voltage comparator 10, can receive the voltage output by the output terminal of the voltage comparator 10, and can determine whether the human body is approaching based on the voltage continuously output by the voltage comparator 10.

[0029] A detection circuit disclosed in an embodiment of the present invention includes a voltage comparator, a capacitor plate, and a main control chip. The first input terminal of the voltage comparator is connected to a power supply, the second input terminal is connected to the capacitor plate, and the output terminal is respectively connected to the capacitor plate and the main control chip. The voltage comparator is configured to receive the power supply voltage provided by the power supply, and output a first voltage when the voltage at the first input terminal is greater than the voltage at the second input terminal, and output a second voltage when the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the first voltage, the capacitor formed by the proximity of the capacitor plate and the human body is charged based on the voltage output by the voltage comparator until the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the second voltage, the capacitor discharges until the voltage at the first input terminal is greater than the voltage at the second input terminal; the main control chip is configured to determine whether the human body is close according to the voltage continuously output by the voltage comparator. Since the human body as a conductor forms a capacitor when approaching the capacitor plate, and the capacitor continuously charges and discharges, the voltage comparator can continuously output the alternating first voltage and second voltage. The main control chip can determine whether the human body is close according to the voltage continuously output by the voltage comparator, and the detection function can be realized through a circuit including a comparator, a capacitor plate, and a main control chip, thereby reducing the device cost.

[0030] In the embodiment of the present invention, the first voltage is a high level, and the second voltage is a low level.

[0031] When power is first applied, the voltage at the positive input terminal of the voltage comparator 10 is greater than the voltage at the negative input terminal, and the voltage comparator 10 outputs a high level. When the human body approaches the capacitor plate 20, the capacitor plate 20 and the human body as a conductor form a capacitor, and the capacitor is charged based on the high level output by the voltage comparator 10. Since the capacitor plate 20 is connected to the negative input terminal of the voltage comparator 10, the charging of the capacitor will affect the voltage at the negative input terminal of the voltage comparator 10. The capacitor is charged until the voltage at the negative input terminal of the voltage comparator 10 is greater than the voltage at the positive input terminal. At this time, the voltage comparator 10 changes from outputting a high level when power is first applied to outputting a low level. When the voltage comparator 10 outputs a low level, the capacitor discharges until the voltage at the negative input terminal of the voltage comparator 10 is less than the voltage at the positive input terminal. At this time, the voltage comparator 10 changes from outputting a low level to outputting a high level.

[0032] The capacitor is charged, which can increase the voltage at the inverting input terminal of the voltage comparator 10, so that the voltage at the inverting input terminal of the voltage comparator 10 is greater than the voltage at the non-inverting input terminal, and the voltage comparator 10 outputs a low level; the capacitor is discharged, which can reduce the voltage at the inverting input terminal of the voltage comparator 10, so that the voltage at the inverting input terminal of the voltage comparator 10 is less than the voltage at the non-inverting input terminal, and the voltage comparator 10 outputs a high level. By continuously charging and discharging, the capacitor can control the voltage comparator 10 to continuously output high and low levels, so that the main control chip 30 determines whether a human body is approaching according to the high and low levels output by this transformation.

[0033] In the embodiment of the present invention, the main control chip 30 is configured to determine that a human body is approaching when it detects that the voltage continuously output by the voltage comparator 10 is an oscillating waveform.

[0034] When a human body approaches the capacitor plate 20, the capacitor plate 20 and the human body as a conductor form a capacitor. By continuously charging and discharging, the capacitor controls the voltage comparator 10 to continuously output high and low levels. The voltage comparator 10 continuously outputs high and low levels, that is, an oscillating waveform. When the main control chip 30 detects that the voltage continuously output by the voltage comparator is an oscillating waveform, it can be determined that a human body is approaching. The detection circuit can be arranged on devices that need to detect the human body position, such as beauty masks, beauty instruments, etc. When the main control chip 30 detects that the voltage continuously output by the voltage comparator 10 is an oscillating waveform, it determines that the user has successfully worn the beauty mask. When it is confirmed that the user has successfully worn the beauty mask, the beauty mask can start to work.

