Readout circuit of uncooled infrared detector, and uncooled infrared detector

Abstract

A readout circuit of an uncooled infrared detector, and an uncooled infrared detector. The readout circuit comprises a pixel circuit (1), a control circuit (2), and a signal processing circuit (3). The pixel circuit (1) comprises first, second and third voltage ends (VSK_L, Vd, VDET) and a pixel resistor (Rs), wherein the pixel resistor (Rs) is connected between the second voltage end (Vd) and the third voltage end (VDET), and the magnitude of the voltage at the first voltage end (VSK_L) and an ambient temperature affect the voltage variation of the second voltage end (Vd). One end of the control circuit (2) is connected to the first voltage end (VSK_L), and the other end thereof is connected to a power supply voltage end (VSK_H) of an uncooled infrared detector. The control circuit (2) can control, on the basis of the voltage of the power supply voltage end (VSK_H) and the ambient temperature, the voltage of the first voltage end (VSK_L) within a voltage range corresponding to the ambient temperature, such that the voltage value of the second voltage end (Vd) is within a preset operating voltage range, wherein when the voltage value of the second voltage end (Vd) is within the preset operating voltage range, the readout circuit can operate normally. An input terminal of the signal processing circuit (3) is connected to the second voltage end (Vd), and is adapted to perform signal processing on the basis of a voltage signal of the second voltage end (Vd).

Description

Non-cooled infrared detector readout circuit and non-cooled infrared detector TECHNICAL FIELD

[0001] The present disclosure relates to the field of infrared imaging technology, and in particular to a non-cooled infrared detector readout circuit and a non-cooled infrared detector. BACKGROUND

[0002] The heat-sensitive material inside the non-cooled infrared detector can absorb the radiant energy of the target object and convert it into heat energy, which changes the physical properties of the sensitive material. By converting the change of the physical properties into an electrical signal, the detection of the target object can be realized.

[0003] The existing non-cooled infrared detector is prone to response rate loss and a large number of noise points in the detection image in a high-temperature environment. SUMMARY

[0004] A first aspect of the embodiments of the present disclosure provides a readout circuit of a non-cooled infrared detector. The readout circuit comprises: a pixel circuit comprising a first voltage terminal, a second voltage terminal, a third voltage terminal and a pixel resistance, the pixel resistance being connected between the second voltage terminal and the third voltage terminal; the first voltage terminal is used to supply power to the pixel circuit, and the voltage of the first voltage terminal and the ambient temperature affect the voltage of the second voltage terminal; a control circuit, one end of which is connected with the first voltage terminal and the other end of which is connected with a power supply voltage terminal of the non-cooled infrared detector, the control circuit being capable of controlling the voltage of the first voltage terminal in a voltage range corresponding to the ambient temperature according to the voltage of the power supply voltage terminal and the ambient temperature, so that the voltage value of the second voltage terminal changes within a preset working voltage range when the readout circuit is working; wherein, when the voltage value of the second voltage terminal changes within the preset working voltage range, the readout circuit can work normally; a signal processing circuit, an input end of the signal processing circuit being connected with the second voltage terminal and being configured to perform signal processing according to the voltage signal of the second voltage terminal to obtain readout data.

[0005] In some embodiments, the control circuit can control the voltage of the first voltage terminal to decrease with the increase of the ambient temperature when the ambient temperature is higher than the normal temperature.

[0006] In some embodiments, the control circuit comprises a low-temperature drift resistance, one end of the low-temperature drift resistance being connected with the first voltage terminal and the other end of the low-temperature drift resistance being connected with the power supply voltage terminal of the non-cooled infrared detector.

[0007] In some embodiments, the temperature coefficient of the low-temperature drift resistance ranges from -100 PPM / ℃ to +100 PPM / ℃.

[0008] In some embodiments, the control circuit comprises a digital-to-analog converter, one end of the digital-to-analog converter is connected with the first voltage terminal, and the other end is connected with a power supply voltage terminal of the uncooled infrared detector; the digital-to-analog converter further comprises a digital input end configured to receive a digital input code determined according to the ambient temperature, and the digital-to-analog converter is configured to control the voltage of the first voltage terminal according to the digital input code, so that the voltage of the first voltage terminal is within a voltage range corresponding to the ambient temperature.

[0009] In some embodiments, when the ambient temperature is higher than the normal temperature, the digital-to-analog converter is configured to control the voltage of the first voltage terminal to decrease with the increase of the ambient temperature.

[0010] In some embodiments, the readout circuit further comprises a temperature detection module for detecting the ambient temperature and determining the digital input code according to the ambient temperature.

[0011] In some embodiments, the pixel circuit comprises a first branch, and the first branch comprises the pixel resistor, a blind pixel resistor, a first field effect transistor and a second field effect transistor; the first field effect transistor is an n-type field effect transistor, and the second field effect transistor is a p-type field effect transistor; one end of the blind pixel resistor is connected with the first voltage terminal, and the other end is connected with the source electrode of the second field effect transistor; the drain electrode of the second field effect transistor is connected with the drain electrode of the first field effect transistor; one end of the pixel resistor is connected with the source electrode of the first field effect transistor, and the other end is connected with the third voltage terminal; and the second voltage terminal is arranged between the drain electrode of the first field effect transistor and the drain electrode of the second field effect transistor.

