Backlight current adaptive adjustment circuit and device

Abstract

The utility model relates to the technical field of backlight compatibility, in particular to a backlight current adaptive adjustment circuit and device. Comprising a voltage trigger module, the input end of which is connected with the positive electrode of an LED and is used for on-off of the voltage trigger module; the input end of the first current adjusting module is connected with the output end of the voltage triggering module, the first output end of the first current adjusting module is grounded, and the first current adjusting module is used for adjusting on-off of the first current adjusting module; the first input end of the second current adjusting module is connected with the positive electrode of the LED, the second input end of the second current adjusting module is connected with the second output end of the first current adjusting module, and the output end of the second current adjusting module is connected with the negative electrode of the LED. And the on-off of the second current adjusting module is adjusted. The application can realize the beneficial effects of meeting the requirements of different screens on current and then improving the product compatibility.

Description

Technical Field

[0001] The present application relates to the technical field of backlight compatibility, and in particular to a backlight current adaptive adjustment circuit and device. Background Art

[0002] There are many types of screens on the market, with different requirements for backlight current and voltage. Now that car navigation has entered the standardization of public boards, a public board product is required to be compatible with more screens. The current public board backlight circuit is a constant current source design, but it faces the possibility that the factory customer's engineering or production operators may install the wrong display screen, resulting in the backlight current set by the motherboard and the backlight current required by the display screen being inconsistent, which in turn leads to problems such as low backlight brightness or excessive brightness burning.

[0003] From the above problems, it can be seen that how to meet the current requirements of different screens and then improve product compatibility is a technical problem that needs to be solved urgently. Utility Model Content

[0004] The purpose of this application is to provide a backlight current adaptive adjustment circuit and device, which can meet the current requirements of different screens and thereby improve the compatibility of products.

[0005] In a first aspect, the present application provides a backlight current adaptive adjustment circuit, comprising:

[0006] A voltage trigger module, the input end of which is connected to the LED anode, and is used to adjust the on and off of the voltage trigger module according to the backlight voltage value output by the LED anode;

[0007] A first current adjustment module, wherein an input end of the first current adjustment module is connected to an output end of the voltage trigger module, a first output end of the first current adjustment module is grounded, and is used to adjust the on / off of the first current adjustment module according to the on / off of the voltage trigger module;

[0008] A second current adjustment module, wherein the first input end of the second current adjustment module is connected to the positive electrode of the LED, the second input end of the second current adjustment module is connected to the second output end of the first current adjustment module, and the output end of the second current adjustment module is connected to the negative electrode of the LED, and is used to adjust the on and off of the second current adjustment module according to the on and off of the first current adjustment module.

[0009] By adopting the above technical solution, the voltage trigger module is used to identify the backlight voltage value and determine whether the magnitude of the backlight voltage value exceeds a preset voltage threshold. The preset voltage threshold is determined by the device selection of the voltage trigger module. If the backlight voltage value does not exceed the preset voltage threshold, the second current adjustment module is turned on to ground the backlight (LED negative electrode). In this case, the current is larger and the screen will be brighter. If the backlight voltage value exceeds the preset voltage threshold, the first current adjustment module is turned on to ground the first current adjustment module, thereby turning off the second current adjustment module. After the second current adjustment module is turned off, the LED negative electrode uses the originally set resistor to adjust the current. Based on this, the function of adaptively adjusting the backlight current according to the magnitude of the identified backlight voltage value is realized, so as to meet the current requirements of different screens, and then the beneficial effect of improving product compatibility is achieved.

[0010] Optionally, the voltage trigger module includes a voltage stabilizing diode;

[0011] The negative electrode of the voltage stabilizing diode is connected to the positive electrode of the LED, and the negative electrode of the voltage stabilizing diode is connected to the input end of the current adjustment module.