[0035] When the main control chip 30 detects that the voltage continuously output by the voltage comparator 10 is an oscillating waveform, it can determine that a human body is approaching. By detecting in this way, there is no need to additionally increase an infrared sensor or an additional detection chip, thus reducing the device cost.

[0036] Refer to Figure 2 , which shows a schematic structural diagram of another detection circuit according to the embodiment of the present invention. The detection circuit further includes a light-emitting device 40; One end of the light-emitting device 40 is arranged between the output terminal of the voltage comparator 10 and the main control chip 30, and the other end is grounded; the light-emitting device 40 is configured to emit light when the voltage comparator 10 outputs a high level and go out when the voltage comparator 10 outputs a low level.

[0037] Exemplarily, the light-emitting device 40 may be a light-emitting diode. One end of the light-emitting device 40 is disposed between the output terminal of the voltage comparator 10 and the main control chip 30, and the other end is grounded. The light-emitting device 40 can receive the voltage output by the voltage comparator 10. When the voltage comparator 10 outputs a high level, the light-emitting device 40 emits light based on the voltage output by the voltage comparator 10. When the voltage comparator 10 outputs a low level, the light-emitting device 40 is extinguished.

[0038] When the human body 21 approaches the capacitor plate 20, the capacitor plate 20 and the human body 21 as a conductor form a capacitor 23. At the beginning of power-on, the voltage at the positive input terminal of the voltage comparator 10 is greater than the voltage at the negative input terminal, and the voltage comparator 10 outputs a high level. The capacitor 23 is charged based on the high level output by the voltage comparator 10. At the same time, the light-emitting device 40 emits light. The capacitor 23 is charged until the voltage at the negative input terminal of the voltage comparator 10 is greater than the voltage at the positive input terminal. At this time, the voltage comparator 10 changes from outputting a high level at the beginning of power-on to outputting a low level. The voltage comparator 10 outputs a low level, and the light-emitting device 40 is extinguished. At the same time, the capacitor 23 discharges until the voltage at the negative input terminal of the voltage comparator 10 is less than the voltage at the positive input terminal. At this time, the voltage comparator 10 changes from outputting a low level to outputting a high level. Then, the light-emitting device 40 emits light again, and the capacitor 23 is charged again, and the cycle continues. The capacitor 23 continuously charges and discharges in a cycle, controlling the voltage comparator 10 to continuously change between outputting a high level and a low level. The light-emitting device 40 also continuously changes between emitting light and being extinguished, so that the light-emitting device 40 forms a flicker. Therefore, if the human body 21 approaches the capacitor plate 20, a capacitor 23 will be formed, and the light-emitting device 40 will also flicker. The state of the light-emitting device 40 can be intuitively checked to determine whether a person is approaching. If the light-emitting device 40 flickers, it can be determined that a person is approaching. Exemplarily, the detection circuit is disposed in a beauty mask. If it is observed that the lamp bead flickers, it can be determined that the user has successfully worn the beauty mask. Determining whether a person is approaching by whether the light-emitting device 40 flickers is not only intuitive and convenient, but also allows the user to easily determine whether the wearing is successful, improving the user experience. Moreover, there is no need to additionally increase an infrared sensor or an additional detection chip, thereby reducing the device cost.

[0039] In the embodiment of the present invention, the detection circuit further includes a first resistor 50 and a second resistor 51.

[0040] The first resistor 50 is disposed between the power supply and the first input terminal.

[0041] Exemplarily, the power supply voltage VCC is 5V. The first resistor 50 is connected between the power supply VCC and the positive input terminal of the voltage comparator 10, which plays a role in voltage division and current limiting. The power supply voltage can provide a high-level signal to the positive input terminal of the voltage comparator 10 through the first resistor 50.

[0042] One end of the second resistor 51 is connected to the first input terminal of the voltage comparator 10, and the other end is grounded.