[0012] In some embodiments, the readout circuit comprises a plurality of first branches and a plurality of signal processing circuits, and the second voltage terminal on each first branch is connected with one signal processing circuit.

[0013] In some embodiments, the pixel circuit further comprises a second branch, the second branch being provided with a reference blind pixel resistor, a reference light-shielded pixel resistor, a third field effect transistor and a fourth field effect transistor; the third field effect transistor is a p-type field effect transistor, and the fourth field effect transistor is an n-type field effect transistor; wherein one end of the reference blind pixel resistor is connected with the first voltage terminal, and the other end is connected with the source electrode of the third field effect transistor; the gate electrode of the second field effect transistor of each first branch is connected with the gate electrode of the third field effect transistor of the second branch; the drain electrode of the third field effect transistor is connected with the drain electrode of the fourth field effect transistor and the gate electrode of the fourth field effect transistor; the connection point of the drain electrode of the third field effect transistor and the drain electrode of the fourth field effect transistor and the gate electrode of the fourth field effect transistor is a connection node; the gate electrode of the first field effect transistor of each first branch is connected with the connection node; one end of the reference light-shielded pixel resistor is connected with the source electrode of the fourth field effect transistor of the second branch, and the other end is connected with the third voltage terminal of the second branch; the voltage of the connection node decreases with the decrease of the voltage of the first voltage terminal; the change range of the second voltage terminal decreases with the decrease of the voltage of the connection node; and the lower limit value of the preset working voltage range decreases with the decrease of the voltage of the connection node.

[0014] In some embodiments, the control circuit and the pixel circuit are integrated in the same integrated circuit structure; or, the control circuit and the pixel circuit are respectively arranged in different integrated circuit structures.

[0015] A second aspect of the embodiments of the present disclosure provides a non-cooled infrared detector, which comprises the readout circuit described above.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0018] FIG. 1 is a structural schematic diagram of a readout circuit of a non-cooled infrared detector in the related art.

[0019] FIG. 2 is a structural schematic diagram of a readout circuit of a non-cooled infrared detector provided by an embodiment of the present disclosure.

[0020] FIG. 3 is a curve diagram of the voltage of the second voltage terminal changing with time when the readout circuit of the non-cooled infrared detector shown in FIG. 1 works in a normal temperature and a high temperature environment.

[0021] Fig. 4 is a comparative graph of the voltage of the second voltage terminal of the non-cooled infrared detector readout circuit shown in Figs. 2 and 1 as a function of time when the non-cooled infrared detector readout circuit is operated in a high temperature environment.

[0022] Fig. 5 is a specific embodiment of the non-cooled infrared detector readout circuit shown in Fig. 2.

[0023] Fig. 6 is another specific embodiment of the non-cooled infrared detector readout circuit shown in Fig. 2. DETAILED DESCRIPTION

[0024] The exemplary embodiments will be described in detail herein with reference to the accompanying drawings. In the following description, like reference numerals refer to like elements, unless the context clearly dictates otherwise. The following exemplary embodiments described herein represent the best currently known modes of implementing the present disclosure. However, the disclosure is not limited to these embodiments.

[0025] The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used in the present disclosure and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0026] It should be understood that the use of "first", "second", and "third" words of similar effect in the present disclosure specification and claims, does not imply any order, number or importance, but is merely used to distinguish different components. Similarly, "one" or "a" and similar words do not imply a quantity limitation, but rather indicate the presence of at least one. Unless otherwise indicated, "front", "back", "lower" and / or "upper" and similar words are used for ease of description to orient a reader, and are not intended to be limiting to a particular position or spatial orientation. "Include" or "comprise" and similar words mean that the elements or objects before the "include" or "comprise" encompass the elements or objects listed after the "include" or "comprise" and equivalents thereof, and do not exclude other elements or objects.

[0027] The non-cooled infrared detector readout circuit and the non-cooled infrared detector of the embodiments of the present disclosure will be described in detail below with reference to Figs. 1 to 6. The features in the following embodiments and specific embodiments can be supplemented or combined with each other without conflict.