[0012] By adopting the above technical solution, the voltage stabilizing diode is used to provide a preset voltage threshold. In this embodiment, the preset voltage threshold can be 12V, that is, if the backlight voltage value is greater than 12V, the voltage stabilizing diode is broken down. In this case, the first current adjustment module is turned on and the second current adjustment module is turned off. If the backlight voltage value is less than 12V (or the voltage stabilizing diode is not broken down), in this case, the second current adjustment module is turned on. According to the on / off of one of the first current adjustment module and the second current adjustment module, two different backlight currents are formed.

[0013] Optionally, the first current adjustment module includes a first triode;

[0014] The gate of the first triode is connected to the positive electrode of the voltage stabilizing diode, the collector of the first triode is connected to the connection point between the negative electrode of the voltage stabilizing diode and the positive electrode of the LED, and the emitter of the first triode is grounded;

[0015] The gate of the first triode is also connected to the ground electrode, and the collector of the first triode is also connected to the second input end of the second current adjustment module.

[0016] By adopting the above technical solution, the on / off of the first triode is controlled by the voltage stabilizing diode. If the backlight voltage value exceeds the preset voltage threshold, in this case, the voltage stabilizing diode is broken down, causing the gate potential of the first triode to be pulled up, thereby turning on the first triode. After the first triode is turned on, the potential level sampled by the second current adjustment module from the collector of the first triode can be adjusted, thereby adjusting the on / off of the second current adjustment module.

[0017] Optionally, the first current adjustment module further includes a first resistor and a second resistor;

[0018] One end of the first resistor is connected to the positive electrode of the voltage stabilizing diode, and the other end is connected to the gate of the first triode;

[0019] One end of the second resistor is connected to the connection point between the first resistor and the first triode, and the other end is grounded.

[0020] By adopting the above technical solution, the first resistor and the second resistor are used for voltage division to adjust the gate potential of the first triode, so as to control the on-off of the first triode and protect the first triode from overvoltage damage.

[0021] Optionally, the first current adjustment module further includes a third resistor. One end of the third resistor is connected to the connection point between the voltage stabilizing diode and the positive electrode of the LED, and the other end is connected to the connection point between the first triode and the second current adjustment module.

[0022] By adopting the above technical solution, the third resistor is used for voltage division protection. The signal divided by the third resistor is output to the first current adjustment module (from the collector of the first triode to the ground) or output to the second current adjustment module (for controlling the on-off of the following second triode).

[0023] Optionally, the second current adjustment module includes a second triode;

[0024] The gate of the second triode is connected to the connection point between the third resistor and the first triode. The collector of the second triode is connected to the negative electrode of the LED, and the emitter of the second triode is grounded.

[0025] By adopting the above technical solution, if the voltage stabilizing diode is not broken down, the signal of the positive electrode of the LED raises the potential of the second triode through the third resistor, making the second triode conduct. In this case, the negative electrode of the LED is grounded through the second triode, and the current is amplified, and the screen will also become brighter. If the voltage stabilizing diode is broken down, the gate of the first triode is raised to conduct, pulling down the gate potential of the second triode, thereby turning off the second triode and making the negative electrode of the LED use the original resistor to adjust the current.

[0026] Optionally, the second current adjustment module further includes a fourth resistor. One end of the fourth resistor is connected to the connection point between the third resistor and the first triode, and the other end is connected to the gate of the second triode.

[0027] By adopting the above technical solution, the fourth resistor is used for voltage division protection of the gate of the second triode to avoid damage to the second triode due to overvoltage caused by potential switching, thereby improving the reliability of use.

[0028] Optionally, the current adjustment module further includes a fifth resistor. One end of the fifth resistor is connected to the collector of the second triode, and the other end is connected to the negative electrode of the LED.

[0029] By adopting the above technical solution, a fifth resistor is connected in series in the circuit where the negative electrode of the LED is grounded for voltage division protection, avoiding damage to the flowing devices due to excessive current, thereby improving the reliability of the circuit.

[0030] The second aspect of the present application provides an adaptive adjustment device for backlight current, which is equipped with the above-mentioned adaptive adjustment circuit for backlight current.