[0043] One end of the second resistor 51 is connected to the positive input terminal of the voltage comparator 10, and the other end is grounded. The second resistor 51 and the first resistor 50 together form a voltage division network for setting the reference voltage of the positive input terminal of the voltage comparator 10. The first resistor 50 and the second resistor 51 form a resistor voltage division circuit. The voltage at the positive input terminal of the voltage comparator 10 is determined by the following formula:

[0044] wherein, R50 is the resistance value of the first resistor 50, and R51 is the resistance value of the second resistor 51. By adjusting the ratio of these two resistors, the trigger threshold of the comparator can be accurately set. The voltage division circuit composed of the first resistor 50 and the second resistor 51 can provide a stable reference voltage for the voltage comparator 10, which is simpler and lower in cost than a zener diode or a dedicated reference source. Moreover, the voltage division circuit can limit the voltage input to the subsequent circuit, such as the voltage comparator 10, to prevent overvoltage damage.

[0045] Exemplarily, the resistance value of the first resistor 50 is 10 kΩ, and the resistance value of the second resistor 51 is 10 kΩ. When power is first applied, the voltage at the positive input terminal of the voltage comparator 10 is 1 / 2 VCC, and the voltage at the negative input terminal of the voltage comparator 10 is 0V, that is, the voltage at the positive input terminal of the voltage comparator 10 is greater than the voltage at the negative input terminal. At this time, the voltage comparator 10 outputs a high level, the light-emitting device 40 emits light, and the capacitor 23 is charged.

[0046] In the embodiment of the present invention, the detection circuit further includes a third resistor 52.

[0047] One end of the third resistor 52 is connected to the first input terminal of the voltage comparator 10, and the other end is connected to the output terminal of the voltage comparator 10.

[0048] One end of the third resistor 52 is connected to the positive input terminal of the voltage comparator 10, and the other end is connected to the output terminal of the voltage comparator 10. In this way, the third resistor 52 and the voltage division network composed of the first resistor 50 and the second resistor 51 together form a feedback network, which affects the input voltage of the positive input terminal of the voltage comparator 10.

[0049] When the voltage comparator 10 outputs a high level, for example, when the voltage comparator 10 outputs VCC, the third resistor 52 will feedback a part of the output voltage of the voltage comparator 10 to the positive input terminal, making the voltage comparator 10 more stably maintain a high level; when the voltage comparator 10 outputs a low level, for example, when the voltage comparator 10 outputs 0V, the third resistor 52 will pull down the voltage of the positive input terminal, making the voltage comparator more stably maintain a low level. Therefore, in this way, the third resistor 52 can prevent false triggering caused by input signal noise, improve the anti-interference ability, and enhance the stability of the circuit.

[0050] Exemplarily, the resistance value of the first resistor 50 is 10 kΩ, the resistance value of the second resistor 51 is 10 kΩ, and the resistance value of the third resistor 52 is 10 kΩ. When just powered on, that is, at the moment of power-on, the voltage of the positive input terminal of the voltage comparator 10 is only divided by the first resistor 50 and the second resistor 51. At this time, the voltage of the positive input terminal of the voltage comparator 10 is 1 / 2 VCC. Since the initial voltage of the capacitor 23 is 0V (not charged), that is, the voltage of the negative input terminal of the voltage comparator 10 is 0V, and the voltage of the positive input terminal of the voltage comparator 10 is greater than the voltage of the negative input terminal, the voltage comparator 10 outputs a high level, that is, VCC.

[0051] Then, after the voltage comparator 10 outputs VCC, the light-emitting device 40 emits light, and the capacitor 23 is charged. At the same time, the third resistor 52 will inject current into the positive input terminal of the voltage comparator 10. At this time, the voltage of the positive input terminal is jointly determined by the first resistor 50, the second resistor 51, and the third resistor 52. The first resistor 50 pulls current from the power supply VCC to the positive input terminal, the second resistor 51 pulls current from the positive input terminal to the ground (GND), and the third resistor 52 pulls current from the output terminal VCC to the positive terminal. Refer to Figure 3 , which shows a schematic structural diagram of an equivalent circuit according to an embodiment of the present invention. Since the first resistor 50 and the third resistor 52 are both connected to VCC and the positive terminal, it is equivalent to the parallel connection of the first resistor 50 and the third resistor 52. The equivalent resistance after parallel connection: , where R is a resistance value of 10 kΩ, and then it is in series with the second resistor 51 for voltage division: , that is, the voltage of the positive input terminal is 2 / 3 VCC.

[0052] Due to the positive feedback of the third resistor 52, the voltage of the positive input terminal rises from 1 / 2 VCC at the moment of power-on to 2 / 3 VCC.

