A temperature compensation circuit, optical sensor chip and optical sensor device

Abstract

The present invention relates to the field of photoelectric detection technology, and discloses a temperature compensation circuit, a light sensor chip, and a light sensor device. The temperature compensation circuit is applied to a light sensor chip with a built-in sensing photodiode, and includes a temperature compensation module, a transimpedance amplifier, and an output interface connected in sequence, wherein: the temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; the transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage output to the output interface; the output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output it to the output terminal. Thus, the temperature compensation circuit provides the function of compensating current, and the leakage current of the sensing photodiode that changes with temperature is compensated by the temperature compensation module therein, thereby eliminating the failure and characteristic instability of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a temperature compensation circuit, a light sensor chip and a light sensor device. Background Art

[0002] In existing optical sensor chips with built-in sensing photodiodes, leakage current is inevitably generated due to the characteristics of the sensing photodiode, especially when the sensing photodiode is manufactured by silicon process to manufacture an optical sensor chip with built-in sensing photodiode. If the leakage current does not change with temperature, there is only an offset in the characteristics, and the same characteristics will be exhibited regardless of temperature changes.

[0003] However, due to the structural characteristics of the sensing photodiode, its leakage current increases with the increase of temperature. Therefore, even if the light source intensity does not change, the output value of the transimpedance amplifier connected to the output of the sensing photodiode will eventually change with temperature. Since the output value of the sensing photodiode is different at low temperature, room temperature or high temperature, the temperature characteristics of the sensing photodiode may cause malfunction of the light sensor chip with the built-in sensing photodiode.

[0004] Therefore, how to eliminate the failure and characteristic instability of optical sensor chips with built-in sensing photodiodes caused by the temperature characteristics of the sensing photodiodes has become a technical problem that needs to be solved. Summary of the invention

[0005] The embodiments of the present invention aim to provide a temperature compensation circuit, a light sensor chip and a light sensor device, which can solve the problem that the existing light sensor chip with a built-in sensing photodiode has malfunction and unstable characteristics due to the temperature characteristics of the sensing photodiode.

[0006] In order to solve the above technical problems, the first embodiment of the present invention provides a temperature compensation circuit, which is applied to a light sensor chip with a built-in sensing photodiode, comprising a temperature compensation module, a transimpedance amplifier and an output interface connected in sequence, wherein:

[0007] The temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature;

[0008] The transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage and output it to the output interface;

[0009] The output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output it to the output terminal.

[0010] Optionally, the temperature compensation module includes a compensation photodiode and a current amplifier; wherein:

[0011] The compensation photodiode is used to generate a compensation current having a magnitude 1 / N times that of a leakage current of the sensing photodiode;

[0012] The current amplifier is used to amplify the compensation current output by the compensation photodiode by N times to output a compensation current of the same magnitude as the leakage current of the sensing photodiode, where N is a natural number greater than 2.

[0013] Optionally, the compensation photodiode has the same structure as the sensing photodiode, and a size is 1 / N times that of the sensing photodiode.

[0014] Optionally, in the manufacturing process of the light sensor chip with a built-in sensing photodiode, a metal layer covers the upper part of the compensation photodiode.

[0015] Optionally, the compensation photodiode and the sensing photodiode are arranged to be spaced apart from each other in a light sensor chip layout having a built-in sensing photodiode.

[0016] Optionally, the input end of the current amplifier is connected to one end of the compensation photodiode, the output end of the current amplifier outputs the compensation current, and the other end of the compensation photodiode is grounded.

[0017] Optionally, the current amplifier comprises a power mirror circuit.

[0018] Optionally, the first input end of the transimpedance amplifier is connected to the output end of the current amplifier to receive the compensation current output by the output end of the current amplifier; the second input end of the transimpedance amplifier is connected to one end of the sensing photodiode to receive the photocurrent output by the sensing photodiode; the output end of the transimpedance amplifier is connected to the output interface to convert the photocurrent generated by the sensing photodiode sensing light into a voltage and output it to the output interface.

