Photoelectric conversion circuit, driving method thereof, and display device

Abstract

The present invention discloses a photoelectric conversion circuit, a driving method thereof, and a display device. The photoelectric conversion circuit includes a photosensitive circuit and a reading circuit. In a first state, the photosensitive circuit couples to a reading node according to an electrical signal converted from an optical signal. The reading circuit is used to convert the signal of the reading node into a detection signal, and outputs the detection signal in response to the control of the reading control signal terminal. In a second state, the photosensitive circuit outputs the electrical signal converted from the optical signal through a reference voltage node to charge the battery. The photoelectric conversion circuit, a driving method thereof, and a display device provided by an embodiment of the present invention perform fingerprint detection through the photosensitive circuit in the first state. In the second state, the photosensitive circuit uses the electrical signal converted from the optical signal to charge the battery using the electrical signal converted from the optical signal, thereby realizing fingerprint recognition and charging functions and improving the battery life of the device.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a photoelectric conversion circuit and a driving method thereof, and a display device. Background Art

[0002] Fingerprints are an innate part of every human being. With the advancement of technology, a variety of display devices with fingerprint recognition capabilities have emerged on the market, including mobile phones, tablets, and smart wearable devices. Before operating a display device with fingerprint recognition, users only need to touch the display with their finger to verify permission, simplifying the authentication process. Furthermore, as the application scenarios of fingerprint recognition gradually expand, the fingerprint recognition area has gradually evolved from partial area to full-screen recognition.

[0003] However, as the area of ​​the fingerprint recognition region increases, the cost also increases significantly, making the value proposition of large-area fingerprint detection low. Summary of the Invention

[0004] The present invention provides a photoelectric conversion circuit and a driving method thereof, and a display device, so as to realize a photoelectric conversion circuit having both fingerprint recognition and charging functions, thereby improving the value of large-area fingerprint detection.

[0005] According to one aspect of the present invention, there is provided a photoelectric conversion circuit, comprising a photosensitive circuit and a reading circuit;

[0006] The photosensitive circuit is electrically connected to a reference voltage node, a reset signal terminal and a read node, the read circuit is electrically connected to the read node and a read control signal terminal, and the reference voltage node is electrically connected to a battery;

[0007] In the first state, the reset signal terminal outputs a reset pulse signal, and the photosensitive circuit is used to couple the electrical signal converted by the photosensitive circuit according to the light signal to the read node in response to the reset pulse signal; the read circuit is used to convert the signal of the read node into a detection signal, and output the detection signal in response to the control of the read control signal terminal;

[0008] In the second state, the photosensitive circuit outputs the electrical signal converted by the photosensitive circuit according to the light signal through the reference voltage node to charge the battery.

[0009] According to another aspect of the present invention, a driving method is provided, the driving method being used to drive the photoelectric conversion circuit according to the first aspect, the driving method comprising a light detection phase and a charging phase; the light detection phase comprising a reset phase and a reading phase sequentially passed through;

[0010] In the reset phase, the reset pulse signal outputs a first level, and the photosensitive circuit resets the read node in response to the first level;

[0011] In the reading phase, the reset pulse signal outputs a second level, and the photosensitive circuit couples the electrical signal converted by the photosensitive circuit according to the light signal to the reading node in response to the second level. The reading circuit converts the signal of the reading node into a detection signal, and outputs the detection signal in response to the control of the reading control signal terminal.

[0012] In the charging stage, the photosensitive circuit outputs the electrical signal converted by the photosensitive circuit according to the light signal through a reference voltage node to charge the battery.

[0013] According to another aspect of the present invention, a display device is provided, comprising the photoelectric conversion circuit according to the first aspect.

[0014] The photoelectric conversion circuit and its driving method, as well as the display device provided by the embodiments of the present invention, in a first state, a reset pulse signal is output by setting a reset signal terminal. The photosensitive circuit couples the electrical signal converted by the photosensitive circuit according to the optical signal to a reading node in response to the reset pulse signal. The reading circuit converts the signal of the reading node into a detection signal and outputs the detection signal in response to the control of the reading control signal terminal to realize the fingerprint recognition function. At the same time, in a second state, the photosensitive circuit is set to output the electrical signal converted by the photosensitive circuit according to the optical signal through a reference voltage node to charge the battery, thereby using the electrical signal converted by the photosensitive circuit from the optical signal to charge the battery, providing the battery with power reserve, thereby realizing a photoelectric conversion circuit with both fingerprint recognition and charging functions, and improving the value of large-area fingerprint detection.

[0015] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic structural diagram of a photoelectric conversion circuit is provided for an embodiment of the present invention;

[0018] Figure 2A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of the working timing of a photoelectric conversion circuit provided by an embodiment of the present invention;

[0020] Figure 4 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0021] Figure 5 A schematic diagram of the operating timing of another photoelectric conversion circuit provided by an embodiment of the present invention;

[0022] Figure 6 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0023] Figure 7 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0024] Figure 8 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention;

[0025] Figure 9 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0026] Figure 10 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0027] Figure 11 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0028] Figure 12 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0029] Figure 13 A schematic structural diagram of another photoelectric conversion circuit is provided for an embodiment of the present invention;

[0030] Figure 14 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention;

[0031] Figure 15 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention;

[0032] Figure 16 A schematic structural diagram of a display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] Figure 1 A schematic diagram of a photoelectric conversion circuit is provided for an embodiment of the present invention. Figure 1 As shown, the photoelectric conversion circuit provided by an embodiment of the present invention includes a photosensitive circuit 10 and a reading circuit 11. The photosensitive circuit 10 is electrically connected to the reference voltage node Vcom, the reset signal terminal RESET and the reading node Q. The reading circuit 11 is electrically connected to the reading node Q and the reading control signal terminal READ. The reference voltage node Vcom is electrically connected to the battery 12.

[0036] In the first state, the reset signal terminal RESET outputs a reset pulse signal, and the photosensitive circuit 10 is configured to respond to the reset pulse signal by coupling an electrical signal converted from the light signal by the photosensitive circuit 10 to a read node Q. The read circuit 11 is configured to convert the signal at the read node Q into a detection signal and output the detection signal in response to control by the read control signal terminal READ.

[0037] In the second state, the photosensitive circuit 10 outputs the electrical signal converted by the photosensitive circuit 10 according to the light signal through the reference voltage node Vcom to charge the battery 12 .

[0038] The photosensitive circuit 10 is used to receive a light signal and convert the light signal into an electrical signal.

[0039] The photoelectric conversion circuit provided by the embodiment of the present invention can realize functions such as fingerprint recognition in the first state.