[0053] In the embodiment of the present invention, the detection circuit further includes a fourth resistor 53.

[0054] One end of the fourth resistor 53 is connected to the output terminal of the voltage comparator 10, and the other end is connected to the capacitor plate 20.

[0055] One end of the fourth resistor 53 is connected to the output terminal of the voltage comparator 10, and the other end is connected to the capacitor plate 20. The fourth resistor 53 is the charging resistor for the capacitor 23. At the beginning of power-on, that is, at the moment of power-on, the voltage at the positive input terminal of the voltage comparator 10 is divided only by the first resistor 50 and the second resistor 51. At this time, the voltage at the positive input terminal of the voltage comparator 10 is 1 / 2VCC. Since the initial voltage of the capacitor 23 is 0V (not charged), that is, the voltage at the negative input terminal of the voltage comparator 10 is 0V, and the voltage at the positive input terminal of the voltage comparator 10 is greater than the voltage at the negative input terminal, the voltage comparator 10 outputs a high level, that is, VCC. At this time, when the capacitor 23 is charged through the fourth resistor 53, the voltage at the inverting input terminal of the voltage comparator 10 also starts to rise from 0V. Since the voltage at the positive input terminal of the voltage comparator 10 has risen from 1 / 2VCC at the moment of power-on to 2 / 3VCC, therefore, when the voltage of the capacitor 23 is charged until the voltage of the capacitor 23 is greater than 2 / 3VCC of the positive input terminal, that is, when the voltage at the negative input terminal is greater than the voltage at the positive input terminal, the voltage comparator 10 outputs a low level, that is, outputs 0V.

[0056] Next, when the voltage comparator 10 outputs 0V, it is equivalent to grounding. The third resistor 52 changes from being connected to the high level VCC output by the output terminal of the voltage comparator 10 to being connected to 0V. Therefore, the third resistor 52 is equivalent to being pulled down from the positive input terminal of the voltage comparator 10 to the ground. At this time, the voltage at the positive input terminal is jointly determined by the first resistor 50, the second resistor 51, and the third resistor 52. The first resistor 50 pulls up from VCC to the positive input terminal, the second resistor 51 pulls down from the positive terminal to the ground, and the third resistor 52 pulls down from the positive terminal to the ground (because the output terminal is 0V). Refer to Figure 4 , which shows the schematic structural diagram of another equivalent circuit of the embodiment of the present invention. Since both the second resistor 51 and the third resistor 52 are connected from the positive input terminal to the ground, the second resistor 51 and the third resistor 52 are in a parallel relationship. The equivalent resistance after parallel connection: , the voltage at the positive input terminal is divided by the first resistor 50 and the equivalent resistance after the parallel connection of the second resistor 51 and the third resistor 52: , that is to say, after the voltage comparator 10 outputs a low level of 0V, the third resistor 52 pulls down the voltage at the positive input terminal and, together with the second resistor 51, makes the voltage at the positive input terminal drop from 2 / 3VCC to 1 / 3VCC.

[0057] Meanwhile, when the voltage comparator 10 outputs a low level of 0V, one end of the fourth resistor 53 is grounded, and the other end is connected to the inverting input terminal. The capacitor 23 was charged to a voltage greater than 2 / 3VCC before. Now, it needs to discharge through the loop formed by the fourth resistor 53 and the ground. The discharge path is as follows: the positive electrode of the capacitor 23, the fourth resistor 53, the output terminal of the voltage comparator 10 (0V), and the ground. The negative electrode of the capacitor is directly grounded to form a complete discharge loop. Both the capacitor 23 and the fourth resistor 53 are connected between the inverting input terminal and the ground. Therefore, the capacitor 23 and the fourth resistor 53 are in a parallel relationship. The discharge current of the capacitor 23 completely flows through the fourth resistor 53 to the ground. That is to say, when the voltage comparator 10 outputs a low level of 0V, the capacitor 23 will discharge, and the light-emitting device 40 will turn off.

[0058] During the capacitor charging stage, the fourth resistor 53 acts as a charging resistor, which can limit the current flowing from the output terminal to the capacitor 23 and prevent the voltage comparator 10 from being damaged by an instantaneous large current. During the capacitor 23 discharge stage, it can provide a discharge path for the capacitor 23. By adjusting the resistance value of the fourth resistor 53, the charge and discharge speed of the capacitor 23 can be directly controlled, thereby adjusting the response time of the voltage comparator 10 to change the output signal.

