Signal receiving circuit of electromagnetic screen, electromagnetic chip and electromagnetic screen

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By employing a differential chain structure and a multi-stage amplification unit design in the signal receiving circuit of the electromagnetic screen, the problems of slow response speed and difficulty in multi-transaction detection of the electromagnetic screen are solved, achieving the effects of fast response and multi-transaction detection.

CN224536497UActive Publication Date: 2026-07-21FOCALTECH ELECTRONICS (SHENZHEN) CO LTD

Patent Information

Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner: FOCALTECH ELECTRONICS (SHENZHEN) CO LTD
Filing Date: 2025-09-09
Publication Date: 2026-07-21

AI Technical Summary

Technical Problem

Existing electromagnetic input devices have low response speeds to electromagnetic pens, making it impossible to detect multiple electromagnetic waves simultaneously.

Method used

The signal receiving circuit design includes a first-stage amplification unit consisting of n-1 amplifiers forming a differential chain structure. The electrical signal from the receiving coil is amplified in multiple stages through the first and second-stage amplification units. Combined with electrical isolation components and multi-stage amplification units, the signal gain and common-mode interference immunity are improved.

Benefits of technology

The response speed of the electromagnetic screen to the electromagnetic pen has been improved, enabling simultaneous detection of the positions of multiple electromagnetic pen touch points, and enhancing the anti-common-mode interference capability and detection accuracy of the signal receiving circuit.

✦ Generated by Eureka AI based on patent content.

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Abstract

The application discloses a signal receiving circuit of an electromagnetic screen, an electromagnetic chip and the electromagnetic screen. The signal receiving circuit comprises a first-stage amplification unit. The input end of the first-stage amplification unit is connected with the second end of each receiving coil. The first-stage amplification unit is used for receiving the electric signals of each receiving coil, performing first-stage signal amplification processing on each electric signal, and obtaining a plurality of first amplified signals. The first-stage amplification unit comprises n-1 amplifiers, wherein n is a positive integer greater than or equal to 2. Each amplifier is connected with the second end of two adjacent receiving coils. All the amplifiers form a differential chain structure. The application can amplify the electric signals of the receiving coils with sufficient amplification gain, and further improve the response speed of the electromagnetic screen to the electromagnetic pen. Moreover, the signal receiving circuit can simultaneously obtain the detection signals of all the receiving coils, and the electromagnetic screen can detect the touch point positions of a plurality of electromagnetic pens.

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Description

Technical Field

[0001] This application relates to the field of electromagnetic technology, specifically to a signal receiving circuit, an electromagnetic chip, and an electromagnetic screen. Background Technology

[0002] Currently, electromagnetic input devices include electromagnetic screens and electromagnetic pens. The electromagnetic pen is charged by receiving electromagnetic waves radiated by the electromagnetic screen and sends a feedback signal back to the electromagnetic screen. The electromagnetic screen then detects the contact position of the electromagnetic pen based on the feedback signal. Finally, the two work together to complete the input operation of the electromagnetic input device.

[0003] However, the electromagnetic screens of existing electromagnetic input devices have a low response speed to electromagnetic pens and cannot detect multiple electromagnetic waves simultaneously. Utility Model Content

[0004] In view of this, this application provides a signal receiving circuit, an electromagnetic chip, and an electromagnetic screen for use with an electromagnetic screen, to improve the response speed of the electromagnetic screen to an electromagnetic pen and to realize the detection of multiple electromagnetic pens. The technical solution of this application is as follows: The first aspect of this application provides a signal receiving circuit for an electromagnetic screen, the electromagnetic screen including n parallel receiving coils, the first ends of each receiving coil being connected in parallel, the receiving coils being used to receive electromagnetic wave signals from an electromagnetic pen and convert the electromagnetic wave signals into electrical signals; the signal receiving circuit includes a first-stage amplification unit, the input end of the first-stage amplification unit being connected to the second end of each receiving coil, the first-stage amplification unit being used to receive the electrical signals from each receiving coil, and performing first-stage signal amplification processing on each electrical signal to obtain multiple first amplified signals; the first-stage amplification unit includes n-1 amplifiers, where n is a positive integer greater than or equal to 2; each amplifier is respectively connected to the second ends of two adjacent receiving coils, and all the amplifiers constitute a differential chain structure.

[0005] In one embodiment of this application, the amplifier is a first operational amplifier, and the non-inverting input terminal and the inverting input terminal of each first operational amplifier are respectively connected to the second terminals of two adjacent receiving coils, and all the first operational amplifiers form a differential chain structure.

