Scanning circuit based on two hardware analog switches

Abstract

The utility model belongs to the technical field of integrated circuits, and particularly relates to a scanning circuit based on two hardware analog switches, which comprises a pressure sensor matrix, a microprocessor, an upper connection scanning circuit, a lower connection scanning circuit and a data acquisition module. The up-connection scanning circuit comprises an up-connection analog switch, an input port and an output port are respectively connected with row terminals of the pressure sensor matrix, a common end is grounded, and a channel selection end is connected with the microprocessor; the lower scanning circuit comprises a lower analog switch, an input port and an output port are respectively connected with column terminals of the pressure sensor matrix through divider resistors, a common end is connected with a reference level, and a channel selection end is connected with the microprocessor; the input end of the data acquisition module is connected between the divider resistors and the pressure sensor matrix, and the output end of the data acquisition module is connected with the microprocessor. According to the utility model, the microprocessor can realize pressure signal acquisition of the pressure sensor matrix only by using few IO ports.

Description

Technical Field

[0001] The utility model belongs to the technical field of integrated circuits, and in particular relates to a scanning circuit based on two-way hardware analog switches. Background Art

[0002] With the increasing popularity of smart homes, smart floors have also emerged. In the prior art, pressure sensors are usually laid inside smart floors to monitor pressure information. Since the floor is usually laid over a large area, there are a large number of pressure sensors distributed on the smart floor, which are usually arranged inside the smart floor in an N*N matrix. If each sensor samples separately, the MCU needs enough IO ports to connect each sensor, which places extremely high requirements on the MCU's resources, undoubtedly increasing the cost and the difficulty of circuit layout and wiring. Utility Model Content

[0003] The utility model aims to solve the technical problems in the prior art that a large number of pressure sensors increases the interface resources of the MCU, resulting in high cost of the smart floor and complex circuit layout and wiring, and aims to provide a scanning circuit based on a two-way hardware analog switch.

[0004] In order to solve the above technical problems, the first aspect of the utility model provides a scanning circuit based on a two-way hardware analog switch, the scanning circuit based on the two-way hardware analog switch includes a pressure sensor matrix and a microprocessor, and the scanning circuit based on the two-way hardware analog switch also includes an upper scanning circuit, a lower scanning circuit and a data acquisition module;

[0005] The upper scanning circuit comprises:

[0006] An analog switch is connected to the upper part, the input and output ports of the analog switch are respectively connected to the row terminals of the pressure sensor matrix, the common end of the analog switch is grounded, and the channel selection end of the analog switch is connected to the microprocessor;

[0007] The bottom scanning circuit comprises:

[0008] An analog switch is connected to the bottom, the input and output ports of the analog switch are connected to the column terminals of the pressure sensor matrix via voltage-dividing resistors, the common end of the analog switch is connected to a reference level, and the channel selection end of the analog switch is connected to the microprocessor;

[0009] The input end of the data acquisition module is connected between each of the voltage-dividing resistors and the pressure sensor matrix, and the output end of the data acquisition module is connected to the microprocessor.

[0010] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the scanning circuit based on two-way hardware analog switches further includes an interface component, and the interface component includes:

[0011] An upper connection interface, the upper connection interface is connected to the input and output ports of the upper connection analog switch, and the upper connection interface is plugged into the row terminals of the pressure sensor matrix;

[0012] A lower connection interface is connected to the input and output ports of the lower connection analog switch via the voltage-dividing resistors, and the lower connection interface is connected to the column terminals of the pressure sensor matrix.

[0013] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the interface component further includes:

[0014] A control interface, wherein the control interface is connected to each control terminal and data output terminal of the data acquisition module, and the control interface is plugged into an interface of the microprocessor.

[0015] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the interface component further includes:

[0016] A data acquisition pin header, wherein the data acquisition pin header is connected between each of the voltage-dividing resistors and the pressure sensor matrix;

[0017] A data acquisition interface, wherein the data acquisition interface is connected to a data input end of the data acquisition module and is plugged into the data acquisition pin header.

