Solution detection circuit, device, driving method, and solution detection method

Abstract

The application relates to a solution detection circuit, a device, a driving method and a solution detection method. The solution detection circuit comprises at least one detection unit, and the detection unit comprises an ion-sensitive field effect transistor, a first reset switch subunit, a synchronous step-down switch subunit, a storage capacitor and an output switch subunit. The threshold voltage of the ion-sensitive field effect transistor can be directly read by the embodiment of the application, and the solution detection speed is improved.

Description

Technical Field

[0001] This invention relates to the field of solution detection technology, and in particular to a solution detection circuit, device, driving method, and solution detection method. Background Technology

[0002] An ion-sensitive field-effect transistor (ISFET) is a microelectronic ion-selective sensing device that combines the characteristics of both electrochemistry and transistors. Currently, pH detection or ion concentration detection of a solution can be achieved by measuring the threshold voltage of the ISFET. However, due to limitations in device structure and circuit characteristics, the threshold voltage of the ISFET cannot be directly read. Summary of the Invention

[0003] This invention provides a solution detection circuit, device, driving method, and solution detection method to directly read the threshold voltage of an ion-sensitive field-effect transistor, thereby improving the solution detection speed.

[0004] In a first aspect, embodiments of the present invention provide a solution detection circuit, including at least one detection unit, the detection unit including an ion-sensitive field-effect transistor, a first reset switch subunit, a synchronous buck switch subunit, a storage capacitor, and an output switch subunit;

[0005] The first terminal of the first reset switch subunit is connected to a reference voltage, the second terminal of the first reset switch subunit is connected to the gate of the ion-sensitive field-effect transistor, and the third terminal of the first reset switch subunit is connected to the drain of the ion-sensitive field-effect transistor. The first terminal of the synchronous buck switch subunit is connected to the gate of the ion-sensitive field-effect transistor, the second terminal of the synchronous buck switch subunit is connected to the drain of the ion-sensitive field-effect transistor, the third terminal of the synchronous buck switch subunit is connected to the source of the ion-sensitive field-effect transistor, and the fourth terminal of the synchronous buck switch subunit is connected to ground. The first plate of the storage capacitor is connected to the gate of the ion-sensitive field-effect transistor, and the second plate of the storage capacitor is connected to ground. The first terminal of the output switch subunit is connected to the drain of the ion-sensitive field-effect transistor. The control terminal of the first reset switch subunit is connected to a first scan signal, the control terminal of the synchronous buck switch subunit is connected to a second scan signal, and the control terminal of the output switch subunit is connected to a third scan signal.

[0006] Secondly, embodiments of the present invention also provide a solution detection device, including the solution detection circuit described in the first aspect.

[0007] Thirdly, embodiments of the present invention also provide a driving method for the solution detection circuit described in the first aspect, the driving method for the solution detection circuit comprising:

[0008] The first reset switch subunit is turned on to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and to charge the storage capacitor.

[0009] Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor.

[0010] Turn on the output switch subunit to output the threshold voltage through the output switch subunit.

[0011] Fourthly, embodiments of the present invention also provide a solution detection method, applied to the solution detection circuit described in the first aspect, the solution detection method comprising:

[0012] The first reset switch subunit is turned on to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and to charge the storage capacitor.

[0013] Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor.

[0014] Turn on the output switch subunit to output the threshold voltage through the output switch subunit;

[0015] The pH value or ion concentration of the solution to be tested is determined based on the threshold voltage.

[0016] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0017] The technical solution provided in this embodiment of the invention first uses a first reset switch subunit to reset both the gate voltage and drain voltage of the ion-sensitive field-effect transistor (IFET) to a reference voltage, enabling the IFET to conduct and simultaneously charging the storage capacitor connected to the gate of the IFET. Then, a synchronous buck switch subunit connects the gate and drain of the IFET, ensuring that during the discharge of the storage capacitor, the gate voltage and drain voltage of the IFET are the same and decrease synchronously. When the gate voltage of the IFET drops to its threshold voltage, the IFET turns off, and the drain voltage of the IFET is output using an output switch subunit, allowing direct reading of the IFET's threshold voltage. Thus, the technical solution provided in this embodiment of the invention can directly read the threshold voltage of the IFET, thereby enabling solution pH detection or ion concentration detection based on the threshold voltage, improving the solution detection speed. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the circuit structure of a solution detection circuit provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the circuit structure of a detection unit provided in an embodiment of the present invention;

[0022] Figure 3 This is a timing diagram of the operation of a detection unit provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0024] Figure 5 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0026] Figure 7A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of the structure of a detection unit provided in an embodiment of the present invention;

[0028] Figure 9 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0029] Figure 10 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0030] Figure 11 The transistor gate-source voltage versus drain current relationship curve provided in the embodiments of the present invention;

[0031] Figure 12 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0032] Figure 13 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0033] Figure 14 A schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention;

[0034] Figure 15 This is a schematic diagram of another detection unit provided in an embodiment of the present invention;

[0035] Figure 16 This is a schematic diagram of an array structure for a solution detection circuit provided in an embodiment of the present invention;

[0036] Figure 17 This is a schematic diagram of an array structure for another solution detection circuit provided in an embodiment of the present invention;

[0037] Figure 18 This is a schematic diagram of an array structure for another solution detection circuit provided in an embodiment of the present invention;

[0038] Figure 19 This is a schematic diagram of an array structure for another solution detection circuit provided in an embodiment of the present invention. Detailed Implementation

