Infrared signal conditioning circuit, infrared signal processing circuit, infrared touch screen and touch equipment

Abstract

The utility model provides an infrared signal conditioning circuit, a processing circuit, an infrared touch screen and touch equipment. The conditioning circuit comprises a voltage following module, a transmitting tube switch module and at least one current amplification module, the input end of the voltage following module is used for accessing digital-to-analog conversion output signals of the control module, the output end of the voltage following module is connected with the controlled end of the current amplification module, the input end of the current amplification module is used for being connected with the output end of the infrared signal transmitting circuit, and the output end of the current amplification module is grounded. The controlled end of the transmitting tube switch module is connected with the control end of the control module, the input end of the transmitting tube switch module is connected with the input end of the voltage following module, and the output end is grounded; the voltage following module comprises an operational amplifier and a first triode. The inverted input end of the operational amplifier is connected with the emitter of the first triode. According to the utility model, the emitter voltage of the first triode is consistent with the input voltage of the in-phase input end of the operational amplifier, so that the current regulation precision of the infrared transmitting tube is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of touch screens, in particular to an infrared signal conditioning circuit, a processing circuit, an infrared touch screen and a touch device. Background Art

[0002] During the use of an infrared touch frame, it is usually necessary to adjust the current of an infrared emitting tube. As shown in the existing infrared signal conditioning circuit Figure 1 it forms a voltage follower by using an operational amplifier UAB, forms an emitter follower by using a triode QA1, a resistor RA1, a resistor RA2 and a resistor RA3, forms a triode current amplification circuit by using a resistor RA4 and a triode QA2, and forms a total emitter switch by using a resistor RA5 and a field effect transistor QA3. By adjusting the input voltage of the non-inverting input terminal of the operational amplifier UAB, the adjustment of the current of the infrared emitting tube can be realized, and the collector current of the triode QA2 is the adjusted current of the infrared emitting tube. The magnitude of the collector current of the triode QA2 is affected by its own Vbe voltage drop and the emitter voltage of the triode QA1. However, the emitter voltage of the triode QA1 cannot be consistent with the input voltage of the non-inverting input terminal of the operational amplifier UAB due to its own Vbe voltage drop loss, which affects the adjustment accuracy of the current of the infrared emitting tube and the touch recognition sensitivity of the touch screen. Summary of the Utility Model

[0003] The utility model provides an infrared signal conditioning circuit, a processing circuit, an infrared touch screen and a touch device. By connecting the inverting input terminal of the operational amplifier to the emitter of the first triode to form a voltage follower module, the emitter voltage of the first triode is made consistent with the input voltage of the non-inverting input terminal of the operational amplifier, ensuring the adjustment accuracy of the current of the infrared emitting tube and the touch recognition sensitivity of the touch screen.

[0004] To solve the above technical problems, in the first aspect of the embodiments of the utility model, an infrared signal conditioning circuit is provided, including a voltage follower module, an emitter switch module and at least one current amplification module;

[0005] The input terminal of the voltage follower module is used to access the digital-to-analog conversion output signal of the control module. The output terminal of the voltage follower module is connected to the controlled terminal of the current amplification module. The input terminal of the current amplification module is used to be connected to the output terminal of the infrared signal transmitting circuit. The output terminal of the current amplification module is grounded. The controlled terminal of the emitter switch module is used to be connected to the control terminal of the control module. The input terminal of the emitter switch module is connected to the input terminal of the voltage follower module. The output terminal of the emitter switch module is grounded;

[0006] The voltage follower module includes an operational amplifier and a first triode, and the inverting input terminal of the operational amplifier is connected to the emitter of the first triode.

[0007] As a preferred solution, the voltage follower module further includes a diode and a first resistor;

[0008] The non-inverting input terminal of the operational amplifier is used to access the digital-to-analog conversion output signal, the output terminal of the operational amplifier is connected to the base of the first triode, the collector of the first triode is used to be connected to a voltage source, one end of the first resistor is connected to the emitter of the first triode, the other end of the first resistor is grounded, the cathode of the diode is connected between the output terminal of the operational amplifier and the base of the first triode, and the anode of the diode is connected between the inverting input terminal of the operational amplifier and the emitter of the first triode.

[0009] As a preferred solution, the emitter tube switch module includes a switch tube, a second resistor and a third resistor;

[0010] The controlled terminal of the switch tube is used to be connected to the control terminal of the control module, the input terminal of the switch tube is connected to one end of the second resistor, the other end of the second resistor is connected to the input terminal of the voltage follower module, the output terminal of the switch tube is grounded, one end of the third resistor is connected to the controlled terminal of the switch tube, and the other end of the third resistor is connected to the output terminal of the switch tube.