[0028] The non-cooled infrared detector readout circuit provided by the embodiments of the present disclosure includes a pixel circuit 1, a control circuit 2 and a signal processing circuit 3. The pixel circuit 1 includes a first voltage terminal V SK_L , a second voltage terminal V d , and a third voltage terminal V DETand a plurality of pixel resistances R s each pixel resistance R s is connected between the second voltage terminal V d and the third voltage terminal V DET . The first voltage terminal V SK_L is used to supply power for the pixel circuit, and the voltage of the first voltage terminal V SK_L is affected by the voltage variation of the second voltage terminal V d and the ambient temperature; one end of a control circuit 2 is connected with the first voltage terminal V SK_L , and the other end is connected with the power supply voltage terminal V SK_H of the uncooled infrared detector, and the control circuit 2 can control the voltage of the first voltage terminal V SK_H in a voltage range corresponding to the ambient temperature according to the voltage of the power supply voltage terminal V SK_L and the ambient temperature, so that the voltage value of the second voltage terminal V d changes in a preset working voltage range when the uncooled infrared detector readout circuit works; wherein, when the voltage value of the second voltage terminal V d changes in the preset working voltage range, the readout circuit can work normally. The input end of a signal processing circuit 3 is connected with the second voltage terminal V d , and is adapted to perform signal processing according to the voltage signal of the second voltage terminal V d to obtain readout data. In some embodiments, the signal processing circuit 3 can include a first resistance R1, a first amplifier, a second resistance R2, a second amplifier and a capacitor. One end of the first resistance R1 is connected with the second voltage terminal V d , and the other end of the first resistance R1 is connected with the voltage V BIAS . The non-inverting input end of the first amplifier is connected with the second voltage terminal V d , the inverting input end of the first amplifier is connected with the output end of the first amplifier, the output end of the first amplifier is connected with one end of the second resistance R2, the other end of the second resistance R2 is connected with the inverting input end of the second amplifier, the non-inverting input end of the second amplifier is connected with the voltage V REF , one end of the capacitor is connected with the inverting input end of the second amplifier, and the other end of the capacitor is connected with the output end of the second amplifier.

[0029] It should be noted that the "preset working voltage range" described in the present application refers to the voltage range in which the field effect tube works in the saturation region, that is, the voltage range of the V d window, and when the voltage value of the second voltage terminal V d changes in the preset working voltage range, the readout circuit can work normally and stably, so that the uncooled infrared detector has good imaging performance, which will be described in detail hereinafter.

[0030] When the uncooled infrared detector works, external infrared radiation causes the resistance of the pixel resistor R s in the pixel circuit 1 to change, and then causes the voltage inside the pixel circuit 1 to change. The signal processing circuit 3 processes the detected voltage change to obtain corresponding readout data, so that the uncooled infrared detector can read the size of the infrared radiation signal. The voltage of the first voltage terminal V SK_L and the environmental temperature affect the voltage change range of the second voltage terminal V d .

[0031] In the readout circuit of the uncooled infrared detector, the first voltage terminal V SK_L is a direct power supply voltage terminal of the pixel circuit 1, and the second voltage terminal V d is a voltage signal acquisition terminal of the signal processing circuit 3. The voltage of the power supply voltage terminal V SK_H of the uncooled infrared detector can be a stable voltage and does not change with the environmental temperature.

[0032] When the uncooled infrared detector works in a low-temperature, normal-temperature or high-temperature environment, the control circuit 2 can keep the voltage value of the second voltage terminal V d always change within a preset working voltage range, which can improve the applicability of the uncooled infrared detector in different environmental temperatures, avoid the response rate loss and excessive imaging picture noise of the uncooled infrared detector caused by the influence of the environmental temperature, and enable the uncooled infrared detector to obtain high-quality imaging pictures in different environmental temperatures.

[0033] FIG. 1 is a structural schematic diagram of a readout circuit of an uncooled infrared detector in the related art, and compared with FIG. 2, the readout circuit in FIG. 1 does not include the control circuit 2. As shown in FIG. 1, when the pixel circuit 1 works, the pixel resistor R s will generate Joule heat, and under the influence of the Joule heat, the resistance of the pixel resistor R s will change, and then the voltage of the second voltage terminal V d will change. When the uncooled infrared detector works in a low-temperature or normal-temperature environment, the voltage change of the second voltage terminal V d caused by the Joule heat can still be kept within an allowed working range, and the performance of the uncooled infrared detector is not affected, and the uncooled infrared detector has good imaging performance in the low-temperature or normal-temperature environment.

[0034] The resistance of the pixel resistor R s in the readout circuit shown in FIG. 1 is smaller than that in a low-temperature or normal-temperature environment, so that the voltage of the second voltage terminal V dThe voltage range of the voltage at the high-temperature environment is larger than that at the low-temperature or normal-temperature environment. When the environmental temperature of the uncooled infrared detector is increased, the resistance R s of the pixel at the high-temperature environment is further decreased under the influence of the Joule heat, and the voltage range of the second voltage V d is further increased compared with that at the normal-temperature environment. Therefore, the voltage of the second voltage V d may exceed the preset working voltage range, resulting in the decrease of the responsivity of the uncooled infrared detector and the increase of the noise of the imaging picture.

[0035] In some embodiments, the control circuit 2 can control the voltage of the first voltage V SK_L to decrease with the increase of the environmental temperature at least when the environmental temperature is higher than the normal temperature.