[0006] In one embodiment of this application, the signal receiving circuit further includes a first isolation unit and a second-stage amplification unit. A first terminal of the first isolation unit is connected to the output terminal of the first-stage amplification unit, and an input terminal of the second-stage amplification unit is connected to the second terminal of the first isolation unit. The first isolation unit is used to receive each of the first amplified signals and perform isolation processing on each of the first amplified signals. The second-stage amplification unit is used to receive each of the isolated first amplified signals, perform second-stage signal amplification processing on each of the first amplified signals, and obtain multiple second amplified signals as detection signals and output them.

[0007] In one embodiment of this application, the second-stage amplification unit includes n-1 second operational amplifiers, and the input terminal of each second operational amplifier is used to receive one of the first amplified signals.

[0008] In one embodiment of this application, the first operational amplifier is a differential input single-ended output operational amplifier, and the second operational amplifier is a single-ended input single-ended output operational amplifier.

[0009] In one embodiment of this application, the first operational amplifier is a differential input differential output operational amplifier; the second operational amplifier is a differential input differential output operational amplifier, or a differential input single-ended output operational amplifier.

[0010] In one embodiment of this application, the first isolation unit includes a plurality of electrical isolation elements, the first end of each electrical isolation element is used to receive one of the first amplified signals, and the second end of each electrical isolation element is connected to the second stage amplification unit; the electrical isolation element is a capacitor, a resistor or a buffer.

[0011] In one embodiment of this application, a second isolation unit and a third amplification unit are further included. The first end of the second isolation unit is connected to the output end of the second amplification unit, and the input end of the third amplification unit is connected to the second end of the second isolation unit. The second isolation unit is used to receive each second amplified signal and perform isolation processing on each second amplified signal. The third amplification unit is used to receive each second amplified signal after isolation processing, perform third-level signal amplification processing on each second amplified signal, and obtain multiple third amplified signals as detection signals and output them.

[0012] A second aspect of this application provides an electromagnetic chip, including the aforementioned signal receiving circuit.

[0013] A third aspect of this application provides an electromagnetic screen, comprising multiple parallel receiving coils, multiple parallel transmitting coils, and an electromagnetic chip; the receiving coils are orthogonal to the transmitting coils, with the first end of each receiving coil connected in parallel, and the receiving coil is used to receive electromagnetic wave signals from an electromagnetic pen and convert the electromagnetic wave signals into electrical signals; the first end of each transmitting coil is connected in parallel, and the second end of each transmitting coil is used to receive a driving signal; the electromagnetic chip is also used to output the driving signal and determine the contact position of the electromagnetic pen on the electromagnetic screen based on the detection signal.

[0014] The signal receiving circuit of this application embodiment includes a first-stage amplification unit comprising n-1 amplifiers, each amplifier connected to the second terminals of two adjacent receiving coils, and all amplifiers forming a differential chain structure. This provides sufficient amplification gain to amplify the electrical signals of the receiving coils, thereby improving the response speed of the electromagnetic screen to the electromagnetic pen. Furthermore, the signal receiving circuit can simultaneously acquire the detection signals from all receiving coils, enabling the electromagnetic screen to detect the positions of multiple electromagnetic pen touch points. Attached Figure Description

[0015] Figure 1 This is a schematic block diagram of an electromagnetic screen provided in an embodiment of this application.

[0016] Figure 2 This is a schematic block diagram of a signal receiving circuit provided in an embodiment of this application.

[0017] Figure 3 This is a schematic block diagram of another signal receiving circuit provided in an embodiment of this application.

[0018] Figure 4 This is a circuit diagram of a signal receiving circuit provided in an embodiment of this application.

[0019] Figure 5 This is a circuit diagram of the second signal receiving circuit provided in the embodiments of this application.

[0020] Figure 6 This is a circuit diagram of the third signal receiving circuit provided in the embodiments of this application.

[0021] Figure 7 This is a schematic block diagram of the third signal receiving circuit provided in the embodiments of this application. Detailed Implementation

[0022] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0023] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0024] Currently, electromagnetic input devices include electromagnetic screens and electromagnetic pens. The electromagnetic pen is charged by receiving electromagnetic waves radiated by the electromagnetic screen and sends a feedback signal back to the electromagnetic screen. The electromagnetic screen then detects the contact position of the electromagnetic pen based on the feedback signal. Finally, the two work together to complete the input operation of the electromagnetic input device.