[0040] For example, Figure 1 As shown, in the first state, the reset signal terminal RESET outputs a reset pulse signal, which may include an alternating first level and a second level. The photosensitive circuit 10 is configured to reset the read node Q in response to the first level, and couple the electrical signal converted by the photosensitive circuit 10 according to the light signal to the read node Q in response to the second level. The read circuit 11 converts the signal at the read node Q into a detection signal, and outputs the detection signal in response to the control of the read control signal terminal READ.

[0041] The reset pulse signal may be a square wave signal formed by alternating between a first level and a second level, and the first level may be higher than the second level, but is not limited thereto. Since the read circuit 11 obtains the detection signal based on the signal conversion at the read node Q, resetting the read node Q using the first level of the reset pulse signal can improve the accuracy of the detection signal.

[0042] Continue to refer Figure 1 In the first state, the reference voltage node Vcom provides a reference voltage to the photosensitive circuit 10. When the first level potential is lower than the second level potential, the reference voltage value may be greater than or equal to the first level value and less than the second level value, but is not limited thereto. The read control signal terminal READ is used to provide a read control signal with a preset timing to the read circuit 11 to control the read circuit 11 to output or stop outputting the detection signal.

[0043] The detection signal may be a voltage, and the change in the light signal detected by the photosensitive circuit 10 may be determined by detecting the difference in the voltage during the reading process.

[0044] Therefore, in the first state, the light signal fed back by the finger is sensed by the photosensitive circuit 10, and the light signal is converted into an electrical signal and coupled to the reading node Q. After the signal of the reading node Q is converted into a detection signal by the reading circuit 11, the change of the light signal detected by the photosensitive circuit 10 can be finally determined according to the difference of the detection signal during the reading process, thereby finally achieving the purpose of fingerprint recognition.

[0045] At the same time, the photoelectric conversion circuit provided by the embodiment of the present invention can also use the electrical signal converted from the optical signal by the photosensitive circuit 10 to charge the battery 12 in the second state, thereby providing the battery 12 with power reserve.

[0046] Specifically, in the second state, the photosensitive circuit 10 outputs the electrical signal converted by the photosensitive circuit 10 according to the light signal to the battery 12 through the reference voltage node Vcom, thereby charging the battery 12.

[0047] When the photoelectric conversion circuit is not performing fingerprint recognition, it can be in the second state, thereby sensing ambient light for a long time and converting it into an electrical signal, and charging the battery 12, thereby improving battery life and realizing a photoelectric conversion circuit with both fingerprint recognition and charging functions. Taking the application of this photoelectric conversion circuit in a mobile phone as an example, in actual use of a mobile phone, fingerprint recognition only accounts for a very short period of time in the entire mobile phone usage. Therefore, the photoelectric conversion circuit can be in the second state most of the time, thereby continuously charging the battery 12, which helps to further extend the battery life of the mobile phone.

[0048] It can be understood that the larger the coverage area of ​​the photoelectric conversion circuit, the larger the area of ​​the fingerprint recognition area. At the same time, the more light signals are received, the greater the power generation power is, and the faster the charging speed of the battery 12 is, which helps to improve the battery life. Therefore, the photoelectric conversion circuit has both fingerprint recognition and charging functions, which can improve the value of large-area fingerprint detection.

[0049] It should be noted that the battery 12 is a rechargeable battery, and the battery 12 may be a lithium-ion battery or a nickel-metal hydride battery, etc. Those skilled in the art may configure it according to actual needs. The embodiment of the present invention does not limit the type, parameters, etc. of the battery 12.

[0050] The photoelectric conversion circuit provided by the embodiment of the present invention, in a first state, outputs a reset pulse signal by setting the reset signal terminal RESET, and the photosensitive circuit 10 couples the electrical signal converted by the photosensitive circuit 10 according to the optical signal to the reading node Q in response to the reset pulse signal, and the reading circuit 11 converts the signal of the reading node Q into a detection signal, and outputs the detection signal in response to the control of the reading control signal terminal READ, so as to realize the fingerprint recognition function; at the same time, in the second state, the photosensitive circuit 10 is set to output the electrical signal converted by the photosensitive circuit 10 according to the optical signal through the reference voltage node Vcom to charge the battery 12, thereby utilizing the electrical signal converted by the photosensitive circuit 10 from the optical signal to charge the battery 12, providing the battery 12 with power reserve, thereby realizing a photoelectric conversion circuit with both fingerprint recognition function and charging function, and improving the value of large-area fingerprint detection.

[0051] Figure 2 The present invention provides another schematic diagram of the structure of a photoelectric conversion circuit, such as Figure 2As shown, optionally, the photosensitive circuit 10 includes a first transistor 21, a photosensitive element 22, a first capacitor 23, and a first switch unit 24. The first terminal 211 of the first transistor 21, the first terminal 221 of the photosensitive element 22, and the first plate 231 of the first capacitor 23 are connected to the read node Q. The second terminal 212 of the first transistor 21 is electrically connected to the first power supply terminal VCC, and the control terminal 213 of the first transistor 21 is electrically connected to the reset signal terminal RESET. The second terminal 222 of the photosensitive element 22 and the second plate 232 of the first capacitor 23 are both electrically connected to the reference voltage node Vcom, which is electrically connected to the positive electrode 121 of the battery 12. The first switch unit 24 is electrically connected to the read node Q and the negative electrode 122 of the battery 12, respectively. In the second state, the first switch unit 24 is on.

[0052] The photosensitive element 22 is used to receive the optical signal and convert the optical signal into an electrical signal.

[0053] Figure 3 A schematic diagram of the working timing of a photoelectric conversion circuit provided by an embodiment of the present invention is shown in FIG. Figure 2 and Figure 3 As shown, the photoelectric conversion circuit includes a light detection stage T1 and a charging stage T2 in sequence, wherein in the light detection stage T1, the photoelectric conversion circuit is in a first state; in the charging stage T2, the photoelectric conversion circuit is in a second state.

[0054] For example, Figure 2 and Figure 3 As shown, the light detection phase T1 includes a reset phase (from time t0 to time t1) and a read phase (from time t1 to time t3) which are passed in sequence.

[0055] In the reset stage, the reset signal terminal RESET outputs a first high level to control the first transistor 21 to be turned on. The reset voltage provided by the first power supply terminal VCC is transmitted to the read node Q through the first transistor 21, and the first capacitor 23 is charged at the same time, so that the potential of the read node Q is reset.

[0056] In the reading phase, from time t1 to time t2, the reset signal terminal RESET outputs a second low level, the first transistor 21 is turned off, the photosensitive element 22 receives the light signal and converts the light signal into an electrical signal to form a photocurrent, the first capacitor 23 discharges, and the potential of the reading node Q gradually decreases.