[0036] As shown in FIG. 2, when the environmental temperature is the normal temperature, the voltage of the first voltage V SK_L in FIG. 2 can be set to be equal to the voltage of the first voltage V SK in FIG. 1, so as to ensure that the uncooled infrared detector has good imaging performance at the low-temperature or normal-temperature environment. When the working environment of the uncooled infrared detector is changed to the high-temperature environment, the control circuit 2 can be used to decrease the voltage of the first voltage V SK_L input to the pixel circuit 1 with the increase of the environmental temperature, for example, to be less than the voltage of the first voltage V SK in FIG. 1, so as to decrease the bias voltage obtained by the pixel resistance R s , and further to decrease the influence of the Joule heat on the pixel resistance R s , decrease the voltage range of the second voltage V d , and finally improve the applicability of the uncooled infrared detector at the high-temperature environment, avoid the problems such as the responsivity loss and the excessive noise of the imaging picture of the uncooled infrared detector at the high-temperature environment, and enable the uncooled infrared detector to obtain high-quality imaging picture at the high-temperature environment.

[0037] In some embodiments, as shown in FIG. 2, the pixel circuit 1 can further include a first branch, and the first branch includes the pixel resistance R s , the blind pixel resistance R d , the first field effect transistor M1 and the second field effect transistor M2. One end of the blind pixel resistance R d is connected with the first voltage V SK_L , the other end is connected with the source of the second field effect transistor M2, the drain of the second field effect transistor M2 is connected with the drain of the first field effect transistor M1, one end of the pixel resistance R s is connected with the source of the first field effect transistor M1, and the other end is connected with the third voltage V s of the pixel circuit R DETconnection, the third voltage terminal V DET may be a ground terminal. The second voltage terminal V d is arranged between the drain of the first field effect transistor M1 and the drain of the second field effect transistor M2. In the readout circuit, the pixel resistance R s and the blind pixel resistance R d are arranged on the same substrate. The pixel resistance R s reflects the temperature change of the target object detected by the uncooled infrared detector, and the blind pixel resistance R d may reflect the temperature change of the substrate. During the process of reading out the signal, the blind pixel resistance R d may eliminate the influence of the output voltage fluctuation caused by the pixel resistance R s due to the temperature change of the substrate to a certain extent.

[0038] In some embodiments, the first field effect transistor M1 is an n-type field effect transistor, and the second field effect transistor M2 is a p-type field effect transistor.

[0039] In some embodiments, as shown in FIG. 2, the readout circuit can include a plurality of first branches and a plurality of signal processing circuits 3. The second voltage terminal V d (V d ’) on each first branch is connected with one signal processing circuit 3, the gates of a plurality of first field effect transistors M1 (M1’) are connected, and the gates of a plurality of second field effect transistors M2 (M2’) are connected. Each first branch is provided with a pixel resistance R s (R s ’). Different pixel resistances R s (R s ’) on different first branches can form an array, so that the uncooled infrared detector can perform image recognition on the target object.

[0040] Each first branch in FIG. 2, FIG. 5 and FIG. 6 includes only one pixel resistance R s . In other embodiments not shown, each first branch can include a plurality of pixel resistances R s according to actual needs. The plurality of pixel resistances R s on different first branches form an array.

[0041] In some embodiments, as shown in FIG. 2, the pixel circuit 1 can further include a second branch provided with a reference blind pixel resistance R a , a reference light-shielded pixel resistance R b , a third field effect transistor M3 and a fourth field effect transistor M4. One end of the reference blind pixel resistance R a is connected with the first voltage terminal V SK_LThe other end of the connection is connected with the source of the third field effect transistor M3. The gate of the second field effect transistor M2 of each first branch is connected with the gate of the third field effect transistor M3 of the second branch. The drain of the third field effect transistor M3 is connected with the drain of the fourth field effect transistor M4. The drain of the third field effect transistor M3 is connected with the gate of the fourth field effect transistor M4. The gate of the first field effect transistor M1 of each first branch is connected with the gate of the fourth field effect transistor M4 of the second branch. One end of the reference light-shielded pixel resistor R is connected with the source of the fourth field effect transistor M4 of the second branch. The other end of the reference light-shielded pixel resistor R is connected with the third voltage terminal V b . DET .

[0042] In this embodiment, the gate of the third field effect transistor M3 is connected with the gate of the second field effect transistor M2. The connection point is the first node V EB . The voltage of the first node V EB is V eb . The gate of the fourth field effect transistor M4 is connected with the gate of the first field effect transistor M1. The drain of the third field effect transistor M3 and the drain of the fourth field effect transistor M4 are both connected with the gate of the first field effect transistor M1. The connection point is the second node V FID . Through the above setting, a bridge structure can be formed inside the readout circuit. On the one hand, the voltage V FID of the second node V fid can be provided. On the other hand, the influence of power supply noise on the uncooled infrared detector can be reduced, which is conducive to improving the imaging quality of the uncooled infrared detector.

[0043] In some embodiments, the third field effect transistor M3 is a p-type field effect transistor, and the fourth field effect transistor M4 is an n-type field effect transistor.

