Low-power control method for wearable device using photoplethysmography sensor.

Abstract

A low-power control method for a wearable device using a PPG sensor is provided. A method for controlling a wearable device according to an embodiment of the present invention comprises: detecting proximity of a human body to the wearable device; attempting heartbeat measurement when the proximity of the human body is detected; attempting oxygen saturation measurement when the heartbeat is measured; and maintaining a heartbeat amplitude in a predetermined range when the oxygen saturation is measured. Accordingly, on the basis of the status of biological signal detection in the wearable device, LED modules and processor modules can be selectively turned on or activated in a distinguishable manner through multi-stage mode operations so as to control low-power operation of the wearable device, thereby reducing battery consumption and maximizing the usage time thereof.

Description

Low-power control method for wearable devices using photoplethysmography sensors

[0001] The present invention relates to control of a wearable device, and more particularly, to a method for controlling low-power mode operation in a wearable device that must measure proximity, heart rate, and oxygen saturation using a PPG (PhotoPlethysmoGraphy) sensor.

[0002] Wearable devices, such as clothing, watches, and accessories, are devices that can be worn on the body. Because they operate on batteries, they require control algorithms for low-power operation, such as sleep / standby mode and shutdown mode, to ensure long-term operation after a single charge. Typically, wearable devices use proximity sensors to determine whether they are being worn and switch to sleep / standby mode when not in use, thereby reducing battery consumption and extending usage time.

[0003] However, recently, wearable devices have gone beyond providing various smart functions and have built-in circuits for measuring bio-signals for health management, such as PPG sensors for measuring heart rate and oxygen saturation. Therefore, low-power control has become more important. However, the problem is that the conventional low-power control method is not enough to secure sufficient usage time.

[0004] The present invention has been devised to solve the above problems, and the purpose of the present invention is to provide a method for controlling low-power operation of a wearable device through operation of multiple stages of modes depending on the bio-signal detection situation of the wearable device, breaking away from the fragmented existing method of relying only on a single proximity sensor for low-power control of a wearable device.

[0005] A method for controlling a wearable device according to one embodiment of the present invention for achieving the above object includes: a step of detecting proximity of a human body to a wearable device; a first attempt step of attempting to measure a heartbeat when proximity of a human body is detected; and a second attempt step of attempting to measure oxygen saturation when the heartbeat is measured.

[0006] The detection step may be performed by turning on the IR-LED and photo-diode that make up the PPG sensor and activating the proximity sensing module within the processor.

[0007] The first attempt step may be performed by activating a DC feedback circuit to remove DC from the detection signal of the photodiode and a heart rate sensing module within the processor.

[0008] The wearable device control method according to the present invention may further include a step of deactivating a DC feedback circuit and a heart rate sensing module within the processor if a heart rate is not measured after the first attempt step.

[0009] The second attempt step may be performed by turning on the RED LED constituting the PPG sensor and activating the oxygen saturation sensing module within the processor.

[0010] The wearable device control method according to the present invention may further include a step of turning off the RED LED and deactivating the oxygen saturation sensing module within the processor if the oxygen saturation is not measured after the second attempt step.

[0011] A wearable device control method according to the present invention may further include a step of determining whether a heartbeat amplitude is within a predetermined range when oxygen saturation is measured; and a step of continuously measuring a heartbeat and oxygen saturation if the heartbeat amplitude is within the predetermined range.

[0012] The judgment step may be performed by turning on the GREEN LED that constitutes the PPG sensor.

[0013] The wearable device control method according to the present invention may further include a step of adjusting the intensity of the RED LED and the GREEN LED if the heartbeat amplitude is not within a predetermined range.

[0014] According to another aspect of the present invention, a method for controlling a wearable device is provided, comprising: a multi-LED including a plurality of LEDs; a photodiode detecting light reflected from a human body after being irradiated by the multi-LED; and a processor detecting proximity of the wearable device to a human body based on a detection result of the photodiode, attempting to measure a heartbeat when proximity of the human body is detected, and attempting to measure oxygen saturation when the heartbeat is measured.

