CN116234093A

CN116234093A - Light emitting device driving circuit, PPG sensor and electronic equipment

Info

Publication number: CN116234093A
Application number: CN202111480481.7A
Authority: CN
Inventors: 杨素林
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2023-06-06

Abstract

The embodiment of the application provides a light emitting device driving circuit, a PPG sensor and electronic equipment, relates to the field of electronic equipment, and can realize detection of abnormal light emission of a light emitting device. The light emitting device driving circuit includes: the light-emitting device comprises a voltage conversion circuit, a light-emitting component, a current driving circuit, a light-emitting control circuit and a detection circuit; any light emitting device in the light emitting assembly and the current driving circuit are connected in series between the output end of the voltage conversion circuit and the grounding end; a light emission control circuit configured to: outputting a light emission control signal to the current driving circuit; a current drive circuit configured to: providing a current to at least one light emitting device according to the light emission control signal; a detection circuit configured to: detecting the light-emitting control signal to generate a detection signal, wherein the detection circuit or a system chip connected with the detection circuit determines that the light-emitting component emits light abnormally according to the detection signal.

Description

Light emitting device driving circuit, PPG sensor and electronic equipment

Technical Field

The application relates to the field of electronic equipment, in particular to a light emitting device driving circuit, a photoplethysmography (PPG) sensor and electronic equipment.

Background

Currently, light emitting devices such as a Laser Diode (LD) or a light emitting diode (light emitting diode, LED) are widely used in electronic devices. In general, a light emitting device is mainly used as a display backlight, a measurement (e.g., a distance, a biological characteristic of a human body, etc.), a signal indication, a lighting, etc. in an electronic apparatus. For example: photoplethysmograph (PPG) sensors emit a test light signal, mainly by driving a light emitting device, a portion of which is reflected inside the skin or at the skin interface; a portion of the test light signal is scattered inside the skin, and a portion of the scattered light signal returns to the PPG sensor and is received by a detector of the PPG sensor, which is referred to as a back-scattered signal, and which receives a portion of the reflected signal in addition to a portion of the scattered signal. The back scattering signal or the reflected signal can be used for continuously measuring the human body, so that data such as heart rate, blood oxygen and the like can be collected.

However, abnormal control of the light emitting device may further cause abnormal light emission of the light emitting device, which may further cause abnormal detection of PPG sensor data, and especially abnormal light emission intensity may also cause skin allergy of the user in some cases. Therefore, how to realize abnormal light emission detection of the light emitting device becomes a key for further improving the function of the device.

Disclosure of Invention

The embodiment of the application provides a light emitting device driving circuit, a photoplethysmography (PPG) sensor and electronic equipment, which can realize the detection of abnormal light emission of a light emitting device.

In order to achieve the above purpose, the present application adopts the following technical scheme:

in a first aspect, there is provided a light emitting device driving circuit including: the light-emitting device comprises a voltage conversion circuit, a light-emitting component, a current driving circuit, a light-emitting control circuit and a detection circuit; any light emitting device in the light emitting assembly and the current driving circuit are connected in series between the output end of the voltage conversion circuit and the grounding end; a light emission control circuit configured to: outputting a light emission control signal to the current driving circuit; a current drive circuit configured to: providing a current to at least one light emitting device according to the light emission control signal; a detection circuit configured to: detecting the light-emitting control signal to generate a detection signal, wherein the detection circuit or a system chip connected with the detection circuit determines that the light-emitting component emits light abnormally according to the detection signal. Thus, when the light-emitting control circuit controls the current driving circuit to output current to at least one light-emitting device in the light-emitting assembly through the light-emitting control signal so as to drive the light-emitting device to emit light, the detection circuit can detect the light-emitting control signal and generate a detection signal; the detection circuit or a controller connected with the detection circuit can determine that the light emitting component emits light abnormally according to the detection signal, so that the abnormal light emitting of the light emitting component is detected.

In one possible implementation, the current drive circuit includes a current source and a switching circuit; the public end of the switching switch circuit is coupled with the current source, and any one of the light emitting devices is coupled with any one of the selection ends of the switching switch circuit; the light emission control signal includes: a switch control signal and a current control signal; the switcher circuit is configured to: switching on a common terminal and a selection terminal coupled with the first light emitting device in at least one light emitting period according to the switch control signal so as to couple a current source with the first light emitting device; a current source configured to: providing current to the first light emitting device according to the current control signal; the detection circuit is configured to generate the detection signal according to an accumulated value of the current control signals corresponding to the first light emitting device in a first time period, wherein when the accumulated value exceeds a judgment threshold value, the light emitting component is determined to be abnormal in light emission, and the first light emitting device continuously emits light in one light emitting period. In this scheme, the detection circuit may detect any of the light emitting devices (Dg, dr and Dir) for a first period of time.

In one possible implementation, the first period of time includes at least one detection period, each of the detection periods including at least one light emission period. In this scheme, the detection circuit may detect any one of the light emitting devices (Dg, dr and Dir) for one or more light emitting periods; or the detection circuit may detect any light emitting device (Dg, dr and Dir) in one or more detection periods, where it is noted that the first light emitting device may be any one of Dg, dr and Dir, and may detect one or more detection periods (e.g. may be pulse repetition frequency (pulse repetition frequency, PRF) periods), where one detection period includes one or more light emitting periods of any one of Dg, dr and Dir.

In one possible implementation, the current drive circuit includes a current source and a switching circuit; the public end of the switching switch circuit is coupled with the current source, and any one of the light emitting devices is coupled with any one of the selection ends of the switching switch circuit; the light emission control signal includes: a switch control signal and a current control signal; the switcher circuit is configured to: switching on the common terminal and a selection terminal coupled with the first light emitting device in at least one light emitting period of the first light emitting device according to the switch control signal so as to couple the current source with the first light emitting device; or, switching on the common terminal and the selection terminal coupled to the second light emitting device in at least one light emitting period of the second light emitting device according to the switching control signal to couple the current source to the second light emitting device; the current source is configured to: providing a current to a first light emitting device according to the current control signal when the current source is coupled to the first light emitting device, and providing a current to a second light emitting device according to the current control signal when the current source is coupled to the second light emitting device; the detection circuit is configured to generate the detection signal according to an accumulated value of the current control signals corresponding to the first light emitting device and the second light emitting device in a first time period, wherein when the accumulated value exceeds a judgment threshold value, the light emitting assembly is determined to be abnormal in light emission, the first time period comprises at least one detection period, at least one light emitting period of the first light emitting device and at least one light emitting period of the second light emitting device are included in one detection period, the first light emitting device continuously emits light in one light emitting period of the first light emitting device, and the second light emitting device continuously emits light in one light emitting period of the second light emitting device. In this arrangement, the detection circuit may detect at least one light emitting device (e.g., two or more of Dg, dr and Dir) for a first period of time (e.g., which may be one or more detection periods, or any configured period of time). The detection period may be a PRF period of the PPG sensor, one detection period including one or more light emission periods of each of Dg, dr and Dir, for example, when the light emitting assembly comprises two light emitting devices, the first light emitting device emits light continuously during one light emission period of the first light emitting device and the second light emitting device emits light continuously during one light emission period of the second light emitting device.