[0019] Correspondingly, the second aspect embodiment of the present invention provides a light sensor chip, which has a built-in sensing photodiode, and the sensing photodiode is used to sense light and generate a photocurrent output; the light sensor chip also includes the temperature compensation circuit described in the first aspect embodiment of the present invention, and the temperature compensation circuit is connected to the sensing photodiode, and is used to compensate for the leakage current of the sensing photodiode that changes with temperature, and convert the photocurrent output by the sensing photodiode into a voltage form or a frequency form for output.

[0020] Correspondingly, the third embodiment of the present invention provides a light sensor device, including the light sensor chip and the control module described in the second embodiment of the present invention, wherein the output interface of the light sensor chip is connected to the control module for outputting the output of the light sensor chip to the control module in the form of voltage or frequency.

[0021] Compared with the prior art, the present invention provides a temperature compensation circuit, a light sensor chip and a light sensor device. The temperature compensation circuit is applied to a light sensor chip with a built-in sensing photodiode, and includes a temperature compensation module, a transimpedance amplifier and an output interface connected in sequence, wherein: the temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; the transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage output to the output interface; the output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output to the output terminal. Thus, the temperature compensation circuit can provide the function of compensating current, and the leakage current of the sensing photodiode that changes with temperature can be compensated by the temperature compensation module therein, eliminating the failure and unstable characteristics of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode. It can solve the problem that the existing light sensor chip with a built-in sensing photodiode has failure and unstable characteristics caused by the temperature characteristics of the sensing photodiode. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0023] Figure 1 It is a schematic diagram of the structure of a light sensor chip with a built-in sensing photodiode in the prior art;

[0024] Figure 2 It is a schematic diagram of the layout of a light sensor chip with a built-in sensing photodiode in the prior art;

[0025] Figure 3 It is a structural schematic diagram of a temperature compensation circuit provided by the present invention;

[0026] Figure 4 It is a structural schematic diagram of a light sensor chip provided by the present invention;

[0027] Figure 5 It is a structural schematic diagram of a light sensing device provided by the present invention. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "bottom" etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0029] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0030] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] See also Figure 1 and Figure 2 . Figure 1 The figure shows a schematic diagram of the configuration of an existing optical sensor chip (IC, Integrated Circuit) with a built-in sensing photodiode. Figure 2 FIG. 1 is a schematic diagram showing the layout of an existing light sensor chip with a built-in photodiode for sensing.

[0032] exist Figure 1 In the existing optical sensor chip with built-in sensing photodiode, it includes a sensing photodiode (Photo Diode) 1 based on wide-spectrum silicon, a transimpedance amplifier 3 (Trans Impedance Amplifier, TIA) for converting the photocurrent generated by the sensing photodiode 1 into a voltage, and an output interface 4 for converting the output voltage of the transimpedance amplifier 3 into an output form and outputting it to the output terminal. The output terminal of the output interface 4 can be connected to a microcontroller unit (Micro Controller Unit, MCU) or other control IC at the back end.

[0033] exist Figure 2 In the present invention, since the photocurrent generated by the sensing photodiode 1 is very small, the sensing photodiode 1 has to be made relatively large, and the area occupied by the sensing photodiode 1 in the semiconductor product of the optical sensor chip with the sensing photodiode built in becomes relatively large.

[0034] If the sensing photodiode 1 is built into the semiconductor of the light sensor chip by the silicon process, a PN diode is required. The spectral characteristics of the PN diode are determined by the energy gap of the depletion region generated by the PN junction. Generally speaking, when the sensing photodiode 1 is reverse biased to make the current zero, the current does not flow. If the light source intensity is greater than the energy difference of the sensing photodiode 1, the photocurrent (PhotoCurrent) flows from the sensing photodiode 1). Since the photocurrent generated in this way is very small compared to the amount of current used in the light sensor chip, it is converted into a voltage form proportional to it after being amplified by the transimpedance amplifier 3. This operation is a DC operation, and a voltage proportional to the photocurrent value is output.

[0035] On the other hand, due to the characteristics of the sensing photodiode 1, especially when the sensing photodiode 1 is manufactured by a silicon process to manufacture a light sensor chip with a built-in sensing photodiode, leakage current is inevitably generated. If this leakage current does not change with temperature, there is only an offset in the characteristics, and the same characteristics will be exhibited regardless of temperature changes.