[0015] According to another aspect of the present invention, a wearable device is provided, characterized by including a first attempt step of attempting to measure a heart rate; if the heart rate is measured, a second attempt step of attempting to measure oxygen saturation; if the oxygen saturation is measured, a step of determining whether the heart rate amplitude is within a predetermined range; and if the heart rate amplitude is within the predetermined range, a step of continuously measuring the heart rate and oxygen saturation.

[0016] According to another aspect of the present invention, a wearable device is provided, comprising: a multi-LED including a plurality of LEDs; a photodiode detecting light reflected from a human body after being irradiated by the multi-LED; and a processor configured to attempt to measure a heart rate based on a detection result of the photodiode, attempt to measure oxygen saturation when the heart rate is measured, determine whether the heart rate amplitude is within a predetermined range when the oxygen saturation is measured, and continue to measure the heart rate and oxygen saturation when the heart rate amplitude is within the predetermined range.

[0017] As described above, according to embodiments of the present invention, rather than determining only whether the wearable device is worn and dividing it into an operation mode or a standby mode, the LEDs and processor modules are selectively turned on / activated through multiple mode operations by distinguishing them according to the bio-signal detection situation in the wearable device, thereby controlling low-power operation of the wearable device, thereby reducing battery consumption of the wearable device and maximizing its usage time.

[0018] Figure 1 is a configuration of a wearable device with a built-in PPG sensor according to one embodiment of the present invention, and

[0019] Figures 2 and 3 are diagrams illustrating the flow of a low-power / optimized control method for a wearable device using a PPG sensor.

[0020] Hereinafter, the present invention will be described in more detail with reference to the drawings.

[0021] An embodiment of the present invention proposes a low-power control method for a wearable device using a PhotoPlethysmography (PPG) sensor. This technology controls low-power mode operation in a wearable device that uses a PPG sensor to measure proximity, heart rate, and oxygen saturation.

[0022] Unlike existing technologies that operate in a dual mode of operation or standby mode by only determining whether the wearable device is worn or not by relying on only one proximity sensor for low-power control of a wearable device, in an embodiment of the present invention, the low-power operation of the wearable device is controlled through operation in multiple stages of modes by distinguishing between LEDs and processor modules depending on the bio-signal detection situation of the wearable device.

[0023] In addition, in an embodiment of the present invention, rather than adding a proximity sensor to detect whether a wearable device is being worn, a PPG sensor is utilized to detect whether the wearable device is being worn.

[0024] A wearable device for performing such a function is illustrated in Fig. 1. Fig. 1 is a diagram illustrating the configuration of a wearable device with a built-in PPG sensor according to one embodiment of the present invention.

[0025] A wearable device according to an embodiment of the present invention is configured to include, as illustrated, a multi-LED (110), an LED driver (120), a DC feedback circuit (130), a photodiode (140), an AFE (Analog Front End, 150), an ADC (Analog-to-Digital Converter, 160), and a DSP (Digital Signal Processor, 170).

[0026] The multi-LED (110) and photodiode (140) are components for implementing a PPG sensor for measuring heart rate and oxygen saturation. The multi-LED (110) includes an IR-LED, a RED-LED, and a GREEN-LED.

[0027] The LED driver (120) applies driving current to the IR-LED, RED-LED, and GREEN-LED constituting the multi-LED (110). The driving current by the LED driver (120) is controlled by the DSP (170) described later.

[0028] The photodiode (140) is a sensor for detecting an optical signal reflected from the human body after being emitted from the multi-LED (110). The DC feedback circuit (130) is a circuit for removing the DC component from the optical signal detected by the photodiode (140).

[0029] The AFE (150) performs necessary analog signal processing, such as amplification and filtering, on the detection signal of the photodiode (140). The ADC (160) converts the analog signal processed by the AFE (150) into a digital signal and transmits it to the DSP (170).

[0030] The DSP (170) performs human proximity detection, heart rate measurement, and oxygen saturation measurement through digital signal processing on the detection signal of the photodiode (140) converted into a digital signal by the ADC (160), and the DSP (170) controls the driving of the multi-LED (110) by the LED driver (120) and the operation of the DC feedback circuit (130) and the AFE (150).