[0039] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0040] Figure 1This is a schematic diagram of the circuit structure of a solution detection circuit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the circuit structure of a detection unit provided in an embodiment of the present invention. Figure 1 and Figure 2 As shown, the solution detection circuit provided in this embodiment of the invention includes at least one detection unit 10. Figure 1 Multiple detection units 10 are shown. Each detection unit 10 includes an ion-sensitive field-effect transistor T, a first reset switch subunit 1, a synchronous buck switch subunit 2, a storage capacitor C, and an output switch subunit 3. The first terminal of the first reset switch subunit 1 is connected to a reference voltage Vref, the second terminal of the first reset switch subunit 1 is connected to the gate of the ion-sensitive field-effect transistor T, and the third terminal of the first reset switch subunit 1 is connected to the drain of the ion-sensitive field-effect transistor T. The first terminal of the synchronous buck switch subunit 2 is connected to the gate of the ion-sensitive field-effect transistor T, and the second terminal of the synchronous buck switch subunit 2 is connected to the gate of the ion-sensitive field-effect transistor T. The drain of the ion-sensitive field-effect transistor T is connected; the third terminal of the synchronous buck switch subunit 2 is connected to the source of the ion-sensitive field-effect transistor T; the fourth terminal of the synchronous buck switch subunit 2 is connected to ground; the first plate of the storage capacitor C is connected to the gate of the ion-sensitive field-effect transistor T; the second plate of the storage capacitor C is connected to ground; the first terminal of the output switch subunit 3 is connected to the drain of the ion-sensitive field-effect transistor T; the control terminal of the first reset switch subunit 1 is connected to the first scan signal S1; the control terminal of the synchronous buck switch subunit 2 is connected to the second scan signal S2; and the control terminal of the output switch subunit 3 is connected to the third scan signal S3.

[0041] It should be noted that the ion-sensitive field-effect transistor T involved in this invention has a dual-gate structure, including a top gate (also known as a floating gate) and a bottom gate (i.e., the gate of the ion-sensitive field-effect transistor T in this embodiment of the invention); wherein, an ion-sensitive layer is formed on the surface of the top gate, and the ion-sensitive membrane can adsorb specific ions or molecules. For the ions to be detected, a corresponding ion-sensitive membrane should be provided. The ion-sensitive field-effect transistor T provided in this embodiment of the invention can be used to detect the concentration of ions such as hydrogen ions or chloride ions. The specific principle is as follows: When the ion-sensitive field-effect transistor T is immersed in the solution to be tested, the surface charge of the ion-sensitive layer changes according to the change in the ion concentration in the solution, thereby affecting the threshold voltage of the ion-sensitive field-effect transistor T. That is, the threshold voltage of the ion-sensitive field-effect transistor T will drift to the left (decrease) or to the right (increase) relative to the reference threshold voltage in the subthreshold region due to the influence of the solution ion concentration. The change in threshold voltage can then be obtained. Based on the relationship between the change in threshold voltage and the change in pH value, the change in pH value can be calculated. Then, based on the reference pH value calibrated from the standard solution, the pH value of the solution to be tested can be obtained. Finally, based on the relationship between ion concentration and pH value, the ion concentration of the solution to be tested can be obtained. Furthermore, the ion-sensitive field-effect transistor T can be N-type; in this case, the threshold voltage of the ion-sensitive field-effect transistor T will drift to the left due to the influence of the solution ion concentration. The ion-sensitive field-effect transistor T can also be P-type; in this case, the threshold voltage of the ion-sensitive field-effect transistor T will drift to the right due to the influence of the solution ion concentration.

[0042] In the above embodiment, the first scan signal S1 is used to control the first reset switch subunit 1 to be turned on or off. When the first reset switch subunit 1 is turned on, the first terminal of the first reset switch subunit 1 is connected to the gate of the ion-sensitive field-effect transistor T via the second terminal of the first reset switch subunit 1, and the first terminal of the first reset switch subunit 1 is connected to the drain of the ion-sensitive field-effect transistor T via the third terminal of the first reset switch subunit 1. This allows the reference voltage Vref to reach nodes N1 and N2 respectively via the first reset switch subunit 1, and to charge the storage capacitor C, so that the gate voltage, drain voltage of the ion-sensitive field-effect transistor T, and voltage of the storage capacitor C are all equal to the reference voltage Vref. The reference voltage Vref enables the ion-sensitive field-effect transistor T to conduct. Specifically, for an N-type ion-sensitive field-effect transistor, the reference voltage Vref is greater than the threshold voltage of the ion-sensitive field-effect transistor T (the threshold voltage that drifts due to the influence of the solution ion concentration). For a P-type ion-sensitive field-effect transistor, the reference voltage Vref is less than the threshold voltage of the ion-sensitive field-effect transistor T. In this way, during the subsequent discharge of the storage capacitor C, the gate voltage of the ion-sensitive field-effect transistor T can reach the threshold voltage, thereby ensuring that the detection unit 10 accurately outputs the threshold voltage and improving the accuracy of solution detection.