[0036] However, due to the structural characteristics of the sensing photodiode 1, its leakage current increases with the increase of temperature. Therefore, even if the light source intensity does not change, the output value of the transimpedance amplifier 3 will eventually change with the temperature. Since the output value of the sensing photodiode 1 is different at low temperature, room temperature or high temperature, the temperature characteristics of the sensing photodiode 1 may cause malfunction and unstable characteristics of the optical sensor chip with the built-in sensing photodiode.

[0037] To this end, the present invention provides a temperature compensation circuit, which is applied to a light sensor chip with a built-in sensing photodiode, including a temperature compensation module, a transimpedance amplifier and an output interface connected in sequence, and the temperature compensation module compensates for the leakage current of the sensing photodiode that changes with temperature, so that the temperature compensation circuit can provide a compensation current function, eliminating the failure and unstable characteristics of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode. Thus, the problem of failure and unstable characteristics of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode in the existing light sensor chip with a built-in sensing photodiode can be solved.

[0038] In order to facilitate understanding of the above inventive concept of the present invention, the above inventive concept of the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments.

[0039] In one embodiment, Figure 3 As shown, the present invention provides a temperature compensation circuit 20, which is applied to a light sensor chip with a built-in sensing photodiode 10, comprising a temperature compensation module 21, a transimpedance amplifier 22 and an output interface 23 connected in sequence, wherein:

[0040] A temperature compensation module 21 is used to compensate for the leakage current of the sensing photodiode 10 that changes with temperature;

[0041] The transimpedance amplifier 22 is used to convert the photocurrent generated by the sensing photodiode 10 into a voltage and output it to the output interface 23;

[0042] The output interface 23 is used to convert the voltage output by the transimpedance amplifier 22 into a voltage form or a frequency form and output it to the output terminal.

[0043] In this embodiment, a temperature compensation circuit is provided, which is applied to a light sensor chip with a built-in sensing photodiode, including a temperature compensation module, a transimpedance amplifier and an output interface connected in sequence, wherein: the temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; the transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage output to the output interface; the output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output it to the output terminal. Thus, the temperature compensation circuit can provide the function of compensating current, and the leakage current of the sensing photodiode that changes with temperature can be compensated by the temperature compensation module therein, eliminating the failure and unstable characteristics of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode. It can solve the problem that the existing light sensor chip with a built-in sensing photodiode has failures and unstable characteristics caused by the temperature characteristics of the sensing photodiode.

[0044] In one embodiment, the temperature compensation module 21 is used to compensate for the leakage current of the sensing photodiode 10 that changes with temperature, and provides a current compensation function.

[0045] According to the previous description, due to the characteristics of the sensing photodiode 10, especially when the sensing photodiode 10 is manufactured by a silicon process to manufacture a photosensor chip with a built-in sensing photodiode, leakage current will inevitably be generated, and the leakage current value will vary according to the temperature, making the output value of the sensing photodiode 10 different at low temperature, room temperature or high temperature. Therefore, the temperature characteristics of the sensing photodiode 1 may cause failure and unstable characteristics of the photosensor chip with a built-in sensing photodiode.

[0046] In the present invention, the method for compensating the leakage current that changes according to the temperature is to connect a compensation photodiode having the same structure as the sensing photodiode 10 but a relatively smaller size to the sensing photodiode 10 to configure a temperature compensation circuit 20 in the direction opposite to the current direction, and the compensation photodiode is used for current compensation purposes to provide a compensation current corresponding to the leakage current, thereby offsetting the leakage current. At the same time, the current reduction caused by the relative reduction in the size of the compensation photodiode is solved by configuring current amplification in the temperature compensation circuit 20. When the temperature compensation circuit 20 is configured in this way, the chip size of the optical sensor with a built-in sensing photodiode is not increased.