[0031] The DSP (170) performing such a function is configured to include an optimization module (171), an oxygen saturation sensing module (172), a heart rate sensing module (173), and a proximity sensing module (174), as shown in FIG. 1.

[0032] The optimization module (171) controls the driving current of the multi-LED (110) generated by the LED driver (120), thereby controlling the intensity of the light emitted from the IR-LED, RED-LED, and GREEN-LED constituting the multi-LED (110).

[0033] The proximity sensing module (174) detects the proximity of a human body based on the intensity of the IR detection signal by the photodiode (140).

[0034] The heart rate sensing module (173) detects a heart rate from a detection signal by a photodiode (140) and measures the heart rate amplitude. The oxygen saturation sensing module (172) measures oxygen saturation from a detection signal by a photodiode (140).

[0035] The process of controlling low-power and optimized operation of a wearable device under the control of a DSP (170) will be described in detail below with reference to FIGS. 2 and 3. FIGS. 2 and 3 are diagrams illustrating the flow of a low-power / optimized control method for a wearable device using a PPG sensor.

[0036] As illustrated, first, an IR signal is detected to detect the proximity of a human body to a wearable device (S210). The IR signal is a light signal that is emitted from the IR-LED of the multi-LED (110), reflected from the human body, and detected by the photo-diode (140). To perform step S210, the IR-LED, photo-diode (140), AFE (150), and ADC (160) of the multi-LED (110) in the wearable device are always turned on. In addition, only the optimization module (171) and the proximity sensing module (174) are enabled in the DSP (170).

[0037] When the proximity of a human body is detected, for example, when a human body approaches the wearable device within 5 mm (S220-Y), the wearable device attempts to measure a heart rate (S230). To perform step S230, the DSP (170) turns on the DC feedback circuit (130) and enables the heart rate sensing module (173).

[0038] On the other hand, if the proximity of a human body is not detected in step S220 (S220-N), it returns to step S210.

[0039] Meanwhile, when the heart rate is measured by performing step S230 (S240-Y), the wearable device attempts to measure oxygen saturation (S250). To perform step S250, the DSP (170) turns on the RED LED of the multi-LED (110) and enables the oxygen saturation sensing module (172).

[0040] On the other hand, if the heart rate is not measured at step S240 (S250-N), the DSP (170) turns off the DC feedback circuit (130), disables the heart rate sensing module (173) (S260), and returns to step S210. This case applies when the heart rate is not measured due to proximity to an object other than the human body, such as when the wearable device is placed on a desk or the like.

[0041] The subsequent operation of the wearable device is described with reference to Fig. 3.

[0042] When oxygen saturation is measured by performing step S250 (S310-Y), the wearable device attempts to measure heartbeat amplitude (S320). To perform step S320, the DSP (170) turns on the GREEN LED of the multi-LED (110).

[0043] On the other hand, if oxygen saturation is not measured in step S310 (S310-N), the RED LED of the multi-LED (110) is turned off, the oxygen saturation sensing module (172) is disabled (S330), and the process returns to step S240 of FIG. 2.

[0044] Meanwhile, if the heartbeat amplitude measured by performing step S320 is within the operating range (S340-Y), the optimization module (171) of the DSP (170) maintains the driving current of the RED-LED and GREEN-LED as is (S350).

[0045] On the other hand, if the heartbeat amplitude measured in step S340 is out of the operating range (S340-N), the optimization module (171) of the DSP (170) adjusts the driving current of the RED-LED and GREEN-LED of the multi-LED (110) so that the heartbeat amplitude is within the operating range (S360). If the wearable device strongly presses the human body, i.e., if the wearable device is tightly tied, the heartbeat amplitude may be out of the operating range, and in this case, the LES intensity is adjusted to adjust the amplitude within the operating range.

[0046] So far, a preferred embodiment of a low-power control method for a wearable device using a PPG sensor has been described in detail.

[0047] Wearable devices are always worn, so battery operation is essential. However, since they are equipped with a circuit for measuring bio-signals to check health status, battery consumption increases rapidly.