[0043] Additionally, the second scan signal S2 is used to control the synchronous buck switch subunit 2 to turn on or off. When the synchronous buck switch subunit 2 is off, the gate and drain of the ion-sensitive field-effect transistor T are disconnected, and simultaneously, the source of the ion-sensitive field-effect transistor T is disconnected from ground. Thus, when the first reset switch subunit 1 is on, the second scan signal S2 controls the synchronous buck switch subunit 2 to turn off. On the one hand, by disconnecting the gate and drain of the ion-sensitive field-effect transistor T, a short circuit between the second and third terminals of the first reset switch subunit 1 can be prevented when the first reset switch subunit 1 is on, thereby preventing the first reset switch subunit 1 from burning out due to an internal short circuit. On the other hand, by disconnecting the source of the ion-sensitive field-effect transistor T from ground, the reference signal source providing the reference signal Vref can be prevented from being connected to ground via the first reset switch subunit 1, the ion-sensitive field-effect transistor T, and the synchronous buck switch subunit 2, i.e., a short circuit of the reference signal source can be prevented, thereby preventing the reference signal source from burning out. When the synchronous buck switch subunit 2 is turned on, the gate and drain of the ion-sensitive field-effect transistor T are connected, and the source of the ion-sensitive field-effect transistor T is connected to ground. Therefore, when the first reset switch subunit 1 is turned off, the second scan signal S2 controls the synchronous buck switch subunit 2 to turn on. At this time, because the gate and drain of the ion-sensitive field-effect transistor T are connected, the drain voltage of the ion-sensitive field-effect transistor T is always the same as the gate voltage. Moreover, when the first reset switch subunit 1 is turned off, and due to the discharge of the storage capacitor C, the gate voltage of the ion-sensitive field-effect transistor T no longer remains at the reference voltage Vref, but the absolute value of the gate voltage gradually decreases, and the drain voltage changes with the gate voltage. Simultaneously, the source of the ion-sensitive field-effect transistor T is connected to ground, and the synchronous buck switch subunit 2 and the ion-sensitive field-effect transistor T form a discharge path for the storage capacitor C, thereby increasing the discharge rate of the storage capacitor C. This allows the gate voltage and drain voltage of the ion-sensitive field-effect transistor T to quickly reach the threshold voltage, improving the solution detection efficiency. When the gate voltage of the ion-sensitive field-effect transistor T reaches the threshold voltage, the ion-sensitive field-effect transistor T is turned off. At this time, the aforementioned discharge path is broken, and the storage capacitor C discharges slowly. Correspondingly, the gate voltage and drain voltage of the ion-sensitive field-effect transistor T change slowly. Therefore, by analyzing the rate of change of the drain voltage, it is easy to determine when the drain voltage reaches the threshold voltage of the ion-sensitive field-effect transistor T, thereby improving the accuracy of the threshold voltage.

[0044] Furthermore, considering that if the detection voltage is continuously output through node N2, it will drift due to interference from external signals, leading to errors in the threshold voltage. Since the change in threshold voltage affected by ion concentration is very slight, even a small error can significantly reduce the accuracy of ion concentration detection. Therefore, this invention uses an output switch subunit 3 to control the output of the detection voltage Vout. Specifically, the third scan signal S3 is used to control the output switch subunit 3 to be turned on or off. Only when the output switch subunit 3 is turned on will the detection voltage of node N2 be output through the output switch subunit 3, thereby allowing the threshold voltage of the ion-sensitive field-effect transistor T to be read. Optionally, the output switch subunit 3 can be turned on simultaneously with the synchronous buck switch subunit 2, or it can be turned on after the synchronous buck switch subunit 2 is turned on (as long as the threshold voltage can be measured). This avoids prolonged output of the detection voltage from node N2, effectively preventing threshold voltage drift due to external signal interference, improving the accuracy of the threshold voltage, and thus improving the accuracy of solution detection.

[0045] Based on the above embodiments, combined with Figure 3 ( Figure 3 Taking the example that all switch sub-units are turned on at a high level (in other examples, all switch sub-units may be turned on at a low level), the working principle of the detection unit 10 is described as follows: First, the first reset switch sub-unit 1 is turned on by the first scan signal S1, so that the gate voltage (voltage of node N1) and drain voltage (voltage of node N2) of the ion-sensitive field-effect transistor T are both reset to the reference voltage Vref, and at the same time, the voltage of the storage capacitor C is charged to the reference voltage Vref. At this time, the ion-sensitive field-effect transistor is turned on. The first reset switch subunit 1 is turned off by the first scan signal S1, the synchronous buck switch subunit 2 is turned on by the second scan signal S2, and the output switch subunit 3 is turned on by the third scan signal S3. The storage capacitor C continues to discharge, and the absolute value of the voltage of the storage capacitor C continues to decrease. Under the action of the voltage of the storage capacitor C, the voltage of node N2 is equal to the voltage of node N1 and decreases synchronously. At the same time, the output switch subunit 3 outputs the voltage of node N2, which is the detection voltage Vout. Before the voltage of node N1 reaches the threshold voltage of the ion-sensitive field-effect transistor T, the ion-sensitive field-effect transistor T remains in the conducting state. When the voltage of node N1 reaches the threshold voltage of the ion-sensitive field-effect transistor T, the ion-sensitive field-effect transistor T is turned off. At this time, the voltage of node N2 output by the output switch subunit 3 is the threshold voltage Vth of the ion-sensitive field-effect transistor T. In addition, the synchronous buck switch subunit 2 can be turned off by the second scan signal S2, and the output switch subunit 3 can be turned off by the third scan signal S3. The voltage of node N2 becomes 0, and the output of the detection voltage Vout is disconnected.