In one possible implementation, the controller is configured to generate the determination threshold value from the largest accumulated value detected during the second period of time. For example, the second period may be any period of time before the first period of time, and the second period of time may be the same as the first period of time in length, for example, a maximum accumulated value may be detected first in the second period of time after the start of detection, and the maximum accumulated value may be taken as a judgment threshold value, and then in the subsequent detection process, the detected accumulated value may be compared with the judgment threshold value in the first period of time.

In one possible implementation, the controller is configured to generate the determination threshold value according to a predetermined offset amount that is increased or decreased by the largest accumulated value detected in the second period of time.

In one possible implementation, the controller is configured to obtain the electrical parameter of the light emitting device through a table, and calculate the determination threshold according to the electrical parameter of the light emitting device, where the table includes a correspondence between the electrical parameter of the light emitting device and the light emitting device, and the electrical parameter includes a maximum current control signal of the light emitting device in one light emitting period.

In one possible implementation, the controller is configured to obtain the determination threshold value through a table lookup, where the table includes a correspondence between an electrical parameter of the light emitting device and the determination threshold value, and the electrical parameter includes a current transmission ratio of the light emitting device to the photodetector.

In one possible implementation, the controller is configured to calculate the determination threshold by a predetermined formula expressed as pth=k×ctr+b, the current transfer ratio (current transfer ratio, CTR) being the current transfer ratio of the light emitting device to the photodetector, k and B being constants, pth being the determination threshold.

In one possible implementation, the controller is configured to determine the determination threshold according to a working scenario, where the working scenario includes at least any one of: standby scene, sleep scene, sports scene. For example: a higher judgment threshold value can be set in a sports scene, and a lower judgment threshold value can be set in a sleeping scene.

In one possible implementation, the light emitting device driving circuit further includes at least one control signal register and the controller, the light emitting control circuit is connected to the at least one control signal register, and the control signal register is connected to the controller; the light-emitting control circuit is specifically configured to generate the light-emitting control signal according to a control instruction configured by the controller in the at least one control signal register; the controller is configured to reconfigure the control instructions when it is determined that the light emitting assembly is abnormally light emitting.

In one possible implementation, the light emitting device driving circuit further includes a threshold register and the controller, the detection circuit is connected to the threshold register, the threshold register is connected to the controller, and the determination threshold is registered in the threshold register; the detection circuit is specifically configured to determine that the light emitting component emits light abnormally according to the detection signal and a judgment threshold value configured in the threshold value register by the controller.

In one possible implementation, the light emitting device driving circuit includes an Analog Front End (AFE) including a current driving circuit, a light emission control circuit, and a detection circuit.

In one possible implementation, the voltage conversion circuit includes at least any one of: boost circuit, buck-boost circuit.

In a second aspect, there is provided a PPG sensor comprising a photodetector and a light emitting device driving circuit as described in the first aspect; wherein the photodetector is used for detecting a test light signal of the light emitting device reflected and/or scattered by the detection object.

In a third aspect, an electronic device comprises a light emitting device driving circuit as described in the first aspect, or a PPG sensor as described in the second aspect.

The technical effects brought about by any one of the possible implementation manners of the second aspect and the third aspect may be referred to the technical effects brought about by different implementation manners of the first aspect, which are not described herein.

Drawings

In order to more clearly describe the technical solutions in the embodiments or the background of the present application, the following description will describe the drawings that are required to be used in the embodiments or the background of the present application.

Fig. 1A is a top view of an electronic device according to an embodiment of the present application;

fig. 1B is a bottom view of an electronic device according to an embodiment of the present application;

fig. 1C is a schematic diagram of an internal structure of an electronic device with a rear cover opened according to an embodiment of the present application;

fig. 2 is a schematic diagram of an operating principle of a PPG sensor according to an embodiment of the present application;

fig. 3 is a schematic diagram of a power supply manner of a light emitting device according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a driving circuit of a light emitting device according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a driving circuit of a light emitting device according to another embodiment of the present application;

fig. 6 is a schematic structural diagram of a driving circuit of a light emitting device according to another embodiment of the present application;

Fig. 7 is a schematic structural diagram of a driving circuit of a light emitting device according to still another embodiment of the present application;

fig. 8 is a schematic structural diagram of a driving circuit of a light emitting device according to another embodiment of the present application;

fig. 9 is a schematic structural diagram of a driving circuit of a light emitting device according to another embodiment of the present application;

fig. 10 is a signal timing diagram of a driving circuit of a light emitting device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments may be some embodiments of the present application, but not all embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In this application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, a and b, a and c, b and c or a, b and c, wherein a, b and c can be single or multiple. In addition, in the embodiments of the present application, the words "first", "second", and the like do not limit the number and order.

In this application, the terms "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion. In the present application, unless explicitly specified and limited otherwise, the term "coupled" may be an electrical connection for signal transmission, and "coupled" may be a direct electrical connection or an indirect electrical connection via an intermediary.

The light emitting device driving circuit and the PPG sensor provided by the embodiment of the application can be applied to electronic equipment, and the electronic equipment is a mobile phone, a tablet personal computer, a personal computer (personal computer, PC), a personal digital assistant (personal digital assistant, PDA), a smart watch, a netbook, a wearable electronic equipment, an augmented reality (augmented reality, AR) device, a Virtual Reality (VR) device, a vehicle-mounted device, an intelligent automobile, an intelligent sound, a robot, an intelligent glasses and other terminals of different types. The embodiment of the application does not particularly limit the specific form of the electronic device.

Taking a mobile phone as an example, fig. 1A to 1C show a schematic structural diagram of an electronic device 100, where fig. 1A shows a top view of the electronic device 100 of the described embodiment. Fig. 1B shows a bottom view of the electronic device 100 of the described embodiment. Fig. 1C shows a schematic internal structure of the electronic device 100 after the rear cover is opened, which illustrates a specific configuration of various internal components according to the described embodiment, and the dashed arrow in fig. 1C indicates the direction in which the rear cover is opened. It is to be understood that the structure illustrated in the present embodiment does not constitute a specific limitation on the electronic apparatus 100. In other embodiments of the present application, electronic device 100 may include more or fewer components than shown, or certain components may be combined, or certain components may be split, or different arrangements of components.

As shown in fig. 1A and 1B, the electronic device 100 may include a housing 100A, and the housing 100A may include a front cover 101, a rear cover 103, and a bezel 102 disposed opposite to the front cover 101 and the rear cover 103, the bezel 102 surrounding the front cover 101 and the rear cover 103 and connecting the front cover 101 and the rear cover 103 together. The front cover 101 may be a glass cover plate and the display 192 is disposed below the front cover 101. The electronic device 100 may provide input/output components around the outer circumference of the housing 100A. For example, a hole 105A such as a front camera and a hole 106 of a receiver may be provided at the top of the front cover 101. A key 180 may be provided at one edge of the frame 102, and a hole 107 for a microphone, a hole 108 for a speaker, and a hole 109 for a USB interface may be provided at the bottom edge of the frame 102. A hole 105C such as a rear camera hole 105B, PPG sensor may be provided at the top of the rear cover 103.