[0018] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the upper analog switch and the lower analog switch both use CD4051 series chips, preferably CD4051BM / TR chips.

[0019] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the data acquisition module uses AD7606 series chips, preferably AD7606BSTZ chips.

[0020] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the scanning circuit based on two-way hardware analog switches also includes a power supply module for powering the circuit, the power supply module provides 5V voltage power supply, and the power supply module also provides 3.3V voltage power supply through a linear regulator.

[0021] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the linear regulator adopts an LDO chip.

[0022] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the upper analog switches in the upper scanning circuit are multiple, and two of the upper analog switches form a group;

[0023] The upper scanning circuit also includes:

[0024] An upper reverse module is connected, a signal input end of the upper reverse module is connected to the microprocessor, a signal output end of the upper reverse module is connected to a chip select end of one of the upper analog switches in a group, and a common end between the upper reverse module and the microprocessor is connected to a chip select end of another of the upper analog switches in a group;

[0025] The number of the lower analog switches in the lower scanning circuit is several, and two lower analog switches form a group;

[0026] The bottom scanning circuit also includes:

[0027] A lower reverse module is connected, a signal input end of the lower reverse module is connected to the microprocessor, a signal output end of the lower reverse module is connected to a chip select end of one of the lower analog switches in a group, and a common end between the lower reverse module and the microprocessor is connected to a chip select end of another of the lower analog switches in a group.

[0028] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, there are several data acquisition modules, two of which form a group, the two data acquisition modules in a group are connected in parallel, and the input ends of the two data acquisition modules in a group are respectively connected between the voltage-dividing resistors connected to the two lower analog switches in a group and the pressure sensor matrix.

[0029] Optionally, in the scanning circuit based on two-way hardware analog switches as described above, the upper reverse module and the lower reverse module both use SN74LVC1G14 series chips, preferably SN74LVC1G14DEVR chips.

[0030] The positive and progressive effects of the utility model are:

[0031] 1. The utility model adopts an upper scanning circuit, a lower scanning circuit and a data acquisition module to perform chip selection scanning and sampling on the pressure sensor matrix. The microprocessor only needs a few IO ports to realize the pressure signal acquisition of the pressure sensor matrix. The larger the pressure sensor matrix, the more significant the advantage of saving microprocessor resources.

[0032] 2. The utility model realizes the plug-in connection between the modules through the interface assembly, which is convenient for circuit layout, connection and maintenance.

[0033] 3. The scanning circuit of the utility model has the advantages of low cost, simple and clear circuit layout, and low wiring difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The disclosure of the present invention will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings:

[0035] Figure 1 It is an overall connection schematic diagram of the utility model;

[0036] Figure 2 A circuit diagram of the utility model connected to a scanning circuit;

[0037] Figure 3 A circuit diagram of the utility model connected to the scanning circuit;

[0038] Figure 4 A circuit diagram of the data acquisition module of the utility model;

[0039] Figure 5 A structural schematic diagram of the upper connection interface of the utility model;

[0040] Figure 6 A structural schematic diagram of the lower connection interface and data acquisition pin header of the utility model;

[0041] Figure 7 A structural schematic diagram of the control interface of the utility model;

[0042] Figure 8 The utility model is a circuit diagram of a power module. DETAILED DESCRIPTION

[0043] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] It should be noted that the following embodiments and features therein may be combined with each other if there is no conflict.

[0045] In the description of the present invention, it should be noted that directional words such as the terms "outside", "middle", "inside", "outside", etc., which indicate directions and positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "several" and "a number" is two or more, unless otherwise clearly and specifically defined.

[0047] Reference Figure 1 The utility model provides a scanning circuit based on two-way hardware analog switches, which includes a pressure sensor matrix 1, a microprocessor 2 (MCU), an upper scanning circuit 3, a lower scanning circuit 4 and a data acquisition module 5 (ADC module).