[0046] In some embodiments, the first scan signal S1 can be transmitted to the control terminal of the first reset switch subunit 1 via the first scan signal line G1; the second scan signal S2 can be transmitted to the control terminal of the synchronous buck switch subunit 2 via the second scan signal line G2; the third scan signal S3 can be transmitted to the control terminal of the output switch subunit 3 via the third scan signal line G3; the reference voltage can be transmitted to the first terminal of the first reset switch subunit 1 via the reference voltage line D1; the ground signal can be transmitted to the fourth terminal of the synchronous buck switch subunit 2 and the second plate of the storage capacitor C via the ground line D2, so as to connect the fourth terminal of the synchronous buck switch subunit 2 to ground and the second plate of the storage capacitor C to ground; the output signal line D3 is connected to the second terminal of the output switch subunit 3, and the detected voltage is output via the output signal line D3.

[0047] The solution detection circuit provided in this embodiment of the invention first uses a first reset switch subunit to reset both the gate voltage and drain voltage of the ion-sensitive field-effect transistor (IFET) to a reference voltage, enabling the IFET to conduct and simultaneously charging the storage capacitor connected to the gate of the IFET. Then, a synchronous buck switch subunit connects the gate and drain of the IFET, ensuring that during the discharge of the storage capacitor, the gate voltage and drain voltage of the IFET are the same and decrease synchronously. When the gate voltage of the IFET drops to its threshold voltage, the IFET turns off, and the drain voltage of the IFET is output using an output switch subunit, allowing direct reading of the IFET's threshold voltage. Thus, the technical solution provided in this embodiment of the invention can directly read the threshold voltage of the IFET, thereby enabling solution pH detection or ion concentration detection based on the threshold voltage, improving the solution detection speed.

[0048] Based on the above technical solution, in one embodiment, such as Figure 4The first reset switch subunit includes a first transistor T1 and a second transistor T2. The gates of both transistors T1 and T2 are connected to a first scan signal S1. The first terminals of both transistors T1 and T2 are connected to a reference voltage Vref. The second terminal of transistor T1 is connected to the drain of an ion-sensitive field-effect transistor T, and the second terminal of transistor T2 is connected to the gate of the ion-sensitive field-effect transistor T. Thus, when the first scan signal S1 controls the first reset switch subunit to conduct, both transistors T1 and T2 are turned on. The reference voltage Vref is transmitted to node N2 via transistor T1 and simultaneously to node N1 via transistor T2, resetting the drain and gate voltages of the ion-sensitive field-effect transistor T to the reference voltage Vref and charging the storage capacitor C. Optionally, both transistors T1 and T2 can be NMOS transistors or PMOS transistors, only with the first scan signal S1 having opposite polarities.

[0049] In one embodiment, such as Figure 5 As shown, the synchronous buck switching subunit includes a third transistor T3 and a fourth transistor T4. The gates of both the third transistor T3 and the fourth transistor T4 are connected to the second scan signal S2. The first terminal of the third transistor T3 is connected to the gate of the ion-sensitive field-effect transistor T, and the second terminal of the third transistor T3 is connected to the drain of the ion-sensitive field-effect transistor T. The first terminal of the fourth transistor T4 is connected to the source of the ion-sensitive field-effect transistor T, and the second terminal of the fourth transistor T4 is grounded. Thus, when the second scan signal S2 controls the synchronous buck switch subunit to turn on, the gate of the third transistor T3 and the fourth transistor T4 are both turned on. The third transistor T3 connects node N1 and node N2, allowing the voltage of node N1 to be synchronized to node N2. The voltage of node N2 is consistent with the voltage of node N1, so that when the voltage of node N1 reaches the threshold voltage of the ion-sensitive field-effect transistor T, this threshold voltage can be output from node N2 through the output switch subunit 3. In addition, the source of the ion-sensitive field-effect transistor T is connected to ground through the fourth transistor T4, so that the third transistor T3, the ion-sensitive field-effect transistor T, and the fourth transistor T4 form the discharge channel of the storage capacitor C. Therefore, before the ion-sensitive field-effect transistor T is turned off, the storage capacitor C can be discharged quickly, so that the voltage of node N1 can quickly reach the threshold voltage of the ion-sensitive field-effect transistor T. Optionally, the third transistor T3 and the fourth transistor T4 can both be NMOS transistors or both can be PMOS transistors, only the positive and negative signs of the second scan signal S2 are reversed.

[0050] In one embodiment, such as Figure 6As shown, the output switch subunit includes a fifth transistor T5. The first terminal of the fifth transistor T5 is connected to the drain of the ion-sensitive field-effect transistor T, and the gate of the fifth transistor T5 is connected to the third scan signal S3. Thus, when the third scan signal S3 controls the output switch subunit to turn on, the fifth transistor T5 turns on, and the voltage of node N2, i.e., the detection voltage Vout, is output through the fifth transistor T5. Optionally, the fifth transistor T5 can be an NMOS transistor or a PMOS transistor, only the polarity of the third scan signal S3 is reversed.