[0011] As a preferred solution, the current amplification module includes a fourth resistor, a fifth resistor and a second triode;

[0012] One end of the fourth resistor is connected to the output terminal of the voltage follower module, the other end of the fourth resistor is connected to the controlled terminal of the second triode, the input terminal of the second triode is used to be connected to the output terminal of the infrared signal transmitting circuit, the output terminal of the second triode is grounded, one end of the fifth resistor is connected to the controlled terminal of the second triode, and the other end of the fifth resistor is connected to the output terminal of the second triode.

[0013] As a preferred solution, the number of the current amplification modules is greater than or equal to 2, and each of the current amplification modules is arranged in parallel.

[0014] As a preferred solution, the switch tube is specifically an N-type MOS tube.

[0015] As a preferred solution, both the first triode and the second triode are NPN-type triodes.

[0016] In the second aspect of the embodiments of the present utility model, an infrared signal processing circuit is provided, which includes an infrared signal transmitting circuit, a control module, and the infrared signal conditioning circuit as described in any one of the first aspects.

[0017] In the third aspect of the embodiments of the present utility model, an infrared touch screen is provided, which includes the infrared signal processing circuit as described in the second aspect.

[0018] In the fourth aspect of the embodiments of the present utility model, a touch device is provided, which includes the infrared touch screen as described in the third aspect.

[0019] Compared with the prior art, the beneficial effect of the embodiments of the present utility model is that by connecting the inverting input terminal of the operational amplifier to the emitter of the first triode to form a voltage follower module, the emitter voltage of the first triode is made to be consistent with the input voltage of the non-inverting input terminal of the operational amplifier, ensuring the adjustment accuracy of the infrared emitting tube current and the touch recognition sensitivity of the touch screen. Description of the Drawings

[0020] Figure 1 is a schematic circuit connection diagram of an infrared signal conditioning circuit in the prior art;

[0021] Figure 2 is a schematic circuit connection diagram of the infrared signal conditioning circuit in the embodiments of the present utility model;

[0022] Figure 3 is a schematic circuit connection diagram of the infrared signal conditioning circuit when multiple boards are cascaded in the embodiments of the present utility model;

[0023] Figure 4 is a schematic circuit connection diagram of the infrared signal conditioning circuit when multiple boards are cascaded in the prior art. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present utility model more thorough and comprehensive. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0025] In the description of this application, the terms "first", "second", "third", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0026] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are only for the purpose of illustration and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] In the description of this application, it should be noted that unless otherwise defined, all technical and scientific terms used in this utility model have the same meaning as commonly understood by those of ordinary skill in the technical field to which this belongs. The terms used in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] See Figure 2 , a first aspect of the embodiment of this utility model provides an infrared signal conditioning circuit, including a voltage follower module, a transmitting tube switching module, and at least one current amplification module;

[0029] The input end of the voltage follower module is used to access the digital-to-analog conversion output signal of the control module. The output end of the voltage follower module is connected to the controlled end of the current amplification module. The input end of the current amplification module is used to be connected to the output end of the infrared signal transmitting circuit. The output end of the current amplification module is grounded. The controlled end of the transmitting tube switching module is used to be connected to the control end of the control module. The input end of the transmitting tube switching module is connected to the input end of the voltage follower module. The output end of the transmitting tube switching module is grounded;

[0030] The voltage follower module includes an operational amplifier U1 and a first triode Q1, and the inverting input terminal of the operational amplifier U1 is connected to the emitter of the first triode Q1.

[0031] Specifically, the control module in this embodiment is specifically an MCU, that is, a micro control unit, and the digital-to-analog converter configured therein continuously outputs different small currents. When the infrared emitting tube is not working, the emitter switch module is in a conducting state, and it discharges the digital-to-analog conversion output signal of the control module to the ground terminal. The digital-to-analog converter configured in the control module does not need to output current only when the infrared emitting tube is working. It can continuously output different small currents throughout the scanning cycle even when the infrared emitting tube is not working, so as to improve the scanning frequency of the infrared touch screen and ensure the touch recognition effect. When the infrared emitting tube is working, the emitter switch module is in a cut-off state. Therefore, the digital-to-analog conversion output signal flows through the voltage follower module and into the current amplification module, so that the current amplification module amplifies the flowing current, thereby realizing the adjustment of the current of the infrared emitting tube. It should be noted that since in the voltage follower module, the inverting input terminal of the operational amplifier U1 is connected to the emitter of the first triode Q1, the voltage at the emitter of the first triode Q1 is equal to the voltage at the non-inverting input terminal of the operational amplifier U1, without being affected by its own Vbe voltage drop loss, effectively ensuring the adjustment accuracy of the current of the infrared emitting tube and the touch recognition sensitivity of the touch screen.