[0047] Specifically, Figure 3 As shown, the temperature compensation module 21 includes: a compensation photodiode 211 and a current amplifier 212; wherein:

[0048] The compensation photodiode 211 is used to generate a compensation current having a magnitude of 1 / N times the leakage current of the sensing photodiode 10. Wherein N is a natural number greater than 2 (i.e., N is a natural number greater than 2), and can be preset when designing a light sensor chip with a built-in sensing photodiode 10, based on considerations of the performance and size of each component.

[0049] Specifically, the compensation photodiode 211 has the same structure as the sensing photodiode 10 built into the optical sensor chip, but the size is 1 / N times that of the sensing photodiode 10. Since the compensation photodiode 211 of the temperature compensation module 21 must perform current compensation only according to temperature, the influence of the external light source must be minimized. For this reason, in the manufacturing process of the optical sensor chip with a built-in sensing photodiode, a metal layer must be covered on the upper part of the compensation photodiode 211 to prevent the compensation photodiode 211 from sensing light and generating photocurrent; in addition, the compensation photodiode 211 and the sensing photodiode 10 are arranged to be as far apart from each other as possible in the optical sensor chip layout with a built-in sensing photodiode 10.

[0050] The current amplifier 212 is used to amplify the compensation current output by the compensation photodiode 211 by N times, so as to output a compensation current having the same magnitude as the leakage current of the sensing photodiode 10 .

[0051] Specifically, Figure 3 As shown, the input end of the current amplifier 212 is connected to one end of the compensation photodiode 211, and the output end of the current amplifier 212 outputs the compensation current. At this time, the other end of the compensation photodiode 211 is grounded.

[0052] For example, the current amplifier 212 may include at least one transistor circuit or a current mirror circuit. In the present invention, since the current amplification method using a current mirror circuit is more advantageous in terms of characteristics, in the embodiment of the present invention, the current amplifier 212 includes a current mirror circuit and is composed of a current mirror circuit.

[0053] In this embodiment, by providing a temperature compensation module, including a compensation photodiode for generating a compensation current having a magnitude of 1 / N times the leakage current of the sensing photodiode, and a current amplifier for amplifying the compensation current output by the compensation photodiode by N times to output a compensation current having the same magnitude as the leakage current of the sensing photodiode, a compensation current corresponding to the leakage current can be provided to offset the leakage current of the sensing photodiode, so as to achieve the purpose of compensating the leakage current of the sensing photodiode that changes with temperature, so that the temperature compensation circuit can provide the function of compensation current, and the failure and characteristic instability of the optical sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode can be eliminated. In addition, the compensation photodiode used for current compensation has the same structure as the sensing photodiode 10 but is relatively smaller in size. At the same time, by configuring the current amplification, the current reduction caused by the relative reduction in the size of the compensation photodiode can be solved, so that when the temperature compensation circuit is configured in this way, the size of the optical sensor chip with a built-in sensing photodiode will not be increased.

[0054] In one embodiment, the transimpedance amplifier 22 is used to convert the photocurrent generated by the sensing photodiode 10 sensing light into a voltage and output it to the output interface 23 .

[0055] The transimpedance amplifier 22, whose English name is Trans Impedance Amplifier (TIA), is a type of amplifier. The amplifier type is defined according to the type of its input and output signals. In the field of electricity, it is assumed that the amplifier gain A = Y / X, Y is the output, and X is the input. Since a signal is characterized by either voltage or current, four types of amplifiers can be combined. Among them, when the input X is a current signal and the output Y is a voltage signal, the amplifier gain A = Y (voltage) / X (current), which has the dimension of resistance. At this time, the amplifier is generally called a transimpedance amplifier. The transimpedance amplifier is a current-to-voltage converter that can convert the input current into an output voltage of the amplifier gain A.

[0056] Specifically, Figure 3 As shown, the first input terminal IN1 of the transimpedance amplifier 22 is connected to the output terminal of the current amplifier 212 of the temperature compensation module 21, and receives the compensation current output by the output terminal of the current amplifier 212; the second input terminal IN2 of the transimpedance amplifier 22 is connected to one end of the sensing photodiode 10, and is used to receive the photocurrent output by the sensing photodiode 10; the output terminal OUT of the transimpedance amplifier 22 is connected to the output interface 23, and is used to convert the photocurrent generated by the sensing photodiode 10 sensing light into a voltage and output it to the output interface 23. At this time, the other end of the sensing photodiode 10 is grounded.