The housing 100A may have a cavity 104 inside, within which the internal components are enclosed. As shown in fig. 1C, internal components may be housed within the cavity 104, which may include components such as a printed circuit board (Printed circuit boards, PCB) 110, a speaker 170A for converting audio electrical signals to sound signals, a receiver 170B for converting audio electrical signals to sound signals, a microphone 170C, USB interface 130 for converting sound signals to electrical signals, a front-facing camera 193A, a rear-facing camera 193B, and a motor 191 for generating vibration cues. The printed circuit board 110 may be provided with a processor 120, a power management integrated circuit (power management integrated circuit, PMIC) 140, at least one power amplifier (in one embodiment, including a Power Amplifier (PA) 152A, a power amplifier PA152B, a power amplifier PA 152C, and a power amplifier PA 152D, where different power amplifiers PA support different frequency bands for amplifying the transmission signals in different frequency bands, for example, the power amplifier PA 152A and the power amplifier PA152B may be used to amplify the transmission signals in a first bandwidth range, the power amplifier PA 152C and the power amplifier PA 152D may be used to amplify the transmission signals in a second bandwidth range, at least one envelope tracking modulator (envelope tracking modulator, ETM) for powering the power amplifier (in one embodiment, including the envelope tracking modulator ETM 151A and the envelope tracking modulator ETM 151B, where different envelope tracking modulator ETM supports different bandwidths, for example, the envelope tracking modulator ETM a is the power amplifier PA 152A and the power amplifier PA152B is powered by the power amplifier PA152B, and the power amplifier PA152B is powered by the power amplifier PA 151D, and the antenna switch circuit is switched. A PPG sensor 160, wherein the PPG sensor 160 comprises a detector 161 and a light emitting device driving circuit 162; wherein the detector 161 is used to detect the test light signal of the light emitting device driving circuit 162 reflected and/or scattered by the detection object. In addition, the printed circuit board 110 may further include a filter, a low noise amplifier, an audio codec, an internal memory, a sensor, an inductor, a capacitor, etc., which are not shown in fig. 1C for clarity of illustration of the present embodiment. The components on the printed circuit board 110 are closely arranged to lay down all the components in a limited space. The arrangement of the components on the printed circuit board 110 is not limited. In some embodiments, components on the printed circuit board 110 may be disposed on a side of the printed circuit board 110 (e.g., a side facing the rear cover 102). In some embodiments, components on the printed circuit board 110 may be disposed on both sides of the printed circuit board 110 (e.g., on a side facing the back cover 102 and on a side facing the front cover 101, respectively).

Processor 120 may include one or more processing units, such as: processor 120 may include an application processor (appl ication processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a neural network processor (neural-network processing unit, NPU), a controller, a video codec, a digital signal processor (digital signal processor, DSP), a baseband, and/or radio frequency circuitry, etc. The controller can generate operation control signals according to the instruction operation codes and the time sequence signals to finish the control of instruction fetching and instruction execution.

A memory may be provided in the processor 120 for storing instructions and data. In some embodiments, the memory in the processor 120 is comprised of a cache memory. The memory may hold instructions or data that the processor 120 has just used or recycled. If the processor 120 needs to reuse the instruction or data, it can be called directly from the memory. Repeated accesses are avoided and the latency of the processor 120 is reduced, thereby improving the efficiency of the system.

The processor 120 may frequency modulate the signal according to a mobile communication technology or a wireless communication technology. The mobile communication technology may include a global system for mobile communications (global system for mobile communications, GSM), general packet radio service (general packet radio service, GPRS), code division multiple access (code division multiple access, CDMA), wideband code division multiple access (wideband code division multiple access, WCDMA), time division code division multiple access (time-division code division multiple access, TD-SCDMA), long term evolution (long term evolution, LTE), emerging wireless communication technologies (also referred to as fifth Generation mobile communication technologies, english: 5th Generation mobile networks or 5th Generation wireless systems, 5th-Generation, 5th-Generation New Radio, 5G technologies or 5G NR), etc. Wireless communication technologies may include wireless local area networks (wireless local area networks, WLAN) (e.g., wireless fidelity (wireless fidelity, wi-Fi) networks), bluetooth (BT), global navigation satellite systems (global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), near field wireless communication technologies (near field communication, NFC), infrared technologies (IR), and the like.

The processor 120 may also include at least one baseband and at least one radio frequency circuit. Baseband refers to the use of baseband signals to be synthesized for transmission, and/or to the use of baseband signals to be decoded for reception. Specifically, when transmitting, the baseband encodes voice or other data signals into baseband signals (baseband codes) for transmission; upon reception, the received baseband signal (baseband code) is decoded into a voice or other data signal. The baseband may include components such as an encoder, a decoder, and a baseband processor. The encoder is used for synthesizing the baseband signal to be transmitted, and the decoder is used for decoding the received baseband signal. The baseband processor may be a Microprocessor (MCU) that may be used to control the encoder and decoder, for example, the baseband processor may be used to perform scheduling of encoding and decoding, communication between the encoder and decoder, and peripheral drivers (which may enable components other than baseband by sending enable signals to components other than baseband), and so forth. The radio frequency circuit is used for processing the baseband signal to form a Transmission (TX) signal and transmitting the transmission signal to the power amplifier PA for amplification; or/and, the radio frequency circuit is used for processing a Received (RX) signal to form a baseband signal, and decoding the formed baseband signal to transmit the baseband. In some embodiments, each baseband corresponds to a radio frequency circuit to frequency modulate signals according to one or more communication techniques. For example, the first baseband and first radio frequency circuit frequency modulate signals according to the 5G technology, the second baseband and second radio frequency circuit frequency modulate signals according to the 4G technology, the third baseband and third radio frequency circuit frequency modulate signals according to the Wi-Fi technology, the fourth baseband and fourth radio frequency circuit frequency modulate signals according to the bluetooth technology, and so on. Alternatively, the first baseband and first radio frequency circuitry may frequency modulate signals according to both 4G technology and 5G technology, the second baseband and second radio frequency circuitry frequency modulate signals according to Wi-Fi technology, and so on. In some embodiments, one baseband may also correspond to a plurality of rf circuits to improve integration.

In some embodiments, baseband and radio frequency circuits may be integrated in one integrated circuit with other components of processor 120. In some embodiments, the baseband and radio frequency circuits may each be a separate device independent of the processor 120. In some embodiments, a baseband and a radio frequency circuit may be integrated into a device separate from the processor 120.

In the processor 120, the different processing units may be separate devices or may be integrated in one or more integrated circuits.

The antenna circuit 154 is used to transmit and receive electromagnetic wave signals (radio frequency signals). The antenna circuit 154 may include multiple antennas or groups of antennas (where a group of antennas includes more than two antennas) that are each operable to cover a single or multiple communication bands. The plurality of antennas may be one or more of a multi-frequency antenna, an array antenna, or an on-chip (on-chip) antenna.

The processor 120 is coupled to the antenna circuit 154 to perform various functions associated with transmitting and receiving radio frequency signals. For example, when the electronic device 100 transmits a signal, the baseband synthesizes data (digital signal) to be transmitted into a baseband signal to be transmitted, the baseband signal is converted into a transmission signal (radio frequency signal) by the radio frequency circuit, the transmission signal is amplified by the power amplifier, and an amplified output signal output by the power amplifier is transferred to the switch 153 and transmitted via the antenna circuit 154. The path along which the transmit signal is sent by the processor 120 to the switch 153 is a transmit chain (or transmit path). When the electronic device 100 needs to receive a signal, the antenna circuit 154 sends the received signal (radio frequency signal) to the switch 153, the switch 153 sends the radio frequency signal to the radio frequency circuit, the radio frequency circuit processes the radio frequency signal into a baseband signal, and the radio frequency circuit converts the processed baseband signal into data and sends the data to the corresponding application processor. The path of the radio frequency signal sent by the switch 153 to the processor 120 is a receive link (or receive path).