[0032] As a preferred solution, the voltage follower module further includes a diode and a first resistor R1;

[0033] The non-inverting input terminal of the operational amplifier U1 is used to access the digital-to-analog conversion output signal, the output terminal of the operational amplifier U1 is connected to the base of the first triode Q1, the collector of the first triode Q1 is used to be connected to a voltage source, one end of the first resistor R1 is connected to the emitter of the first triode Q1, the other end of the first resistor R1 is grounded, the cathode of the diode is connected between the output terminal of the operational amplifier U1 and the base of the first triode Q1, and the anode of the diode is connected between the inverting input terminal of the operational amplifier U1 and the emitter of the first triode Q1.

[0034] Specifically, in this embodiment, the digital-to-analog conversion output signal is connected to the non-inverting input terminal of the operational amplifier U1, its output terminal is connected to the base of the first triode Q1, and its inverting input terminal is connected to the emitter of the first triode Q1. Thus, the voltage at the emitter of the first triode Q1 is equal to the voltage at the non-inverting input terminal of the operational amplifier U1. And the current of the infrared emitting diode after being adjusted by the current amplification module is affected by the voltage at the emitter of the first triode Q1. Therefore, by adjusting the input voltage at the non-inverting input terminal of the operational amplifier U1, the adjustment of the current of the infrared emitting diode can be achieved. In addition, by setting the diode, it can prevent a reverse high voltage from being applied to the emitter of the first triode Q1 and prevent the emitter from being broken down.

[0035] As a preferred solution, the emitter switch module includes a switching transistor Q3, a second resistor R2, and a third resistor R3;

[0036] The controlled terminal of the switching transistor Q3 is used to be connected to the control terminal of the control module. The input terminal of the switching transistor Q3 is connected to one end of the second resistor R2. The other end of the second resistor R2 is connected to the input terminal of the voltage follower module. The output terminal of the switching transistor Q3 is grounded. One end of the third resistor R3 is connected to the controlled terminal of the switching transistor Q3, and the other end of the third resistor R3 is connected to the output terminal of the switching transistor Q3.

[0037] Specifically, when the infrared emitting diode is not working, the switching transistor Q3 is in the conducting state, which discharges the digital-to-analog conversion output signal of the control module to the ground terminal. And the digital-to-analog converter configured by the control module does not need to output current only when the infrared emitting diode is working. It can continuously output different small currents throughout the scanning cycle even when the infrared emitting diode is not working, thereby being able to increase the scanning frequency of the infrared touch screen and ensure the touch recognition effect. When the infrared emitting diode is working, the switching transistor Q3 is in the cut-off state. Therefore, the digital-to-analog conversion output signal flows through the voltage follower module and into the current amplification module, enabling the current amplification module to amplify the incoming current, thus achieving the adjustment of the current of the infrared emitting diode.

[0038] As a preferred solution, the current amplification module includes a fourth resistor R4, a fifth resistor R5, and a second triode Q2;

[0039] One end of the fourth resistor R4 is connected to the output terminal of the voltage follower module. The other end of the fourth resistor R4 is connected to the controlled terminal of the second triode Q2. The input terminal of the second triode Q2 is used to be connected to the output terminal of the infrared signal emitting circuit. The output terminal of the second triode Q2 is grounded. One end of the fifth resistor R5 is connected to the controlled terminal of the second triode Q2, and the other end of the fifth resistor R5 is connected to the output terminal of the second triode Q2.

[0040] Specifically, the current amplification module in this embodiment consists of a fourth resistor R4, a fifth resistor R5, and a second triode Q2. Thus, the collector current of the second triode Q2 is equal to the input voltage of the voltage follower module multiplied by [R5 / (R4 + R5)], and then multiplied by the current gain of the second triode Q2, which is also the adjusted current magnitude of the infrared emitting tube.

[0041] See Figure 3 As a preferred solution, the number of the current amplification modules is greater than or equal to 2, and each of the current amplification modules is arranged in parallel.

[0042] It should be noted that there are usually multiple emitter plates in an infrared touch frame, and an infrared signal conditioning circuit needs to be configured on each emitter plate. When multiple plates are cascaded, the circuit connection diagram in the prior art is as shown in Figure 4 As shown, it needs to configure an emitter follower, an emitter tube total switch, and a triode current amplification circuit on each emitter plate, while in this embodiment, only one current amplification module needs to be configured in the subsequent cascaded emitter plates. Compared with the prior art, this embodiment reduces the setting of one triode and one field effect transistor in the subsequent cascaded emitter plates, greatly simplifying the structural complexity of the infrared signal conditioning circuit when multiple plates are cascaded.

[0043] As a preferred solution, the switching transistor Q3 is specifically an N-type MOS transistor.

[0044] As a preferred solution, both the first triode Q1 and the second triode Q2 are NPN-type triodes.