[0057] For example, the first input terminal IN1 of the transimpedance amplifier 22 is a non-inverting input terminal, and the second input terminal IN2 of the transimpedance amplifier 22 is an inverting output terminal. The non-inverting input terminal of the transimpedance amplifier 22 is connected to the output terminal of the current amplifier 212 of the temperature compensation module 21, and receives the compensation current output by the output terminal of the current amplifier 212; the reverse input terminal of the transimpedance amplifier 22 is connected to one end of the sensing photodiode 10, and is used to receive the photocurrent output by the sensing photodiode 10; the output terminal OUT of the transimpedance amplifier 22 is connected to the output interface 23, and is used to convert the photocurrent generated by the sensing photodiode 10 sensing light into a voltage and output it to the output interface 23.

[0058] In this embodiment, in a light sensor chip with a built-in sensing photodiode, when the light sensor chip is irradiated with detection light, the sensing photodiode senses the light and generates a photocurrent, and the photocurrent is converted into a voltage and amplified and output through a transimpedance amplifier, thereby realizing the function of converting the photocurrent signal into a voltage signal and then amplifying the voltage signal.

[0059] In one embodiment, the output interface 23 is used to convert the voltage output by the transimpedance amplifier 22 into a voltage form or a frequency form and output it to the output terminal.

[0060] Specifically, Figure 3 As shown, the output terminal of the output interface 23 can be connected to a control module (e.g., a microcontroller unit (MCU) or other control chip) at the back end, and the output interface 23 can convert the voltage output by the transimpedance amplifier 22 into a voltage form or a frequency form and output it to the control module connected thereto, so that the control module can process it according to actual needs.

[0061] Based on the same concept, in one embodiment, Figure 4 As shown, the present invention provides a light sensor chip 100, which has a built-in sensing photodiode 10, and the light sensor chip 100 also includes a temperature compensation circuit 20, wherein:

[0062] The sensing photodiode 10 is a broad-spectrum silicon-based photodiode for sensing light and generating a photocurrent output.

[0063] The temperature compensation circuit 20 is connected to the sensing photodiode 10 and is used to compensate for the leakage current of the sensing photodiode 10 that changes with temperature and to convert the photocurrent output by the sensing photodiode 10 into a voltage form or a frequency form for output.

[0064] Among them, Figure 3As shown, the temperature compensation circuit 20 includes a temperature compensation module 21, a transimpedance amplifier 22 and an output interface 23 connected in sequence, wherein:

[0065] The temperature compensation module 21 is used to compensate for the leakage current of the sensing photodiode 10 that changes with temperature, and provides a current compensation function.

[0066] According to the previous description, due to the characteristics of the sensing photodiode 10, especially when the sensing photodiode 10 is manufactured by a silicon process to manufacture a photosensor chip with a built-in sensing photodiode, leakage current will inevitably be generated, and the leakage current value will vary according to the temperature, making the output value of the sensing photodiode 10 different at low temperature, room temperature or high temperature. Therefore, the temperature characteristics of the sensing photodiode 1 may cause failure and unstable characteristics of the photosensor chip with a built-in sensing photodiode.

[0067] In the present invention, the method for compensating the leakage current that changes according to the temperature is to connect a compensation photodiode having the same structure as the sensing photodiode 10 but a relatively smaller size to the sensing photodiode 10 to configure a temperature compensation circuit 20 in the direction opposite to the current direction, and the compensation photodiode is used for current compensation purposes to provide a compensation current corresponding to the leakage current, thereby offsetting the leakage current. At the same time, the current reduction caused by the relative reduction in the size of the compensation photodiode is solved by configuring current amplification in the temperature compensation circuit 20. When the temperature compensation circuit 20 is configured in this way, the chip size of the optical sensor with a built-in sensing photodiode is not increased.