[0048] The pressure sensor matrix 1 is an N*N pressure sensor matrix 1, where N is usually a natural number greater than 1. In the prior art, the pressure sensor matrix 1 usually has row terminals and column terminals for connection. Therefore, the pressure sensor matrix 1 of the present invention can directly adopt the prior art.

[0049] The microprocessor 2 is used to control the channel selection of the upper scanning circuit 3 and the lower scanning circuit 4, and is also used to control the data acquisition work of the data acquisition module. One selection of the microprocessor 2 is to use STM32F407VET6.

[0050] The upper scanning circuit includes an upper analog switch, the input and output ports of the upper analog switch are respectively connected to the row terminals of the pressure sensor matrix, the common end of the upper analog switch is grounded, and the channel selection end of the upper analog switch is connected to the microprocessor.

[0051] The lower scanning circuit includes a lower analog switch, the input and output ports of the lower analog switch are respectively connected to the column terminals of the pressure sensor matrix through voltage divider resistors, the common end of the lower analog switch is connected to the reference level, and the channel selection end of the lower analog switch is connected to the microprocessor.

[0052] The input end of the data acquisition module is connected between each voltage-dividing resistor and the pressure sensor matrix, and the output end of the data acquisition module is connected to the microprocessor.

[0053] The upper analog switch and the lower analog switch of the utility model are controlled by a microprocessor respectively, so as to realize the function of opening one channel in the multi-channel signal channel and closing the other channels. After one channel is opened, the pressure sensor is divided by the voltage dividing resistor, and the common end between the two is led out as the ADC sampling end to the data acquisition module for sampling and sent to the processor, so as to realize the purpose of scanning and sampling of the pressure sensor matrix.

[0054] The utility model forms a collection circuit of a matrix sensor through an upper scanning circuit and a lower scanning circuit, thereby realizing simultaneous row and column scanning and redundant processing.

[0055] In some embodiments, there are several upper analog switches in the upper scanning circuit, and two upper analog switches form a group. In this case, the upper scanning circuit also includes an upper reverse module, the signal input end of the upper reverse module is connected to the microprocessor, the signal output end of the upper reverse module is connected to the chip select end of one of the upper analog switches in the group, and the common end between the upper reverse module and the microprocessor is connected to the chip select end of another upper analog switch in the group.

[0056] There are several lower-connected analog switches in the lower-connected scanning circuit, and two lower-connected analog switches form a group. At this time, the lower-connected scanning circuit also includes a lower-connected reverse module, the signal input end of the lower-connected reverse module is connected to the microprocessor, the signal output end of the lower-connected reverse module is connected to the chip select end of one lower-connected analog switch in the group, and the common end between the lower-connected reverse module and the microprocessor is connected to the chip select end of another lower-connected analog switch in the group.

[0057] The number M of input and output ports of the upper analog switch and the lower analog switch (M is usually a natural number greater than 1) is limited. When N (N is usually a natural number greater than 1) in the N*N pressure sensor matrix is ​​greater than M, one upper analog switch and one lower analog switch obviously cannot meet the connection requirements of the pressure sensor matrix.

[0058] Therefore, this embodiment matches multiple upper analog switches and multiple lower analog switches according to the size of the pressure sensor matrix to ensure that the multiple upper analog switches can be respectively connected to the row terminals of the pressure sensor matrix, and the multiple lower analog switches can be respectively connected to the column terminals of the pressure sensor matrix.

[0059] In the case where there are multiple upper analog switches and multiple lower analog switches, this embodiment uses an upper reverse module to implement chip selection for two upper analog switches in a group, and uses a lower reverse module to implement chip selection for two lower analog switches in a group.

[0060] In some embodiments, there are several data acquisition modules, two data acquisition modules form a group, the two data acquisition modules in a group are connected in parallel, and the input ends of the two data acquisition modules in a group are respectively connected between two voltage-dividing resistors connected to the analog switches in a group and the pressure sensor matrix.