[0051] Based on the above embodiments, in one specific embodiment of the present invention, Figure 7 This is a schematic diagram of the circuit structure of another detection unit provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of a detection unit provided in an embodiment of the present invention. Figure 7 and Figure 8As shown, the detection unit includes an ion-sensitive field-effect transistor T, a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, and a storage capacitor. In this configuration, the gates of the first transistor T1 and the second transistor T2 are both connected to the first scan signal S1 via the first scan signal line G1. The first terminals of the first transistor T1 and the second transistor T2 are both connected to the reference voltage Vref via the reference voltage line D1. The second terminal of the first transistor T1 is connected to the drain of the ion-sensitive field-effect transistor T, and the second terminal of the second transistor T2 is connected to the gate of the ion-sensitive field-effect transistor T. The gates of the third transistor T3 and the fourth transistor T4 are both connected to the second scan signal S2 via the second scan signal line G2. The first terminal of the third transistor T3 is connected to the gate of the ion-sensitive field-effect transistor T, and the second terminal of the third transistor T3 is connected to the drain of the ion-sensitive field-effect transistor T. The first terminal of the fourth transistor T4 is connected to the source of the ion-sensitive field-effect transistor T, and the second terminal of the fourth transistor T4 is connected to ground via the ground line D2. The gate of the fifth transistor T5 is connected to the third scan signal S3 via the third scan signal line G3. The first terminal of the fifth transistor T5 is connected to the drain of the ion-sensitive field-effect transistor T, and the second terminal of the fifth transistor T5 is connected to the output signal line D3. Based on this implementation, specifically, the first transistor T1 and the second transistor T2 are first turned on by the first scan signal S1. The reference voltage Vref is transmitted to the N2 node via the first transistor T1, and at the same time, the reference voltage Vref is transmitted to the N1 node via the second transistor T2. The drain voltage and gate voltage of the ion-sensitive field-effect transistor T are reset to the reference voltage Vref, and the storage capacitor C is charged. The voltage of the storage capacitor C is maintained at the reference voltage Vref. Then, the first scanning signal S1 controls the first transistor T1 and the second transistor T2 to turn off, the second scanning signal S2 controls the third transistor T3 and the fourth transistor T4 to turn on, and the third scanning signal S3 controls the fifth transistor T5 to turn on. In this way, the storage capacitor C continues to discharge, and the voltage of node N1 is transmitted to node N2, so that the voltage of node N2 is consistent with the voltage of node N1. When the voltage of node N1 reaches the threshold voltage of ion-sensitive field-effect transistor T, the threshold voltage can be output by node N2 through output switch subunit 3. Then, the threshold voltage is output through output signal line D3, and the threshold voltage of ion-sensitive field-effect transistor T can be directly read, so as to calculate the pH value or ion concentration of the test solution based on the threshold voltage.

[0052] Furthermore, considering that the threshold voltage of an ion-sensitive field-effect transistor changes very slightly due to ion concentration, typically by tens of millivolts, and given the limitations of signal acquisition accuracy, it is difficult to capture this change in threshold voltage. Therefore, the acquired detection voltage needs to be amplified. Based on this, in one embodiment, such as... Figure 9As shown, the detection unit also includes a signal amplification subunit 4, which amplifies the threshold voltage of the ion-sensitive field-effect transistor T output by the output switch subunit 3 into a current, and outputs the detection current Iout via the signal amplification subunit 4. Therefore, by amplifying the threshold voltage, it is easier to detect, thereby improving the accuracy of solution detection.

[0053] Based on the above embodiments, in one implementation, such as Figure 10 As shown, specifically, the signal amplification subunit includes a sixth transistor T6. The gate of the sixth transistor T6 is connected to the second terminal of the output switch subunit 3, the drain of the sixth transistor T6 is connected to the supply voltage VDD, and the source of the sixth transistor T6 outputs current. The source of the sixth transistor T6 is grounded, i.e., the output signal line is grounded; only the current on the output signal line needs to be sampled. Thus, the gate-source voltage Vgs of the sixth transistor T6 is equal to the threshold voltage of the ion-sensitive field-effect transistor T output via the output switch subunit 3. (Reference) Figure 11 Considering that even a slight change in the threshold voltage within the subthreshold region will result in a significant change in the corresponding drain current (in this invention, the source current equals the drain current), a larger current is obtained by setting the threshold voltage of the sixth transistor T6 to be the same as the reference threshold voltage of the ion-sensitive field-effect transistor T. This ensures that the gate-source voltage of the sixth transistor T6 remains within the subthreshold region, thereby achieving a larger current. Then, based on... Figure 11 The curve showing the relationship between the gate-source voltage Vgs and the drain current Id reveals the gate-source voltage corresponding to the detected current, which is the threshold voltage of the ion-sensitive field-effect transistor T output via the output switch subunit 3. Therefore, the change in threshold voltage is determined based on the threshold voltage and the reference threshold voltage. Then, the change in pH value is obtained based on the correlation between the change in threshold voltage and the change in pH value. Finally, the pH value of the test solution is obtained by comparing it with the reference pH value. Optionally, the supply voltage VDD ranges from 10V to 20V.

[0054] In one embodiment, such as Figure 12 As shown, the detection unit also includes a second reset switch subunit 5, which is used to reset the second terminal of the output switch subunit 3. For example, before the output switch subunit 3 is turned on, the second reset switch subunit 5 can be controlled to reset the N3 node at the second terminal of the output switch subunit 3 before the output switch subunit 3 is turned on. This eliminates interference from external signals on the threshold voltage of the ion-sensitive field-effect transistor T output by the output switch subunit 3, thereby further ensuring the accuracy of the threshold voltage.

[0055] Based on the above embodiments, in one implementation, such as Figure 13As shown, the second reset switch subunit includes a seventh transistor T7. The first terminal of the seventh transistor T7 is connected to the reset voltage Reset, the second terminal of the seventh transistor T7 is connected to the second terminal (node ​​N3) of the output switch subunit, and the gate of the seventh transistor T7 is connected to the fourth scan signal S4. Thus, when node N3 needs to be reset, the fourth scan signal S4 controls the seventh transistor T7 to turn on, directly resetting node N3 to the reset voltage Reset. Optionally, the reset voltage Reset is 0.