[0057] From time t2 to time t3, the reset signal terminal RESET outputs a second low level, and the first transistor 21 is turned off. The read control signal terminal READ outputs a control signal, and the read circuit 11 converts the signal at the read node Q into a detection signal and outputs the detection signal in response to the control signal.

[0058] The detection signal is determined by the voltage at read node Q, which is determined by the photocurrent of photosensitive element 22, which in turn is determined by the light intensity to which it is exposed. Therefore, the detection signal varies under different light intensities. By processing the detection signal, detection of different light intensities can be achieved. During fingerprint detection, due to the varying light intensities reflected from fingerprint valleys and ridges, the light intensity reflected from different fingerprint regions to photosensitive element 22 varies. Therefore, fingerprint recognition can be achieved by detecting the detection signal corresponding to the photoelectric conversion circuit at each location within the fingerprint recognition area.

[0059] It should be noted that, in the light detection phase T1 , the battery 12 provides a reference voltage to the light sensing circuit 10 via the reference voltage node Vcom.

[0060] Continue to refer Figure 2 and Figure 3 During the charging phase T2 (from time t5 to time t6), the reset signal terminal RESET outputs a second low level, and the first transistor 21 is turned off. The first switch unit 24 is turned on, connecting the read node Q to the negative electrode 122 (ground) of the battery 12. The photosensitive element 22 receives the light signal and converts it into an electrical signal to form a photocurrent, generating a photo-generated voltage at the reference voltage node Vcom. At this time, the voltage at the reference voltage node Vcom becomes the forward photo-generated voltage of the photosensitive element 22, thereby charging the battery 12.

[0061] Continue to refer Figure 3 Optionally, between the light detection stage T1 and the charging stage T2, a stabilization stage T3 (from time t4 to time t5) is also included. In the stabilization stage T3, the reset signal terminal RESET outputs a second low level, the first transistor 21 is turned off, and waits for the potential of each node to stabilize.

[0062] It should be noted that the transistors used in the embodiments of the present invention may be thin film transistors, field effect transistors or other switching devices with the same characteristics. Those skilled in the art may set them according to actual needs. The embodiments of the present invention are described using thin film transistors as an example.

[0063] In addition, in the working timing diagram provided by the present invention, the signal and the signal end use the same symbol. For example, the reset pulse signal output by the reset signal end RESET is also represented by RESET, and the signals output by other signal ends are also represented by the same symbol as the signal end, which will not be repeated here.

[0064] Figure 4 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 4As shown, optionally, the first switch unit 24 includes a second transistor 25, wherein a first terminal 251 of the second transistor 25 is electrically connected to the read node Q, a second terminal 252 of the second transistor 25 is electrically connected to the negative electrode 122 of the battery 12, and a control terminal 253 of the second transistor 25 is electrically connected to the state switching signal terminal Charge. In the second state, the state switching signal terminal Charge outputs a state switching signal, and the second transistor 25 is turned on in response to the state switching signal.

[0065] Figure 5 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention is shown in FIG. Figure 4 and Figure 5 As shown, taking the second transistor 25 as an N-type transistor as an example, in the light detection stage T1, the state switching signal terminal Charge outputs a low-level state switching signal, and the second transistor 25 is turned off. At this time, the photoelectric conversion circuit is in the first state to perform fingerprint detection.

[0066] In the charging stage T2, the state switching signal terminal Charge outputs a high-level state switching signal, controlling the second transistor 25 to turn on, so that the reading node Q is connected to the negative electrode 122 (ground) of the battery 12, and the voltage at the reference voltage node Vcom becomes the forward photogenerated voltage of the photosensitive element 22, so as to charge the battery 12.

[0067] Among them, by setting the first switching unit 24 to the second transistor 25, the state switching signal can be output through the state switching signal terminal Charge to control the conduction and cutoff of the second transistor 25, so that the photoelectric conversion circuit can be flexibly controlled to switch between the first state and the second state, thereby realizing flexible switching of the fingerprint recognition function and the charging function.

[0068] It should be noted that the above embodiment is described only by taking the second transistor 25 as an N-type transistor as an example. The second transistor 25 may also be a P-type transistor, which is not limited in the embodiment of the present invention.

[0069] Optionally, since the photocurrent formed by the photosensitive element 22 converting the optical signal into an electrical signal is small and the power is small, the second transistor 25 can be set to a metal-oxide-semiconductor (CMOS) transistor. The use of a CMOS transistor can ensure that there is no current consumption from the power supply to the ground. Therefore, the power consumption is small, which helps to improve the charging efficiency of the battery 12.

[0070] Figure 6 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 6As shown, optionally, the photosensitive element 22 includes a photodiode 26 , the cathode of the photodiode 26 serves as the first end 221 of the photosensitive element 22 , and the anode of the photodiode 26 serves as the second end 222 of the photosensitive element 22 .

[0071] Specifically, such as Figure 6 As shown, by setting the photosensitive element 22 as a photodiode 26, the photodiode 26 can generate different photocurrents when receiving light of different intensities, thereby realizing the fingerprint recognition function and the charging function.

[0072] Among them, the type structure of the photodiode 26 can be set according to actual needs. For example, the photodiode 26 can adopt a PIN-type photodiode to achieve higher sensitivity, but is not limited to this. In other embodiments, the photodiode 26 can adopt a PN-type photodiode or an avalanche photodiode, etc., and the embodiment of the present invention is not limited to this.

[0073] It should be noted that the photosensitive element 22 is not limited to a photodiode, and the photosensitive element 22 may also be other photosensitive components known to those skilled in the art, such as a photosensitive thin film transistor, etc. The embodiment of the present invention does not elaborate on this and does not limit it.

[0074] Figure 7 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 7 As shown, the photoelectric conversion circuit provided in this embodiment of the present invention optionally further includes a voltage conversion circuit 13, through which the photosensitive circuit 10 is electrically connected to the battery 12. In a first state, the voltage conversion circuit 13 is configured to convert the output voltage of the battery 12 into a reference voltage to provide a reference voltage for a reference voltage node Vcom, wherein the reference voltage is less than the output voltage of the battery. In a second state, the voltage conversion circuit 13 is configured to convert the voltage at the reference voltage node Vcom into a charging voltage to charge the battery 12, wherein the voltage at the reference voltage node Vcom is less than the charging voltage, and the charging voltage is greater than the output voltage of the battery.

[0075] The voltage conversion circuit 13 may be a bidirectional DC / DC converter.

