Key voltage limiting circuit and terminal
By using a key voltage limiting circuit composed of a Zener diode and a switching transistor, the problems of high design cost and large space occupation of key voltage limit design are solved, realizing safe control of key voltage and miniaturized terminal design.
Patent Information
- Application Number
- CN202520334449.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-02-27
AI Technical Summary
In the existing technology, the design of limiting the withstand voltage of buttons is costly and takes up a lot of space, which cannot meet the miniaturization requirements of terminals, and they are easily damaged when the voltage exceeds the withstand voltage.
The button voltage limiting circuit, composed of a Zener diode and a switching transistor, ensures that the voltage across the button is within a safe range by dividing the voltage and controlling the conduction state of the switching transistor. It is simple to use and low in cost.
While achieving the function of a push-button switch, it ensures that the voltage is within a safe range, reduces costs and saves PCB space, and meets the miniaturization design requirements of terminals.
Smart Images
Figure CN223809764U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of key voltage limiting circuit, especially relates to a key voltage limiting circuit and terminal. BACKGROUND
[0002] The voltage resistance value of the key refers to the maximum voltage value that the key can bear when being used, that is, the critical value of the highest voltage value that the key can bear without insulation damage, which can guarantee the stability and safety of the equipment when being used.
[0003] The key circuit is a commonly used circuit for controlling various functions of terminal equipment, such as computers, mobile phones, etc., which generally have power-on keys, volume adjustment keys and switching function keys, etc. Since the key is an electronic component, it generally has a voltage resistance parameter limit. When the voltage loaded on both ends of the key exceeds the voltage resistance value of the key, the performance of the key will be damaged, affecting user use.
[0004] Therefore, the voltage on both ends of the key needs to be limited, that is, an additional voltage reduction module needs to be added. When the power voltage exceeds the voltage resistance value of the key, the voltage reduction module provides power to the key, but this design also needs to consider the upper limit of the voltage resistance of the voltage reduction module. If the voltage exceeds the upper limit of the voltage resistance, it cannot be used. The commonly used voltage reduction modules in the industry, such as LDO modules (Low Drop-Out, also known as low dropout regulators) or DC-DC modules, have high design costs, many components, and large PCB space area, which do not match the miniaturization design requirements of the terminal.
[0005] The above information is given as background information only to assist with understanding the present disclosure, and does not determine or acknowledge whether any of the above content can be used as prior art against the present disclosure. UTILITY MODEL CONTENT
[0006] The utility model aims at providing a key voltage limiting circuit and terminal to solve or at least partially solve the technical problems existing in the prior art.
[0007] To achieve this purpose, the utility model adopts the following technical solutions:
[0008] In a first aspect, the utility model provides a key voltage limiting circuit, which comprises a voltage stabilizing diode Z1, a switch tube M1 and a resistor R2.
[0009] The negative electrode of the voltage stabilizing diode Z1 is electrically connected to the positive connection end of the switch tube M1, the positive electrode of the voltage stabilizing diode Z1 is electrically connected to the first end of the resistor R2, and the second end of the resistor R2 is grounded.
[0010] The positive electrode of the voltage stabilizing diode Z1 is used for electrically connecting the first terminal of the key switch, the control terminal of the switch tube M1 is used for electrically connecting the second terminal of the key switch, and the negative terminal of the switch tube M1 is used for electrically connecting the voltage input terminal of the load circuit controlled by the key switch.
[0011] When S1 is closed, the switch tube M1 is turned on, and when S1 is disconnected, the switch tube M1 is cut off or not turned on.
[0012] Optionally, the switch tube M1 is an enhancement mode PMOS tube, the positive terminal of the switch tube M1 is the source of the PMOS tube, the negative terminal of the switch tube M1 is the drain of the PMOS tube, and the control terminal of the switch tube M1 is the gate of the PMOS tube.
[0013] The negative electrode of the voltage stabilizing diode Z1 is also electrically connected with the first terminal of the resistor R1, and the second terminal of the resistor R1 is electrically connected with the control terminal of the switch tube M1.
[0014] Optionally, the voltage between the two ends of the voltage stabilizing diode Z1 is lower than the withstand voltage value of the key switch.
[0015] Optionally, the voltage between the two ends of the voltage stabilizing diode Z1 is lower than the withstand voltage value between the gate and the source of the switch tube M1.
[0016] Optionally, the resistor R1 and / or the resistor R2 are adjustable resistors.
[0017] In a second aspect, the utility model provides a kind of terminal, including several key switches, and the two ends of the key switch are electrically connected with key voltage limiting circuit, and the key voltage limiting circuit uses the key voltage limiting circuit described above.
[0018] Optionally, the key switch includes the on-off key, volume adjustment key and function switching key of the terminal.
[0019] Optionally, the terminal is a computer, a mobile phone or a tablet computer.