[0061] When the number of input terminals of the data acquisition module is insufficient, multi-channel synchronous sampling can be achieved by connecting two data acquisition modules in parallel.

[0062] In some embodiments, both the upper analog switch and the lower analog switch use CD4051 series chips, preferably CD4051BM / TR chips.

[0063] The CD4051BM / TR chip is a single 8-channel multiplexer designed with advanced CMOS technology. It is an analog switch in the form of a single-pole eight-throw configuration. When INH=1, all switches are disconnected. When INH=0, the switch connects one channel. The channel number connected is determined by the selection signal input at the channel selection terminal (A0, A1, A2). The three channel selection terminals are binary input signals, which control one of the eight channels to be turned on and the rest to be turned off.

[0064] In some embodiments, the data acquisition module uses AD7606 series chips, preferably AD7606BSTZ chips.

[0065] The AD7606 module consists of an 8-channel synchronous sampling analog-to-digital data acquisition system with built-in analog input clamp protection, second-order anti-aliasing filter, track-and-hold amplifier, 16-bit charge redistribution successive approximation analog-to-digital converter, flexible digital filter, and high-speed serial and parallel interfaces.

[0066] The data acquisition module operates from a single 5V power supply and can handle ±10V and ±5V true bipolar input signals while all channels can sample at throughput rates up to 200kSPS.

[0067] In some embodiments, the voltage divider resistor is a 470k resistor.

[0068] In some embodiments, both the upper reverse module and the lower reverse module use SN74LVC1G14 series chips, preferably SN74LVC1G14DEVR chips.

[0069] In some embodiments, the scanning circuit based on the two-way hardware analog switch further includes an interface component, which includes an upper interface and a lower interface. The upper interface is connected to the input and output ports of the upper analog switch, and the upper interface is plugged into the row terminals of the pressure sensor matrix. The lower interface is connected to the input and output ports of the lower analog switch via each voltage dividing resistor, and the lower interface is connected to the column terminals of the pressure sensor matrix.

[0070] In some embodiments, the interface component also includes a control interface, which is connected to each control terminal and data output terminal of the data acquisition module, and the control interface is plugged into an interface of the microprocessor.

[0071] In some embodiments, the interface assembly further includes a data acquisition pin header and a data acquisition interface, wherein the data acquisition pin header is connected between each voltage divider resistor and the pressure sensor matrix, the data acquisition interface is connected to the data input end of the data acquisition module, and the data acquisition interface is plugged into the data acquisition pin header.

[0072] In some embodiments, the scanning circuit based on the two-way hardware analog switch further includes a power supply module for powering the circuit, the power supply module provides 5V voltage power supply, and the power supply module also provides 3.3V voltage power supply through a linear regulator. The power supply module converts the 5V voltage into a 3.3V voltage through a linear regulator. The linear regulator preferably uses an LDO chip.

[0073] Reference Figure 8 , is a circuit structure diagram of the power module of this embodiment, which can provide 3.3V or 5V voltage power supply for the utility model. For example, 5V voltage power supply is provided for the analog switch connected below, and 3.3V voltage power supply is provided for the data acquisition module.

[0074] Embodiment 1:

[0075] A 16*16 matrix column distributed flexible film pressure sensor is arranged in the smart floor as the pressure sensor matrix 1.

[0076] Reference Figure 2 The upper scanning circuit 3 uses a group of two upper analog switches and an upper reverse module. The upper analog switch uses the CD4051BM / TR chip, and the upper reverse module uses the SN74LVC1G14DEVR chip.

[0077] Reference Figure 5 The upper interface PFCE2 uses an interface with a total of 16 ports.

[0078] Reference Figure 2 and Figure 5 , the input and output ports of the two upper analog switches, totaling 16 ports, are respectively connected to the 16 ports of the upper interface. The upper interface is plugged into the row terminals of the pressure sensor matrix, so that the output ends of the 16 sensors in a row of the pressure sensor matrix are respectively connected to the 16 ports of the upper interface. This enables the row terminals of the pressure sensor matrix to be connected to the input and output ports of the two upper analog switches.

