Tablet computer and backlight power supply circuit thereof

Abstract

The utility model provides a tablet personal computer and a backlight power supply circuit thereof, which are characterized in that a boost circuit is enabled through a controller, then a power supply is boosted through the boost circuit, the boosted circuit is stabilized at 5V through a voltage division circuit, and the 5V voltage is further output to a backlight circuit, the controller outputs the PWM signal to the enabling end of the backlight circuit, so that the backlight circuit can output voltage and current based on requirements, a screen backlight assembly can work normally, and the problem that screen flashing possibly occurs when the power supply voltage of a large-screen tablet computer is low is solved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics, and in particular to a tablet computer and its backlight power supply circuit. Background Technology

[0002] Tablet computers typically operate within a 3.4V-4.35V battery voltage range. Conventional backlight designs connect the backlight IC's input voltage to the battery voltage. However, as the battery level decreases, the backlight IC's input voltage also decreases, leading to reduced efficiency and unstable output from the backlight circuit, resulting in screen flicker. Currently, tablets commonly range in size from 6 inches to 12 inches. For large-screen tablets, conventional backlight designs are prone to low-battery screen flicker.

[0003] In view of the above, this application is hereby submitted. Utility Model Content

[0004] This utility model discloses a tablet computer and its backlight power supply circuit, which aims to solve the problem of screen flickering that may occur in existing large-screen tablet computers when their power supply voltage is low.

[0005] The first embodiment of this utility model provides a backlight power supply circuit for a tablet computer, including: a power supply, a boost circuit, a voltage divider circuit, a backlight circuit, and a controller;

[0006] The output terminal of the power supply is electrically connected to the input terminal of the boost circuit. The output terminal of the boost circuit is electrically connected to the input terminal of the backlight circuit through the voltage divider circuit. The output terminal of the backlight circuit is used to electrically connect to the screen backlight assembly.

[0007] The output terminal of the controller is electrically connected to the enable terminal of the boost circuit and the enable terminal of the backlight circuit, wherein the signal received by the enable terminal of the backlight circuit is a PWM signal.

[0008] The backlight circuit is configured to adjust the stable voltage after passing through the voltage divider circuit based on the PWM signal and then provide it to the screen backlight assembly.

[0009] Preferably, the boost circuit includes a first IC, a first filter circuit, and a boost inductor;

[0010] The output terminal of the power supply is electrically connected to the input terminal of the first IC through the boost inductor, and the first filter circuit is configured between the boost inductor and the output terminal of the power supply.

[0011] Preferably, it further includes a first current-limiting resistor disposed between the first filter circuit and the boost inductor.

[0012] Preferably, the first IC is model ETA1090D3M.

[0013] Preferably, the voltage divider circuit includes: a first resistor and a second resistor;

[0014] Wherein, the first end of the first resistor is electrically connected to the output terminal of the first IC, the second end of the first resistor is grounded through the second resistor, and the first end of the first resistor is electrically connected to the feedback terminal of the first IC.

[0015] Preferably, the backlight circuit includes a second IC, an energy storage inductor, and a freewheeling diode;

[0016] The output terminal of the voltage divider circuit is electrically connected to the input terminal of the second IC. The energy storage inductor is connected in parallel to the input and output terminals of the second IC. The output terminal of the second IC is electrically connected to the input terminal of the screen backlight assembly through the freewheeling diode. The feedback terminal of the screen backlight assembly is electrically connected to the feedback terminal of the second IC.

[0017] Preferably, the second current-limiting resistor is configured between the controller and the second IC.

[0018] Preferably, the second IC is an SGM3766YTN5G / TR.

[0019] The second embodiment of this utility model provides a tablet computer, characterized in that it includes a backlight power supply circuit for a tablet computer as described in any one of the above claims.