[0076] For example, Figure 8 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention is shown in FIG. Figure 7 and Figure 8As shown, in the light detection stage T1, the photoelectric conversion circuit is in the first state. At this time, the voltage Vbat at the positive electrode 121 of the battery 12 is the output voltage of the battery 12. The voltage conversion circuit 13 steps down the output voltage of the battery 12 to obtain a reference voltage, and transmits the reference voltage to the reference voltage node Vcom to provide a reference voltage for the photosensitive circuit 10 through the reference voltage node Vcom.

[0077] Continue to refer Figure 7 and Figure 8 In the charging stage T2, the photoelectric conversion circuit is in the second state, the voltage conversion circuit 13 boosts the voltage at the reference voltage node Vcom to obtain a charging voltage, and applies the charging voltage to the positive electrode 121 of the battery 12. At this time, the voltage Vbat at the positive electrode 121 of the battery 12 is the charging voltage, wherein the charging voltage is greater than the output voltage of the battery 12, thereby feeding back electrical energy to the battery 12 to realize the function of charging the battery 12.

[0078] It should be noted that the voltage values ​​of each signal in the embodiment of the present invention can be set according to actual needs. For example, the first level output by the reset signal terminal RESET is +10V, the second level output by the reset signal terminal RESET is -7V, and the output voltage of the battery 12 is +3.7V, but it is not limited to this. In fact, the output voltage of the battery 12 fluctuates around +3.7V with the power status of the battery 12, and the embodiment of the present invention does not limit this.

[0079] Figure 9 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 9 As shown, optionally, the voltage conversion circuit 13 includes a second switch unit 31, a third switch unit 32, an inductor 33, and a second capacitor 34. The first end 331 of the inductor 33 is electrically connected to the reference voltage node Vcom, the second switch unit 31 is electrically connected to the second end 332 of the inductor 33 and the negative electrode 122 of the battery 12, respectively, and the third switch unit 32 is electrically connected to the second end 332 of the inductor 33 and the positive electrode 121 of the battery 12, respectively. The first plate 341 of the second capacitor 34 is electrically connected to the reference voltage node Vcom, and the second plate 342 of the second capacitor 34 is electrically connected to the negative electrode 122 of the battery 12.

[0080] Specifically, such as Figure 9As shown, when the photoelectric conversion circuit is in the first state, the second switch unit 31 and the third switch unit 32 in the voltage conversion circuit 13 are alternately turned on. When the third switch unit 32 is turned on, the second switch unit 31 is turned off. At this time, the battery 12 magnetizes the inductor 33, the inductor 33 stores energy, the current flowing through the inductor 33 gradually increases, and the second capacitor 34 is charged at the same time; when the second switch unit 31 is turned on, the third switch unit 32 is turned off. At this time, since the inductor 33 will hinder the current change, the inductor 33 becomes an energy source for discharge, the current flowing through the inductor 33 gradually decreases, and the voltage across the second capacitor 34 is maintained by the discharge of the second capacitor 34 and the reduced inductor current. Since the load is always consuming energy, the voltage across the second capacitor 34 is always lower than the voltage input by the battery 12 to the voltage conversion circuit 13, thereby achieving the goal of reducing the output voltage of the battery 12.

[0081] Continue to refer Figure 9 When the photoelectric conversion circuit is in the second state, the second switch unit 31 and the third switch unit 32 in the voltage conversion circuit 13 are alternately turned on. When the second switch unit 31 is turned on, the third switch unit 32 is turned off. At this time, the voltage at the reference voltage node Vcom is applied to the inductor 33, and the inductor 33 stores energy, and the current flowing through the inductor 33 gradually increases; when the third switch unit 32 is turned on, the second switch unit 31 is turned off. At this time, the voltage at the reference voltage node Vcom and the energy stored in the inductor 33 are released to the battery 12 together, thereby achieving the voltage boosting of the reference voltage node Vcom.

[0082] It can be understood that, the longer the second switch unit 31 is turned on, the more energy is stored in the inductor 33 , and the higher the charging voltage obtained by boosting.

[0083] It should be noted that the inductance value of the inductor 33 can be set according to the actual power required. For example, the inductance value of the inductor 33 can be 4.7 μH to 10 μH, but is not limited thereto.

[0084] In addition, the type of inductor 33 can also be set according to actual needs. For example, the inductor 33 can be an alloy inductor, which is small in size and can reduce the space occupied by the voltage conversion circuit 13, but is not limited to this. In other embodiments, the inductor 33 can also directly use an 0805 model inductor, and the embodiment of the present invention is not limited to this.

[0085] Figure 10 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 10As shown, optionally, the second switch unit 31 includes a third transistor 35, and the third switch unit 32 includes a fourth transistor 36. A first terminal 351 of the third transistor 35 is electrically connected to the second terminal 332 of the inductor 33, a second terminal 352 of the third transistor 35 is electrically connected to the negative electrode 122 of the battery 12, and a control terminal 353 of the third transistor 35 is electrically connected to the first pulse-width modulation signal terminal PWM1. A first terminal 361 of the fourth transistor 36 is electrically connected to the second terminal 332 of the inductor 33, a second terminal 362 of the fourth transistor 36 is electrically connected to the positive electrode 121 of the battery 12, and a control terminal 363 of the fourth transistor 36 is electrically connected to the second pulse-width modulation signal terminal PWM2.

[0086] Specifically, such as Figure 10 As shown, the first pulse width modulation signal terminal PWM1 is used to output a first pulse width modulation signal, and the second pulse width modulation signal terminal PWM2 is used to output a second pulse width modulation signal.

[0087] The first pulse width modulation signal outputted by the first pulse width modulation signal terminal PWM1 and the second pulse width modulation signal outputted by the second pulse width modulation signal terminal PWM2 control the third transistor 35 and the fourth transistor 36 to be alternately turned on.

[0088] Among them, when the photoelectric conversion circuit is in the first state, when the first pulse width modulation signal is at a low level and the second pulse width modulation signal is at a high level, the fourth transistor 36 is controlled to be turned on and the third transistor 35 is turned off. At this time, the battery 12 magnetizes the inductor 33, the inductor 33 stores energy, and at the same time charges the second capacitor 34; when the first pulse width modulation signal is at a high level and the second pulse width modulation signal is at a low level, the third transistor 35 is controlled to be turned on and the fourth transistor 36 is turned off. At this time, the inductor 33 becomes an energy source for discharge, and the voltage across the second capacitor 34 is lower than the voltage input by the battery 12 to the voltage conversion circuit 13, thereby reducing the output voltage of the battery 12.