[0079] A control interface H8 may be provided on the upper scanning circuit 3. The control interface H8 has 4 ports. The first 3 bits of the control interface H8 are respectively connected to the three ports of the channel selection ends of the two upper analog switches. The last bit of the control interface H8 is connected to the input end of the upper reverse module, the output end of the upper reverse module is connected to the chip selection end of one of the upper analog switches, and the last bit of the control interface H8 is also connected to the chip selection end of another upper analog switch. The common end of the two upper analog switches is grounded.

[0080] Reference Figure 3 The lower scanning circuit 4 uses a group of two lower analog switches and a lower reverse module. The lower analog switch uses the CD4051BM / TR chip, and the lower reverse module uses the SN74LVC1G14DEVR chip.

[0081] Reference Figure 4 The data acquisition module 5 uses dual AD7606 in parallel, that is, there are two data acquisition modules 5.

[0082] Reference Figure 6 The lower interface FPCF1 uses a total of 16 ports. The data acquisition pin header uses 1*16 pin headers. The voltage divider resistors are R17~R32, a total of 16, and 470k resistors are selected.

[0083] Reference Figure 3 and Figure 6 The input and output ports of the two lower analog switches, totaling 16 ports, are connected to the 16 ports of the lower interface through voltage divider resistors. The lower interface is plugged into the column terminals of the pressure sensor matrix, so that the output ends of the 16 sensors in one column of the pressure sensor matrix are respectively connected to the 16 ports of the lower interface. This enables the column terminals of the pressure sensor matrix to be connected to the input and output ports of the two lower analog switches.

[0084] A control interface H6 may be provided on the lower scanning circuit 4. The control interface H6 has 4 ports. The first 3 bits of the control interface H6 are respectively connected to the 3 ports of the channel selection ends of the two lower analog switches. The last bit of the control interface H6 is connected to the input end of the lower reverse module, and the output end of the lower reverse module is connected to the chip selection end of one of the lower analog switches. The last bit of the control interface H6 is also connected to the chip selection end of another lower analog switch. The common end of the two lower analog switches is connected to a 5V reference level to achieve a stable reference voltage.

[0085] Reference Figure 6 The 16 common ends between the 16 voltage-dividing resistors and the column terminals of the pressure sensor matrix are used as ADC sampling ends and are led out to the 16 pin headers for data acquisition.

[0086] Reference Figure 4The data acquisition interface J3 is connected to the data input end of the data acquisition module. Since the data acquisition module 5 has an 8-channel data input end, the 8 ports of the data acquisition interface J3 are respectively connected to the 8 data input ends of the data acquisition module 5. The data acquisition interface J3 corresponding to one of the two data acquisition modules 5 is plugged into 8 of the data acquisition pin headers, and the data acquisition interface J3 corresponding to the other data acquisition module is plugged into the other 8 of the data acquisition pin headers.

[0087] Reference Figure 7 The control interface J5 is respectively connected to each control terminal and data output terminal of the data acquisition module 5, and the control interface is plugged into the interface of the microprocessor.

[0088] The scanning circuit realizes 16*16 pressure sensor matrix coding scanning and the measurement of scanning points and scanning values.

[0089] The utility model is described in detail above in conjunction with the embodiments of the drawings. A person skilled in the art can make various variations of the utility model according to the above description. Therefore, some details in the embodiments should not constitute a limitation of the utility model, and the utility model shall be protected within the scope defined by the attached claims.

