Low-cost high-precision time sequence control circuit, driving circuit and liquid crystal module

Abstract

The utility model provides a sequential control circuit with low cost and high precision, a driving circuit and a liquid crystal module. The sequential control circuit comprises a delay circuit module and an output module, the delay circuit module comprises a second voltage power supply end, a resistor R1, a capacitor C1, a precision timer U1 and a second voltage output end; one end of the capacitor C1 is connected with the second voltage power supply end, and the other end of the capacitor C1 is connected with the precision timer U1 and grounded through the resistor R1; the second voltage output end is connected with the output end of the precision timer U1; the output module comprises a first voltage power supply end, a control switch unit and a first voltage output end; the control switch unit is connected with the first voltage power supply end, the second voltage output end and the first voltage output end. According to the utility model, the voltage delay output can be accurately controlled, so that the power-on time sequence can be accurately controlled; in addition, an I / O port does not need to be occupied, and meanwhile the advantages of being low in cost and more flexible are achieved.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a low-cost and high-precision timing control circuit, a driving circuit and a liquid crystal module. Background Art

[0002] Traditional LCD modules, consisting of a backlight and LCD, require separate drivers for the backlight and LCD. Even with current technology, integrating the backlight and LCD requires different drive voltages. The backlight's supply voltage must be higher than the LCD's, and current motherboards all use a single power supply. Therefore, the LCD still needs to be powered on first, followed by the backlight.

[0003] The motherboard's power supply voltage is typically 24V, and the 12V voltage must be generated from the 24V voltage through a step-down circuit. While the 12V power supply is typically supplied later than the 24V power supply, proper display requires the LCD to be powered on first, followed by the backlight (i.e., the 12V power supply first, followed by the 24V power supply). Failure to ensure that the 12V power supply to the LCD is supplied first, followed by the 24V power supply to the backlight, can result in abnormal display on the LCD glass and may even damage the glass. Therefore, controlling the power-on sequence of the backlight and LCD is crucial.

[0004] To address these issues, current I / O ports are often used to control transistors and MOSFETs to achieve 24V delayed power-up. However, this approach not only occupies I / O ports, wasting I / O resources, but also offers limited flexibility. Therefore, a timing control circuit that can precisely control the power-up sequence is essential. Utility Model Content

[0005] The technical problem to be solved by the present invention is to provide a low-cost and high-precision timing control circuit, a driving circuit and a liquid crystal module, which can not only save I / O port resources, but also can be well matched with external boards and cards, and have greater flexibility.

[0006] In order to solve the above technical problems, the first technical solution adopted by the present invention is:

[0007] A low-cost and high-precision timing control circuit includes a delay circuit module and an output module;

[0008] The delay circuit module includes a second voltage supply terminal, a resistor R1, a capacitor C1, a precision timer U1, and a second voltage output terminal; one end of the capacitor C1 is connected to the second voltage supply terminal, and the other end thereof is connected to the precision timer U1 and to ground via the resistor R1; the second voltage output terminal is connected to the output terminal of the precision timer U1;

[0009] The output module includes a first voltage power supply end, a control switch unit and a first voltage output end; the control switch unit is respectively connected to the first voltage power supply end, the second voltage output end and the first voltage output end, so as to be turned on when the second voltage output end outputs the second voltage, and control the first voltage output end to output the first voltage.

[0010] Optionally, the control switch unit includes a transistor Q1 and a MOS tube U2;

[0011] The base of the transistor Q1 is connected to the second voltage output terminal, the emitter thereof is grounded, and the collector thereof is connected to the first voltage supply terminal;

[0012] The source of the MOS transistor U2 is connected to the first voltage supply terminal, the gate thereof is connected to the collector of the transistor Q1 , and the drain thereof is connected to the first voltage output terminal.

[0013] Optionally, the output module further includes a diode D1;

[0014] The anode of the diode D1 is connected to the first voltage supply terminal and the collector of the transistor Q1 respectively; and the cathode of the diode D1 is connected to the gate of the MOS transistor U2.