[0089] Continue to refer Figure 10 When the photoelectric conversion circuit is in the second state, when the first pulse width modulation signal is at a high level and the second pulse width modulation signal is at a low level, the third transistor 35 is controlled to be turned on and the fourth transistor 36 is turned off. At this time, the voltage at the reference voltage node Vcom is applied to the inductor 33, and the inductor 33 stores energy; when the first pulse width modulation signal is at a low level and the second pulse width modulation signal is at a high level, the fourth transistor 36 is controlled to be turned on and the third transistor 35 is turned off. At this time, the voltage at the reference voltage node Vcom and the energy stored in the inductor 33 are released to the battery 12 together, thereby boosting the voltage at the reference voltage node Vcom.

[0090] Among them, by setting the second switching unit 31 as the third transistor 35 and the third switching unit 32 as the fourth transistor 36, the conduction and cutoff of the third transistor 35 can be controlled by the first pulse width modulation signal output by the first pulse width modulation signal terminal PWM1, and the conduction and cutoff of the fourth transistor 36 can be controlled by the second pulse width modulation signal output by the second pulse width modulation signal terminal PWM2, thereby realizing the alternating conduction of the third transistor 35 and the fourth transistor 36. At the same time, by adjusting the duty cycle of the first pulse width modulation signal and the second pulse width modulation signal, the degree of boost and buck can be adjusted, thereby improving the flexibility of the voltage conversion circuit 13.

[0091] It should be noted that the above embodiment is only described by taking the third transistor 35 and the fourth transistor 36 as NMOS transistors as an example, and is not limited to this. In other embodiments, the third transistor 35 and the fourth transistor 36 can also be set as other types of transistors, and the embodiment of the present invention is not limited to this.

[0092] Figure 11 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 11 As shown, optionally, the voltage conversion circuit 13 further includes a third capacitor 37 , a first plate 371 of the third capacitor 37 is electrically connected to the positive electrode 121 of the battery 12 , and a second plate 372 of the third capacitor 37 is electrically connected to the negative electrode 122 of the battery 12 .

[0093] Specifically, such as Figure 11 As shown, the first plate 371 of the third capacitor 37 is electrically connected to the second terminal 362 of the fourth transistor 36 and the positive electrode 121 of the battery 12, respectively. The second plate 372 of the third capacitor 37 is electrically connected to the second terminal 352 of the third transistor 35. In this embodiment, by providing the third capacitor 37 between the positive electrode 121 and the negative electrode 122 of the battery 12, an interference prevention effect can be achieved, thereby preventing interference from damaging the battery.

[0094] The capacitance value of the third capacitor 37 can be set according to actual needs. For example, the capacitance value of the third capacitor 37 is 0.1 μF to 1 μF, but is not limited thereto and is not limited in the embodiment of the present invention.

[0095] Figure 12 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 12As shown, optionally, the reading circuit 11 includes a fifth transistor 41 and a sixth transistor 42, the first terminal 411 of the fifth transistor 41 is electrically connected to the second power supply terminal VDD, the second terminal 412 of the fifth transistor 41 is electrically connected to the first terminal 421 of the sixth transistor 42, the control terminal 413 of the fifth transistor 41 is electrically connected to the reading node Q, and the control terminal 423 of the sixth transistor 42 is electrically connected to the reading control signal terminal READ.

[0096] The fifth transistor 41 is used to convert the signal of the read node Q into a detection signal, and the sixth transistor 42 is used to output the detection signal in response to the control of the read control signal terminal READ.

[0097] Specifically, such as Figure 8 and Figure 12 As shown, during the read phase, from time t1 to time t2, the reset signal terminal RESET outputs a second low level, the first transistor 21 is turned off, the photosensitive element 22 receives the light signal and converts it into an electrical signal to form a photocurrent, the first capacitor 23 discharges, and the potential of the read node Q gradually decreases. The fifth transistor 41 operates in the linear region, and its leakage current is proportional to the potential of the read node Q.

[0098] From time t2 to time t3, the reset signal terminal RESET outputs a second low level, and the first transistor 21 is turned off. The read control signal terminal READ outputs a high control signal, turning on the sixth transistor 42. The second power supply voltage provided by the second power supply terminal VDD flows through the fifth transistor 41 and the sixth transistor 42 to the fingerprint recognition data reading terminal Vdata. The degree of conduction of the fifth transistor 41 determines the potential of the fingerprint recognition data reading terminal Vdata. The degree of conduction of the fifth transistor 41 is determined by the voltage of the read node Q. That is, the potential of the read node Q determines the potential at the fingerprint recognition data reading terminal Vdata. The photocurrent of the photodiode 26 is determined by the light intensity it receives. Therefore, the potential of the fingerprint recognition data reading terminal Vdata varies under different light intensities. During fingerprint detection, different fingerprint regions have different light intensities reflected to the photodiode 26. Therefore, by detecting the potential information of the fingerprint recognition data reading terminal Vdata corresponding to the fingerprint recognition unit at each position in the fingerprint recognition region, the fingerprint recognition function can be achieved.

[0099] Optionally, the first power supply terminal VCC and the second power supply terminal VDD may be the same power supply terminal, thereby simplifying the circuit and reducing costs.

[0100] In other embodiments, the first power supply terminal VCC and the second power supply terminal VDD may also be different power supply terminals, so that the first power supply voltage output by the first power supply terminal VCC and the second power supply voltage output by the second power supply terminal VDD can be independently adjusted according to the characteristic requirements of the first transistor 21 and the fifth transistor 41, respectively, to increase the potential range of the detection signal of the fifth transistor 41, which helps to improve the sensitivity and accuracy of fingerprint recognition.

[0101] Figure 13 The present invention provides another structural diagram of a photoelectric conversion circuit, such as Figure 13 As shown, optionally, the photoelectric conversion circuit includes a plurality of photosensitive circuits 10 and a voltage conversion circuit 13 , and the plurality of photosensitive circuits 10 are electrically connected to the voltage conversion circuit 13 .

[0102] For example, Figure 13 As shown, for example, a photoelectric conversion circuit includes two photosensitive circuits 10. The two photosensitive circuits 10 are connected in parallel, and the reference voltage node Vcom connected to each photosensitive circuit 10 is electrically connected to the voltage conversion circuit 13. If, under a certain light intensity, the power generated by a single photosensitive circuit 10 is Pi, then the power generated by the two photosensitive circuits 10 is: Pt = Pi * 2. Therefore, by increasing the number of photosensitive circuits 10, the power generated can be increased, thereby increasing the charging speed of the battery 12 and helping to improve battery life.

[0103] Continue to refer Figure 13 Optionally, the photoelectric conversion circuit further includes a plurality of reading circuits 11 connected one-to-one with the photosensitive circuits 10 to perform fingerprint recognition more accurately.