The switch 153 may be configured to selectively electrically connect the antenna circuit 154 to either the transmit chain or the receive chain. In some embodiments, the switch 153 may include a plurality of switches. The switch 153 may also be configured to provide additional functions including filtering and/or switching (multiplexing) the signals.

The SIM card interface 194 is used to connect to a SIM card. The SIM card may be inserted into the SIM card interface 194, or removed from the SIM card interface 194 to enable contact and separation with the electronic device 100. The electronic device 100 may support 1 or N SIM card interfaces, N being a positive integer greater than 1. The SIM card interface 194 may support a Nano SIM card, micro SIM card, etc. The same SIM card interface 194 may be used to insert multiple cards simultaneously. The types of the plurality of cards may be the same or different. Each SIM card may support one or more communication standards, each having a defined frequency band and defining a different maximum bandwidth. The SIM card interface 194 may also be compatible with different types of SIM cards. The SIM card interface 194 may also be compatible with external memory cards. The electronic device 100 interacts with the network through the SIM card to realize functions such as communication and data communication. In some embodiments, the electronic device 100 employs esims, i.e.: an embedded SIM card. The eSIM card can be embedded in the electronic device 100 and cannot be separated from the electronic device 100.

The PMIC 140 is used to manage power in the electronic device 100. For example, the PMIC 140 may include a charge management circuit and a power management circuit. Wherein the charge management circuitry is to receive a charge input from the charger, for example, in some wired charging embodiments, the charge management circuitry may receive a charge input of the wired charger through USB interface 130. The power management circuit is configured to receive input from the battery 141 and/or the charge management circuit, and to power the processor 120, the display 192, the front camera 193A, the rear camera 193B, the motor 191, and the like. In other embodiments, the charge management circuitry and the power management circuitry may also be provided in the processor 120. In other embodiments, the charge management circuitry and the power management circuitry may also be provided in different devices.

Particular embodiments of the present application provide light emitting device driving circuits that include at least one light emitting device that may be used in the PPG sensor described above. The basic principle of the PPG sensor, as shown in connection with fig. 2, is: emitting a test light signal through the light emitting device, a portion of the test light signal being reflected at a test object (e.g., inside the skin or skin interface); a portion of the test light signal is scattered inside the test object (e.g. the skin) and a portion of the scattered signal is returned to the PPG sensor and received by the detector of the PPG sensor, this portion of the scattered signal being referred to as the back scattered signal. The detector is capable of receiving a portion of the scattered signal and a portion of the reflected signal.

Typically, the light emitted by the PPG sensor is implemented with multiple wavelengths, and each wavelength generally corresponds to a light emitting device (e.g., a Laser Diode (LD), a light-emitting diode (LED), an organic light-emitting diode (OLED), a vertical-cavity surface-emitting laser (VCSEL), etc.); of course, one light emitting device may emit light of different wavelengths at different currents. Taking PPG sensors as an example, PPG sensors on a typical wearable product use 3 wavelengths, green (green), red (red) and infrared (infrared radiation, IR) light, respectively. The center wavelength of the green light emitting device is generally 530nm, the center wavelength of the red light emitting device is generally 670nm, and the center wavelength of the infrared light emitting device is generally 850nm, 900nm or 940nm.

As shown in fig. 3, in the electronic apparatus, a fixed voltage is generally supplied to the light emitting device by a power supply, the light emitting device is controlled by a current source controlling a current I flowing through the light emitting device, the current I flowing through the light emitting device is generally increased, and the light emitting device increases in light emission intensity; the current I flowing through the light emitting device is reduced and the light emitting intensity of the light emitting device is reduced. Taking an LED (Dg, dr, dir; where Dg is a green LED, dr is a red LED, and Dir is an infrared LED) as an example, in general, in a PPG sensor, power supply and driving modes shown in fig. 4 are generally used for the LED. The voltage conversion circuit 41 (for example, the voltage conversion circuit 41 may use a boost (boost) circuit or a buck-boost (buck-boost) circuit) to input the system voltage (Vsys) to the input terminal, and the output terminal Vout may supply power to 1 or more LEDs (Dg, dr, dir) with different wavelengths (for example, an Anode (Anode) connected to the LEDs). The cathode of the LED (Dg, dr, dir) is connected to a current driving circuit 42 (Tx Driver), and the current driving circuit 42 generally includes a current source 422 and a switch circuit 421, and when the current source 422 turns on the cathode (cathode) of one of the LEDs (for example, one of Dg, dr, and Dir) through the switch circuit 421, the turned-on LED emits light by flowing a current. The magnitude of the current provided by the current source 422 and the opening or closing of the switch circuit 421 are controlled by respective control signals. As shown in fig. 4, the light emission control circuit 43 may generate the control signal according to a control instruction of the controller 45 (for example, a system on chip (SoC) or a micro control unit (micro controller unit, MCU)). In some examples, the lighting control circuit 43 and the current drive circuit 42 may be integrated in an Analog Front End (AFE), wherein control instructions provided by the controller 45 may be registered in one or more registers provided by the AFE. However, abnormal control of the light emitting device may further cause abnormal light emission of the light emitting device, thereby causing abnormal detection of PPG sensor data, and especially abnormal light emission intensity may cause skin allergy of the user in some cases. Therefore, how to realize abnormal light emission detection of the light emitting device becomes a key to further improve the function of the device.

To solve the above-described problems, an embodiment of the present application provides a light emitting device driving circuit, as shown with reference to fig. 5, including: a voltage conversion circuit 41, a light emitting component, a current drive circuit 42, a light emission control circuit 43, and a detection circuit 44, wherein the light emitting component in fig. 5 is exemplified by at least one light emitting device (e.g., LED (Dg, dr, dir)); any one of the light emitting devices (Dg, dr, dir) and the current driving circuit 42 are connected in series between the output terminal Vout of the voltage converting circuit 41 and the ground terminal GND. In the embodiment of the present application, the serial relationship between the light emitting device (Dg, dr, dir) and the current driving circuit 72 is not limited. For example, referring to fig. 5, one end of any one of the light emitting devices (Dg, dr, dir) is connected to the output terminal of the voltage conversion circuit 41, the other end of the any one of the light emitting devices (Dg, dr, dir) is connected to one end of the current drive circuit 42, and the other end of the current drive circuit 42 is connected to the ground GND. In fig. 6, one end of the current drive circuit 42 is connected to the output terminal of the voltage conversion circuit 41, the other end of one end of the current drive circuit 42 is connected to one end of any one of the light emitting devices (Dg, dr, dir), and the other end of any one of the light emitting devices (Dg, dr, dir) is connected to the ground GND. Taking the light emitting device as an example, in the example of fig. 5, an anode of the LED is connected to an output end of the voltage conversion circuit 41, and a cathode of the LED is connected to the current driving circuit 42; in the example of fig. 6 the anode of the LED is connected to the current drive circuit 42 and the cathode of the LED is connected to ground GND.