[0015] Optionally, the output module further includes a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, and a capacitor C6;

[0016] One end of the capacitor C2 is connected to the first voltage supply end, and the other end is grounded; the collector of the transistor Q1 is connected to the first voltage supply end via the resistor R2 and the resistor R3 connected in series; the anode of the diode D1 is connected to the first voltage supply end via the resistor R2, and the cathode of the diode D1 is connected to the source of the MOS transistor U2 via the capacitor C4; the resistor R4 is connected in parallel with the diode D1; the gate of the transistor Q1 is divided into two paths after passing through the capacitor C5, one path is connected to the first voltage output end, and the other path is grounded via the capacitor C6; the base of the transistor Q1 is connected to the second voltage output end via the resistor R5; and the base of the transistor Q1 is grounded via the capacitor C3.

[0017] Optionally, the MOS transistor U2 is a PMOS transistor.

[0018] Optionally, the second voltage power supply end is a 12V power supply end; and the second voltage output end is a 12V output end.

[0019] Optionally, the first voltage power supply end is a 24V power supply end; and the first voltage output end is a 24V output end.

[0020] Optionally, a time constant t of an RC network formed by the resistor R1 and the capacitor C1 is 1.1RC.

[0021] The second technical solution adopted in this utility model is:

[0022] A driving circuit includes the above-mentioned low-cost and high-precision timing control circuit.

[0023] The third technical solution adopted in this utility model is:

[0024] A liquid crystal module comprises a backlight module, an LCD module and the above-mentioned driving circuit; the first voltage output end in the driving circuit is connected to the backlight module.

[0025] The beneficial effects of the present invention are as follows: the timing control circuit provided by the present invention can control the second voltage output terminal to output the second voltage after a certain delay time through the RC network in the delay circuit, and then control the control switch unit of the output module to delay for a corresponding time before turning on, thereby achieving the purpose of accurately controlling the delayed output of the voltage of the first voltage output terminal. At the same time, the driving circuit provided at the same time based on the above timing control circuit will have the advantage of accurately controlling the power-on timing; the liquid crystal module provided at the same time based on the above timing control circuit will have the advantage of being able to accurately control the LCD module to power on first and the backlight module to power on later. Therefore, the present invention can realize accurate control of the power-on timing without occupying the I / O port, and the timing control circuit board design can better match the external board card and is more flexible; it also has the advantage of low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of a low-cost and high-precision timing control circuit provided by an embodiment of the present utility model;

[0027] Figure 2 A schematic diagram of the circuit structure of a delay circuit module in a low-cost and high-precision timing control circuit provided by an embodiment of the present utility model;

[0028] Figure 3 A schematic diagram of the circuit structure of an output module in a low-cost and high-precision timing control circuit provided by an embodiment of the utility model;

[0029] Figure 4 A schematic structural diagram of a liquid crystal module provided by an embodiment of the present utility model.

[0030] Description of labels:

[0031] 10. Timing control circuit;

[0032] 1. Delay circuit module;

[0033] 11. Second voltage supply terminal; 12. Second voltage output terminal;

[0034] 2. Output module;

[0035] 21. First voltage supply terminal; 22. Control switch unit; 23. First voltage output terminal;

[0036] 20. Driving circuit;

[0037] 100. Liquid crystal module;

[0038] 30. Backlight module; 40. LCD module. DETAILED DESCRIPTION

[0039] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of the present invention, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0040] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0041] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit the present application.

[0042] In the description of this utility model, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0043] In the present invention, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0044] Without further restrictions, in the present invention, the words "include", "comprise", "have" or other similar expressions used in sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0045] Consistent with the understanding in the Examination Guidelines, in this utility model, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this utility model, "multiple" means two or more (including two), and similar expressions related to "multiple," such as "multiple groups" and "multiple times," are also understood in this manner, unless otherwise specifically defined.

[0046] In the description of the embodiments of the present invention, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present invention or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present invention.

[0047] Unless otherwise expressly specified or limited, in the description of the embodiments of the present invention, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the technical field of the present invention, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0048] Figure 1 A schematic structural diagram of a low-cost and high-precision timing control circuit provided by an embodiment of the utility model.

[0049] The embodiment of the utility model provides a low-cost and high-precision timing control circuit for controlling the power-on timing of a mainboard.

[0050] like Figure 1 As shown, a low-cost and high-precision timing control circuit 10 provided by this embodiment includes a delay circuit module 1 and an output module 2 connected to each other.

[0051] The delay circuit module is used to control the specific time of the delay, and when the delay is reached, controls the output of the second voltage to the output module.