[0025] However, the electromagnetic screens of existing electromagnetic input devices have a low response speed to electromagnetic pens and cannot detect multiple electromagnetic waves simultaneously.

[0026] This application provides a signal receiving circuit, an electromagnetic chip, and an electromagnetic screen for improving the response speed of the electromagnetic screen to an electromagnetic pen and for detecting multiple electromagnetic pens.

[0027] Please refer to Figure 1 , Figure 1 The present application provides a schematic block diagram of an electromagnetic screen 10, wherein the electromagnetic screen 10 includes multiple parallel transmitting coils TX (4 TX in the example in the figure) and multiple parallel receiving coils RX (5 RX in the example in the figure).

[0028] In this embodiment of the application, the transmitting coil TX and the receiving coil RX are orthogonal, and all transmitting coils TX are evenly distributed with the same distance between adjacent transmitting coils TX. Similarly, all receiving coils RX are evenly distributed with the same distance between adjacent receiving coils RX.

[0029] In this configuration, the first ends of each transmitting coil TX are connected in parallel, and the second end of each transmitting coil TX is used to receive the driving signal, converting the driving signal into electromagnetic waves that are radiated outward to charge the electromagnetic pen. After receiving the electromagnetic waves and being charged, the electromagnetic pen feeds back an electromagnetic wave signal to the electromagnetic screen 10, so that the electromagnetic screen 10 receives the electromagnetic wave signal through the receiving coil RX. The first ends of each receiving coil RX are connected in parallel, and the second end of each receiving coil RX is connected to a signal receiving circuit. The receiving coil RX is used to receive the electromagnetic wave signal from the electromagnetic pen and convert the electromagnetic wave signal into an electrical signal.

[0030] The electromagnetic screen 10 is used in various electromagnetic input devices, such as graphics tablets and handwriting tablets, and works in conjunction with an electromagnetic pen. The electromagnetic pen has a resonant circuit inside to receive electromagnetic waves radiated outward by the transmitting coil TX for charging, and then converts the electromagnetic waves into electromagnetic wave signals, which are fed back to the electromagnetic screen 10 through the receiving coil RX.

[0031] Please refer to Figure 2 , Figure 2 This is a schematic block diagram of a signal receiving circuit provided in an embodiment of this application. The signal receiving circuit 100 includes a first-stage amplifier unit 110.

[0032] In this embodiment, the input terminal of the first-stage amplification unit 110 is connected to the second terminal of each receiving coil RX. The first-stage amplification unit 110 is used to receive the electrical signal from each receiving coil RX, perform first-stage signal amplification processing on each electrical signal, and obtain multiple first amplified signals.

[0033] The first-stage amplification unit 110 includes n-1 amplifiers 111, where n is a positive integer greater than or equal to 2 (n=5 in the example in the figure). Each amplifier 111 is connected to the second end of two adjacent receiving coils RX, and all amplifiers 111 form a differential chain structure.

[0034] It is understood that the signal receiving circuit 100 in this embodiment of the application, by setting a first-stage amplification unit 110 including n-1 amplifiers 111, each amplifier 111 being connected to the second end of two adjacent receiving coils RX, and all amplifiers 111 forming a differential chain structure, can obtain sufficient amplification gain to amplify the electrical signal of the receiving coils RX, thereby improving the response speed of the electromagnetic screen to the electromagnetic pen. Furthermore, the signal receiving circuit 100 can simultaneously obtain the detection signals of all receiving coils, enabling the electromagnetic screen to detect the positions of multiple electromagnetic pen touch points.

[0035] Among them, amplifier 111 is a first operational amplifier. The non-inverting input terminal and the inverting input terminal of each first operational amplifier are respectively connected to the second terminals of two adjacent receiving coils. All the first operational amplifiers form a differential chain structure.

[0036] Please refer to Figure 3 , Figure 3 This is a schematic block diagram of another signal receiving circuit provided in an embodiment of this application. The signal receiving circuit 100 includes a first-stage amplification unit 110, a first isolation unit 120, and a second-stage amplification unit 130.

[0037] In this embodiment, the input terminal of the first-stage amplification unit 110 is connected to the second terminal of each receiving coil RX, the first terminal of the first isolation unit 120 is connected to the output terminal of the first-stage amplification unit 110, and the input terminal of the second-stage amplification unit 130 is connected to the second terminal of the first isolation unit 120.

