A key scanning control circuit and an electronic device

Abstract

The present invention discloses a key scanning control circuit and an electronic device. The key scanning control circuit includes: at least one control circuit, at least one first load, at least one second load, and at least one key module. With such an arrangement, the first port can be used as both the low-level end of the load and the low-level end or zero-potential end when scanning the key module. Furthermore, the first port can have a dual function, eliminating the need to separately provide a low-level end or zero-potential end for scanning the key module, reducing the electrical connection wires on the circuit board, decreasing the size of the circuit board, and saving production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and particularly relates to a key scanning control circuit and an electronic device. Background Art

[0002] At present, due to reasons such as the structural limitations of smart appliances, the functions of the whole machine need to be split, so that each operation part cannot be integrated together. Therefore, multiple controllers are required to work, and the multiple controllers need to be connected by wires to work together. The increase in the number of controllers will increase the number of electrical connection wires on the circuit board, thereby increasing the size of the circuit board. Moreover, the increase in the number of wires to be connected also increases the production cost. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is the problem that there are many electrical connection wires on the circuit board, the size of the circuit board is large, and the production cost is high in the prior art, so as to provide a key scanning control circuit and an electronic device.

[0004] To achieve the above object, an embodiment of the present invention provides a key scanning control circuit, which includes: at least one control circuit for generating a control signal; at least one first load, the first end of the first load is connected to the output end of the control circuit, and the second end of the first load is connected to the first port of the key scanning control circuit; at least one second load, the first end of the second load is connected to the output end of the control circuit, and the second end of the second load is connected to the second port of the key scanning control circuit; at least one key module, the first end of the key module is connected to the second port, and the second end of the key module is connected to the first port.

[0005] Optionally, the key module is connected to the second load in a one-to-one correspondence.

[0006] Optionally, the first load and the second load are light-emitting diodes; the anode of the first load is connected to the output end of the control circuit, and the cathode is connected to the first port; the anode of the second load is connected to the output end of the control circuit, and the cathode is connected to the second port in a one-to-one correspondence.

[0007] Optionally, the control circuit includes: a switching tube, the control end of the switching tube is used to receive a second control signal, the first end is connected to a power supply, and the output end is connected to the first end of the first load and the first end of the second load; a first resistor, the first end is connected to the output end of the switching tube, and the second end is grounded.

[0008] Optionally, when key scanning is performed, the first port provides a low-level signal.

[0009] Optionally, the control circuit further includes:

[0010] A second resistor, having a first end connected to the first load and a second end connected to the first port.

[0011] Optionally, the control circuit further includes: at least one third resistor, with a first end of each third resistor connected to a second load and a second end respectively connected to the second port in a one-to-one correspondence.

[0012] Optionally, the control circuit further includes: at least one fourth resistor, with each fourth resistor connected in series with each key module respectively.

[0013] An embodiment of the present invention further provides an electronic device, which includes: the key scan control circuit as described in any of the above embodiments.

[0014] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0015] 1. An embodiment of the present invention provides a key scan control circuit, which includes: at least one control circuit for generating a control signal; at least one first load, with a first end of the first load connected to an output end of the control circuit and a second end of the first load connected to a first port of the key scan control circuit; at least one second load, with a first end of the second load connected to the output end of the control circuit and a second end of the second load connected to a second port of the key scan control circuit; at least one key module, with a first end of the key module connected to the second port and a second end of the key module connected to the first port.

[0016] With such a setting, in practical applications, the control circuit can output a high level through its output end and make the first port and the second port output low levels, so that the first load and the second load can work properly. When scanning the key module, at this time, the control circuit can be made not to work, the first port outputs a low level or a zero potential end, and the second port is set as an input port, so that the key module can be scanned. Thus, the first port can be used both as the low level end of the load and as the low level end or zero potential end when scanning the key module, and further, the first port has a dual function, without the need to additionally set a low level end or zero potential end for scanning the key module, which can reduce the electrical connection lines on the circuit board, reduce the size of the circuit board, and save production costs.

[0017] 2. An embodiment of the present invention further provides a switching tube and a first resistor. A control end of the switching tube is used to receive a second control signal, a first end is connected to a power supply, and an output end is connected to the first end of the first load and the first end of the second load; a first end of the first resistor is connected to the output end of the switching tube and a second end is grounded.