[0052] In this embodiment, if Figure 1 As shown, the delay circuit module 1 specifically includes a second voltage supply terminal 11, a resistor R1, a capacitor C1, a precision timer U1 and a second voltage output terminal 12; one end of the capacitor C1 is connected to the second voltage supply terminal 11, and the other end thereof is respectively connected to the precision timer U1 and to the ground via the resistor R1; the second voltage output terminal 12 is connected to the output terminal of the precision timer U1.

[0053] The output module 2 is used to control the output of a first voltage after the delay circuit module is powered on.

[0054] In this embodiment, if Figure 1 As shown, the output module 2 specifically includes a first voltage power supply terminal 21, a control switch unit 22 and a first voltage output terminal 23; the control switch unit 22 is respectively connected to the first voltage power supply terminal 21, the second voltage output terminal 12 and the first voltage output terminal 23, so as to be turned on when the second voltage output terminal 12 outputs the second voltage, and control the first voltage output terminal 23 to output the first voltage.

[0055] The working principle of a low-cost and high-precision timing control circuit provided by this embodiment is as follows:

[0056] The first voltage is powered on first, and then the first voltage power supply terminal of the output module has voltage input. At this time, the control switch unit of the output module is in the off state, and the first voltage output terminal has no voltage output;

[0057] When the second voltage is powered on, the second voltage supply terminal of the delay circuit module receives voltage input, but the precision timer U1 of the delay circuit module performs a delayed triggering operation. The specific delay time is determined by the RC network formed by the resistor R1 and the capacitor C1. When the delay time expires, the precision timer U1 is triggered, and the second voltage output terminal is controlled to output the second voltage.

[0058] The second voltage outputted to the output module by the delay circuit module after delay control will turn on the control switch unit of the output module, thereby controlling the first voltage output terminal to output the first voltage.

[0059] Therefore, through the timing control circuit of this embodiment, it is possible to accurately control the first voltage delay output, which well meets the requirements of scenarios with voltage delay output; and the timing control circuit of this embodiment does not need to occupy the I / O interface, which can save I / O resources; at the same time, the circuit board design can also better match the external board card, greatly improving flexibility.

[0060] Figure 2 A schematic diagram of the circuit structure of a delay circuit module in a low-cost and high-precision timing control circuit provided by an embodiment of the present utility model; Figure 3 A schematic diagram of the circuit structure of an output module in a low-cost and high-precision timing control circuit provided by an embodiment of the utility model.

[0061] Another embodiment of the utility model is based on the above Figure 1 The embodiment is further expanded and its circuit structure is further refined.

[0062] like Figure 2 As shown, this embodiment provides a low-cost and high-precision timing control circuit, in which the "other end" of the capacitor C1 in the delay circuit module is specifically connected to the TRIG pin and the THRES pin of the precision timer U1; the second voltage output end is also connected to the VCC pin of the precision timer U1; the second voltage output end is specifically connected to the OUT pin, that is, the output end, of the precision timer U1, and at the same time, the second voltage output end is also connected to the control switch unit of the output module.

[0063] In some specific implementations, the precision timer U1 is a NE555 chip.

[0064] The delay circuit module of this embodiment works as follows:

[0065] When the second voltage supply terminal of the delay circuit module receives the second voltage, the TRIG pin of precision timer U1 is high and then slowly pulled down. When its voltage drops to the trigger level (1 / 3 of the second voltage), the OUT pin of precision timer U1 outputs a high level, indicating that the second voltage output terminal outputs the second voltage. The time it takes for the TRIG pin of precision timer U1 to drop from a high level to the trigger voltage, i.e., the delayed output time of the delay circuit module, is determined by the RC network composed of resistor R1 and capacitor C1 in the delay circuit module, with the RC network's time constant t = 1.1RC. This allows the delay circuit module to precisely control the delayed output.

[0066] like Figure 3As shown, this embodiment provides a low-cost, high-precision timing control circuit, whose output module specifically includes a first voltage supply terminal, a control switch unit, a first voltage output terminal, a diode D1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, and a capacitor C6. The control switch unit specifically includes a transistor Q1 and a MOS transistor U2.