[0068] Specifically, Figure 3 As shown, the temperature compensation module 21 includes: a compensation photodiode 211 and a current amplifier 212; wherein:

[0069] The compensation photodiode 211 is used to generate a compensation current having a magnitude of 1 / N times the leakage current of the sensing photodiode 10. Wherein N is a natural number greater than 2 (i.e., N is a natural number greater than 2), and can be preset when designing a light sensor chip with a built-in sensing photodiode 10, based on considerations of the performance and size of each component.

[0070] Specifically, the compensation photodiode 211 has the same structure as the sensing photodiode 10 built into the light sensor chip, but the size is 1 / N times that of the sensing photodiode 10. Since the compensation photodiode 211 of the temperature compensation module 21 must perform current compensation only according to temperature, the influence of the external light source must be minimized. For this reason, in the semiconductor manufacturing process of the built-in temperature compensation circuit 20, a metal layer must be covered on the upper part of the compensation photodiode 211 to prevent the compensation photodiode 211 from sensing light and generating photocurrent; in addition, the compensation photodiode 211 and the sensing photodiode 10 are arranged to be as far apart from each other as possible in the layout of the light sensor chip with the built-in sensing photodiode 10.

[0071] The current amplifier 212 is used to amplify the compensation current output by the compensation photodiode 211 by N times, so as to output a compensation current having the same magnitude as the leakage current of the sensing photodiode 10 .

[0072] Specifically, Figure 3 As shown, the input end of the current amplifier 212 is connected to one end of the compensation photodiode 211, and the output end of the current amplifier 212 outputs the compensation current. At this time, the other end of the compensation photodiode 211 is grounded.

[0073] For example, the current amplifier 212 may include at least one transistor circuit or a current mirror circuit. In the present invention, since the current amplification method using a current mirror circuit is more advantageous in terms of characteristics, in the embodiment of the present invention, the current amplifier 212 includes a current mirror circuit and is composed of a current mirror circuit.

[0074] In this embodiment, by providing a temperature compensation module, including a compensation photodiode for generating a compensation current having a magnitude of 1 / N times the leakage current of the sensing photodiode, and a current amplifier for amplifying the compensation current output by the compensation photodiode by N times to output a compensation current having the same magnitude as the leakage current of the sensing photodiode, a compensation current corresponding to the leakage current can be provided to offset the leakage current of the sensing photodiode, so as to achieve the purpose of compensating the leakage current of the sensing photodiode that changes with temperature, so that the temperature compensation circuit can provide the function of compensation current, and the failure and characteristic instability of the optical sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode can be eliminated. In addition, the compensation photodiode used for current compensation has the same structure as the sensing photodiode 10 but is relatively smaller in size. At the same time, by configuring the current amplification, the current reduction caused by the relative reduction in the size of the compensation photodiode can be solved, so that when the temperature compensation circuit is configured in this way, the size of the optical sensor chip with a built-in sensing photodiode will not be increased.

[0075] The transimpedance amplifier 22 is used to convert the photocurrent generated by the sensing photodiode 10 when sensing light into a voltage and output it to the output interface 23 .

[0076] Specifically, Figure 3 As shown, the first input terminal IN1 of the transimpedance amplifier 22 is connected to the output terminal of the current amplifier 212 of the temperature compensation module 21, and receives the compensation current output by the output terminal of the current amplifier 212; the second input terminal IN2 of the transimpedance amplifier 22 is connected to one end of the sensing photodiode 10, and is used to receive the photocurrent output by the sensing photodiode 10; the output terminal OUT of the transimpedance amplifier 22 is connected to the output interface 23, and is used to convert the photocurrent generated by the sensing photodiode 10 sensing light into a voltage and output it to the output interface 23. At this time, the other end of the sensing photodiode 10 is grounded.

[0077] For example, the first input terminal IN1 of the transimpedance amplifier 22 is a non-inverting input terminal, and the second input terminal IN2 of the transimpedance amplifier 22 is an inverting output terminal. The non-inverting input terminal of the transimpedance amplifier 22 is connected to the output terminal of the current amplifier 212 of the temperature compensation module 21, and receives the compensation current output by the output terminal of the current amplifier 212; the reverse input terminal of the transimpedance amplifier 22 is connected to one end of the sensing photodiode 10, and is used to receive the photocurrent output by the sensing photodiode 10; the output terminal OUT of the transimpedance amplifier 22 is connected to the output interface 23, and is used to convert the photocurrent generated by the sensing photodiode 10 sensing light into a voltage and output it to the output interface 23.