[0020] Based on the tablet computer and its backlight power supply circuit provided by this utility model, the boost circuit is first enabled by the controller, then the power supply is boosted by the boost circuit, and the voltage divider circuit stabilizes the boosted circuit at 5V. The 5V voltage is then output to the backlight circuit. The controller outputs a PWM signal to the enable terminal of the backlight circuit, so that the backlight circuit can output voltage and current according to demand, enabling the screen backlight component to work normally. This solves the problem of screen flickering that may occur in large-screen tablet computers when their power supply voltage is low. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a backlight power supply circuit for a tablet computer provided by this utility model.

[0022] Figure 2 This is a schematic diagram of the boost circuit provided by this utility model;

[0023] Figure 3 This is a schematic diagram of the backlight circuit provided by this utility model. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely represents selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0025] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0026] This utility model discloses a tablet computer and its backlight power supply circuit, which aims to solve the problem of screen flickering that may occur in existing large-screen tablet computers when their power supply voltage is low.

[0027] Please see Figure 1 The first embodiment of this utility model provides a backlight power supply circuit for a tablet computer, including: a power supply 2, a boost circuit 3, a voltage divider circuit 4, a backlight circuit 5, and a controller 1;

[0028] The output terminal of the power supply 2 is electrically connected to the input terminal of the boost circuit 3. The output terminal of the boost circuit 3 is electrically connected to the input terminal of the backlight circuit 5 through the voltage divider circuit 4. The output terminal of the backlight circuit 5 is used to electrically connect to the screen backlight assembly.

[0029] The output terminal of the controller 1 is electrically connected to the enable terminal of the boost circuit 3 and the enable terminal of the backlight circuit 5, wherein the signal received by the enable terminal of the backlight circuit 5 is a PWM signal.

[0030] The backlight circuit 5 is configured to adjust the stable voltage after passing through the voltage divider circuit 4 based on the PWM signal and then provide it to the screen backlight assembly.

[0031] It should be noted that power supply 2 is responsible for providing the necessary operating voltage for the entire tablet computer system. The main function of boost circuit 3 is to convert the low voltage output by power supply 2 to provide sufficient voltage to drive backlight circuit 5. In practical applications, the voltage of power supply 2 may fluctuate with changes in battery power. However, by enabling boost circuit 3 through controller 1 (which can be the tablet computer's CPU or an embedded microcontroller, such as an STM32 series microcontroller), boost circuit 3 can effectively convert these fluctuations into a stable voltage output, ensuring that backlight circuit 5 always receives the required voltage. In this embodiment, voltage divider circuit 4 is used to appropriately distribute the voltage output by boost circuit 3 to ensure that the input terminal of backlight circuit 5 receives an accurate operating voltage. Then, the voltage after voltage division is output to the output terminal of backlight circuit 5, which is connected to the screen backlight assembly. Similarly, the enable terminal of backlight circuit 5 starts working after receiving the enable signal from controller 1.

[0032] Backlight circuit 5 is responsible for providing the required backlight voltage to the screen. Backlight circuit 5 is controlled using a PWM (Pulse Width Modulation) signal to adjust backlight brightness and stability. Through the PWM signal, controller 1 can precisely adjust the operating state of backlight circuit 5, enabling it to provide the necessary current and voltage according to demand, thereby ensuring the normal operation of the screen backlight components. The use of PWM signals allows backlight circuit 5 to adjust brightness efficiently while reducing power consumption and maintaining good performance even when battery power is low.

[0033] Please combine Figure 2 In one possible implementation of this utility model, the boost circuit 3 includes a first IC, a first filter circuit 31, and a boost inductor L1;

[0034] The output terminal of the power supply 2 is electrically connected to the input terminal of the first IC through the boost inductor L1, and the first filter circuit 31 is disposed between the boost inductor L1 and the output terminal of the power supply 2.