A light emission control circuit 43 configured to: outputting a light emission control signal to the current drive circuit 42; a current drive circuit 42 configured to: providing a current to at least one light emitting device according to the light emission control signal; detection circuitry 44 configured to: the light emission control signal is detected, and a detection signal is generated, wherein the detection circuit 44 or the controller 45 connected to the detection circuit 44 determines that the light emitting element emits light abnormally based on the detection signal. As shown in fig. 5, the light emission control circuit 43 may generate the above-described light emission control signal according to a control instruction of the controller 45 (for example, may be an SoC or an MCU). In some examples, the lighting control circuit 43, the detection circuit 44, and the current drive circuit 42 may be integrated in an AFE, wherein control instructions provided by the controller 45 may be configured in one or more control signal registers provided by the AFE.

Thus, when the light-emitting control circuit controls the current driving circuit to output current to at least one light-emitting device through the light-emitting control signal so as to drive the light-emitting device to emit light, the detection circuit can detect the light-emitting control signal and generate a detection signal; the detection circuit or a controller connected with the detection circuit can determine that the light emitting component emits light abnormally according to the detection signal, so that abnormal light emission of the light emitting device is detected.

As illustrated with reference to fig. 5 or 6, the current driving circuit 42 includes a current source 422 and a switching circuit 421. The common terminal ct of the switch circuit 421 is coupled to the current source 422, and any one of the light emitting devices (Dg, dr, and Dir) is coupled to any one of the select terminals of the switch circuit 421 (as shown in fig. 5 or 6, the switch circuit 421 includes three select terminals c1, c2, and c3, wherein the light emitting device Dg is coupled to the select terminal c1, the light emitting device Dr is coupled to the select terminal c2, and the light emitting device Dir is coupled to the select terminal c 3). The light emission control signal includes: a switch control signal and a current control signal. The switching circuit 421 is configured to: the common terminal ct is turned on with a selection terminal coupled to the first light emitting device according to the switching control signal to couple the current source 422 to the first light emitting device. For example, referring to fig. 7, the light emission control circuit 43 has a timing control function, and when the switch control signal controls the switch circuit 421 to turn on the common terminal ct and the selection terminal c1 in at least one light emission period, the current source 422 is coupled to the light emitting device Dg, for example, the switch control signal may be a pulse signal having a pulse width, and the common terminal ct and the selection terminal c1 may be controlled to be turned on during a time period of the pulse width. Wherein, the switch control signal is synchronous with the lighting time sequence of the light emitting device Dg, that is, when the switch control signal controls the current source 422 to be coupled with the light emitting device Dg, the current source 422 is configured to: the light emitting device Dg is lit in accordance with a predetermined current supplied to the light emitting device Dg in accordance with a current control signal, for example, as shown with reference to fig. 7, and the light emission control circuit 43 has a dimming control function to supply the current lit Dg to the light emitting device Dg by sending the current control signal to the current source 422. In another aspect, when the common terminal ct is turned on with the selection terminal c2, the switching control signal is synchronized with the lighting timing of the light emitting device Dr, that is, the switching control signal controls the current source 422 to be coupled with the light emitting device Dr in at least one light emitting period, the current source 422 is configured to: providing a predetermined current to the light emitting device Dr according to the current control signal, the light emitting device Dr being lit; for another example, when the common terminal ct is turned on with the selection terminal c3, the switching control signal is synchronized with the lighting timing of the light emitting device Dir, that is, the switching control signal controls the current source 422 to be coupled with the light emitting device Dir in at least one light emitting period, the current source 422 is configured to: the predetermined current is supplied to the light emitting device Dir according to the current control signal, and the light emitting device Dir is lighted.

In the solution provided in the embodiments of the present application, the detection circuit 44 may detect the light emission control signal during a first period of time (for example, the first period of time may include at least one light emission period, or include at least one detection period (for example, the detection period may be a PRF period), or include a custom arbitrary duration), and generate the detection signal, and this process may be applied in the following scenario.

Scene one: the detection circuit 44 may detect any one of the light emitting devices (Dg, dr, and Dir) for at least one light emitting period in which the any one of the light emitting devices emits light continuously, for example: the detection circuit 44 is configured to generate a detection signal according to an accumulated value of the current control signal corresponding to the first light emitting device in at least one light emitting period, wherein when the accumulated value exceeds the judgment threshold value, it is determined that the light emitting component emits light abnormally, and the first light emitting device emits light continuously in the one light emitting period. The lighting period may be, for example, a duration of one continuous lighting of any one of the light emitting devices (Dg, dr and Dir) in one pulse repetition frequency (pulse repetition frequency, PRF) period of the PPG sensor, wherein the PRF period includes a plurality of lighting periods of the light emitting devices Dg, dr and Dir in a predetermined order. It should be noted that, if the first light emitting device may be any one of Dg, dr and Dir, in the first scenario, detection may be performed for each light emitting period, and the light emitting period may be one or more light emitting periods of any one of Dg, dr and Dir (one light emitting period is the pulse width of the switch control signal of any one of Dg, dr and Dir) ) Control value I input to current source by current control signal _dac For example, the accumulated value in one lighting period may be expressed as P _i ＝I _daci ×T_PW _i The method comprises the steps of carrying out a first treatment on the surface of the Wherein T_PW _i For the time length of the ith light emitting period of the first light emitting device, I _daci A control value of a current source of the first light emitting device in the ith light emitting period; in some examples, the accumulated value may also be represented as P _i ＝V _out ×I _daci ×T_PW _i ，V _out Is the output voltage of the voltage conversion circuit 41. It is also possible in some schemes to detect the accumulated value of the current control signal in one lighting period for only one of Dg, dr and Dir, and in other schemes to detect the accumulated value of the current control signal in two or more lighting periods for one of Dg, dr and Dir. It should be noted that, when detecting the accumulated value of the current control signal in one or more light emitting periods for different light emitting devices, different judgment thresholds may be set for different light emitting devices, and in the first scenario, the corresponding detection circuit 44 may also be separately set for different light emitting devices to detect the accumulated value of the current control signal in one or more light emitting periods for the light emitting devices.

Scene II: the detection circuit 44 may detect any of the light emitting devices (Dg, dr and Dir) in at least one detection period, and it should be noted that the first light emitting device may be any of Dg, dr and Dir, and then in the second scenario, the detection period includes one or more light emitting periods of any of Dg, dr and Dir. For example: a detection circuit 44 configured to generate a detection signal according to an accumulated value of the current control signal corresponding to the first light emitting device in at least one detection period, wherein when the accumulated value exceeds a judgment threshold value, it is determined that the light emitting assembly emits light abnormally; at least one light emitting period of the first light emitting device is included in one detection period, and the first light emitting device continuously emits light in one light emitting period. The detection period may be, for example, one PRF period of the PPG sensor. The accumulated value canRepresented as

Wherein T_PW _i For the light-emitting period duration of the ith light emission of the first light-emitting device in one detection period, I _daci The current control signal is used for the ith light emission of the first light emitting device in one detection period, and m is the number of light emission times of the first light emitting device in one detection period; in some examples, the accumulated value may also be represented as

V _out Is the output voltage of the voltage conversion circuit 41. It is also possible in some schemes to detect the accumulated value of the current control signal in one detection period of only one of Dg, dr and Dir, and in other schemes to detect the accumulated value of the current control signal in two or more detection periods of one of Dg, dr and Dir. The difference from the first scenario is that in the second scenario, the detection circuit 44 may detect a light emitting device of a certain color in one detection period, for example, one PRF period, and generate, as the detection signal, an accumulated value of current control signals of the light emitting device of the certain color in the detection period, and the one detection period may include a plurality of light emitting periods. Similar to the first scenario, in the second scenario, when detecting the accumulated value of the current control signal in one detection period for different light emitting devices, different judgment thresholds may be set for the different light emitting devices, and in the second scenario, the corresponding detection circuit 44 may also be set separately for the different light emitting devices to detect the accumulated value.