[0056] Based on the above embodiments, in one specific implementation, such as Figure 14 and Figure 15 As shown, the detection unit includes an ion-sensitive field-effect transistor T, a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, a storage capacitor, a sixth transistor T6, and a seventh transistor T7. The gates of the first transistor T1 and the second transistor T2 are both connected to the first scan signal S1 via the first scan signal line G1. The first terminals of the first transistor T1 and the second transistor T2 are both connected to the reference voltage Vref via the reference voltage line D1. The second terminal of the first transistor T1 is connected to the drain of the ion-sensitive field-effect transistor T, and the second terminal of the second transistor T2 is connected to the gate of the ion-sensitive field-effect transistor T. The gates of the third transistor T3 and the fourth transistor T4 are both connected to the second scan signal S2 via the second scan signal line G2. The first terminal of the third transistor T3 is connected to the gate of the ion-sensitive field-effect transistor T, and the second terminal of the third transistor T3 is connected to the drain of the ion-sensitive field-effect transistor T. The first terminal of the fourth transistor T4 is connected to the drain of the ion-sensitive field-effect transistor T. The source of transistor T is connected, and the second terminal of the fourth transistor T4 is connected to ground via ground line D2. The gate of the fifth transistor T5 is connected to the third scan signal S3 via the third scan signal line G3. The first terminal of the fifth transistor T5 is connected to the drain of the ion-sensitive field-effect transistor T. The second terminal of the fifth transistor T5 is connected to the gate of the sixth transistor T6. The drain of the sixth transistor T6 is connected to the supply voltage VDD via the supply voltage line D4. The source of the sixth transistor T6 is connected to the output signal line D3, and the current Iout is output through the output signal line D3. The first terminal of the seventh transistor T7 is connected to the reset voltage Reset via the reset voltage line D5. The second terminal of the seventh transistor T7 is connected to node N3. The gate of the seventh transistor T7 is connected to the fourth scan signal S4 via the fourth scan signal line G4. The working principle of the detection unit provided in this embodiment is not described in detail; please refer to the previous embodiment for details.

[0057] In some embodiments, reference Figure 1The solution detection circuit includes multiple detection units 10 arranged in an array along rows and columns. The circuit also includes multiple first scan signal lines G1, multiple second scan signal lines G2, and multiple third scan signal lines G3 arranged along the column direction and extending along the row direction, as well as multiple reference voltage lines D1, multiple ground lines D2, and multiple output signal lines D3 arranged along the row direction and extending along the column direction. The control terminal of the first reset switch subunit in the same row of detection units 10 is connected to the same first scan signal line G1; the control terminal of the synchronous buck switch subunit in the same row of detection units 10 is connected to the same second scan signal line G2; and the control terminal of the output switch subunit in the same row of detection units 10 is connected to the same third scan signal line G3. The first reset switch subunit in the same column of detection units 10 is connected to the same reference voltage line D1; the synchronous buck switch subunit and the second plate of the storage capacitor in the same column of detection units 10 are connected to the same ground line D2; and the second terminal of the output switch subunit in the same column of detection units 10 is connected to the same output signal line D3.

[0058] In this way, by scanning multiple detection units 10 in the solution detection circuit line by line, the detection signal (detection voltage or detection current) detected by one line of detection units 10 can be output at a time. The detection signals detected by all detection units 10 can be output within one frame, thereby enabling rapid detection of ion concentration at multiple sites and greatly improving the efficiency of multi-sample detection.

[0059] In one specific embodiment, the first reset switch subunit, the synchronous buck switch subunit, and the output switch subunit are all composed of thin-film transistors (TFTs). The gates of each TFT, the gates of the ion-sensitive field-effect transistors, the first plate of the storage capacitor, the first scan signal line, the second scan signal line, and the third scan signal line are located on the same layer and are made of the same material. The sources and drains of each TFT, the sources and drains of the ion-sensitive field-effect transistors, the second plate of the storage capacitor, the reference voltage line, the ground line, and the output signal line are located on the same layer and are made of the same material. Therefore, partial film layers of each device can be fabricated using the same process, saving process costs. Figure 16 It shows the corresponding Figure 8 The array structure of the solution detection circuit with the detection unit structure. Figure 17 It shows the corresponding Figure 15 The array structure of the solution detection circuit with the detection unit structure is described above. The working principle and driving method of the two solution detection circuits mentioned above can be referred to the above embodiments, and will not be repeated here.

[0060] In one embodiment, reference Figure 16Each detection unit is located between its corresponding reference voltage line D1 and ground line D2, while the output signal line D3 is located on the side of ground line D2 away from the corresponding detection unit. This is because ground line D2 needs to be connected to the fourth transistor T4 and the storage capacitor C, while the output signal line D3 only needs to be connected to the fifth transistor T5. This configuration simplifies the wiring by requiring only one bridge structure connecting the output signal line D3 to the fifth transistor T5.

[0061] In one embodiment, the second and third scan signal lines corresponding to the same row detection unit are interconnected. Considering that the second and third scan signals can be the same (same amplitude and synchronous change), interconnecting the second and third scan signal lines corresponding to the same row detection unit allows the first and second scan signals to be provided by the same signal source, thereby reducing the number of pins on the driver chip.