[0045] The infrared signal conditioning circuit provided by the embodiment of the present invention forms a voltage follower module by connecting the inverting input terminal of the operational amplifier U1 to the emitter of the first triode Q1, so that the emitter voltage of the first triode Q1 is kept consistent with the input voltage of the non-inverting input terminal of the operational amplifier U1, ensuring the adjustment accuracy of the infrared emitting tube current and the touch recognition sensitivity of the touch screen.

[0046] The second aspect of the embodiment of the present invention provides an infrared signal processing circuit, including an infrared signal transmitting circuit, a control module, and the infrared signal conditioning circuit as described in any embodiment of the first aspect.

[0047] Specifically, the controlled terminal of the infrared signal transmitting circuit is connected to the control terminal of the control module. The infrared signal transmitting circuit further includes an infrared emitting diode array, an NPN-type triode array corresponding to the infrared emitting diode array one by one, and a decoder. The emitters of the triodes in the NPN-type triode array are connected to the input terminals of the current amplification modules in the infrared signal conditioning circuit.

[0048] The third aspect of the embodiment of the present utility model provides an infrared touch screen, including the infrared signal processing circuit as described in the second aspect.

[0049] The fourth aspect of the embodiment of the present utility model provides a touch device, including the infrared touch screen as described in the third aspect.

[0050] For the infrared signal conditioning circuit, processing circuit, infrared touch screen and touch device provided by the embodiment of the present utility model, by connecting the inverting input terminal of the operational amplifier to the emitter of the first triode to form a voltage follower module, the emitter voltage of the first triode is made to be consistent with the input voltage of the non-inverting input terminal of the operational amplifier, ensuring the adjustment accuracy of the infrared emitting tube current and the touch recognition sensitivity of the touch screen.

[0051] The above is the preferred embodiment of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present utility model.

Claims

1. An infrared signal conditioning circuit, characterized in that, It includes a voltage follower module, a transmitting tube switch module, and at least one current amplification module; The input end of the voltage follower module is used to access the digital-to-analog conversion output signal of the control module. The output end of the voltage follower module is connected to the controlled end of the current amplification module. The input end of the current amplification module is used to be connected to the output end of the infrared signal transmitting circuit. The output end of the current amplification module is grounded. The controlled end of the transmitting tube switch module is used to be connected to the control end of the control module. The input end of the transmitting tube switch module is connected to the input end of the voltage follower module. The output end of the transmitting tube switch module is grounded; The voltage follower module includes an operational amplifier and a first triode. The inverting input end of the operational amplifier is connected to the emitter of the first triode.

2. The infrared signal conditioning circuit according to claim 1, wherein The voltage follower module further includes a diode and a first resistor; The non-inverting input end of the operational amplifier is used to access the digital-to-analog conversion output signal. The output end of the operational amplifier is connected to the base of the first triode. The collector of the first triode is used to be connected to a voltage source. One end of the first resistor is connected to the emitter of the first triode. The other end of the first resistor is grounded. The cathode of the diode is connected between the output end of the operational amplifier and the base of the first triode. The anode of the diode is connected between the inverting input end of the operational amplifier and the emitter of the first triode.

3. The infrared signal conditioning circuit according to claim 1, characterized in that, The transmitting tube switch module includes a switching tube, a second resistor, and a third resistor; The controlled end of the switching tube is used to be connected to the control end of the control module. The input end of the switching tube is connected to one end of the second resistor. The other end of the second resistor is connected to the input end of the voltage follower module. The output end of the switching tube is grounded. One end of the third resistor is connected to the controlled end of the switching tube. The other end of the third resistor is connected to the output end of the switching tube.

4. The infrared signal conditioning circuit according to claim 1, characterized in that, The current amplification module includes a fourth resistor, a fifth resistor, and a second triode; One end of the fourth resistor is connected to the output end of the voltage follower module. The other end of the fourth resistor is connected to the controlled end of the second triode. The input end of the second triode is used to be connected to the output end of the infrared signal transmitting circuit. The output end of the second triode is grounded. One end of the fifth resistor is connected to the controlled end of the second triode. The other end of the fifth resistor is connected to the output end of the second triode.

5. The infrared signal conditioning circuit according to claim 1, wherein The number of the current amplification modules is greater than or equal to 2, and each of the current amplification modules is arranged in parallel.

6. The infrared signal conditioning circuit according to claim 3, wherein The switching tube is specifically an N-type MOS tube.

7. The infrared signal conditioning circuit according to claim 4, characterized in that Both the first triode and the second triode are NPN-type triodes.

8. An infrared signal processing circuit, characterized in that, It includes an infrared signal transmitting circuit, a control module, and the infrared signal conditioning circuit according to any one of claims 1 to 7.

9. An infrared touch screen, characterized in that, It includes the infrared signal processing circuit according to claim 8.

10. A touch device, characterized in that, It includes the infrared touch screen according to claim 9.

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