Scene III: the detection circuit 44 may detect at least one light emitting device (e.g., one or more of Dg, dr, and Dir) for a first period of time, such as: a detection circuit 44 configured to generate a detection signal according to an accumulated value of the current control signals corresponding to the first light emitting device and the second light emitting device in a first period of time, wherein when the accumulated value exceeds a judgment threshold, it is determined that the light emitting assembly is abnormal in light emission, wherein the first period of time The segment includes at least one detection period including at least one light emitting period of the first light emitting device and at least one light emitting period of the second light emitting device in one detection period. The first period of time includes one or more light emission periods of two or more of Dg, dr and Dir, and may be, for example, one or more detection periods (e.g., may be PRF periods), or a custom arbitrary duration. The first light emitting device continuously emits light in one light emitting period of the first light emitting device, and the second light emitting device continuously emits light in one light emitting period of the second light emitting device. Of course, the above only illustrates two light emitting devices, and in some examples detection of three light emitting devices may be performed simultaneously. For example, dg, dr and Dir are controlled to emit light during a detection period, then in the third scenario, detection may be performed for a first period of time (e.g., may be a PRF period) including one or more periods of light emission of any of Dg, dr and Dir, then the accumulated value may be expressed as

Wherein T_PW _i For the light-emitting period duration of the ith lit light-emitting device (where the ith lit light-emitting device may be any one of Dg, dr and Dir) in one PRF period, I _daci A current control signal for a light emitting device that is lit for the ith time in one PRF period, N being the number of times the light emitting device is lit in one PRF period; in some examples, the accumulated value may also be represented as

V _out Is the output voltage of the voltage conversion circuit 41.

The mode of setting the determination threshold is specifically described as follows:

mode one: the system chip is configured to generate a determination threshold value based on the largest accumulated value detected during the second period of time. For example, the second time period may be any time period prior to the first time period, and the second time period may be the same length as the first time period, which may be, for example, atAfter the detection is started, the maximum accumulated value is detected in a second time period, the maximum accumulated value is used as a judging threshold value, and then the detected accumulated value is compared with the judging threshold value in a first time period in the later detection process. For the first scenario, a maximum accumulated value of the current control signal of the first light emitting device in one or more light emitting periods may be detected over a period of time, and the maximum accumulated value may be used as the determination threshold. For example: the maximum accumulated value of the current control signal in one lighting period of the first light emitting device may occur in a lighting period of a certain time period with a maximum time length, or occur in a lighting period of a certain time period with a maximum current control signal, for example, the duration of each lighting period of Dg is the same, and the lighting period of the maximum accumulated value of the current control signal corresponding to Dg in 10min may be selected to generate the judgment threshold; or, the light-emitting period occurs for a certain maximum time length and is the maximum current control signal. For example, during a period of time, detecting the maximum time length T_PW of the first light emitting device in the ith light emitting period according to the switch control signal _i-max Detecting a maximum control value I of a current control signal of the first light emitting device in an ith light emitting period _daci-max . Then, the judgment threshold value can be expressed as P _th ＝I _daci-max ×T_PW _i-max The method comprises the steps of carrying out a first treatment on the surface of the In some examples, the decision threshold may also be denoted as P _th ＝V _out ×I _daci-max ×T_PW _i-max ，V _out Is the output voltage of the voltage conversion circuit 41. It should be noted that, when detecting the accumulated value of the current control signal in one lighting period for different light emitting devices, different judgment thresholds may be set for different light emitting devices with reference to the above manner. For the second scenario, a maximum accumulated value of the current control signal of the first light emitting device in one or more detection periods may be detected in a period of time, and the maximum accumulated value may be used as the determination threshold. For example: the maximum accumulated value of the current control signal in one detection period of the first light emitting device may occur in one detection period with the longest light emitting period or in the current controlIn addition, the current control signal may be generated in a detection period in which the system signal is maximum, or in a detection period in which the system signal is maximum and the light emission period is longest. For example, the maximum time length T_PW of the first light emitting device in the ith light emitting period is detected in one detection period of a period of time _i-max Maximum control value I of current control signal of first light emitting device in ith light emitting period _daci-max The method comprises the steps of carrying out a first treatment on the surface of the The decision threshold may be expressed as

Wherein N is the number of light emission times of the first light emitting device (i.e., the number of light emission cycles of the first light emitting device) in the detection period; in some examples, the decision threshold may also be expressed as +.>

V _out Is the output voltage of the voltage conversion circuit 41. It should be noted that, when detecting the accumulated value of the current control signal in the first period for different light emitting devices, different determination thresholds may be set for different light emitting devices with reference to the above manner. For the third scenario, a maximum accumulated value of the current control signals of the plurality of light emitting devices (for example, dg, dr and Dir) in a first period (the first period may be one or more detection periods (for example, may be a PRF period)) is detected for a period of time, and the maximum accumulated value is used as a determination threshold. For example: the maximum accumulated value of the current control signals in one detection period may occur in a detection period in which the light emission period of each light emitting device is longest, or in a detection period in which the current control signal corresponding to each light emitting device is largest, or in a detection period in which the light emission period of each light emitting device is longest and in which the current control signal corresponding to each light emitting device is largest. For example, in a detection period of a period of time, the maximum time length T_PW of the light emitting device in the ith light emitting period is detected _i-max Current control signal of light emitting device in ith light emitting periodMaximum control value I _daci-max The method comprises the steps of carrying out a first treatment on the surface of the The judgment threshold value can be expressed as +.>

Wherein M is the number of light emission times of the respective light emitting devices (i.e., the number of light emitting periods of the light emitting devices (Dg, dr and Dir)) in the detection period; in some examples, the decision threshold may also be expressed as

V _out Is the output voltage of the voltage conversion circuit 41.