[0020] Compared with the prior art, the utility model has the following beneficial effects:
[0021] The key voltage limiting circuit provided by the utility model can realize the on-off function of the key, ensure that the voltage between the two ends of the key remains within a safe range when the power supply voltage is randomly switched, has low cost, and is convenient and reliable.
[0022] The utility model has other characteristics and advantages, which will be obvious from the drawings incorporated herein and the subsequent specific embodiments, or will be described in detail in the drawings and subsequent specific embodiments incorporated herein, which are used together to explain the specific principles of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0024] Figure 1 It is a schematic diagram of a key voltage limiting circuit provided in the embodiments of the present application. DETAILED DESCRIPTION
[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0026] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit the independence or association between other embodiments. In principle, in this application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.
[0027] Unless otherwise defined, the meanings of the technical terms used in this paper are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms in this paper is only for the purpose of describing specific embodiments, and is not intended to limit the present application.
[0028] In the description of the present application, the word "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this paper generally represents that the associated objects before and after are a "or" logical relationship.
[0029] In this application, such as "first" and "second" language is only used to distinguish one entity or operation from another entity or operation, and does not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.
[0030] In the present application, the terms "comprise", "contain", "have" or other similar terms used in the statements are intended to cover non-exclusive inclusion, and the terms do not exclude the presence of additional elements in the process, method or product comprising the elements, so that the process, method or product comprising a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.
[0031] As the same understanding as in the "Examination Guidelines", in the present application, the expressions such as "greater than", "less than", "exceed" are understood as not including the number; the expressions such as "above", "below", "within" are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times", etc., unless otherwise explicitly specified.
[0032] In the description of the embodiments of the present application, the spatial-related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. The indicated orientation or position relationship is based on the orientation or position relationship shown in the specific embodiment or the drawing, and is only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and does not indicate or imply that the indicated device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, therefore it cannot be understood as a limitation on the embodiments of the present application.
[0033] Unless otherwise explicitly specified or limited, in the description of the embodiments of the present application, the terms "mount", "connect", "connect", "fix", "set", etc. should be understood broadly. For example, the "connection" can be a fixed connection, or a detachable connection, or an integral setting; it can be a mechanical connection, or an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0034] Embodiment one:
[0035] Please refer to Figure 1 , Figure 1 is a structure principle diagram of a key voltage limiting circuit provided by the embodiment of the present application;
[0036] AsFigure 1 As shown for ease of illustration, Figure 1 The left end or upper end of the electronic component is referred to as a first end, Figure 1 The right end or lower end of the electronic component is referred to as a second end;
[0037] Specifically, the key voltage limiting circuit includes a voltage stabilizing diode Z1, a switch tube M1 and a resistor R2.
[0038] The negative electrode of the voltage stabilizing diode Z1 is electrically connected to the positive connection end of the switch tube M1, the positive electrode of the voltage stabilizing diode Z1 is electrically connected to the first end of the resistor R2, and the second end of the resistor R2 is grounded.
[0039] The positive electrode of the voltage stabilizing diode Z1 is used to electrically connect the first connection end of the key switch, the control end of the switch tube M1 is used to electrically connect the second connection end of the key switch, and the negative connection end of the switch tube M1 is used to electrically connect the voltage input end of the load circuit controlled by the key switch.
[0040] When S1 is closed, the switch tube M1 is turned on; when S1 is disconnected, the switch tube M1 is turned off or not turned on.
[0041] Exemplarily, the switch tube M1 can be a triode or an MOS tube;
[0042] As a more preferred embodiment, in the embodiment, the switch tube M1 is an enhancement mode PMOS tube, the positive connection end of the switch tube M1 is the source electrode of the PMOS tube, the negative connection end of the switch tube M1 is the drain electrode of the PMOS tube, and the control end of the switch tube M1 is the gate electrode of the PMOS tube.
[0043] The negative electrode of the voltage stabilizing diode Z1 is also electrically connected to the first end of the resistor R1, and the second end of the resistor R1 is electrically connected to the control end of the switch tube M1.
[0044] The working principle of the key voltage limiting circuit is as follows:
[0045] Figure 1 VDD is the power supply voltage, S1 is the key, and the control of the corresponding function circuit is realized by converting the conduction of the key S1 into the conduction of the MOS tube.
[0046] Specifically, when the key S1 is pressed, that is, Figure 1 The BT1 node and the BT2 node are turned on, the voltage between the two ends of the key S1 is 0V, the MOS tube M1 is in a conduction state through voltage division of the resistors R1 and R2, the voltage of BT_VDD is consistent with the voltage VDD, and the key switch conduction function is realized.