[0104] It should be noted that the above embodiment only takes the parallel arrangement of multiple photosensitive circuits 10 as an example. In another embodiment, multiple photosensitive circuits 10 can also be arranged in series, which helps to increase the charging voltage; in another embodiment, multiple photosensitive circuits 10 can also be arranged in series and parallel. For example, multiple photosensitive circuits 10 are divided into multiple circuit groups, and the photosensitive circuits 10 in the circuit group are arranged in parallel, and multiple circuit groups are arranged in series. Those skilled in the art can make settings according to actual needs, and the embodiments of the present invention are not limited to this.

[0105] It should be noted that the above embodiment only uses the example of a photoelectric conversion circuit including two photosensitive circuits 10. In other embodiments, those skilled in the art may set the number of photosensitive circuits 10 according to actual needs. It is understood that the more photosensitive circuits 10 there are, the more electrical signals converted from the optical signal, and the more electricity can be charged to the battery 12, thereby further helping to improve the battery life.

[0106] Based on the same inventive concept, an embodiment of the present invention further provides a driving method, which is used to drive any photoelectric conversion circuit provided by the above embodiments. The structures and terminology that are the same or corresponding to the above embodiments are not repeated here.

[0107] Continue to refer Figure 2 and Figure 3 The driving method includes a light detection phase T1 and a charging phase T2. The light detection phase T1 includes a reset phase (from time t0 to time t1) and a reading phase (from time t1 to time t3) which are sequentially passed.

[0108] In the reset phase, the reset pulse signal RESET outputs a first level, and the photosensitive circuit 10 resets the read node Q in response to the first level.

[0109] During the reading phase, the reset pulse signal RESET outputs a second level, and the photosensitive circuit 10 responds to the second level by coupling the electrical signal converted by the photosensitive circuit 10 according to the optical signal to the reading node Q. The reading circuit 11 converts the signal of the reading node Q into a detection signal, and outputs the detection signal in response to the control of the reading control signal terminal READ.

[0110] During the charging phase, the photosensitive circuit 10 outputs the electrical signal converted by the photosensitive circuit 10 according to the light signal through the reference voltage node Vcom to charge the battery 12 .

[0111] Among them, in the light detection stage T1, by setting the reset signal terminal RESET to output a reset pulse signal including a first level and a second level, the photosensitive circuit 10 responds to the reset pulse signal to couple the electrical signal converted by the photosensitive circuit 10 according to the light signal to the reading node Q, and the reading circuit 11 converts the signal of the reading node Q into a detection signal, and outputs the detection signal in response to the control of the read control signal terminal READ to realize the fingerprint recognition function; at the same time, in the charging stage T2, by setting the photosensitive circuit 10, the electrical signal converted by the photosensitive circuit 10 according to the light signal is output through the reference voltage node Vcom to charge the battery 12, thereby using the electrical signal converted by the photosensitive circuit 10 from the light signal to charge the battery 12, providing the battery 12 with power reserve, and realizing the fingerprint recognition function and the charging function.

[0112] Continue to refer Figure 2Optionally, the photosensitive circuit 10 includes a first transistor 21, a photosensitive element 22, a first capacitor 23, and a first switch unit 24. The first end 211 of the first transistor 21, the first end 221 of the photosensitive element 22, and the first plate 231 of the first capacitor 23 are connected to the read node Q. The second end 212 of the first transistor 21 is electrically connected to the first power supply terminal VCC, and the control end 213 of the first transistor 21 is electrically connected to the reset signal terminal RESET. The second end 222 of the photosensitive element 22 and the second plate 232 of the first capacitor 23 are both electrically connected to the reference voltage node Vcom, and the reference voltage node Vcom is electrically connected to the positive electrode 121 of the battery 12. The first switch unit 24 is electrically connected to the read node Q and the negative electrode 122 of the battery 12, respectively. During the charging stage, the first switch unit 24 is also turned on.

[0113] Continue to refer Figure 2 and Figure 3 During the charging phase T2 (from time t5 to time t6), the reset signal terminal RESET outputs a second low level, and the first transistor 21 is turned off. The first switch unit 24 is turned on, connecting the read node Q to the negative electrode 122 (ground) of the battery 12. The photosensitive element 22 receives the light signal and converts it into an electrical signal to form a photocurrent, generating a photo-generated voltage at the reference voltage node Vcom. At this time, the voltage at the reference voltage node Vcom becomes the forward photo-generated voltage of the photosensitive element 22, thereby charging the battery 12.

[0114] Continue to refer Figure 4 Optionally, the first switch unit 24 includes a second transistor 25, wherein a first terminal 251 of the second transistor 25 is electrically connected to the read node Q, a second terminal 252 of the second transistor 25 is electrically connected to the negative electrode 122 of the battery 12, and a control terminal 253 of the second transistor 25 is electrically connected to the state switching signal terminal Charge. During the charging phase, the state switching signal terminal Charge outputs a state switching signal, and the second transistor 25 is turned on in response to the state switching signal.

[0115] Among them, such as Figure 4 and Figure 5 As shown, taking the second transistor 25 as an N-type transistor as an example, in the light detection stage T1, the state switching signal terminal Charge outputs a low-level state switching signal, and the second transistor 25 is turned off. At this time, the photoelectric conversion circuit is in the first state to perform fingerprint detection.

[0116] In the charging stage T2, the state switching signal terminal Charge outputs a high-level state switching signal, controlling the second transistor 25 to turn on, so that the reading node Q is connected to the negative electrode 122 (ground) of the battery 12, and the voltage at the reference voltage node Vcom becomes the forward photogenerated voltage of the photosensitive element 22, so as to charge the battery 12.

[0117] Figure 14 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention is shown in FIG. Figure 14 As shown, optionally, in the reset phase, the method further includes: the reading circuit 11 converts the signal when the read node Q is reset into a reset detection signal, and outputs the reset detection signal in response to the control of the read control signal terminal READ.

[0118] Specifically, such as Figure 14 As shown, in the reset phase (from time t0 to time t1), the read control signal terminal READ outputs a high-level control signal, and the read circuit 11 converts the signal when the read node Q is reset into a reset detection signal, and outputs the reset detection signal in response to the control of the read control signal terminal READ, thereby resetting the read circuit 11 at the same time, which helps to improve the accuracy of fingerprint recognition.

[0119] Figure 15 A schematic diagram of the working timing of another photoelectric conversion circuit provided by an embodiment of the present invention is shown in FIG. Figure 15 As shown, optionally, the read phase (from moment t1 to moment t3) includes a pre-read sub-phase (from moment t1 to moment t1'). In the pre-read sub-phase (from moment t1 to moment t1'), the read circuit 11 converts the signal of the read node Q into a detection signal and outputs the detection signal in response to the control of the read control signal terminal READ.

[0120] Furthermore, from time t1 ′ to time t2 , the read circuit 11 stops outputting the detection signal in response to the control of the read control signal terminal READ.