[0059] Since, after the voltage comparator 10 outputs a low level of 0V, the voltage at the non-inverting input terminal drops from 2 / 3VCC to 1 / 3VCC, the capacitor 23 discharges, and the light-emitting device 40 turns off. When the capacitor 23 gradually discharges and the voltage of the capacitor 23 gradually discharges from greater than 2 / 3VCC until it is less than 1 / 3VCC, at this time, the voltage at the non-inverting input terminal becomes greater than the voltage at the inverting input terminal again, the voltage comparator 10 outputs a high level of VCC again, the capacitor 23 is charged again, and the light-emitting device 40 lights up again. Working in this way repeatedly, the capacitor 23 is repeatedly charged and discharged, the light-emitting device 40 repeatedly flashes, the voltage comparator 10 repeatedly outputs high and low levels, and the output waveform of the voltage comparator 10 is similar to an oscillating waveform.

[0060] When the human body 21 is close to the capacitor plate 20, the human body 21 and the capacitor plate 20 form a capacitor 23. On the basis of forming the capacitor 23, at the moment of power-on, the voltage at the positive input terminal of the voltage comparator 10 is 1 / 2VCC. The output terminal of the voltage comparator 10 outputs a high level VCC, and the light-emitting device 40 emits light. The capacitor 23 is charged. At the same time, due to the positive feedback of the third resistor 52, the voltage at the positive input terminal rises from 1 / 2VCC at the moment of power-on to 2 / 3VCC. Then, the capacitor 23 is charged through the fourth resistor 53 until the charged voltage is greater than the voltage 2 / 3VCC at the positive input terminal. At this time, the voltage at the negative input terminal is greater than the voltage at the positive input terminal, and the voltage comparator 10 outputs a low level 0V. At this time, the voltage at the positive input terminal drops from 2 / 3VCC to 1 / 3VCC, and the light-emitting device 40 goes out. The capacitor 23 discharges through the fourth resistor 53. When the voltage of the capacitor 23 gradually discharges from being greater than 2 / 3VCC until it is less than 1 / 3VCC, the voltage at the negative input terminal is less than the voltage at the positive input terminal, and the output terminal of the voltage comparator 10 outputs a high level VCC again. The capacitor 23 is charged again, and the light-emitting device 40 emits light again. It works repeatedly like this, and the light-emitting device 40 blinks repeatedly. The voltage comparator 10 outputs an oscillating waveform. Therefore, when the main control chip 30 detects the oscillating waveform output by the voltage comparator 10, it can determine that it is close to the human body, and the user wears the beauty mask successfully. At the same time, the user can also determine that the beauty mask is worn successfully by observing the blinking of the lamp beads.

[0061] In the embodiment of the present invention, the detection circuit further includes a fifth resistor 54.

[0062] The fifth resistor 54 is arranged between the output terminal of the voltage comparator 10 and the light-emitting device 40.

[0063] The fifth resistor 54 is a current-limiting resistor for the light-emitting device 40 and is connected between the output terminal of the voltage comparator 10 and the light-emitting device 40. The fifth resistor 54 can prevent the light-emitting device 40 from being damaged by overcurrent and can also adjust the brightness of the light-emitting device 40 by adjusting the resistance value. The larger the resistance value of the fifth resistor 54, the smaller the current of the light-emitting device 40 and the lower the brightness. On the contrary, the smaller the resistance value of the fifth resistor 54, the larger the current of the light-emitting device 40 and the higher the brightness.

[0064] The light-emitting device 40 can be an LED (Light Emitting Diode). A light-emitting diode is a semiconductor device that can directly convert electrical energy into light energy. It belongs to a type of diode and has unidirectional conductivity, emitting light only when forward-biased. Since a light-emitting diode is a non-linear device, rapid switching may cause voltage oscillation. The fifth resistor 54 can damp the transient response, reduce noise, and also prevent reverse breakdown. For example, if the comparator outputs a low level (0V) while the cathode of the light-emitting diode is connected to a high voltage (wrong design), the fifth resistor 54 can limit the reverse current. Therefore, the fifth resistor 54 is a current-limiting resistor, which can prevent the light-emitting device 40 from being damaged due to overcurrent. Moreover, by adjusting the resistance value, the brightness of the light-emitting device 40 can be changed. Additionally, it can suppress noise and voltage spikes.