[0047] When the key S1 is disconnected, the voltage at the BT1 end of the key S1 is VDD minus the voltage of the voltage stabilizing tube Z1, and the voltage at the BT2 end of the key S1 is VDD, so the voltage difference between the two ends of the key S1, i.e. the voltage of the voltage stabilizing tube Z1, is obtained. At this time, as long as the voltage stabilizing tube selected is lower than the voltage resistance value of the key S1 and the gate-source voltage resistance value of the switch tube M1, the function of controlling the voltage resistance between the two ends of the key S1 can be realized. Meanwhile, when the key S1 is disconnected, the drain and gate voltages of the switch tube M1 are consistent, the switch tube M1 is cut off, and the key switch is disconnected.
[0048] In the embodiment, the on-off state of the key switch is converted into the off-on state of the MOS tube according to the on-off characteristics of the MOS tube, and the voltage loaded between the two ends of the key is converted from the power supply voltage into the voltage of the voltage stabilizing tube Z1, so that the controllable stability of the voltage between the two ends of the key is realized.
[0049] It should be noted that in the embodiment, the voltage between the two ends of the voltage stabilizing diode Z1 is lower than the voltage resistance value of the key switch, and the voltage between the two ends of the voltage stabilizing diode Z1 is lower than the voltage resistance value between the gate and source of the switch tube M1.
[0050] As an optional implementation, the resistance R1 and / or the resistance R2 are adjustable resistors.
[0051] After the key voltage limiting circuit is adopted, the VDD voltage is adjustable, which only needs to adjust the resistance values of R1 and R2, so that the voltage between the two ends of R1 when R1 and R2 are divided can meet the opening condition of the MOS tube M1; and if there is power consumption control, only the resistance value of R2 needs to be appropriately increased, so that low power consumption processing can be realized.
[0052] Embodiment two:
[0053] The embodiment provides a terminal, which comprises a plurality of key switches, and a key voltage limiting circuit is electrically connected between the two ends of each key switch. The key voltage limiting circuit adopts the key voltage limiting circuit as described in embodiment one.
[0054] Specifically, the key switches comprise a power-on key, a volume adjustment key and a function switching key of the terminal.
[0055] In the embodiment, the terminal is a computer, a mobile phone or a tablet computer.
[0056] As the key voltage limiting circuit has been described in detail in embodiment one, the description is not repeated in this embodiment.
[0057] The terminal provided in the embodiment adds a key voltage limiting circuit between the two ends of the key switch. The key voltage limiting circuit only adopts simple, low-cost and convenient and reliable electronic components, has low cost and does not occupy much PCB space area, and meets the miniaturization design requirement of the terminal.
[0058] The above-described and above-embodied examples are merely used to illustrate the technical solutions of the present application, but not to limit the same; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can still be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A key voltage limiting circuit, characterized by comprising: The voltage stabilizing diode Z1, the switch tube M1 and the resistor R2 are included. The negative pole of the voltage stabilizing diode Z1 is electrically connected to the positive terminal of the switch tube M1, the positive pole of the voltage stabilizing diode Z1 is electrically connected to the first terminal of the resistor R2, and the second terminal of the resistor R2 is grounded. The positive pole of the voltage stabilizing diode Z1 is used to electrically connect the first terminal of the key switch, the control terminal of the switch tube M1 is used to electrically connect the second terminal of the key switch, and the negative terminal of the switch tube M1 is used to electrically connect the voltage input terminal of the load circuit controlled by the key switch. When S1 is closed, the switch tube M1 is turned on; when S1 is opened, the switch tube M1 is turned off or not turned on.
2. The key voltage limiting circuit according to claim 1, wherein The switch tube M1 is an enhancement mode PMOS tube, the positive terminal of the switch tube M1 is the source of the PMOS tube, the negative terminal of the switch tube M1 is the drain of the PMOS tube, and the control terminal of the switch tube M1 is the gate of the PMOS tube. The negative pole of the voltage stabilizing diode Z1 is also electrically connected to the first terminal of the resistor R1, and the second terminal of the resistor R1 is electrically connected to the control terminal of the switch tube M1.
3. The key voltage limiting circuit according to claim 2, wherein The voltage between the two terminals of the voltage stabilizing diode Z1 is lower than the voltage resistance value of the key switch.
4. The key voltage limiting circuit according to claim 3, wherein The voltage between the two terminals of the voltage stabilizing diode Z1 is lower than the voltage resistance value between the gate and the source of the switch tube M1.
5. The key voltage limiting circuit according to claim 3, wherein The resistor R1 and / or the resistor R2 are adjustable resistors.
6. A terminal comprising a plurality of key switches, both ends of the key switches being electrically connected with a key voltage limiting circuit, characterized in that, The key voltage limiting circuit adopts the key voltage limiting circuit according to any one of claims 1-5.
7. A terminal according to claim 6, characterized in that The key switch includes the power on / off key, the volume adjustment key and the function switching key of the terminal.
8. A terminal according to claim 6, characterized in that The terminal is a computer, a mobile phone or a tablet computer.