[0031] In summary, the beneficial effects of the present application are as follows: The voltage trigger module is used to identify the backlight voltage value and determine whether the magnitude of the backlight voltage value exceeds the preset voltage threshold. The preset voltage threshold is determined by the device selection of the voltage trigger module. If the backlight voltage value does not exceed the preset voltage threshold, the second current adjustment module is turned on, making the backlight (negative electrode of the LED) grounded. In this case, the current is larger and the screen will be brighter. If the backlight voltage value exceeds the preset voltage threshold, the first current adjustment module is turned on to ground the first current adjustment module, thereby turning off the second current adjustment module. After the second current adjustment module is turned off, the negative electrode of the LED uses the originally set resistor to adjust the current. Based on this, the function of adaptively adjusting the backlight current based on the identified magnitude of the backlight voltage value is realized, so as to meet the current requirements of different screens, and then the beneficial effect of improving product compatibility is achieved. Description of the Drawings

[0032] Figure 1 is a module connection diagram of the adaptive adjustment circuit for backlight current provided by an embodiment of the present application;

[0033] Figure 2 is a circuit schematic diagram of the adaptive adjustment circuit for backlight current provided by an embodiment of the present application. Detailed Embodiments

[0034] The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several deformations and improvements without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0035] In the following description, specific details such as specific system structures and technologies are proposed for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0036] It should be understood that when used in the specification and appended claims of this application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0037] It should also be understood that the term "and / or" used in the specification and appended claims of this application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0038] In addition, in the description of the specification and appended claims of this application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0039] Reference to "one embodiment" or "some embodiments" etc. described in the specification of this application means that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0040] The following further describes this application in detail with reference to the accompanying drawings.

[0041] Refer to Figure 1 , which is a module connection diagram of an adaptive adjustment circuit for backlight current provided by an embodiment of this application, including:

[0042] A voltage trigger module, the input end of the voltage trigger module is connected to the positive electrode of the LED, LED+, and is used to adjust the on / off of the voltage trigger module according to the backlight voltage value output by the positive electrode of the LED, LED+;

[0043] A first current adjustment module, the input end of the first current adjustment module is connected to the output end of the voltage trigger module, and the first output end of the first current adjustment module is grounded, and is used to adjust the on / off of the first current adjustment module according to the on / off of the voltage trigger module;

[0044] The second current adjustment module, the first input end of the second current adjustment module is connected to the positive electrode of the LED, LED+, the second input end of the second current adjustment module is connected to the second output end of the first current adjustment module, and the output end of the second current adjustment module is connected to the negative electrode of the LED, LED-, and is used to adjust the on / off of the second current adjustment module according to the on / off of the first current adjustment module.

[0045] Specifically, the voltage trigger module is used to identify the backlight voltage value and determine whether the magnitude of the backlight voltage value exceeds a preset voltage threshold. The preset voltage threshold is determined by the device selection of the voltage trigger module. If the backlight voltage value does not exceed the preset voltage threshold, the second current adjustment module is turned on, so that the backlight (negative electrode of the LED, LED-) is grounded. In this case, the current is larger and the screen will be brighter. If the backlight voltage value exceeds the preset voltage threshold, the first current adjustment module is turned on to ground the first current adjustment module, thereby turning off the second current adjustment module. After the second current adjustment module is turned off, the negative electrode of the LED, LED- uses the originally set resistor to adjust the current. Based on this, the function of adaptively adjusting the backlight current according to the magnitude of the identified backlight voltage value is realized, so as to meet the current requirements of different screens, and then the beneficial effect of improving product compatibility is achieved.

[0046] Further, please refer to Figure 2 , Figure 2 FIG. is the circuit schematic diagram of the adaptive adjustment circuit of the backlight current provided by the embodiment of the present application, including a voltage trigger module, a first current adjustment module and a second current adjustment module. The following is a specific description of each module:

[0047] Regarding the voltage trigger module: The voltage trigger module includes a voltage stabilizing diode ZD1;

[0048] The negative electrode of the voltage stabilizing diode ZD1 is connected to the positive electrode of the LED, LED+, and the negative electrode of the voltage stabilizing diode ZD1 is connected to the input end of the current adjustment module.