[0038] The first-stage amplification unit 110 receives the electrical signal from each receiving coil RX, performs first-stage signal amplification on each signal, and obtains multiple first amplified signals. The first isolation unit 120 receives each first amplified signal and isolates it. The second-stage amplification unit 130 receives each isolated first amplified signal, performs second-stage signal amplification on each signal, and obtains multiple second amplified signals as detection signals, which are then output.

[0039] It is understood that the signal receiving circuit in this embodiment of the application, by setting a first-stage amplification unit and a second-stage amplification unit, can simultaneously amplify the electrical signals of all receiving coils RX to obtain a further sufficient amplification gain. Furthermore, the signal receiving circuit can simultaneously obtain the detection signals of all receiving coils RX, thereby enabling the electromagnetic screen to detect the positions of multiple electromagnetic pen contact points.

[0040] Please refer to Figure 4 , Figure 4 This is a circuit diagram of a signal receiving circuit 100 provided in an embodiment of this application. The electromagnetic screen 10 includes n parallel receiving coils RX, where n is a positive integer greater than or equal to 1 (n is shown as 5 in the figure). The signal receiving circuit 100 includes a first-stage amplification unit 110, a first isolation unit 120, and a second-stage amplification unit 130.

[0041] The first-stage amplification unit 110 includes n-1 first operational amplifiers U1, the second-stage amplification unit 130 includes n-1 second operational amplifiers U2, and the first isolation unit 120 includes multiple electrical isolation elements 121.

[0042] In this embodiment, the first operational amplifier U1 is a differential input single-ended output operational amplifier, and the second operational amplifier U2 is a single-ended input single-ended output operational amplifier. That is, the non-inverting and inverting input terminals of each first operational amplifier U1 are respectively connected to the second terminals of two adjacent receiving coils RX. All first operational amplifiers U1 form a differential chain structure. This differential chain structure can simultaneously receive electromagnetic signals from multiple electromagnetic pens, improving the common-mode interference immunity of the signal receiving circuit 100. Furthermore, it can simultaneously amplify the electrical signals of multiple receiving coil circuits without time-division amplification, resulting in a faster response.

[0043] The output of the first operational amplifier U1 is connected to the first terminal of one of the electrical isolation elements 121, meaning the first terminal of each electrical isolation element 121 is used to receive one of the first amplified signals. The second terminal of the electrical isolation element 121 is connected to the input of one of the second operational amplifiers U2, meaning the input of each second operational amplifier U2 is used to receive one of the first amplified signals. The output of the second operational amplifier U2 is used to output one of the operationally amplified second signals.

[0044] In some embodiments, the second terminal of the electrical isolation element 121 is connected to the non-inverting input terminal of one of the second operational amplifiers U2, and the inverting input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2 as a feedback terminal through a feedback resistor. Alternatively, the second terminal of the electrical isolation element 121 is connected to the inverting input terminal of one of the second operational amplifiers U2, and the inverting input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2 as a feedback terminal through a feedback resistor.

[0045] It is understandable that when the first operational amplifier U1 is a differential input single-ended output operational amplifier and the second operational amplifier U2 is a single-ended input single-ended output operational amplifier, the first operational amplifier U1 differentially amplifies the electrical signal, and the second operational amplifier U2 operationally amplifies the first amplified signal and then outputs it single-ended, thereby reducing the complexity of the signal receiving circuit 100 and thus reducing the manufacturing cost of the signal receiving circuit 100.

[0046] Please refer to Figure 5 , Figure 5 This is a circuit diagram of a second signal receiving circuit 100 provided in an embodiment of this application. The electromagnetic screen 10 includes n parallel receiving coils RX, where n is a positive integer greater than or equal to 1. The signal receiving circuit 100 includes a first-stage amplification unit 110, a first isolation unit 120, and a second-stage amplification unit 130.

[0047] The first-stage amplification unit 110 includes n-1 first operational amplifiers U1, the second-stage amplification unit 130 includes n-1 second operational amplifiers U2, and the first isolation unit 120 includes multiple electrical isolation elements 121.

[0048] In this embodiment of the application, the first operational amplifier U1 is a differential input differential output operational amplifier, and the second operational amplifier U2 is a differential input differential output operational amplifier.

[0049] Each first operational amplifier U1 has its non-inverting and inverting input terminals connected to the second terminals of two adjacent receiving coils RX, forming a differential chain structure. The non-inverting output terminal of each first operational amplifier U1 is connected to the non-inverting input terminal of one of the second operational amplifiers U2 via an electrical isolation element 121, and the inverting output terminal of each first operational amplifier U1 is connected to the corresponding inverting input terminal of the second operational amplifier U2 via an electrical isolation element 121. The non-inverting and inverting output terminals of the second operational amplifier U2 are used to output one of the second amplified signals.