[0035] It should be noted that in this embodiment, the first IC model can be, but is not limited to, ETA1090D3M. The function of the first filter circuit 31 is to smooth the pulse signal output by the inductor, removing high-frequency noise and fluctuations, thus making the output voltage more stable. The filter circuit can effectively reduce the interference of voltage fluctuations on other circuits, avoiding system failures or performance degradation of the backlight circuit 5 caused by voltage instability.

[0036] It should be noted that the ETA109D3M chip integrates a MOSFET switch. The boost inductor L1 stores and releases energy in each current cycle to boost the voltage. Specifically, when the internal MOSFET is turned on, current flows through the boost inductor L1 to store energy, and when the MOSFET is turned off, the boost inductor L1 discharges. It can achieve voltage boosting and regulation by adjusting the conduction time of the internal MOSFET.

[0037] In one possible implementation of this utility model, a first current-limiting resistor R3 is further included, which is disposed between the first filter circuit 31 and the boost inductor L1.

[0038] It should be noted that in practical applications, due to the instability of battery voltage, the output current of the boost inductor L1 may fluctuate excessively, which could negatively impact the stability of the entire circuit. To prevent this, a first current-limiting resistor R3 is configured between the first filter circuit 31 and the boost inductor L1 to limit the current. This current-limiting resistor ensures that the current flowing into the boost inductor L1 is within a safe range, thereby preventing overcurrent damage to the boost inductor L1 and other circuit components.

[0039] In one possible implementation of this utility model, the voltage divider circuit 4 includes: a first resistor R1 and a second resistor R2;

[0040] Wherein, the first end of the first resistor R1 is electrically connected to the output terminal of the first IC, the second end of the first resistor R1 is grounded through the second resistor R2, and the second end of the first resistor R1 is electrically connected to the feedback terminal of the first IC.

[0041] It should be noted that the voltage output by the first IC is a voltage adjusted by the boost circuit 3, which is usually relatively high. Therefore, it needs to be reduced to a suitable voltage level for the backlight circuit 5 by the voltage divider circuit 4. The second terminal of the first resistor R1 is grounded through the second resistor R2, thus forming a typical voltage divider network. The series relationship between the second resistor R2 and the first resistor R1 determines the voltage distribution ratio, ensuring that the voltage is appropriately stepped down before being input to the backlight circuit 5. This ensures that the backlight circuit 5 can always obtain a stable operating voltage under different battery voltage conditions. The second terminal of the first resistor R1 is electrically connected to the feedback terminal of the first IC to implement a feedback regulation mechanism, adjusting the output voltage in real time to ensure that the output voltage of the voltage divider circuit 4 remains stable.

[0042] Please combine Figure 3 In one possible implementation of this utility model, the backlight circuit 5 includes a second IC, an energy storage inductor L2, and a freewheeling diode D902;

[0043] The output terminal of the voltage divider circuit 4 is electrically connected to the input terminal of the second IC. The energy storage inductor L2 is connected in parallel to the input and output terminals of the second IC. The output terminal of the second IC is electrically connected to the input terminal of the screen backlight assembly through the freewheeling diode D902. The feedback terminal of the screen backlight assembly is electrically connected to the feedback terminal of the second IC.

[0044] It should be noted that in this embodiment, the second IC can be, but is not limited to, SGM3766YTN5G / TR. The PWM signal controls the second IC switch via the EN terminal to achieve dimming. The MOSFET inside the second IC, together with the MOSFET, forms a boost circuit 3, thus creating a current storage and release mechanism. The energy storage inductor L2 stores energy from the power supply 2 and releases it when needed to maintain current stability. In the backlight circuit 5, the use of an inductor helps smooth current fluctuations, reduce high-frequency noise interference, and ensure stable screen backlight brightness. When current passes through the inductor, it converts it into magnetic energy and stores it, releasing it when needed, thereby ensuring the continuity and stability of the current. The freewheeling diode D902 guides the current between the output terminal of the second IC and the screen backlight assembly, ensuring unidirectional current flow and preventing reverse current from damaging the circuit.