[0078] In this embodiment, in a light sensor chip with a built-in sensing photodiode, when the light sensor chip is irradiated with detection light, the sensing photodiode senses the light and generates a photocurrent, and the photocurrent is converted into a voltage and amplified and output through a transimpedance amplifier, thereby realizing the function of converting the photocurrent signal into a voltage signal and then amplifying the voltage signal.

[0079] The output interface 23 is used to convert the voltage output by the transimpedance amplifier 22 into a voltage form or a frequency form and output it to the output terminal.

[0080] Specifically, Figure 3 As shown, the output terminal of the output interface 23 can be connected to a control module (e.g., a microcontroller unit (MCU) or other control chip) at the back end, and the output interface 23 can convert the voltage output by the transimpedance amplifier 22 into a voltage form or a frequency form and output it to the control module connected thereto, so that the control module can process it according to actual needs.

[0081] In this embodiment, a light sensor chip is provided, which has a sensing photodiode and a temperature compensation circuit built in. The sensing photodiode is used to sense light and generate a photocurrent output; the temperature compensation circuit is used to compensate for the leakage current of the sensing photodiode that changes with temperature, and convert the photocurrent output by the sensing photodiode into a voltage form or a frequency form for output. The temperature compensation circuit includes a temperature compensation module, a transimpedance amplifier and an output interface connected in sequence, wherein: the temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; the transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage and output it to the output interface; the output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output it to the output terminal. Thus, the light sensor chip itself can provide a compensation current function through the temperature compensation circuit, and the leakage current of the sensing photodiode that changes with temperature can be compensated by the temperature compensation module therein, eliminating the failure and unstable characteristics of the light sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode. It can solve the problem that the existing light sensor chip with a built-in sensing photodiode has a failure and unstable characteristics caused by the temperature characteristics of the sensing photodiode.

[0082] It should be noted that the above-mentioned light sensor chip embodiment and the above-mentioned temperature compensation circuit embodiment belong to the same concept, and the specific implementation process is detailed in the temperature compensation circuit embodiment, and the technical features in the temperature compensation circuit embodiment are correspondingly applicable in the above-mentioned light sensor chip embodiment, which will not be repeated here.

[0083] Based on the same concept, in one embodiment, Figure 5 As shown, the present invention provides a light sensor device 500, including: a light sensor chip 100 and a control module 200, wherein the output interface 23 of the light sensor chip 100 is connected to the control module 200, and is used to output the output of the light sensor chip 100 to the control module 200 in the form of voltage or frequency.

[0084] In this embodiment, the optical sensor chip 100 is consistent with the optical sensor chip 100 described in any of the above embodiments. The specific structure and function may refer to the optical sensor chip 100 described in any of the above embodiments, which will not be described in detail here.

[0085] For example, the control module 200 may be a microcontroller unit (MCU) or other control chips (IC).

[0086] For example, the optical sensor chip 100 of the optical sensor device 500 has a built-in sensing photodiode 10 and a temperature compensation circuit 20 , and the optical sensor device 500 may be a light-to-voltage converter (LTV) and a light-to-frequency converter (LTF).

[0087] In this embodiment, a light sensor device is provided, including a light sensor chip and a control module, wherein the output interface of the light sensor chip is connected to the control module, and is used to output the output interface of the light sensor chip to the control module in the form of voltage or frequency. The light sensor chip includes a built-in sensing photodiode and a temperature compensation circuit, wherein the sensing photodiode is used to sense light and generate a photocurrent output; the temperature compensation circuit is used to compensate for the leakage current of the sensing photodiode that changes with temperature, and convert the photocurrent output by the sensing photodiode into a voltage output. The temperature compensation circuit includes a temperature compensation module, a transimpedance amplifier, and an output interface connected in sequence, wherein: the temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; the transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage output to the output interface; the output interface is used to convert the voltage output by the transimpedance amplifier into a voltage or frequency output to the output terminal. Thus, the optical sensor chip in the optical sensor device can provide the function of compensation current through the temperature compensation circuit, and the leakage current of the sensing photodiode that changes with the temperature can be compensated through the temperature compensation module therein, thereby eliminating the failure and unstable characteristics of the optical sensor chip with a built-in sensing photodiode caused by the temperature characteristics of the sensing photodiode. This can solve the problem that the existing optical sensor chip with a built-in sensing photodiode has a failure and unstable characteristics caused by the temperature characteristics of the sensing photodiode.