[0050] It is understandable that when the first operational amplifier U1 is a differential input differential output operational amplifier and the second operational amplifier U2 is a differential input differential output operational amplifier, the first operational amplifier U1 differentially amplifies the electrical signal, and the second operational amplifier U2 differentially amplifies the first amplified signal again and outputs it differentially. This further improves the common-mode interference immunity of the signal receiving circuit 100, increases the dynamic range of the detection signal 100, and reduces the harmonic distortion of the detection signal. This further improves the response speed of the electromagnetic screen 10 to the electromagnetic pen and increases the detection accuracy of the electromagnetic pen contact position.

[0051] Please refer to Figure 6 , Figure 6 This is a circuit diagram of a third signal receiving circuit 100 provided in an embodiment of this application. The electromagnetic screen 10 includes n parallel receiving coils RX, where n is a positive integer greater than or equal to 1. The signal receiving circuit 100 includes a first-stage amplification unit 110, a first isolation unit 120, and a second-stage amplification unit 130.

[0052] The first-stage amplification unit 110 includes n-1 first operational amplifiers U1, the second-stage amplification unit 130 includes n-1 second operational amplifiers U2, and the first isolation unit 120 includes multiple electrical isolation elements 121.

[0053] In this embodiment of the application, the first operational amplifier U1 is a differential input differential output operational amplifier, and the second operational amplifier U2 is a differential input single-ended output operational amplifier.

[0054] Each first operational amplifier U1 has its non-inverting and inverting input terminals connected to the second terminals of two adjacent receiving coils RX, forming a differential chain structure. The non-inverting output terminal of each first operational amplifier U1 is connected to the non-inverting input terminal of one of the second operational amplifiers U2 via an electrical isolation element 121, and the inverting output terminal of each first operational amplifier U1 is connected to the corresponding inverting input terminal of the second operational amplifier U2 via an electrical isolation element 121. The output terminal of the second operational amplifier U2 is used to output the second amplified signal of one of the second operational amplifiers U2.

[0055] It is understandable that when the first operational amplifier U1 is a differential input differential output operational amplifier and the second operational amplifier U2 is a differential input single-ended output operational amplifier, the first operational amplifier U1 differentially amplifies the electrical signal, and the second operational amplifier U2 differentially amplifies the first amplified signal again before single-ended output, so as to further improve the common-mode interference immunity of the signal receiving circuit 100 and reduce the complexity of the signal receiving circuit 100. This improves the response speed of the electromagnetic screen 10 to the electromagnetic pen and the detection accuracy of the electromagnetic pen touch position while taking into account the manufacturing cost of the signal receiving circuit 100.

[0056] In any of the above embodiments, the electrical isolation element 121 is a capacitor, a resistor, or a buffer.

[0057] Please refer to Figure 7 , Figure 7 This is a schematic block diagram of a third signal receiving circuit 100 provided in an embodiment of this application. Wherein, with Figure 3 Compared to the signal receiving circuit 100 shown, the difference lies in that, Figure 7 The signal receiving circuit 100 shown also includes a second isolation unit 140 and a third-stage amplification unit 150.

[0058] The first end of the second isolation unit 140 is connected to the output end of the second stage amplification unit 130, and the input end of the third stage amplification unit 150 is connected to the second end of the second isolation unit 140.

[0059] In this embodiment, the second isolation unit 140 is used to receive each second amplified signal and isolate each second amplified signal. The third amplification unit 150 is used to receive each second amplified signal after isolation processing, perform third-level signal amplification processing on each second amplified signal, obtain multiple third amplified signals as detection signals, and output them.

[0060] It is understood that when the signal gain of the signal receiving circuit 100 in any of the above embodiments is insufficient for detecting the position of the electromagnetic pen contact, the number of signal amplification stages can be further increased, such as the three-stage amplification in the embodiments of this application. In some embodiments, four-stage amplification, five-stage amplification, and more signal amplification stages can also be provided.

[0061] This application also provides an electromagnetic chip, which includes the signal receiving circuit 100 of any of the above embodiments. Furthermore, this application also provides an electromagnetic screen, which includes multiple parallel receiving coils RX, multiple parallel transmitting coils, and the electromagnetic chip.