[0018] In the key detection stage, since the switching transistors in the control circuit are all cut off, the positive terminal of the light-emitting diode charges and discharges due to the parasitic capacitance existing in the drive circuit. When the switching transistor is turned off, the voltage is in a slow discharge state. By the time of the key scanning stage, the discharge is not yet complete, and at this time, the first port is set to output a low level. Therefore, there is a positive voltage difference between the cut-off switching transistor and the first port, which will cause the lamp cores of multiple light-emitting diodes sharing the first port to have a phenomenon of slightly bright conduction in the standby state. With such a setting, after setting the first resistor, the parasitic capacitance discharge is accelerated, so that when the light-emitting diode is in the standby state, the anode of the light-emitting diode reaches a low level when it is turned off, preventing a positive voltage difference between the output terminal of the switching transistor and the first port during the key scanning stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the key scanning control circuit according to an embodiment of the present invention.

[0021] Reference Signs:

[0022] The first resistor R1; the second resistor R2; the third resistor R3; the fourth resistor R4;

[0023] The control circuit 10; the first port 20; the second port 30; the first load 40; the second load 50; the key module 60;

[0024] The switching transistor Q. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Embodiment 1

[0030] As Figure 1 shown, the embodiment of the present invention provides a key scanning control circuit, which includes: at least one control circuit 10, at least one first load 40, at least one second load 50, and at least one key module 60.

[0031] The control circuit is used to generate a first control signal, and the control signal is output outward from the output terminal of the control circuit. The first end of the first load is connected to the output terminal of the control circuit, and the second end of the first load is connected to the first port 20 of the key scanning control circuit. The first end of the second load is connected to the output terminal of the control circuit, and the second end of the second load is connected to the second port 30 of the key scanning control circuit. The first end of the key module is connected to the second port, and the second end of the key module is connected to the first port. Of course, when there are multiple second loads, second ports, and key modules, each second load is connected to each second port in a one-to-one correspondence, and the key module is connected to the second load in a one-to-one correspondence.

[0032] With such a setting, in practical applications, the control circuit can output a high level through its output terminal and make the first port and the second port output low levels, so that the first load and the second load can work properly. When scanning the key module, the control circuit can be made not to work at this time. The first port outputs a low level or a zero-potential terminal, and the second port is set as an input port, so that the key module can be scanned. Thus, the first port can be used as both the low-level terminal of the load and the low-level terminal or zero-potential terminal when scanning the key module, and furthermore, the first port can have a dual function, eliminating the need to additionally set a low-level terminal or zero-potential terminal for scanning the key module, reducing the electrical connection wires on the circuit board, decreasing the size of the circuit board, and saving production costs.

[0033] Optionally, in some embodiments of the present invention, both the first load and the second load can be light-emitting diodes. The anode of the first load is connected to the output terminal of the control circuit, and the cathode is connected to the first port. The anode of the second load is connected to the output terminal of the control circuit, and the cathode is respectively connected to the second port in one-to-one correspondence.

[0034] Specifically, the working process of the key scanning control circuit is as follows:

[0035] First, scan the LED lights (i.e., light-emitting diodes), and then scan the keys. When scanning the LED lights, first open the output terminal port of the first control circuit, then set the first port and all the second ports as output ports, respectively assign values to light up the lights that need to be lit, then close the first port and all the second ports, and then close the output terminal port of the control circuit. Then, perform the scanning of the output terminal port of the second control circuit, repeat the above steps until all the output terminal ports of the control circuits are scanned, and then enter the key scanning stage.

[0036] When scanning the keys, all the output terminal ports of the control circuits are closed, the first port is set to output a low level, all the second ports are set as input ports, the potential of all the second ports is simultaneously increased, the second ports are set to a high level, and the key situation is detected simultaneously.

[0037] Specifically, the embodiment of the present invention further includes a switching transistor Q and a first resistor R1. The control end of the switching transistor is used to receive a second control signal, and the second control signal can be generated by a control chip. The first end of the switching transistor is connected to the power supply, and the output end is connected to the first ends of the first load and the second load. The first end of the first resistor is connected to the output end of the switching transistor, and the second end of the first resistor is grounded.