[0048] Accordingly, in the above embodiment, rather than determining only whether the wearable device is worn and dividing it into an operating mode or a standby mode, the LEDs and processor modules are selectively activated through operation in multiple stages of mode by distinguishing them according to the bio-signal detection situation in the wearable device, thereby controlling the low-power operation of the wearable device, thereby reducing the battery consumption of the wearable device and maximizing the usage time.

[0049] Meanwhile, it goes without saying that the technical idea of ​​the present invention can also be applied to a computer-readable recording medium containing a computer program that performs the functions of the device and method according to the present embodiment. In addition, the technical idea according to various embodiments of the present invention can be implemented in the form of computer-readable code recorded on a computer-readable recording medium. The computer-readable recording medium can be any data storage device that can be read by a computer and store data. For example, the computer-readable recording medium can be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical disk, a hard disk drive, etc. In addition, the computer-readable code or program stored on the computer-readable recording medium can be transmitted through a network connected between computers.

[0050] In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and various modifications can be made by a person having ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the claims, and such modifications should not be understood individually from the technical idea or prospect of the present invention.

Claims

1. A step of detecting the proximity of a wearable device to a human body; When the proximity of a human body is detected, the first attempt is made to measure the heart rate; A wearable device control method characterized by comprising a second attempt step of attempting to measure oxygen saturation when a heart rate is measured.

2. In claim 1, The detection phase is, A method for controlling a wearable device, characterized in that it is performed by turning on an IR-LED and a photo-diode constituting a PPG sensor and activating a proximity sensing module within a processor.

3. In claim 1, The first stage of the trial is, A method for controlling a wearable device, characterized in that it is performed by activating a heart rate sensing module within a processor and a DC feedback circuit for removing DC from a detection signal of a photodiode.

4. In claim 3, A method for controlling a wearable device, further comprising: a step of disabling a DC feedback circuit and a heart rate sensing module within a processor if a heart rate is not measured after the first attempt step.

5. In claim 1, The second attempt is, A method for controlling a wearable device, characterized in that it is performed by turning on a RED LED constituting a PPG sensor and activating an oxygen saturation sensing module within a processor.

6. In claim 5, A wearable device control method further comprising a step of turning off the RED LED and deactivating the oxygen saturation sensing module within the processor if the oxygen saturation is not measured after the second attempt step.

7. In claim 1, When oxygen saturation is measured, a step is taken to determine whether the heart rate amplitude is within a set range; A wearable device control method, characterized in that it further includes a step of continuously measuring heart rate and oxygen saturation when the heart rate amplitude is within a predetermined range.

8. In claim 7, The judgment stage is, A wearable device control method characterized by performing the operation by turning on the GREEN LED constituting the PPG sensor.

9. In claim 7, A wearable device control method, characterized in that it further includes a step of adjusting the intensity of a RED LED and a GREEN LED when the heartbeat amplitude is not within a predetermined range.

10. Multi-LED containing multiple LEDs; A photodiode that detects light reflected from the human body after being illuminated by a multi-LED; A wearable device control method, characterized in that it includes a processor that detects the proximity of a human body to the wearable device based on the detection result of a photodiode, attempts to measure a heart rate when the proximity of a human body is detected, and attempts to measure oxygen saturation when the heart rate is measured.

11. First attempt to measure heart rate; Once the heart rate is measured, a second attempt is made to measure oxygen saturation; When oxygen saturation is measured, a step is taken to determine whether the heart rate amplitude is within a set range; A wearable device characterized by comprising a step of continuously measuring heart rate and oxygen saturation when the heart rate amplitude is within a predetermined range.

12. Multi-LED containing multiple LEDs; A photodiode that detects light reflected from the human body after being illuminated by a multi-LED; A wearable device characterized by including a processor that attempts to measure heart rate based on the detection result of a photodiode, attempts to measure oxygen saturation when the heart rate is measured, determines whether the heart rate amplitude is within a predetermined range when the oxygen saturation is measured, and continues to measure the heart rate and oxygen saturation when the heart rate amplitude is within the predetermined range.

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