[0044] In the pixel circuit 1, the voltage V FID of the second node V fid is positively correlated with the voltage of the first voltage terminal V SK_L . The voltage V FID of the second node V fid decreases as the voltage of the first voltage terminal V SK_L decreases. The change range of the second voltage terminal V d decreases as the voltage V FID of the second node V fid decreases. The lower limit value of the preset working voltage range decreases as the voltage V FID of the second node V fid decreases.

[0045] In a normal working state, the readout circuit needs to ensure that the first field effect transistor M1 and the second field effect transistor M2 work in the saturation region at the same time. At this time, the second voltage terminal V dthe voltage of the second voltage terminal V d needs to be set within a preset working voltage range, i.e., needs to be set within V d the voltage of the second voltage terminal V d needs to satisfy the following condition:

[0046] the saturation condition of the first field effect transistor M1: V fid > V th,M1 -V dsat,M1

[0047] the saturation condition of the second field effect transistor M2: V d < V eb + |V th,M2 - |V dsat,M2

[0048] wherein V th,M1 , V th,M2 are threshold voltages of the first field effect transistor M1 and the second field effect transistor M2 respectively, V dsat,M1 , V dsat,M2 are overdrive voltages of the first field effect transistor M1 and the second field effect transistor M2 respectively.

[0049] In the process of signal processing, if the voltage of the second node V FID is constant, under the influence of Joule heat, the resistance of the pixel resistor R s gradually decreases, thus the current I1 flowing through the pixel resistor R s gradually increases. Assuming that the current flowing through the blind pixel resistor R d is I2, according to the following formula, it can be known that the voltage of the second voltage terminal V d will gradually decrease. V d -V BIAS = (I2-I1) x R1

[0050] As shown in FIG. 3, which is a curve diagram of the voltage of the second voltage terminal V d changing with time when the readout circuit shown in FIG. 1 works in a normal temperature environment and a high temperature environment, wherein A is the minimum value of V d when the first field effect transistor M1 is in the saturation region, B is the maximum value of V d when the second field effect transistor M2 is in the saturation region, curve S1 is the voltage of the second voltage terminal V d changing with time in the normal temperature environment, and curve S2 is the voltage of the second voltage terminal V d changing with time when the readout circuit shown in FIG. 1 works in the high temperature environment. In the normal temperature environment, the voltage of the first voltage terminal V SK_L in FIG. 2 can be equal to the voltage of the first voltage terminal V SK in FIG. 1, so as to ensure that the imaging performance of the uncooled infrared detector in the normal temperature environment is not affected.

[0051] Under normal temperature conditions, the second voltage terminal V d The voltage will vary within a certain range, but this voltage variation still satisfies V d Window condition, that is, the second voltage terminal V d The extreme points of the voltage change curve S1 are between A and B.

[0052] In high-temperature environments, the elemental resistance R s The resistance is smaller compared to that at room temperature, and the flow through the pixel resistor R s The current I1 is larger than that under normal temperature conditions, therefore the second voltage terminal V d The voltage variation range is greater at high temperatures than at normal temperatures. Under the influence of Joule heating, the voltage at the second voltage terminal V... d The voltage variation range will be further expanded, making the second voltage terminal V d The voltage may exceed V d Window (i.e., the second voltage terminal V) d If the maximum value of the voltage change curve S2 is greater than B or its minimum value is less than A, it will cause the first field-effect transistor M1 or the second field-effect transistor M2 to enter the linear region, resulting in a decrease in the responsivity of the uncooled infrared detector and an increase in noise in the image.

[0053] Therefore, as shown in Figure 2, as the ambient temperature increases, the uncooled infrared detector readout circuit provided in this application can use control circuit 2 to control the first voltage terminal V. SK_L The voltage gradually decreases, causing the second node V to... FID The voltage at the point decreases, and the pixel resistance R s The bias voltage decreases, thereby reducing the Joule heating effect on the pixel resistance R. s The effect of reducing the second voltage terminal V d The range of variation.

[0054] As shown in Figure 4, curve S2 represents the second voltage terminal V of the readout circuit shown in Figure 1 under high temperature conditions. d The voltage change curve over time, curve S3 is the second voltage terminal V of the readout circuit shown in Figure 2 under high temperature environment. d The voltage change curve over time shows that, under high-temperature conditions, control circuit 2 can be used to adjust the voltage at the second voltage terminal V. d The voltage variation range is relatively reduced, meaning the fluctuation range of curve S3 in Figure 4 can be limited to within a window region. Furthermore, according to the following saturation condition formula for the first field-effect transistor M1, the voltage at the second node V... FID A voltage drop at point V can cause the second voltage terminal V to... d The lower voltage limit is reduced: V d >VFID - V th,M1 + V dsat,M1

[0055] For example, as shown in FIG. 4, A' is the minimum value of V SK_L when the first field effect transistor M1 is in the saturation region after the voltage of the first voltage terminal V d is reduced, that is, the window width between A' and B is greater than the window width between A and B, so that the window range of V d is increased, and the curve S3 is more likely to fall within the window range of V d , so that the risk of the voltage of the second voltage terminal V d exceeding V d in the high-temperature environment can be greatly reduced, and the high-temperature applicability of the uncooled infrared detector is improved.