[0062] In one embodiment, such as Figure 18 As shown, the second and third scan signal lines corresponding to the same row detection unit are the same signal line G5. Similarly, considering that the second and third scan signals can be the same, and that using the same signal line will not cause interference to the third transistor T3, the fourth transistor, and the fifth transistor T5, setting the second and third scan signal lines corresponding to the same row detection unit as the same signal line reduces wiring and further simplifies the circuit structure.

[0063] In some embodiments, such as Figure 19 As shown, multiple reference voltage lines D1 are interconnected, and multiple ground lines D2 are interconnected. Since the reference voltage provided to each detection unit 10 can be the same, multiple reference voltage lines D1 can be interconnected, allowing multiple reference voltage lines D1 to be connected to the same reference voltage source, thereby greatly reducing the number of reference voltage sources or the number of pins on the driver chip. Similarly, interconnecting multiple ground lines D2 can achieve the same effect.

[0064] In some embodiments, a plurality of detection units arranged in an array along rows and columns constitute a detection unit array; the input terminals of the first scan signal line, the second scan signal line, and the third scan signal line are located on a first side of the detection unit array; the input terminals of the reference voltage line, the ground line, and the output terminals of the output signal line are located on a second side of the detection unit array; the first side and the second side are adjacent sides or the same side of the detection unit array.

[0065] For example, the first side and the second side are adjacent sides of the detection unit array. For instance, the input terminals of the first scan signal line, the second scan signal line, and the third scan signal line are located on the left side of the detection unit array, while the input terminals of the reference voltage line, the ground line, and the output signal line are located on the upper side of the detection unit array. This allows for a more compact pixel structure, with a pixel size of 350µm*350µm. Alternatively, the first side and the second side are the same side of the detection unit array. For instance, the input terminals of the first scan signal line, the second scan signal line, and the third scan signal line are located on the left side of the detection unit array, while the input terminals of the reference voltage line, the ground line, and the output signal line are led out from the upper side of the detection unit array and routed to the left side of the array via line swapping. This allows for driving by a single driver chip, reducing the number of driver chips required.

[0066] This invention also provides a solution detection device, including the solution detection circuit provided in any embodiment of this invention. This solution detection device has the same functions and beneficial effects as the solution detection circuit, and will not be described further here.

[0067] In addition, this embodiment of the invention also provides a driving method for the solution detection circuit provided in this embodiment of the invention. Specifically, the driving method for the solution detection circuit includes:

[0068] S110. Open the first reset switch subunit to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and charge the storage capacitor.

[0069] S120: Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor.

[0070] S130. Turn on the output switch subunit to output the threshold voltage through the output switch subunit.

[0071] In some embodiments, the solution detection circuit further includes a signal amplification subunit, and after the output switch subunit is turned on, it further includes:

[0072] Turn on the signal amplification subunit to amplify the threshold voltage into current.

[0073] In some embodiments, the solution detection circuit further includes a second reset switch subunit, which, before opening the output switch subunit, also includes:

[0074] Open the second reset switch subunit to reset the second terminal of the output switch subunit.

[0075] Furthermore, embodiments of the present invention also provide a solution detection method, applied to the solution detection circuit provided in any embodiment of the present invention. Specifically, the solution detection method includes:

[0076] S210. Open the first reset switch subunit to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and charge the storage capacitor.

[0077] S220: Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor.

[0078] S230, Open the output switch subunit to output the threshold voltage through the output switch subunit.

[0079] S240. Determine the pH value or ion concentration of the solution to be tested based on the threshold voltage.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A solution detection circuit, characterized in that, It includes at least one detection unit, which includes an ion-sensitive field-effect transistor, a first reset switch subunit, a synchronous buck switch subunit, a storage capacitor, and an output switch subunit; The first terminal of the first reset switch subunit is connected to a reference voltage, the second terminal of the first reset switch subunit is connected to the gate of the ion-sensitive field-effect transistor, and the third terminal of the first reset switch subunit is connected to the drain of the ion-sensitive field-effect transistor; the first terminal of the synchronous buck switch subunit is connected to the gate of the ion-sensitive field-effect transistor, the second terminal of the synchronous buck switch subunit is connected to the drain of the ion-sensitive field-effect transistor, the third terminal of the synchronous buck switch subunit is connected to the source of the ion-sensitive field-effect transistor, and the fourth terminal of the synchronous buck switch subunit is connected to ground; the first plate of the storage capacitor is connected to the gate of the ion-sensitive field-effect transistor, and the second plate of the storage capacitor is connected to ground; The first terminal of the output switch subunit is connected to the drain of the ion-sensitive field-effect transistor; the control terminal of the first reset switch subunit is connected to the first scan signal, the control terminal of the synchronous buck switch subunit is connected to the second scan signal, and the control terminal of the output switch subunit is connected to the third scan signal.

2. The solution detection circuit according to claim 1, characterized in that, The first reset switch subunit includes a first transistor and a second transistor. The gates of the first transistor and the second transistor are both connected to the first scan signal. The first terminals of the first transistor and the second transistor are both connected to the reference voltage. The second terminal of the first transistor is connected to the drain of the ion-sensitive field-effect transistor, and the second terminal of the second transistor is connected to the gate of the ion-sensitive field-effect transistor.