[0045] In one possible implementation of this utility model, the second current-limiting resistor R4 is configured between the controller 1 and the second IC.

[0046] It should be noted that the second current-limiting resistor R4 is located between the controller 1 and the second IC to prevent the PWM signal amplitude from being too large and damaging the chip. Furthermore, it can limit the current flowing into the chip when there is an abnormality in the signal line (such as static electricity).

[0047] The second embodiment of this utility model provides a tablet computer, characterized in that it includes a backlight power supply circuit for a tablet computer as described in any one of the above claims.

[0048] Based on the tablet computer and its backlight power supply circuit provided by this utility model, the boost circuit is first enabled by the controller 1, then the power supply 2 is boosted by the boost circuit 3, and the boost circuit 4 stabilizes the boosted circuit at 5V. The 5V voltage is then output to the backlight circuit 5. The controller 1 outputs a PWM signal to the enable terminal of the backlight circuit 5, so that the backlight circuit 5 can output voltage and current according to demand, so that the screen backlight component can work normally. This solves the problem of screen flickering that may occur when the power supply 2 voltage of a large-screen tablet computer is low.

[0049] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions that fall within the scope of this utility model's concept are protected by this utility model.

Claims

1. A backlight power supply circuit for a tablet computer, characterized in that, include: Power supply, boost circuit, voltage divider circuit, backlight circuit, and controller; The output terminal of the power supply is electrically connected to the input terminal of the boost circuit. The output terminal of the boost circuit is electrically connected to the input terminal of the backlight circuit through the voltage divider circuit. The output terminal of the backlight circuit is used to electrically connect to the screen backlight assembly. The output terminal of the controller is electrically connected to the enable terminal of the boost circuit and the enable terminal of the backlight circuit, wherein the signal received by the enable terminal of the backlight circuit is a PWM signal. The backlight circuit is configured to adjust the stable voltage after passing through the voltage divider circuit based on the PWM signal and then provide it to the screen backlight assembly.

2. The backlight power supply circuit for a tablet computer according to claim 1, characterized in that, The boost circuit includes a first IC, a first filter circuit, and a boost inductor; The output terminal of the power supply is electrically connected to the input terminal of the first IC through the boost inductor, and the first filter circuit is configured between the boost inductor and the output terminal of the power supply.

3. The backlight power supply circuit for a tablet computer according to claim 2, characterized in that, It also includes a first current-limiting resistor configured between the first filter circuit and the boost inductor.

4. The backlight power supply circuit for a tablet computer according to claim 2, characterized in that, The first IC model is ETA1090D3M.

5. The backlight power supply circuit for a tablet computer according to claim 2, characterized in that, The voltage divider circuit includes: a first resistor and a second resistor; Wherein, the first end of the first resistor is electrically connected to the output terminal of the first IC, the second end of the first resistor is grounded through the second resistor, and the first end of the first resistor is electrically connected to the feedback terminal of the first IC.

6. The backlight power supply circuit for a tablet computer according to claim 1, characterized in that, The backlight circuit includes a second IC, an energy storage inductor, and a freewheeling diode; The output terminal of the voltage divider circuit is electrically connected to the input terminal of the second IC. The energy storage inductor is connected in parallel to the input and output terminals of the second IC. The output terminal of the second IC is electrically connected to the input terminal of the screen backlight assembly through the freewheeling diode. The feedback terminal of the screen backlight assembly is electrically connected to the feedback terminal of the second IC.

7. The backlight power supply circuit for a tablet computer according to claim 6, characterized in that, The second current-limiting resistor is configured between the controller and the second IC.

8. The backlight power supply circuit for a tablet computer according to claim 6, characterized in that, The second IC is SGM3766YTN5G / TR.

9. A tablet computer, characterized in that, Includes a backlight power supply circuit for a tablet computer as described in any one of claims 1 to 8.

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