[0065] In the embodiment of the present invention, the main control chip 30 includes an analog-to-digital conversion interface. The main control chip 30 is configured to determine whether a human body is approaching based on the voltage output by the voltage comparator 10 through the analog-to-digital conversion interface.

[0066] The main control chip 30 can sample the output signal of the voltage comparator 10 in real time through the analog-to-digital conversion interface, and determine whether the continuously output signal of the voltage comparator 10 is an oscillating waveform. When the human body 21 approaches the capacitor plate 20, a capacitor is formed. At the moment of power-on, the voltage at the positive input terminal of the voltage comparator 10 is 1 / 2VCC, the output terminal of the voltage comparator 10 outputs a high level VCC, and the light-emitting device 40 emits light. The capacitor 23 is charged. At the same time, due to the positive feedback of the third resistor 52, the voltage at the positive input terminal rises from 1 / 2VCC at the moment of power-on to 2 / 3VCC. Then, the capacitor 23 is charged through the fourth resistor 53 until the charged voltage is greater than the voltage 2 / 3VCC at the positive input terminal. At this time, the voltage at the negative input terminal is greater than the voltage at the positive input terminal, and the voltage comparator 10 outputs a low level 0V. At this time, the voltage at the positive input terminal drops from 2 / 3VCC to 1 / 3VCC, and the light-emitting device 40 goes out. The capacitor 23 discharges through the fourth resistor 53. When the voltage of the capacitor 23 gradually discharges from greater than 2 / 3VCC until it is less than 1 / 3VCC, the voltage at the negative input terminal is less than the voltage at the positive input terminal, and the output terminal of the voltage comparator 10 outputs a high level VCC again. The capacitor 23 is charged again, and the light-emitting device 40 emits light again. This process repeats, and the light-emitting device 40 flashes repeatedly, and the voltage comparator 10 outputs an oscillating waveform. Therefore, when the main control chip 30 samples the output signal of the voltage comparator 10 in real time through the analog-to-digital conversion interface and determines that the continuously output signal of the voltage comparator 10 is an oscillating waveform, it can be determined that a human body is approaching; if the main control chip 30 samples the output signal of the voltage comparator 10 in real time through the analog-to-digital conversion interface and determines that the continuously output signal of the voltage comparator 10 is not an oscillating waveform, it can be determined that no human body is approaching, and at this time the lamp beads will not flash.

[0067] The main control chip 30 samples the output signal of the voltage comparator 10 in real time through the analog-to-digital conversion interface, so as to determine whether a human body is approaching. There is no need to additionally add an infrared sensor or a detection chip, thus reducing the device cost.

[0068] A detection circuit disclosed in an embodiment of the present invention includes a voltage comparator, a capacitor plate and a main control chip. The first input end of the voltage comparator is connected to a power supply, the second input end is connected to the capacitor plate, and the output end is respectively connected to the capacitor plate and the main control chip. The voltage comparator is used to receive the power supply voltage provided by the power supply, and output a first voltage when the voltage at the first input end is greater than the voltage at the second input end, and output a second voltage when the voltage at the first input end is less than the voltage at the second input end; when the voltage comparator outputs the first voltage, the capacitor formed by the approach of the capacitor plate and the human body is charged based on the voltage output by the voltage comparator until the voltage at the first input end is less than the voltage at the second input end; when the voltage comparator outputs the second voltage, the capacitor discharges until the voltage at the first input end is greater than the voltage at the second input end; the main control chip is used to determine whether a human body is approaching according to the voltage continuously output by the voltage comparator. Since the human body as a conductor forms a capacitor when approaching the capacitor plate, and the capacitor continuously charges and discharges, the voltage comparator can continuously output the alternating first voltage and second voltage. The main control chip can determine whether a human body is approaching according to the voltage continuously output by the voltage comparator, and the detection function can be realized through a circuit including a comparator, a capacitor plate and a main control chip, thus reducing the device cost.