Mode two: the system chip is configured to increase or decrease the predetermined offset amount based on the detected maximum accumulated value to generate a determination threshold. For example, the judgment threshold P determined in the mode one can be _th Increase or decrease of the predetermined offset δp (P _th ±δp)。

Mode three: the system chip is configured to obtain the electrical parameters of the light emitting device through table lookup, calculate the judgment threshold according to the electrical parameters of the light emitting device, wherein the table contains the correspondence between the electrical parameters of the light emitting device and the light emitting device, and the electrical parameters comprise the maximum current control signal of the light emitting device in one light emitting period. For example, regarding the first and second scenario, taking the light emitting device Dir as an example, the electrical parameters of the light emitting device may further include I of Dir _daci-max Or the electrical parameters of Dri may also include the I of Dir _daci-max And T_PW _i-max The method comprises the steps of carrying out a first treatment on the surface of the Directly calculating P according to the electrical parameters of Dir and formulas provided in scene one and scene two _th . For scene three, I of multiple light emitting devices (Dg, dr and Dir) need to be acquired simultaneously _daci-max Or I _daci-max And T_PW _i-max Directly calculating P according to the formulas provided in the third scene and the electrical parameters of the light emitting devices _th 。

Mode four: the system chip is configured to obtain a judgment threshold value through a table lookup, wherein the table contains the corresponding relation between the electrical parameters of the light emitting device and the judgment threshold value, and the electrical parameters comprise the current transmission ratio (current transfer ratio, CTR) of the light emitting device and the photoelectric detector. Example(s)Such as: the light emitting device is driven by a predetermined light emission control signal I to light the current source for a period of time, and the light intensity of the light emitting device is detected by the photodetector to generate a detection current Ipd _dac Current I supplied to the light emitting device with a current source _ref Is in a fixed proportion corresponding relation. Then according to ctr=i _ref and/Ipd, determining CTR, and acquiring a judging threshold value according to the CTR table lookup. It will be appreciated that, since different light emitting devices correspond to different CTRs in this manner, the manner of acquiring the determination threshold value by the scheme of the fourth manner is generally adapted to the above-described first and second scenarios.

Mode five: the system chip is configured to calculate a judgment threshold value by a predetermined formula, the predetermined formula being expressed as pth=k×ctr+b, CTR being a current transfer ratio of the light emitting device to the photodetector, k and B being constants, and the judgment threshold value being Pth. After the CTR is obtained by referring to the fourth method, the determination threshold may be calculated directly according to the formula pth=k×ctr+b, and since different light emitting devices in the fourth method correspond to different CTRs, the method of obtaining the determination threshold by the fifth method is generally adapted to the first and second scenes.

Mode six: the system chip is configured to determine a judgment threshold according to a working scene, wherein the working scene at least comprises any one of the following: standby scene, sleep scene, sports scene. For example: a higher judgment threshold value can be set in a sports scene, and a lower judgment threshold value can be set in a sleeping scene.

In the above example, referring to fig. 8, the light emitting device driving circuit further includes at least one control signal register (e.g., a pulse width control register, a current control register, a repetition frequency register, and others shown in fig. 8) which may be connected by the light emission control circuit 43, and a controller 45; the light emission control circuit 43 is specifically configured to generate a light emission control signal according to a control instruction configured by the controller 45 in at least one control signal register; and a controller 45 configured to reconfigure the control instructions when it is determined that the light emitting assembly is abnormal in light emission. Specifically, the repetition frequency register is used for storing control instructions of a detection period (for example, a PRF period), the pulse width control register is used for storing control instructions of a light emitting period of the light emitting device, the current control register is used for storing control instructions of a current control signal, and for example, different currents can be mapped by adopting 8-system or 16-system control words.

In some examples, the light emission control circuit 43 may report only the detected detection signal, and the controller (MCU or SOC) may determine that the light emission is abnormal based on the determination threshold. Alternatively, the light emission control circuit 43 may store only the detected signal, and the controller (MCU or SOC) may read the detected signal monitored by the light emission control circuit 43 through an interface with the light emission control circuit 43 and determine the abnormal light emission based on the determination threshold. Of course, the light emission control circuit 43 may determine the light emission abnormality directly from the detection signal and the determination threshold value, and then send the determination result to the controller. The final controller 45 reconfigures the control instruction according to the judgment result, or sends out an alarm prompt, and records the relevant information of the judgment result. For example, the information on the determination result may include the time, period, number of times, and the like at which the abnormal light emission occurs. When the light emission control circuit 43 directly performs the judgment of the light emission abnormality based on the detection signal and the judgment threshold value, in another example, the light emitting device driving circuit further includes a threshold value register and a controller, the detection circuit 44 is connected to the threshold value register, the threshold value register is connected to the controller 45, and the judgment threshold value is registered in the threshold value register; the detection circuit 44 is specifically configured to determine that at least one light emitting device emits light abnormally in accordance with the detection signal and the judgment threshold value configured in the threshold value register by the controller 45. Wherein the threshold register may be one of the other registers in fig. 8. The control signal register and the threshold value register can be integrated in the same chip with the current driving circuit, the detection circuit and the like in any combination, or can be separately arranged in different chips on the PCB, for example, can be integrated in the AFE.

Specifically, referring to fig. 9, the detection circuit 44 may be implemented by an accumulator (count) with an enable and reset function, where the input of the accumulator is the current control signal Idac of the light emitting device, and the output is the accumulated value Qn. At the beginning of each detection period (which may be, for example, one PRF period), the PRF signal resets the accumulator and the Qn output is 0. When the light emitting device is driven to be lighted, the switching control signal outputs a pulse, the switching control signal en=1, and the enable accumulator starts to be operable, and the accumulator counts the current control signal Idac of the light emitting device at the rising edge of each clock period CLK. The counting result is output from Qn, when the comparator determines that the counting result Qn is greater than the judging threshold, the comparator outputs an alarm or indication signal from the output terminal m_out, indicating that the energy of the light emitting device for lighting has exceeded the set judging threshold in the PRF period. The prompting system needs to process or record. Typically, in oximetry, 1 PRF cycle includes two light emitting cycles of Dir, one light emitting cycle of Dr; in heart rate measurement, 1 PRF period includes one light emitting period of Dg and one light emitting period of Dir; in the wearing detection of the electronic device, 1 PRF period includes one light-emitting period of Dir, which of course mainly exemplifies three application scenarios of the electronic device, and in other application scenarios, 1 PRF period may also include one or more light-emitting periods of one light-emitting device, or 1 PRF period may also include one or more light-emitting periods of multiple light-emitting devices. In the following examples, one light emitting period each including Dir, dg, dr in 1 PRF period is described in detail as follows. Referring to the signal timing chart shown in fig. 10, based on the above-mentioned light emitting device driving circuit of fig. 9, it can be seen that in the detected PRF period, the accumulator reset Qn is output to 0 by the pulse initiated by the PRF period, in the first light emitting period T-PW1 of the light emitting device Dg, the switch control signal en=1 couples the common terminal ct to the free terminal c1, the light emission control signal Idac outputs the light emission control signal idac=10 to the current source, the light emitting device Dg is lighted, in the T-PW1, the first rising edge of CLK, the accumulator counts the current control signal Idac, qn=10; in T-PW1, the accumulator again counts the current control signal Idac, qn=20, at the second rising edge of CLK. In the first lighting period T-PW2 of the light emitting device Dr, the switching control signal en=1 couples the common terminal ct with the free terminal c2, the lighting control signal Idac outputs the lighting control signal idac=15 to the current source, the light emitting device Dr is lit, in the first rising edge of CLK in T-PW2, the accumulator counts the current control signal Idac again, qn=35; in T-PW2, the second rising edge of CLK, the accumulator again counts the current control signal Idac, qn=50; in T-PW2, the third rising edge of CLK, the accumulator again counts the current control signal Idac, qn=65; in the first light emitting period T-PW3 of the light emitting device Dir, the switch control signal en=1 couples the common terminal ct with the free terminal c3, the light emitting control signal Idac outputs the light emitting control signal idac=60 to the current source, the light emitting device Dir is lighted, in the first rising edge of CLK in T-PW3, the accumulator counts the current control signal Idac again, qn=125; in T-PW3, the second rising edge of CLK, the accumulator again counts the current control signal Idac, qn=185; then when Pth is set to 180, then in T-PW3, before the second rising edge of CLK, M-out of the comparator outputs a logic 0 indicating that the light is normal because 125 < 180; in T-PW3, after the second rising edge of CLK, M-out of the comparator outputs a logic 1, indicating an illumination anomaly, as 185 > 180; of course, pth may also be set to 200 in some examples, with 185 < 200, the entire PRF period M-out outputting a logic 0 indicating that the light is normal. Of course, the above schemes provided in fig. 9 and fig. 10 are mainly illustrated for the third scenario of the above embodiment, and of course, the accumulator may also be reset by the rising edge of en, so as to implement accumulating the current control signals Idac of each light emitting device respectively, thereby implementing detection of each light emitting device, which is not repeated herein.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