[0056] In some embodiments, as shown in FIG. 5, the control circuit 2 includes a low-temperature-drift resistor R, one end of the low-temperature-drift resistor R is connected with the first voltage terminal V SK_L , and the other end is connected with the power supply voltage terminal V SK_H of the uncooled infrared detector.

[0057] The low-temperature-drift resistor R can be a resistor with a positive temperature coefficient, that is, a resistor with an increasing resistance value as the temperature rises. The low-temperature-drift resistor R can be a resistor with a negative temperature coefficient, that is, a resistor with a decreasing resistance value as the temperature rises.

[0058] In some embodiments, the temperature coefficient of the low-temperature-drift resistor ranges from -100 PPM / °C to +100 PPM / °C.

[0059] As shown in FIG. 5, the voltage of the first voltage terminal V SK_L of FIG. 5 can be set to be equal to the voltage of the first voltage terminal V SK in FIG. 1, so that in the normal-temperature environment, compared with FIG. 1, the voltage of the second node V FID does not change, the bias on the pixel resistor R s does not change, and the influence of the Joule heat on the pixel resistor R s does not change, and at this time, the voltage change of the second voltage terminal V d in FIG. 5 is still consistent with the curve S1 in FIG. 3, which is beneficial to ensure that the uncooled infrared detector has good normal-temperature performance.

[0060] As the environmental temperature rises, the resistance of the pixel resistor R s decreases, the current I1 flowing through the pixel resistor R s increases, and then the total current I _VSK increases. Since the resistor R is a low-temperature-drift resistor, its resistance value almost does not change with the change of the environmental temperature, and the total current I_VSK After being enlarged, the voltage of the first voltage terminal V SK_L is reduced, at this time, the voltage of the second node V FID is reduced, the bias of the pixel resistance R s is reduced, and in turn, the window width of V d can be enlarged while reducing the change range of the second voltage terminal V d , and the risk of the voltage of the second voltage terminal V d exceeding the window range of V d in a high-temperature environment is reduced.

[0061] It should be noted that in the non-cooled infrared detector readout circuit shown in FIG. 5, the voltage of the power supply voltage terminal of the non-cooled infrared detector can be slightly greater than the voltage of the first voltage terminal V SK in FIG. 1, or equal to the voltage of the first voltage terminal V SK in FIG. 1.

[0062] In other embodiments, as shown in FIG. 6, the control circuit 2 includes a digital-to-analog converter DAC, one end of the digital-to-analog converter DAC is connected with the first voltage terminal V SK_L , the other end is connected with the power supply voltage terminal V SK_H of the non-cooled infrared detector, and the digital-to-analog converter DAC further includes a digital input end, the digital input end receives a digital input code determined according to the ambient temperature, and the digital-to-analog converter can control the voltage of the first voltage terminal V SK_L to make the voltage of the first voltage terminal V SK_L be in a voltage range corresponding to the ambient temperature.

[0063] In some embodiments, in the non-cooled infrared detector readout circuit shown in FIG. 6, in an environment with an ambient temperature higher than a normal temperature, the digital-to-analog converter DAC controls the voltage of the first voltage terminal V SK_L to decrease with the increase of the temperature; and the voltage of the first voltage terminal V SK_L is less than the voltage of the power supply voltage terminal V SK_H of the non-cooled infrared detector; and when the ambient temperature is the normal temperature, the digital-to-analog converter DAC can control the voltage of the first voltage terminal V SK_L to be equal to the voltage of the power supply voltage terminal V SK_H of the non-cooled infrared detector.

[0064] The voltage of the power supply voltage terminal V SK_H of the non-cooled infrared detector can be equal to the voltage of the first voltage terminal V SK in FIG. 1. As shown in FIG. 6, in a normal temperature environment, the digital-to-analog converter DAC can control the voltage of the first voltage terminal V SK_L to be equal to the voltage of the first voltage terminal V SKthe voltage of the second node V FID is unchanged, the bias voltage of the pixel resistor R s is unchanged, the bias voltage of the pixel resistor R s is unchanged, the Joule heat of the pixel resistor R d is unchanged, the voltage of the second voltage terminal V SK_L is still consistent with the curve S1 in FIG. 3, which is conducive to ensuring that the uncooled infrared detector has good normal temperature performance.

[0065] With the increase of the ambient temperature, the digital-to-analog converter DAC controls the voltage of the first voltage terminal V SK_L to decrease with the increase of the ambient temperature, so that the voltage of the second node V FID decreases, the bias voltage of the pixel resistor R s decreases, and then the change range of the second voltage terminal V d is reduced while the window width of V d is expanded, and the risk that the voltage of the second voltage terminal V d exceeds the window range of V d in a high-temperature environment is reduced.