[0049] Specifically, the voltage stabilizing diode ZD1 is used to provide a preset voltage threshold. In this embodiment, the preset voltage threshold can be 12V, that is, if the backlight voltage value is greater than 12V, the voltage stabilizing diode ZD1 is broken down. In this case, the first current adjustment module is turned on and the second current adjustment module is turned off. If the backlight voltage value is less than 12V (or the voltage stabilizing diode ZD1 is not broken down), in this case, the second current adjustment module is turned on. According to the on / off of one of the first current adjustment module and the second current adjustment module, two different backlight currents are formed.

[0050] Regarding the first current adjustment module: The first current adjustment module includes a first triode Q1;

[0051] The gate of the first triode Q1 is connected to the positive electrode of the voltage stabilizing diode ZD1, the collector of the first triode Q1 is connected to the connection point of the negative electrode of the voltage stabilizing diode ZD1 and the positive electrode of the LED (LED+), and the emitter of the first triode Q1 is grounded;

[0052] The gate of the first triode Q1 is also connected to the ground electrode, and the collector of the first triode Q1 is also connected to the second input terminal of the second current adjustment module.

[0053] Specifically, the on / off of the first triode Q1 is controlled by the voltage stabilizing diode ZD1. If the backlight voltage value exceeds the preset voltage threshold, in this case, the voltage stabilizing diode ZD1 is broken down, causing the gate potential of the first triode Q1 to rise, thereby turning on the first triode Q1. After the first triode Q1 is turned on, the potential sampled by the second current adjustment module from the collector of the first triode Q1 can be adjusted, thereby adjusting the on / off of the second current adjustment module.

[0054] Optionally, the first current adjustment module further includes a first resistor R1 and a second resistor R2;

[0055] One end of the first resistor R1 is connected to the positive electrode of the voltage stabilizing diode ZD1, and the other end is connected to the gate of the first triode Q1;

[0056] One end of the second resistor R2 is connected to the connection point of the first resistor R1 and the first triode Q1, and the other end is grounded.

[0057] Specifically, the first resistor R1 and the second resistor R2 are used for voltage division to adjust the gate potential of the first triode Q1, so as to control the on / off of the first triode Q1 and protect the first triode Q1 from overvoltage damage.

[0058] Optionally, the first current adjustment module further includes a third resistor R3. One end of the third resistor R3 is connected to the connection point of the voltage stabilizing diode ZD1 and the positive electrode of the LED (LED+), and the other end is connected to the connection point of the first triode Q1 and the second current adjustment module.

[0059] Specifically, the third resistor R3 is used for voltage division protection. The signal passing through the third resistor R3 is divided and output to the first current adjustment module (from the collector of the first triode Q1 to the ground) or output to the second current adjustment module (for controlling the on / off of the following second triode Q2).

[0060] Optionally, the second current adjustment module includes a second triode Q2;

[0061] The gate of the second triode Q2 is connected to the connection point of the third resistor R3 and the first triode Q1. The collector of the second triode Q2 is connected to the negative electrode LED- of the LED, and the emitter of the second triode Q2 is grounded.

[0062] Specifically, if the voltage regulator diode ZD1 is not broken down, the signal of the positive electrode LED+ of the LED pulls up the potential of the second triode Q2 through the third resistor R3, causing the second triode Q2 to conduct. In this case, the negative electrode LED- of the LED is grounded through the second triode Q2, and the current is amplified, and the screen will also become brighter. If the voltage regulator diode ZD1 is broken down, the gate of the first triode Q1 is pulled up and conducts, causing the gate potential of the second triode Q2 to be pulled down, thereby turning off the second triode Q2 and enabling the negative electrode LED- of the LED to adjust the current using the original resistor.

[0063] Optionally, the second current adjustment module further includes a fourth resistor R4. One end of the fourth resistor R4 is connected to the connection point of the third resistor R3 and the first triode Q1, and the other end is connected to the gate of the second triode Q2.