[0062] In this embodiment, the receiving coil RX is orthogonal to the transmitting coil, and the first end of each receiving coil RX is connected in parallel. The receiving coil RX is used to receive the electromagnetic wave signal from the electromagnetic pen and convert the electromagnetic wave signal into an electrical signal. The first end of each transmitting coil is connected in parallel, and the second end of each transmitting coil is used to receive the drive signal. The electromagnetic chip is also used to output the drive signal and determine the contact position of the electromagnetic pen on the electromagnetic screen based on the detection signal.

[0063] It is understood that the beneficial effects of the electromagnetic chip and electromagnetic screen can be referred to the beneficial effects of the signal receiving circuit 100 in the foregoing embodiment, and will not be repeated here.

[0064] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A signal receiving circuit for an electromagnetic screen, characterized in that, The electromagnetic screen includes n parallel receiving coils, with the first end of each receiving coil connected in parallel. The receiving coils are used to receive electromagnetic wave signals from the electromagnetic pen and convert the electromagnetic wave signals into electrical signals. The signal receiving circuit includes a first-stage amplification unit, the input of which is connected to the second end of each receiving coil. The first-stage amplification unit is used to receive the electrical signal of each of the receiving coils, and to perform first-stage signal amplification processing on each of the electrical signals to obtain multiple first amplified signals; The first-stage amplification unit includes n-1 amplifiers, where n is a positive integer greater than or equal to 2; Each of the amplifiers is connected to the second end of two adjacent receiving coils, and all the amplifiers form a differential chain structure.

2. The signal receiving circuit as described in claim 1, characterized in that, The amplifier is a first operational amplifier. The non-inverting input terminal and the inverting input terminal of each first operational amplifier are respectively connected to the second terminals of two adjacent receiving coils. All the first operational amplifiers form a differential chain structure.

3. The signal receiving circuit as described in claim 2, characterized in that, The signal receiving circuit further includes a first isolation unit and a second-stage amplification unit. The first end of the first isolation unit is connected to the output end of the first-stage amplification unit, and the input end of the second-stage amplification unit is connected to the second end of the first isolation unit. The first isolation unit is used to receive each of the first amplified signals and to isolate and process each of the first amplified signals. The second-stage amplification unit is used to receive each of the first amplified signals after isolation processing, perform second-stage signal amplification processing on each of the first amplified signals, obtain multiple second amplified signals as detection signals and output them.

4. The signal receiving circuit as described in claim 3, characterized in that, The second-stage amplification unit includes n-1 second operational amplifiers, each of which receives one of the first amplified signals at its input.

5. The signal receiving circuit as described in claim 4, characterized in that, The first operational amplifier is a differential input single-ended output operational amplifier, and the second operational amplifier is a single-ended input single-ended output operational amplifier.

6. The signal receiving circuit as described in claim 4, characterized in that, The first operational amplifier is a differential input differential output operational amplifier; the second operational amplifier is a differential input differential output operational amplifier, or a differential input single-ended output operational amplifier.

7. The signal receiving circuit as described in claim 3, characterized in that, The first isolation unit includes multiple electrical isolation elements, each of which has a first end for receiving one of the first amplified signals and a second end for connecting to the second stage amplification unit; the electrical isolation elements are capacitors, resistors, or buffers.

8. The signal receiving circuit as described in claim 7, characterized in that, It also includes a second isolation unit and a third-stage amplification unit. The first end of the second isolation unit is connected to the output end of the second-stage amplification unit, and the input end of the third-stage amplification unit is connected to the second end of the second isolation unit. The second isolation unit is used to receive each of the second amplified signals and to isolate and process each of the second amplified signals. The third-stage amplification unit is used to receive each of the second amplified signals after isolation processing, perform third-stage signal amplification processing on each of the second amplified signals, obtain multiple third amplified signals as detection signals and output them.

9. An electromagnetic chip, characterized in that, Includes the signal receiving circuit as described in any one of claims 1 to 8.

10. An electromagnetic screen, characterized in that, It includes multiple parallel receiving coils, multiple parallel transmitting coils, and the electromagnetic chip as described in claim 9; The receiving coil is orthogonal to the transmitting coil, and the first end of each receiving coil is connected in parallel. The receiving coil is used to receive the electromagnetic wave signal of the electromagnetic pen and convert the electromagnetic wave signal into an electrical signal. The first end of each transmitting coil is connected in parallel, and the second end of each transmitting coil is used to receive the driving signal. The electromagnetic chip is also used to output the driving signal and determine the contact position of the electromagnetic pen on the electromagnetic screen based on the detection signal.