[0066] In some embodiments, the readout circuit further comprises a temperature detection module for detecting the current ambient temperature and determining the digital input code according to the current ambient temperature. When the temperature detection module detects that the current ambient temperature increases, the value of the digital input code Din decreases, so that the digital-to-analog converter DAC controls the voltage of the first voltage terminal V SK_L to decrease. Here, the value of the digital input code Din and the change of the voltage of the first voltage terminal V SK_L may be in a proportional relationship, and in other embodiments, they can also be set in an inverse proportional relationship, that is, when the temperature detection module detects that the ambient temperature increases, the value of the digital input code Din increases, and the digital-to-analog converter DAC controls the voltage of the first voltage terminal V SK_L to decrease.

[0067] In other embodiments, the resistance values of the pixel resistor R s , the blind pixel resistor R d , the reference blind pixel resistor R a , and the reference light-shielded pixel resistor R b , and other parameters that can reflect the change of the ambient temperature can be detected, and the value of the digital input code Din is determined according to the detection result.

[0068] It should be noted that the ambient temperature described in the present application can be the temperature of the space where the device with the readout circuit of the uncooled infrared detector is located.

[0069] Correspondingly, the temperature detection module can be used to detect the temperature of the space where the device with the readout circuit of the uncooled infrared detector is located.

[0070] Of course, the ambient temperature described in the present application can also be the temperature of a structure in which the readout circuit of the uncooled infrared detector is integrated. For example, the readout circuit of the uncooled infrared detector is located in an integrated circuit structure having a substrate, and the readout circuit of the uncooled infrared detector is arranged on the substrate. In this case, the ambient temperature can be the temperature of the substrate or the temperature of any position of the integrated circuit structure.

[0071] Correspondingly, the temperature detection module can detect the temperature of the substrate on which the readout circuit of the uncooled infrared detector is arranged or the temperature of any position of the integrated circuit structure in which the readout circuit of the uncooled infrared detector is integrated. For example, the ambient temperature can be obtained by detecting parameters such as the resistance values of the pixel resistance Rs, the blind pixel resistance Rd, the reference blind pixel resistance Ra, and the reference light-shielded pixel resistance Rb, which can reflect the change of the ambient temperature.

[0072] It should be further noted that, in some embodiments, the control circuit 2 and the pixel circuit 1 are integrated in the same integrated circuit structure.

[0073] For example, as shown in FIG. 5, the control circuit 2 includes a low-temperature-drift resistor R, which can be integrated in the same integrated circuit structure as the pixel circuit 1.

[0074] For example, as shown in FIG. 6, the control circuit 2 includes a digital-to-analog converter DAC, which can be integrated in the same integrated circuit structure as the pixel circuit 1.

[0075] In other embodiments, the control circuit 2 and the pixel circuit 1 are arranged in different integrated circuit structures, respectively.

[0076] For example, as shown in FIG. 5, the control circuit 2 includes a low-temperature-drift resistor R, which can be arranged in two different integrated circuit structures, and the two different integrated circuit structures are connected.

[0077] For example, as shown in FIG. 6, the control circuit 2 includes a digital-to-analog converter DAC, which can be arranged in two different integrated circuit structures, and the two different integrated circuit structures are connected.

[0078] Compared with the embodiment in which the control circuit 2 and the pixel circuit 1 are arranged in different integrated circuit structures, respectively, the embodiment in which the control circuit 2 and the pixel circuit 1 are integrated in the same integrated circuit structure is easier to manufacture, and the stability of the control work of the control circuit is higher.

[0079] In addition, the signal processing circuit 3 and the pixel circuit 1 can be integrated in the same integrated circuit structure, or can be arranged in different integrated circuit structures.

[0080] The embodiment of the present application further provides a non-cooled infrared detector, which comprises the non-cooled infrared detector readout circuit of any one of the above embodiments. The non-cooled infrared detector of the present application has good imaging performance in a normal temperature environment, and has a high response rate in a high temperature environment, so that a high-quality imaging picture can be obtained in the high temperature environment.

[0081] The above only describes the preferred embodiments of the present application and does not limit the present application in any form. Although the above has disclosed the preferred embodiments of the present application, the present application is not limited thereto. Any person skilled in the art can make some changes or modifications to the above disclosed technical contents without departing from the scope of the technical scheme of the present application, and any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application still belong to the scope of the technical scheme of the present application.

[0082] The content disclosed in the present patent document contains copyright-protected material. The copyright is owned by the copyright owner. The copyright owner does not object to any person copying the patent document or the patent disclosure existing in the official records and archives of the Patent and Trademark Office.