[0069] An embodiment of the present invention further provides a wearable device, including the detection circuit described in any one of the above.

[0070] Exemplarily, the wearable device can be a beauty mask, a beauty instrument, a bracelet and other devices. The detection circuit is arranged in the wearable device, and only the internal circuit of the wearable device, that is, the detection circuit, can be used to realize the function of detecting the human body position. For example, it can detect whether the beauty mask is successfully worn, avoiding the need to additionally add an infrared sensor for detection and not requiring a detection chip, thus reducing the device cost.

[0071] In the embodiment of the present invention, the distance between the capacitor plates and the parameters can be adjusted according to the wearing distance requirement to adapt to different application products, and the distance between the human body and the capacitor plates when wearing successfully can be adjusted according to the demand.

[0072] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0073] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, apparatus, or computer program product. Therefore, the embodiments of the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0074] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate a device for implementing the functions specified in Figure 1 one or more of the processes and / or blocks Figure 1 or multiple blocks.

[0075] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one or more of the processes and / or blocks Figure 1 or multiple blocks.

[0076] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, such that a series of operation steps are executed on the computer or other programmable terminal device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable terminal device provide steps for implementing the functions specified in Figure 1 one or more of the processes and / or blocks Figure 1 or multiple blocks.

[0077] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the embodiments of the present invention.

[0078] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising said element.

[0079] The above has introduced in detail a detection circuit and a wearable device provided by the present invention. Specific examples are used in this text to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A detection circuit, characterized in that, The detection circuit includes a voltage comparator, a capacitor plate, and a main control chip; The first input terminal of the voltage comparator is connected to a power supply, the second input terminal is connected to the capacitor plate, and the output terminal is respectively connected to the capacitor plate and the main control chip; the voltage comparator is configured to receive the power supply voltage provided by the power supply, and output a first voltage when the voltage at the first input terminal is greater than the voltage at the second input terminal; Output a second voltage when the voltage at the first input terminal is less than the voltage at the second input terminal; When the voltage comparator outputs the first voltage, the capacitor formed by the proximity of the capacitor plate to the human body is charged based on the voltage output by the voltage comparator until the voltage at the first input terminal is less than the voltage at the second input terminal; when the voltage comparator outputs the second voltage, the capacitor discharges until the voltage at the first input terminal is greater than the voltage at the second input terminal; The main control chip is configured to determine whether it is close to a human body according to the voltage continuously output by the voltage comparator.

2. The detection circuit according to claim 1, wherein The first voltage is a high level, and the second voltage is a low level.

3. The detection circuit according to claim 1, characterized in that, The main control chip is configured to determine that it is close to a human body when it detects that the voltage continuously output by the voltage comparator is an oscillating waveform.

4. The detection circuit according to claim 2, wherein The detection circuit further includes a light-emitting device; One end of the light-emitting device is disposed between the output terminal of the voltage comparator and the main control chip, and the other end is grounded; the light-emitting device is configured to emit light when the voltage comparator outputs a high level, and go out when the voltage comparator outputs a low level.

5. The detection circuit according to claim 1, wherein The detection circuit further includes a first resistor and a second resistor; The first resistor is disposed between the power supply and the first input terminal; One end of the second resistor is connected to the first input terminal of the voltage comparator, and the other end is grounded.

6. The detection circuit according to claim 5, wherein The detection circuit further includes a third resistor; One end of the third resistor is connected to the first input terminal of the voltage comparator, and the other end is connected to the output terminal of the voltage comparator.

7. The detection circuit according to claim 6, characterized in that The detection circuit further includes a fourth resistor; One end of the fourth resistor is connected to the output terminal of the voltage comparator, and the other end is connected to the capacitor plate.

8. The detection circuit according to claim 4, wherein The detection circuit further includes a fifth resistor; The fifth resistor is disposed between the output terminal of the voltage comparator and the light-emitting device.

9. The detection circuit according to claim 1, wherein The main control chip includes an analog-to-digital conversion interface, and the main control chip is configured to determine whether it is close to a human body according to the voltage output by the voltage comparator through the analog-to-digital conversion interface.

10. A wearable device, characterized in that, Including the detection circuit according to any one of claims 1-9.

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