[0038] Before the scanning key detection stage, since the switching transistors in the control circuit are all cut off, the positive terminal of the light-emitting diode charges and discharges due to the parasitic capacitance existing in the driving circuit. When the switching transistor is turned off, the voltage is in a slow discharge state. During the process of scanning the keys, the discharge is not completed yet. At this time, the first port is set to output a low level. Therefore, there is a positive pressure difference between the switching transistor when it is cut off and the first port, which will cause the lamp cores of multiple light-emitting diodes sharing the first port to be slightly lit and conducting in the standby state.

[0039] With such a setting, after setting the first resistor, the parasitic capacitance discharge can be accelerated, so that in the standby state of the light-emitting diode, the anode of the light-emitting diode reaches a low level when it is turned off, so that there is no positive pressure difference between the output end of the switching transistor and the first port during the key scanning stage.

[0040] Of course, the switching transistor can be a triode or a MOS transistor, as long as it can play the same control role.

[0041] Optionally, in some embodiments of the present invention, the key scanning control circuit further includes a second resistor. The first end of the second resistor R2 is connected to the first load, and the second end is connected to the first port.

[0042] Of course, the key scanning control circuit may further include at least one third resistor R3. The first end of each third resistor is connected to the second load, and the second ends of the third resistors are respectively connected to the second ports in one-to-one correspondence.

[0043] The key scanning control circuit may further include at least one fourth resistor R4. Each fourth resistor is connected in series with each key module.

[0044] Embodiment 2

[0045] An embodiment of the present invention further provides an electronic device, which includes the key scanning control circuit described in any of the above embodiments.

[0046] With such a setting, in actual application, the control circuit of the electronic device can output a high level through its output end and make the first port and the second port output low levels, so that the first load and the second load can work normally. When scanning the key module, at this time, the control circuit can be made not to work, the first port outputs a low level or a zero potential end, and the second port is set as an input port, and the key module can be scanned. Thus, the first port can be used both as the low level end of the load and as the low level end or zero potential end when scanning the key module. Furthermore, the first port can have a dual function, and there is no need to additionally set a low level end or zero potential end for scanning the key module, which can reduce the electrical connection wires on the circuit board, reduce the size of the circuit board, and save production costs.

[0047] Obviously, the above embodiments are merely examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom still fall within the protection scope of the present invention.

Claims

1. A key scanning control circuit, characterized in that, Comprising: At least one control circuit for generating a first control signal; At least one first load, a first end of the first load being connected to an output end of the control circuit, and a second end of the first load being connected to a first port of the key scanning control circuit; At least one second load, a first end of the second load being connected to the output end of the control circuit, and a second end of the second load being connected to a second port of the key scanning control circuit; At least one key module, a first end of the key module being connected to the second port, and a second end of the key module being connected to the first port; Such that the first port serves as a low-level end when scanning the first load and also serves as a low-level end or a zero-potential end when scanning the key module.

2. The key scan control circuit according to claim 1, wherein The key module is connected to the second load in a one-to-one correspondence.

3. The key scanning control circuit according to claim 2, wherein: The first load and the second load are light-emitting diodes; An anode of the first load is connected to the output end of the control circuit, and a cathode is connected to the first port; An anode of the second load is connected to the output end of the control circuit, and cathodes are respectively connected to the second ports in a one-to-one correspondence.

4. The key scan control circuit according to claim 3, wherein The control circuit includes: A switching transistor, a control end of the switching transistor being configured to receive a second control signal, a first end being connected to a power supply, and an output end being connected to the first end of the first load and the first end of the second load; A first resistor, a first end being connected to the output end of the switching transistor, and a second end being grounded.

5. The key scan control circuit according to any one of claims 1-4, characterized in that, During key scanning, the first port provides a low-level signal.

6. The key scan control circuit according to any one of claims 1-4, characterized in that, Further comprising: A second resistor, a first end being connected to the first load, and a second end being connected to the first port.

7. The key scan control circuit according to any one of claims 1-4, characterized in that, Further comprising: At least one third resistor, a first end of each third resistor being connected to the second load, and second ends being respectively connected to the second ports in a one-to-one correspondence.

8. The key scan control circuit according to any one of claims 1-4, characterized in that, Further comprising: At least one fourth resistor, each fourth resistor being connected in series with each key module.

9. An electronic device, characterized in that, Comprising: The key scanning control circuit according to any one of claims 1-7.

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