3. The solution detection circuit according to claim 1, characterized in that, The synchronous buck switch subunit includes a third transistor and a fourth transistor. The gates of the third transistor and the fourth transistor are both connected to the second scan signal. The first terminal of the third transistor is connected to the gate of the ion-sensitive field-effect transistor, the second terminal of the third transistor is connected to the drain of the ion-sensitive field-effect transistor, the first terminal of the fourth transistor is connected to the source of the ion-sensitive field-effect transistor, and the second terminal of the fourth transistor is grounded.

4. The solution detection circuit according to claim 1, characterized in that, The output switch subunit includes a fifth transistor, the first terminal of which is connected to the drain of the ion-sensitive field-effect transistor, and the gate of which is connected to the third scan signal.

5. The solution detection circuit according to claim 1, characterized in that, The detection unit further includes a signal amplification subunit, which is used to amplify the threshold voltage of the ion-sensitive field-effect transistor output by the output switch subunit into a current.

6. The solution detection circuit according to claim 5, characterized in that, The signal amplification subunit includes a sixth transistor, the gate of which is connected to the second terminal of the output switch subunit, the drain of which is connected to the power supply voltage, and the second terminal of which outputs the current.

7. The solution detection circuit according to claim 1, characterized in that, The detection unit further includes a second reset switch subunit, which is used to reset the second terminal of the output switch subunit.

8. The solution detection circuit according to claim 7, characterized in that, The second reset switch subunit includes a seventh transistor, the first terminal of which is connected to a reset voltage, the second terminal of which is connected to the second terminal of the output switch subunit, and the gate of which is connected to a fourth scan signal.

9. The solution detection circuit according to claim 1 or 5, characterized in that, The solution detection circuit includes multiple detection units arranged in an array along rows and columns. The solution detection circuit also includes multiple first scan signal lines, multiple second scan signal lines, multiple third scan signal lines arranged along the column direction and extending along the row direction, as well as multiple reference voltage lines, multiple ground lines, and multiple output signal lines arranged along the row direction and extending along the column direction. The control terminal of the first reset switch subunit in the same row of the detection units is connected to the same first scan signal line; the control terminal of the synchronous step-down switch subunit in the same row of the detection units is connected to the same second scan signal line; and the control terminal of the output switch subunit in the same row of the detection units is connected to the same third scan signal line. The first reset switch subunit in the same column of the detection units is connected to the same reference voltage line, the synchronous buck switch subunit in the same column of the detection units and the second plate of the storage capacitor are connected to the same ground line, and the second terminal of the output switch subunit in the same column of the detection units is connected to the same output signal line.

10. The solution detection circuit according to claim 9, characterized in that, The first reset switch subunit, the synchronous buck switch subunit, and the output switch subunit are all composed of thin-film transistors; The gates of the thin-film transistors, the gates of the ion-sensitive field-effect transistors, the first plate of the storage capacitor, the first scan signal line, the second scan signal line, and the third scan signal line are located in the same layer and are made of the same material; The source and drain of each thin-film transistor, the source and drain of the ion-sensitive field-effect transistor, the second plate of the storage capacitor, the reference voltage line, the ground line, and the output signal line are located on the same layer and are made of the same material.

11. The solution detection circuit according to claim 9, characterized in that, Each of the detection units is located between the corresponding reference voltage line and the ground line, and the output signal line is located on the side of the ground line away from the detection unit.

12. The solution detection circuit according to claim 9, characterized in that, The second scan signal line and the third scan signal line corresponding to the detection unit in the same row are interconnected.

13. The solution detection circuit according to claim 9, characterized in that, The second scan signal line and the third scan signal line corresponding to the detection unit in the same row are the same signal line.

14. The solution detection circuit according to claim 9, characterized in that, The multiple reference voltage lines are interconnected, and the multiple ground lines are interconnected.

15. The solution detection circuit according to claim 9, characterized in that, The plurality of detection units arranged in an array along rows and columns constitute a detection unit array; the input ends of the first scan signal line, the second scan signal line, and the third scan signal line are located on the first side of the detection unit array; The input terminal of the reference voltage line, the input terminal of the ground line, and the output terminal of the output signal line are located on the second side of the detection unit array; the first side and the second side are adjacent sides or the same side of the detection unit array.

16. A solution detection device, characterized in that, Includes the solution detection circuit as described in any one of claims 1-15.

17. A driving method for a solution detection circuit according to any one of claims 1-15, characterized in that, The driving method of the solution detection circuit includes: The first reset switch subunit is turned on to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and to charge the storage capacitor. Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor. Turn on the output switch subunit to output the threshold voltage through the output switch subunit.

18. The driving method for the solution detection circuit according to claim 17, characterized in that, The solution detection circuit further includes a signal amplification subunit, and after the output switch subunit is turned on, it also includes: The signal amplification subunit is turned on to amplify the threshold voltage into current.

19. The driving method for the solution detection circuit according to claim 18, characterized in that, The solution detection circuit further includes a second reset switch subunit, which, before opening the output switch subunit, also includes: Open the second reset switch subunit to reset the second terminal of the output switch subunit.

20. A solution detection method, characterized in that, The solution detection method, applied to the solution detection circuit as described in any one of claims 1-15, comprises: The first reset switch subunit is turned on to reset the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the reference voltage and to charge the storage capacitor. Turn off the first reset switch subunit and turn on the synchronous buck switch subunit to reduce the gate voltage and drain voltage of the ion-sensitive field-effect transistor to the threshold voltage of the ion-sensitive field-effect transistor. Turn on the output switch subunit to output the threshold voltage through the output switch subunit; The pH value or ion concentration of the solution to be tested is determined based on the threshold voltage.

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