Although the present application has been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the application. Accordingly, the specification and drawings are merely exemplary illustrations of the present application as defined in the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present application. It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims

1. A light emitting device driving circuit, comprising: the light-emitting device comprises a voltage conversion circuit, a light-emitting component, a current driving circuit, a light-emitting control circuit and a detection circuit; any one of the light emitting devices in the light emitting assembly and the current driving circuit are connected in series between the output end of the voltage conversion circuit and the grounding end;

The light emission control circuit is configured to: outputting a light emission control signal to the current driving circuit;

the current drive circuit is configured to: providing a current to the at least one light emitting device according to the light emission control signal;

the detection circuit is configured to: and detecting the light-emitting control signal to generate a detection signal, wherein the detection circuit or a controller connected with the detection circuit determines that the light-emitting component emits light abnormally according to the detection signal.

2. The light-emitting device driving circuit according to claim 1, wherein the current driving circuit includes a current source and a switching circuit; the public end of the switching switch circuit is coupled with the current source, and any one of the light emitting devices is coupled with any one of the selection ends of the switching switch circuit;

the light emission control signal includes: a switch control signal and a current control signal;

the switcher circuit is configured to: switching on a selection end coupled with the first light emitting device at least once in a light emitting period according to the switch control signal so as to couple the current source with the first light emitting device;

The current source is configured to: providing current to the first light emitting device according to the current control signal;

the detection circuit is configured to generate the detection signal according to an accumulated value of the current control signals corresponding to the first light emitting device in a first time period, wherein when the accumulated value exceeds a judgment threshold value, the light emitting component is determined to be abnormal in light emission, and the first light emitting device continuously emits light in one light emitting period.

3. The light-emitting device driving circuit according to claim 2, wherein,

the first period of time includes at least one detection period, each of the detection periods including at least one light emission period.

4. The light-emitting device driving circuit according to claim 1, wherein the current driving circuit includes a current source and a switching circuit; the public end of the switching switch circuit is coupled with the current source, and any one of the light emitting devices is coupled with any one of the selection ends of the switching switch circuit;

the switcher circuit is configured to: switching on a selection terminal coupled to the first light emitting device at least once in a light emitting period of the first light emitting device according to the switching control signal to couple the current source to the first light emitting device; or, switching on the common terminal and a selection terminal coupled to the second light emitting device in at least one light emitting period of the second light emitting device according to the switching control signal to couple the current source to the second light emitting device;

The current source is configured to: providing a current to the first light emitting device according to the current control signal when the current source is coupled to the first light emitting device, and providing a current to the second light emitting device according to the current control signal when the current source is coupled to the second light emitting device;

the detection circuit is configured to generate the detection signal according to an accumulated value of the current control signals corresponding to the first light emitting device and the second light emitting device in a first time period, wherein when the accumulated value exceeds a judgment threshold value, the light emitting assembly is determined to be abnormal in light emission, the first time period comprises at least one detection period, at least one light emitting period of the first light emitting device and at least one light emitting period of the second light emitting device are included in one detection period, the first light emitting device continuously emits light in one light emitting period of the first light emitting device, and the second light emitting device continuously emits light in one light emitting period of the second light emitting device.

5. The light-emitting device driving circuit according to any one of claims 2 to 4, wherein the controller is configured to generate the determination threshold value from the largest accumulated value detected in the second period of time.

6. The light-emitting device driving circuit according to any one of claims 2 to 4, wherein the controller is configured to generate the determination threshold value in accordance with a predetermined offset amount that is increased or decreased by the largest accumulated value detected in the second period.

7. A light-emitting device driving circuit according to any one of claims 2-4, wherein the controller is configured to obtain the electrical parameter of the light-emitting device by looking up a table, the determination threshold value is calculated according to the electrical parameter of the light-emitting device, and the table contains the correspondence between the electrical parameter of the light-emitting device and the light-emitting device, and the electrical parameter includes a maximum current control signal of the light-emitting device in one light-emitting period.

8. A light-emitting device driver circuit according to any one of claims 2-4, wherein the controller is configured to obtain the determination threshold value by looking up a table containing correspondence between electrical parameters of the light-emitting device and the determination threshold value, the electrical parameters including a current transmission ratio of the light-emitting device to a photodetector.

9. The light-emitting device driving circuit according to any one of claims 2 to 4, wherein the controller is configured to calculate the judgment threshold value by a predetermined formula,

The predetermined formula is expressed as pth=k×ctr+b, CTR is a current transmission ratio of the light emitting device to the photodetector, k and B are constants, and Pth is the judgment threshold.

10. The light-emitting device driving circuit according to any one of claims 2 to 4, wherein the controller is configured to determine the determination threshold value according to an operation scenario including at least any one of: standby scene, sleep scene, sports scene.

11. The light-emitting device driver circuit of claim 1, further comprising at least one control signal register and the controller, wherein the light-emitting control circuit is coupled to the at least one control signal register, wherein the control signal register is coupled to the controller;

the light-emitting control circuit is specifically configured to generate the light-emitting control signal according to a control instruction configured by the controller in the at least one control signal register;

the controller is configured to reconfigure the control instructions when it is determined that the light emitting assembly is abnormally light emitting.

12. The light-emitting device driving circuit according to claim 1, further comprising a threshold register and the controller, wherein the detection circuit is connected to the threshold register, wherein the threshold register is connected to the controller, and wherein the determination threshold is registered in the threshold register;

The detection circuit is specifically configured to determine that the light emitting component emits light abnormally according to the detection signal and a judgment threshold value configured in the threshold value register by the controller.

13. The light-emitting device driver circuit of claim 1, wherein the light-emitting device driver circuit comprises an analog front end AFE comprising a current driver circuit, a light emission control circuit, and a detection circuit.

14. The light-emitting device driving circuit according to claim 1, wherein the voltage conversion circuit includes at least any one of: boost circuit, buck-boost circuit.

15. A PPG sensor comprising a photodetector and a light emitting device driving circuit according to any one of claims 1 to 14; wherein the detector is used for detecting a test light signal of the light emitting device reflected and/or scattered by the detected object.

16. An electronic device comprising a light emitting device driving circuit according to any one of claims 1-14, or a PPG sensor according to claim 15.