Claims

1. A scanning circuit based on a two-way hardware analog switch, the scanning circuit based on a two-way hardware analog switch comprising a pressure sensor matrix and a microprocessor, characterized in that: The scanning circuit based on two-way hardware analog switch also includes an upper scanning circuit, a lower scanning circuit and a data acquisition module; The upper scanning circuit comprises: An analog switch is connected to the upper part, the input and output ports of the analog switch are respectively connected to the row terminals of the pressure sensor matrix, the common end of the analog switch is grounded, and the channel selection end of the analog switch is connected to the microprocessor; The bottom scanning circuit comprises: An analog switch is connected to the bottom, the input and output ports of the analog switch are connected to the column terminals of the pressure sensor matrix via voltage-dividing resistors, the common end of the analog switch is connected to a reference level, and the channel selection end of the analog switch is connected to the microprocessor; The input end of the data acquisition module is connected between each of the voltage-dividing resistors and the pressure sensor matrix, and the output end of the data acquisition module is connected to the microprocessor.

2. The scanning circuit based on two-way hardware analog switch according to claim 1, characterized in that: The scanning circuit based on two-way hardware analog switch also includes an interface component, and the interface component includes: An upper connection interface, the upper connection interface is connected to the input and output ports of the upper connection analog switch, and the upper connection interface is plugged into the row terminals of the pressure sensor matrix; A lower connection interface is connected to the input and output ports of the lower connection analog switch via the voltage-dividing resistors, and the lower connection interface is connected to the column terminals of the pressure sensor matrix.

3. The scanning circuit based on two-way hardware analog switch according to claim 1, characterized in that: The scanning circuit based on two-way hardware analog switch also includes an interface component, and the interface component includes: A control interface, wherein the control interface is connected to each control terminal and data output terminal of the data acquisition module, and the control interface is plugged into an interface of the microprocessor.

4. The scanning circuit based on two-way hardware analog switch according to claim 1, characterized in that: The scanning circuit based on two-way hardware analog switch also includes an interface component, and the interface component includes: A data acquisition pin header, wherein the data acquisition pin header is connected between each of the voltage-dividing resistors and the pressure sensor matrix; A data acquisition interface, wherein the data acquisition interface is connected to a data input end of the data acquisition module and is plugged into the data acquisition pin header.

5. The scanning circuit based on two-way hardware analog switch according to claim 1, characterized in that: The upper analog switch and the lower analog switch both use CD4051 series chips; The data acquisition module adopts AD7606 series chips.

6. The scanning circuit based on two-way hardware analog switch according to claim 5, characterized in that: The scanning circuit based on two-way hardware analog switches also includes a power supply module for powering the circuit, the power supply module provides 5V voltage power supply, and the power supply module also provides 3.3V voltage power supply through a linear regulator.

7. The scanning circuit based on two-way hardware analog switch according to claim 6, characterized in that: The linear regulator adopts an LDO chip.

8. The scanning circuit based on two-way hardware analog switches according to any one of claims 1 to 7, characterized in that: There are a plurality of upper-connected analog switches in the upper-connected scanning circuit, and two upper-connected analog switches form a group; The upper scanning circuit also includes: An upper reverse module is connected, a signal input end of the upper reverse module is connected to the microprocessor, a signal output end of the upper reverse module is connected to a chip select end of one of the upper analog switches in a group, and a common end between the upper reverse module and the microprocessor is connected to a chip select end of another of the upper analog switches in a group; The number of the lower analog switches in the lower scanning circuit is several, and two lower analog switches form a group; The bottom scanning circuit also includes: A lower reverse module is connected, a signal input end of the lower reverse module is connected to the microprocessor, a signal output end of the lower reverse module is connected to a chip select end of one of the lower analog switches in a group, and a common end between the lower reverse module and the microprocessor is connected to a chip select end of another of the lower analog switches in a group.

9. The scanning circuit based on two-way hardware analog switch according to claim 8, characterized in that: There are several data acquisition modules, two of which form a group, the two data acquisition modules in a group are connected in parallel, and the input ends of the two data acquisition modules in a group are respectively connected between the voltage-dividing resistors connected to the two lower analog switches in a group and the pressure sensor matrix.

10. The scanning circuit based on two-way hardware analog switch according to claim 9, characterized in that: The upper reverse module and the lower reverse module both adopt SN74LVC1G14 series chips.

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