[0067] Specifically, the internal connection relationship of the output module is:

[0068] The first voltage supply terminal is grounded via capacitor C2, which acts as a filter. Diode D1 acts as a freewheeling diode, with its anode connected to the first voltage supply terminal via resistor R2. The anode of diode D1 is also connected to the collector of transistor Q1 via resistor R3. The cathode of diode D1 is connected to the source of PMOS transistor U2 via capacitor C4. The cathode of diode D1 is also connected to the gate of PMOS transistor U2 and to the drain of PMOS transistor U2 via capacitor C5. Capacitor C5 improves system stability. Resistor R4 is connected in parallel with diode D1. The source of MOS transistor U2 is connected to the first voltage supply terminal. The drain of MOS transistor U2 is also grounded via capacitor C6. Capacitor C6 serves to mitigate interference and enhance system stability. One end of resistor R5 is connected to the second voltage output by the OUT pin of precision timer U1, that is, to the second voltage output terminal, and the other end is connected to the base of transistor Q1. One end of capacitor C3 is connected to the base of transistor Q1, and the other end is grounded. Here, the function of capacitor C3 is to resist interference and improve system stability. The emitter of transistor Q1 is directly grounded. Here, transistor Q1 acts as a switch in the circuit.

[0069] In some specific implementations, the MOS transistor U2 is a PMOS transistor.

[0070] The output module of this embodiment works as follows:

[0071] The first supply voltage is powered on first, meaning the first supply terminal outputs the first voltage before the second supply terminal. At this point, PMOS transistor U2 is turned off, and the first voltage output terminal of the output module outputs no voltage. When the second supply voltage is powered on, the delay circuit module performs precise delay control. After the delay time expires, the delay circuit module controls its second voltage output terminal to output the second voltage, which is the delayed second voltage. This second voltage is divided by resistor R5 and connected to the base of transistor Q1, turning on transistor Q1. After transistor Q1 turns on, the first voltage output from the first supply terminal is divided by resistors R2 and R3 and reaches the gate of PMOS transistor U2. At this point, the gate voltage of PMOS transistor U2 is lower than the source voltage of PMOS transistor U2, turning on PMOS transistor U2. The drain of PMOS transistor U2 then outputs the first voltage to the first voltage output terminal.

[0072] The low-cost, high-precision timing control circuit provided in this embodiment can control the conduction timing of the transistor Q1 in the output module and, in turn, the conduction timing of the MOS transistor U2 by adjusting the resistance and capacitance values ​​of the RC circuit in the delay circuit, thereby precisely controlling the output timing of the first voltage and achieving the purpose of precisely controlling the delayed output time of the first voltage.

[0073] As a preferred embodiment of the present utility model, the first voltage power supply end in the above embodiment is a 24V power supply end; the first voltage output end is a 24V output end; at the same time, the second voltage power supply end is a 12V power supply end; the second voltage output end is a 12V output end.

[0074] Therefore, the above preferred embodiment can achieve the purpose of accurately controlling the delayed output of the 24V voltage by accurately controlling the output timing of the 24V voltage when the 24V voltage is powered on first and the 12V voltage is powered on later; furthermore, it can be well applied to scenarios where there is a need for accurate delay control of the output timing of the 24V voltage, such as the scenario of delayed output of the backlight drive voltage.

[0075] Based on any of the above embodiments, an embodiment of the present invention further provides a driving circuit, comprising the low-cost, high-precision timing control circuit described in any of the above embodiments. The specific structure and operating principle of the timing control circuit will not be repeated here; please refer to the description of the above embodiments for details.

[0076] The driving circuit provided in this embodiment can accurately control the voltage delay output based on the timing control circuit; for scenarios where there are two different voltage outputs and the output timing of different voltages needs to be controlled, the power-on timing of the two different voltages can be accurately controlled.

[0077] See also Figure 4 , Figure 4 This is a schematic diagram of the structure of a liquid crystal module provided by an embodiment of the present utility model. Figure 4 As shown, the liquid crystal module 100 provided in this embodiment includes a backlight module 30, an LCD module 40, and the driving circuit 20 described in any of the above embodiments. The first voltage output terminal 23 of the driving circuit 20 is connected to the backlight module 30, and the second voltage supply terminal 11 of the driving circuit is connected to the LCD module 40. The specific structure and operating principle of the driving circuit will not be repeated here; please refer to the description of the above embodiments for details.