Claims

1. A readout circuit for an uncooled infrared detector, characterized in that, The readout circuit includes: A pixel circuit includes a first voltage terminal, a second voltage terminal, a third voltage terminal, and a pixel resistor, wherein the pixel resistor is connected between the second voltage terminal and the third voltage terminal; the first voltage terminal is used to supply power to the pixel circuit, and the voltage of the second voltage terminal is affected by the voltage of the first voltage terminal and the ambient temperature; The control circuit has one end connected to the first voltage terminal and the other end connected to the power supply voltage terminal of the uncooled infrared detector. The control circuit can control the voltage of the first voltage terminal within a voltage range corresponding to the ambient temperature based on the voltage of the power supply voltage terminal and the ambient temperature, so that when the readout circuit is working, the voltage value of the second voltage terminal can change within a preset operating voltage range; wherein, when the voltage value of the second voltage terminal changes within the preset operating voltage range, the readout circuit can work normally. A signal processing circuit, wherein the input terminal of the signal processing circuit is connected to the second voltage terminal, and is configured to perform signal processing based on the voltage signal of the second voltage terminal to obtain readout data.

2. The uncooled infrared detector readout circuit as described in claim 1, characterized in that, The control circuit can control the voltage at the first voltage terminal to decrease as the ambient temperature increases when the ambient temperature is higher than normal.

3. The uncooled infrared detector readout circuit as described in claim 2, characterized in that, The control circuit includes a low-temperature drift resistor. One end of the cryogenic drift resistor is connected to the first voltage terminal, and the other end is connected to the power supply voltage terminal of the uncooled infrared detector.

4. The uncooled infrared detector readout circuit as described in claim 3, characterized in that, The temperature coefficient of the cryogenic drift resistor is in the range of -100PPM / ℃ to +100PPM / ℃.

5. The uncooled infrared detector readout circuit as described in claim 2, characterized in that, The control circuit includes a digital-to-analog converter. One end of the digital-to-analog converter is connected to the first voltage terminal, and the other end is connected to the power supply voltage terminal of the uncooled infrared detector; The digital-to-analog converter further includes a digital input terminal configured to receive a digital input code determined based on the ambient temperature. The digital-to-analog converter is configured to control the voltage of the first voltage terminal based on the digital input code, so that the voltage of the first voltage terminal is within a voltage range corresponding to the ambient temperature.

6. The uncooled infrared detector readout circuit as described in claim 5, characterized in that, In an environment where the ambient temperature is higher than normal, the digital-to-analog converter is configured to control the voltage at the first voltage terminal to decrease as the ambient temperature increases.

7. The uncooled infrared detector readout circuit as described in claim 5, characterized in that, The readout circuit also includes a temperature detection module. The temperature detection module is used to detect the ambient temperature and determine the digital input code based on the ambient temperature.

8. The uncooled infrared detector readout circuit as described in any one of claims 1 to 7, characterized in that, The pixel circuit includes a first branch, which includes the pixel resistor, the blind pixel resistor, the first field-effect transistor, and the second field-effect transistor. The first field-effect transistor is an n-type field-effect transistor, and the second field-effect transistor is a p-type field-effect transistor; One end of the blind pixel resistor is connected to the first voltage terminal, and the other end is connected to the source of the second field-effect transistor. The drain of the second field-effect transistor is connected to the drain of the first field-effect transistor. One end of the pixel resistor is connected to the source of the first field-effect transistor, and the other end is connected to the third voltage terminal; The second voltage terminal is located between the drain of the first field-effect transistor and the drain of the second field-effect transistor.

9. The uncooled infrared detector readout circuit as described in claim 7, characterized in that, The readout circuit includes multiple first branches and multiple signal processing circuits, with the second voltage terminal on each first branch connected to one of the signal processing circuits.

10. The uncooled infrared detector readout circuit as described in claim 9, characterized in that, The pixel circuit also includes a second branch, which is provided with a reference blind pixel resistor, a reference light-shielding pixel resistor, a third field-effect transistor and a fourth field-effect transistor. The third field-effect transistor is a p-type field-effect transistor, and the fourth field-effect transistor is an n-type field-effect transistor; One end of the reference blind pixel resistor is connected to the first voltage terminal, and the other end is connected to the source of the third field-effect transistor. The gate of the second field-effect transistor in each of the first branches is connected to the gate of the third field-effect transistor in the second branch. The drain of the third field-effect transistor is connected to the drain and gate of the fourth field-effect transistor, and the connection point between the drain of the third field-effect transistor and the drain and gate of the fourth field-effect transistor is a connection node. The gate of the first field-effect transistor in each of the first branches is connected to the connection node. One end of the reference light-shielding pixel resistor is connected to the source of the fourth field-effect transistor in the second branch, and the other end is connected to the third voltage terminal of the second branch. The voltage of the connection node decreases as the voltage of the first voltage terminal decreases, the range of variation of the second voltage terminal decreases as the voltage of the connection node decreases, and the lower limit of the preset operating voltage range decreases as the voltage of the connection node decreases.

11. The uncooled infrared detector readout circuit as described in claim 1, characterized in that, The control circuit and the pixel circuit are integrated into the same integrated circuit structure; or... The control circuit and the pixel circuit are respectively housed in different integrated circuit structures.

12. An uncooled infrared detector, characterized in that, The uncooled infrared detector includes the uncooled infrared detector readout circuit as described in any one of claims 1 to 11.

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