[0121] From time t2 to time t3 , the read circuit 11 converts the signal of the read node Q into a detection signal, and outputs the detection signal in response to the control of the read control signal terminal READ.

[0122] Among them, by outputting a detection signal in the pre-reading sub-stage (from moment t1 to moment t1'), and then obtaining the change of the light signal detected by the photosensitive element 22 based on the difference between the detection signal in the pre-reading sub-stage (from moment t1 to moment t1') and the detection signal from moment t2 to moment t3, it helps to improve the accuracy of fingerprint recognition.

[0123] Based on the same inventive concept, an embodiment of the present invention further provides a display device, Figure 16 A schematic structural diagram of a display device provided by an embodiment of the present invention is shown in FIG. Figure 16As shown, the display device 50 includes the photoelectric conversion circuit 51 described in any embodiment of the present invention. Therefore, the display device 50 provided by the embodiment of the present invention has the technical effect of the technical solution in any of the above embodiments, and the structures and terminology that are the same or corresponding to the above embodiments are not repeated here.

[0124] The display device 50 provided in the embodiment of the present invention can be Figure 16 The mobile phone shown can also be any electronic product with a display function, including but not limited to the following categories: televisions, laptops, desktop monitors, tablet computers, digital cameras, smart bracelets, smart glasses, car displays, medical equipment, industrial control equipment, touch interactive terminals, etc. The embodiments of the present invention do not specifically limit this.

[0125] Continue to refer Figure 16 Exemplarily, the display device 50 includes a display area, in which a plurality of pixel units arranged in an array can be provided for displaying images.

[0126] The photoelectric conversion circuit 51 includes a voltage conversion circuit 13 , a plurality of photosensitive circuits, and a plurality of reading circuits connected to the photosensitive circuits in a one-to-one correspondence, wherein the photosensitive circuits and the reading circuits connected thereto constitute a photoelectric conversion sub-circuit 511 .

[0127] The display area may include a fingerprint recognition area, and a plurality of photoelectric conversion sub-circuits 511 may be arranged in an array in the fingerprint recognition area to implement a fingerprint recognition function.

[0128] The fingerprint recognition area may only cover a portion of the display area, such as half the screen, so as to use fewer photoelectric conversion sub-circuits 511 and reduce costs.

[0129] Optionally, the fingerprint recognition area can also cover the entire display area to achieve full-screen fingerprint recognition. In this case, the number of photoelectric conversion sub-circuits 511 is relatively large. For example, the photoelectric conversion circuit 51 includes m*n photoelectric conversion sub-circuits 511. Under a certain light intensity, the power generated by the photosensitive circuit in a single photoelectric conversion sub-circuit 511 is Pi, and the total power generated is: Pt = Pi*m*n, which can increase the charging speed of the battery 12 and help improve the battery life.

[0130] Optionally, taking the example of each pixel unit including three sub-pixels, each pixel unit can be set to correspond to a photoelectric conversion sub-circuit 511, or multiple pixel units can be set to correspond to one photoelectric conversion sub-circuit 511. Those skilled in the art can make settings according to actual needs, and the embodiments of the present invention are not limited to this.

[0131] Continue to refer Figure 16Optionally, the display device 50 also includes a battery 12, and multiple photoelectric conversion sub-circuits 511 are arranged in parallel. The reference voltage node Vcom connected to the photosensitive circuit in each photoelectric conversion sub-circuit 511 is electrically connected to the voltage conversion circuit 13, and the voltage conversion circuit 13 is connected to the battery 12, wherein the negative pole of the battery 12 can be grounded GND.

[0132] In the light detection stage, the photoelectric conversion circuit 51 is in the first state. At this time, the voltage Vbat at the positive electrode of the battery 12 is the output voltage of the battery 12. The voltage conversion circuit 13 steps down the output voltage of the battery 12 to obtain a reference voltage, and transmits the reference voltage to the reference voltage node Vcom to provide a reference voltage for the photosensitive circuit 10 through the reference voltage node Vcom.

[0133] During the charging stage, the photoelectric conversion circuit 51 is in the second state, the voltage conversion circuit 13 boosts the voltage at the reference voltage node Vcom to obtain a charging voltage, and applies the charging voltage to the positive electrode of the battery 12. At this time, the voltage Vbat at the positive electrode of the battery 12 is the charging voltage, wherein the charging voltage is greater than the output voltage of the battery 12, thereby feeding back electrical energy to the battery 12 and realizing the function of charging the battery 12.

[0134] Continue to refer Figure 16 Optionally, the display device 50 further includes a chip IC, which receives a detection signal through the fingerprint recognition data reading terminal Vdata and processes the detection signal to implement a fingerprint recognition function.

[0135] Optionally, the chip IC may be electrically connected to the battery 12 (not shown in the figure) so that the battery 12 provides power for the chip IC.

[0136] Optionally, the power signals of the first power terminal VCC and the second power terminal VDD may be provided by a chip IC or other power modules, and those skilled in the art may configure them according to actual needs.

[0137] Continue to refer Figure 16 Optionally, the display device 50 further includes a scan driving circuit 60 , which is connected to the photoelectric conversion circuit 51 .

[0138] In the reset phase, the scanning driving circuit 60 provides a reset pulse signal to the photoelectric conversion sub-circuit 511 row by row to reset the photoelectric conversion sub-circuit 511 and avoid interference from the previous fingerprint recognition process or the circuit's own signal.

[0139] In the reading phase, the scanning driving circuit 60 provides a reading control signal to the photoelectric conversion sub-circuit 511 row by row, so that the photoelectric conversion sub-circuit 511 outputs a detection signal.

[0140] In other embodiments, in order to improve the fingerprint recognition accuracy, the fingerprint recognition process may perform multiple resets and signal outputs. In this case, it is only necessary to cyclically execute the reset phase and the reading phase in the subsequent process.

[0141] Optionally, during the charging stage, the chip IC may provide a state switching signal to all photoelectric conversion sub-circuits 511 so that the photoelectric conversion sub-circuit 511 outputs the electrical signal converted by the photosensitive circuit according to the light signal through the reference voltage node to charge the battery 12.

[0142] Optionally, the scan driving circuit 60 is connected to a chip IC, and the chip IC provides the scan driving circuit 60 with required power signals and clock signals, etc., so that the chip IC drives the scan driving circuit 60 to work.