[0078] In some specific embodiments, the first voltage power supply terminal is a 24V power supply terminal; the first voltage output terminal is a 24V output terminal; at the same time, the second voltage power supply terminal is a 12V power supply terminal; and the second voltage output terminal is a 12V output terminal.

[0079] This embodiment provides a liquid crystal module that precisely controls a first voltage, namely, a 24V voltage, by delaying its output for a predetermined period of time through a timing control circuit. Furthermore, the module first controls a second voltage, namely, a 12V voltage, to drive the LCD module, and then precisely controls the first voltage, namely, a 24V voltage, to drive the backlight module, after a predetermined period of time. This ensures that the LCD is powered on first, followed by the backlight, ensuring normal display. Furthermore, because the LCD module of this embodiment utilizes a circuit board-based timing control circuit to achieve precise voltage delay control, it eliminates the need for I / O ports, freeing up I / O port resources. Furthermore, the circuit board design allows for better compatibility with external boards, providing greater flexibility.

[0080] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the description and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A low-cost and high-precision timing control circuit, characterized in that: including a delay circuit module and an output module; The delay circuit module includes a second voltage supply terminal, a resistor R1, a capacitor C1, a precision timer U1, and a second voltage output terminal; one end of the capacitor C1 is connected to the second voltage supply terminal, and the other end thereof is connected to the precision timer U1 and to ground via the resistor R1; the second voltage output terminal is connected to the output terminal of the precision timer U1; The output module includes a first voltage power supply end, a control switch unit and a first voltage output end; the control switch unit is respectively connected to the first voltage power supply end, the second voltage output end and the first voltage output end, so as to be turned on when the second voltage output end outputs the second voltage, and control the first voltage output end to output the first voltage.

2. A low-cost and high-precision timing control circuit as claimed in claim 1, characterized in that: The control switch unit includes a transistor Q1 and a MOS tube U2; The base of the transistor Q1 is connected to the second voltage output terminal, the emitter thereof is grounded, and the collector thereof is connected to the first voltage supply terminal; The source of the MOS transistor U2 is connected to the first voltage supply terminal, the gate thereof is connected to the collector of the transistor Q1 , and the drain thereof is connected to the first voltage output terminal.

3. A low-cost and high-precision timing control circuit as claimed in claim 2, characterized in that: The output module further includes a diode D1; The anode of the diode D1 is connected to the first voltage supply terminal and the collector of the transistor Q1 respectively; and the cathode of the diode D1 is connected to the gate of the MOS transistor U2.

4. A low-cost and high-precision timing control circuit as claimed in claim 3, characterized in that: The output module further includes a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, and a capacitor C6; One end of the capacitor C2 is connected to the first voltage supply end, and the other end is grounded; the collector of the transistor Q1 is connected to the first voltage supply end via the resistor R2 and the resistor R3 connected in series; the anode of the diode D1 is connected to the first voltage supply end via the resistor R2, and the cathode of the diode D1 is connected to the source of the MOS transistor U2 via the capacitor C4; the resistor R4 is connected in parallel with the diode D1; the gate of the transistor Q1 is divided into two paths after passing through the capacitor C5, one path is connected to the first voltage output end, and the other path is grounded via the capacitor C6; the base of the transistor Q1 is connected to the second voltage output end via the resistor R5; and the base of the transistor Q1 is grounded via the capacitor C3.

5. The low-cost and high-precision timing control circuit according to claim 2, characterized in that: The MOS transistor U2 is a PMOS transistor.

6. The low-cost and high-precision timing control circuit according to claim 1, characterized in that: The second voltage power supply end is a 12V power supply end; the second voltage output end is a 12V output end.

7. The low-cost and high-precision timing control circuit according to claim 1, characterized in that: The first voltage power supply end is a 24V power supply end; the first voltage output end is a 24V output end.

8. The low-cost and high-precision timing control circuit according to claim 1, characterized in that: The time constant of the RC network formed by the resistor R1 and the capacitor C1 is t=1.1RC.

9. A driving circuit, characterized in that: A low-cost and high-precision timing control circuit comprising any one of claims 1 to 8.

10. A liquid crystal module, characterized in that: The device comprises a backlight module, an LCD module and the driving circuit according to claim 9; the first voltage output terminal in the driving circuit is connected to the backlight module.

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