[0064] Specifically, the fourth resistor R4 is used for voltage division to protect the gate of the second triode Q2, so as to avoid damage to the second triode Q2 due to overvoltage generated by potential switching, thereby improving the reliability of use.

[0065] Optionally, the current adjustment module further includes a fifth resistor R5. One end of the fifth resistor R5 is connected to the collector of the second triode Q2, and the other end is connected to the negative electrode LED- of the LED.

[0066] Specifically, a fifth resistor R5 is connected in series in the circuit where the negative electrode LED- of the LED is grounded for voltage division protection to avoid damage to the devices passing through due to excessive current, thereby improving the reliability of the circuit.

[0067] The second aspect of the present application provides an adaptive adjustment device for backlight current, which is loaded with the above-mentioned adaptive adjustment circuit for backlight current.

[0068] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; 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, and should all be included in the protection scope of the present application.

Claims

1. A backlight current adaptive adjustment circuit, characterized in that: include: A voltage trigger module, the input end of which is connected to the LED anode, and is used to adjust the on and off of the voltage trigger module according to the backlight voltage value output by the LED anode; A first current adjustment module, wherein an input end of the first current adjustment module is connected to an output end of the voltage trigger module, a first output end of the first current adjustment module is grounded, and is used to adjust the on / off of the first current adjustment module according to the on / off of the voltage trigger module; A second current adjustment module, wherein the first input end of the second current adjustment module is connected to the positive electrode of the LED, the second input end of the second current adjustment module is connected to the second output end of the first current adjustment module, and the output end of the second current adjustment module is connected to the negative electrode of the LED, and is used to adjust the on and off of the second current adjustment module according to the on and off of the first current adjustment module.

2. The backlight current adaptive adjustment circuit according to claim 1, characterized in that: The voltage trigger module includes a voltage regulator tube; The cathode of the voltage regulator tube is connected to the anode of the LED, and the cathode of the voltage regulator tube is connected to the input end of the current adjustment module.

3. The backlight current adaptive adjustment circuit according to claim 2, characterized in that: The first current adjustment module includes a first transistor; The gate of the first transistor is connected to the positive electrode of the voltage regulator tube, the collector of the first transistor is connected to the connection point between the negative electrode of the voltage regulator tube and the positive electrode of the LED, and the emitter of the first transistor is grounded; The gate of the first transistor is also connected to the ground, and the collector of the first transistor is also connected to the second input end of the second current adjustment module.

4. The backlight current adaptive adjustment circuit according to claim 3, characterized in that: The first current adjustment module also includes a first resistor and a second resistor; One end of the first resistor is connected to the positive electrode of the voltage regulator tube, and the other end is connected to the gate of the first transistor; One end of the second resistor is connected to the connection point between the first resistor and the first transistor, and the other end is grounded.

5. The backlight current adaptive adjustment circuit according to claim 3, characterized in that: The first current adjustment module also includes a third resistor, one end of which is connected to the connection between the voltage regulator and the positive electrode of the LED, and the other end of which is connected to the connection between the first transistor and the second current adjustment module.

6. The backlight current adaptive adjustment circuit according to claim 5, characterized in that: The second current adjustment module includes a second transistor; The gate of the second transistor is connected to the connection point between the third resistor and the first transistor, the collector of the second transistor is connected to the cathode of the LED, and the emitter of the second transistor is grounded.

7. The backlight current adaptive adjustment circuit according to claim 6, characterized in that: The second current adjustment module further includes a fourth resistor, one end of which is connected to the connection point between the third resistor and the first transistor, and the other end of which is connected to the gate of the second transistor.

8. The backlight current adaptive adjustment circuit according to claim 6, characterized in that: The current adjustment module further includes a fifth resistor, one end of which is connected to the collector of the second transistor, and the other end of which is connected to the cathode of the LED.

9. An adaptive adjustment device for backlight current, characterized in that: A backlight current adaptive adjustment circuit is provided.

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