[0088] It should be noted that the above-mentioned optical sensor device embodiments and the above-mentioned temperature compensation circuit and / or optical sensor chip embodiments belong to the same concept, and their specific implementation process is detailed in the temperature compensation circuit and / or optical sensor chip embodiments, and the technical features in the temperature compensation circuit and / or optical sensor chip embodiments are correspondingly applicable in the above-mentioned optical sensor device embodiments, which will not be repeated here.

[0089] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0090] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature compensation circuit, characterized in that: An optical sensor chip for a built-in sensing photodiode includes a temperature compensation module, a transimpedance amplifier, and an output interface connected in sequence, wherein: The temperature compensation module is used to compensate for the leakage current of the sensing photodiode that changes with temperature; The transimpedance amplifier is used to convert the photocurrent generated by the sensing photodiode sensing light into a voltage and output it to the output interface; The output interface is used to convert the voltage output by the transimpedance amplifier into a voltage form or a frequency form and output it to the output terminal.

2. The temperature compensation circuit according to claim 1, characterized in that: The temperature compensation module includes a compensation photodiode and a current amplifier; wherein: The compensation photodiode is used to generate a compensation current having a magnitude 1 / N times that of a leakage current of the sensing photodiode; The current amplifier is used to amplify the compensation current output by the compensation photodiode by N times to output a compensation current of the same magnitude as the leakage current of the sensing photodiode, where N is a natural number greater than 2.

3. The temperature compensation circuit according to claim 2, characterized in that: The compensation photodiode has the same structure as the sensing photodiode, and its size is 1 / N times that of the sensing photodiode.

4. The temperature compensation circuit according to claim 3, characterized in that: In the manufacturing process of a light sensor chip with a built-in sensing photodiode, a metal layer covers the upper part of the compensation photodiode.

5. The temperature compensation circuit according to claim 4, characterized in that: The compensating photodiode and the sensing photodiode are arranged to be spaced apart from each other in a light sensor chip layout having a built-in sensing photodiode.

6. The temperature compensation circuit according to claim 2, characterized in that: The input end of the current amplifier is connected to one end of the compensation photodiode, the output end of the current amplifier outputs the compensation current, and the other end of the compensation photodiode is grounded.

7. The temperature compensation circuit according to claim 2, characterized in that: The current amplifier includes a power mirror circuit.

8. The temperature compensation circuit according to claim 6, characterized in that: The first input end of the transimpedance amplifier is connected to the output end of the current amplifier to receive the compensation current output by the output end of the current amplifier; the second input end of the transimpedance amplifier is connected to one end of the sensing photodiode to receive the photocurrent output by the sensing photodiode; the output end of the transimpedance amplifier is connected to the output interface to convert the photocurrent generated by the sensing photodiode sensing light into a voltage and output it to the output interface.

9. A light sensor chip, having a built-in sensing photodiode, wherein the sensing photodiode is used to sense light and generate a photocurrent output; characterized in that: The light sensor chip also includes a temperature compensation circuit as described in any one of claims 1 to 8, wherein the temperature compensation circuit is connected to the sensing photodiode and is used to compensate for the leakage current of the sensing photodiode that changes with temperature, and to convert the photocurrent output by the sensing photodiode into a voltage form or a frequency form for output.

10. A light sensing device, characterized in that: It comprises the optical sensor chip and the control module as claimed in claim 9, wherein the output interface of the optical sensor chip is connected to the control module for outputting the output of the optical sensor chip to the control module in the form of voltage or frequency.

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