[0143] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0144] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A photoelectric conversion circuit, characterized in that: Including photosensitivity circuit and reading circuit; The photosensitive circuit is electrically connected to a reference voltage node, a reset signal terminal and a read node, the read circuit is electrically connected to the read node and a read control signal terminal, and the reference voltage node is electrically connected to a battery; In the first state, the reset signal terminal outputs a reset pulse signal, and the photosensitive circuit is used to couple the electrical signal converted by the photosensitive circuit according to the light signal to the read node in response to the reset pulse signal; the read circuit is used to convert the signal of the read node into a detection signal, and output the detection signal in response to the control of the read control signal terminal; In the second state, the photosensitive circuit outputs the electrical signal converted by the photosensitive circuit according to the light signal to the positive electrode of the battery through the reference voltage node to charge the battery; The photosensitive circuit includes a first transistor, a photosensitive element, a first capacitor and a first switching unit; The first terminal of the first transistor, the first terminal of the photosensitive element and the first plate of the first capacitor are connected to the read node; The second terminal of the first transistor is electrically connected to the first power supply terminal, and the control terminal of the first transistor is electrically connected to the reset signal terminal; The second terminal of the photosensitive element and the second plate of the first capacitor are both electrically connected to the reference voltage node; The reference voltage node is electrically connected to the positive electrode of the battery, and the first switch unit is electrically connected to the read node and the negative electrode of the battery respectively; In the first state, the positive electrode of the battery provides a reference voltage to the photosensitive circuit through the reference voltage node; In the second state, the first switch unit is turned on.

2. The photoelectric conversion circuit according to claim 1, wherein: The first switching unit includes a second transistor; The first terminal of the second transistor is electrically connected to the read node, the second terminal of the second transistor is electrically connected to the negative electrode of the battery, and the control terminal of the second transistor is electrically connected to the state switching signal terminal; In the second state, the state switching signal terminal outputs a state switching signal, and the second transistor is turned on in response to the state switching signal.

3. The photoelectric conversion circuit according to claim 1, wherein: The photosensitive element includes a photodiode, a cathode of the photodiode serves as a first end of the photosensitive element, and an anode of the photodiode serves as a second end of the photosensitive element.

4. The photoelectric conversion circuit according to claim 1, wherein: The photoelectric conversion circuit further includes a voltage conversion circuit; The photosensitive circuit is electrically connected to the battery through the voltage conversion circuit; In the first state, the voltage conversion circuit is used to convert the output voltage of the battery into a reference voltage to provide the reference voltage for the reference voltage node, wherein the reference voltage is lower than the output voltage of the battery; In the second state, the voltage conversion circuit is used to convert the voltage at the reference voltage node into a charging voltage to charge the battery, wherein the voltage at the reference voltage node is less than the charging voltage, and the charging voltage is greater than the output voltage of the battery.

5. The photoelectric conversion circuit according to claim 4, wherein: The voltage conversion circuit includes a second switch unit, a third switch unit, an inductor and a second capacitor; The first end of the inductor is electrically connected to the reference voltage node, the second switch unit is electrically connected to the second end of the inductor and the negative electrode of the battery respectively, and the third switch unit is electrically connected to the second end of the inductor and the positive electrode of the battery respectively; The first plate of the second capacitor is electrically connected to the reference voltage node, and the second plate of the second capacitor is electrically connected to the negative electrode of the battery.

6. The photoelectric conversion circuit according to claim 5, wherein: The second switch unit includes a third transistor, and the third switch unit includes a fourth transistor; The first end of the third transistor is electrically connected to the second end of the inductor, the second end of the third transistor is electrically connected to the negative electrode of the battery, and the control end of the third transistor is electrically connected to the first pulse width modulation signal end; The first end of the fourth transistor is electrically connected to the second end of the inductor, the second end of the fourth transistor is electrically connected to the positive electrode of the battery, and the control end of the fourth transistor is electrically connected to the second pulse width modulation signal end.

7. The photoelectric conversion circuit according to claim 5, wherein: The voltage conversion circuit further includes a third capacitor, wherein a first plate of the third capacitor is electrically connected to the positive electrode of the battery, and a second plate of the third capacitor is electrically connected to the negative electrode of the battery.

8. The photoelectric conversion circuit according to claim 1, wherein: The read circuit includes a fifth transistor and a sixth transistor; The first end of the fifth transistor is electrically connected to the second power supply end, the second end of the fifth transistor is electrically connected to the first end of the sixth transistor, the control end of the fifth transistor is electrically connected to the read node, and the control end of the sixth transistor is electrically connected to the read control signal end.

9. The photoelectric conversion circuit according to any one of claims 4 to 7, characterized in that: The photoelectric conversion circuit includes a plurality of the photosensitive circuits and one voltage conversion circuit, and the plurality of the photosensitive circuits are electrically connected to the voltage conversion circuit.

10. A driving method, characterized in that: The driving method is used to drive the photoelectric conversion circuit according to any one of claims 1 to 9, the driving method comprising a light detection phase and a charging phase; the light detection phase comprises a reset phase and a reading phase which are sequentially passed; In the reset phase, the reset pulse signal outputs a first level, and the photosensitive circuit resets the read node in response to the first level; In the reading phase, the reset pulse signal outputs a second level, and the photosensitive circuit couples the electrical signal converted by the photosensitive circuit according to the light signal to the reading node in response to the second level. The reading circuit converts the signal of the reading node into a detection signal, and outputs the detection signal in response to the control of the reading control signal terminal. In the charging stage, the photosensitive circuit outputs the electrical signal converted by the photosensitive circuit according to the light signal through a reference voltage node to charge the battery.

11. The driving method according to claim 10, wherein: The photosensitive circuit includes a first transistor, a photosensitive element, a first capacitor and a first switching unit; The first terminal of the first transistor, the first terminal of the photosensitive element and the first plate of the first capacitor are connected to the read node; The second terminal of the first transistor is electrically connected to the first power supply terminal, and the control terminal of the first transistor is electrically connected to the reset signal terminal; The second terminal of the photosensitive element and the second plate of the first capacitor are both electrically connected to the reference voltage node; The reference voltage node is electrically connected to the positive electrode of the battery, and the first switch unit is electrically connected to the read node and the negative electrode of the battery respectively; During the charging stage, the first switch unit is also turned on.

12. The driving method according to claim 11, wherein: The first switching unit includes a second transistor; The first terminal of the second transistor is electrically connected to the read node, the second terminal of the second transistor is electrically connected to the negative electrode of the battery, and the control terminal of the second transistor is electrically connected to the state switching signal terminal; During the charging stage, the state switching signal terminal further includes: outputting a state switching signal, and the second transistor is turned on in response to the state switching signal.

13. The driving method according to claim 10, wherein: In the reset phase, the method further includes: the read circuit converting the signal when the read node is reset into a reset detection signal, and outputting the reset detection signal in response to the control of the read control signal terminal.

14. A display device, characterized in that: The display device comprises the photoelectric conversion circuit according to any one of claims 1 to 9.

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