Ripple suppression circuit for notebook displays

Abstract

The application relates to a notebook display ripple suppression circuit. The notebook display ripple suppression circuit comprises an input module, a voltage reduction module and a suppression module, the voltage reduction module is electrically connected with the input module; the suppression module comprises a capacitor C5, an inductor L2 and a capacitor C6, one end of the capacitor C5 is electrically connected with the voltage reduction module, the second end of the capacitor C5 is grounded, the first end of the inductor L2 is electrically connected with the first end of the capacitor C5, the second end of the inductor L2 is electrically connected with the first end of the capacitor C6, and the second end of the capacitor C6 is grounded. The scheme provided by the application can eliminate the ripple interference signal, thereby solving the picture flickering phenomenon.

Description

Technical Field

[0001] This utility model relates to the field of circuit design technology, and in particular to a ripple suppression circuit for a notebook computer display. Background Technology

[0002] Laptop monitors typically use DC power. When there is a high voltage difference between the input and output voltages, energy loss is dissipated as heat, which reduces the efficiency of the circuit and makes it susceptible to ripple voltage, causing the laptop monitor screen to flicker. Currently, laptop monitors cannot eliminate ripple interference signals internally. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a ripple suppression circuit for a notebook computer display that can eliminate ripple interference signals, thereby solving the problem of screen flickering.

[0004] The objective of this utility model is achieved through the following technical solution: The first aspect of this application provides a ripple suppression circuit for a notebook computer display, comprising: an input module; a step-down module electrically connected to the input module; and a suppression module including a capacitor C5, an inductor L2, and a capacitor C6, wherein one end of the capacitor C5 is electrically connected to the step-down module, the second end of the capacitor C5 is grounded, the first end of the inductor L2 is electrically connected to the first end of the capacitor C5, the second end of the inductor L2 is electrically connected to the first end of the capacitor C6, and the second end of the capacitor C6 is grounded.

[0005] The input module includes capacitor C1 and capacitor C2. The first end of capacitor C1 is electrically connected to the first end of capacitor C2, and the second ends of capacitor C1 and capacitor C2 are both grounded.

[0006] The step-down module includes a chip U1 and a resistor R2. The chip U1 is electrically connected to the first terminal of the capacitor C1 and the first terminal of the capacitor C2, respectively. The first terminal of the resistor R2 is electrically connected to the chip U1, and the second terminal of the resistor R2 is grounded.

[0007] The step-down module also includes a capacitor C7 and a resistor R3. The first end of the capacitor C7 is electrically connected to the chip U1, the second end of the capacitor C7 is electrically connected to the first end of the resistor R3, and the second end of the resistor R3 is grounded.

[0008] The step-down module also includes a capacitor C3, the first end of which is electrically connected to the chip U1.

[0009] The step-down module also includes an inductor L1, a resistor R1, and a resistor R4. The first end of the inductor L1 is electrically connected to the second end of the capacitor C3, the second end of the inductor L1 is electrically connected to the first end of the resistor R1, the second end of the resistor R1 is electrically connected to the first end of the resistor R4, and the second end of the resistor R4 is grounded.

[0010] The step-down module also includes a capacitor C4, the first end of which is electrically connected to the second end of the inductor L1, the second end of which is electrically connected to the chip U1, and the first end of the inductor L2 is electrically connected to the first end of the capacitor C4.

[0011] Compared with the prior art, the present invention has at least the following advantages: The π-type ripple suppression circuit, composed of capacitor C5, inductor L2, and capacitor C6, results in a very low impedance of the DC voltage output from the step-down module across inductor L2. Consequently, the voltage drop and losses across inductor L2 are minimal, ensuring that the output voltage of inductor L2 is the same as the output voltage. Then, capacitor C6 is connected to the other end of inductor L2 for secondary filtering, further suppressing high-frequency noise and filtering out low-frequency ripple. This ensures that both the input and output of the π-type ripple suppression circuit exhibit low impedance, reducing mutual interference between the preceding and following stages and guaranteeing the integrity of the output voltage. Finally, the output voltage BL_VCC provides an efficient and stable operating voltage for the laptop display. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.

[0013] Figure 1 This is a functional block diagram of the ripple suppression circuit of a notebook computer display in one embodiment of the present invention; Figure 2 This is a circuit diagram of a ripple suppression circuit for a notebook computer display according to one embodiment of the present invention. Detailed Implementation

[0014] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0015] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0016] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0017] Laptop monitors typically use DC power. When there is a high voltage difference between the input and output voltages, energy loss is dissipated as heat, which reduces the efficiency of the circuit and makes it susceptible to ripple voltage, causing the laptop monitor screen to flicker. Currently, laptop monitors cannot eliminate ripple interference signals internally.

[0018] To address the aforementioned problems, this application provides a ripple suppression circuit for a notebook computer display, which can eliminate ripple interference signals and thus solve the problem of screen flickering.

[0019] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0020] See Figure 1 and Figure 2 A ripple suppression circuit for a notebook computer display includes: an input module 100, a step-down module 200, and a suppression module 300. The step-down module 200 is electrically connected to the input module 100. The suppression module 300 includes a capacitor C5, an inductor L2, and a capacitor C6. One end of the capacitor C5 is electrically connected to the step-down module 200, and the second end of the capacitor C5 is grounded. The first end of the inductor L2 is electrically connected to the first end of the capacitor C5, and the second end of the inductor L2 is electrically connected to the first end of the capacitor C6. The second end of the capacitor C6 is grounded.

[0021] It should be noted that the π-type ripple suppression circuit composed of capacitor C5, inductor L2, and capacitor C6 has a large inductive reactance for the AC component of the voltage. Together with the capacitive reactance of capacitors C5 and C6, it forms a ripple suppression circuit that attenuates the ripple interference signal in the output voltage, thereby achieving the suppression effect.

[0022] See Figure 2 In one embodiment, the input module 100 includes capacitor C1 and capacitor C2. The first end of capacitor C1 is electrically connected to the first end of capacitor C2, and the second ends of capacitor C1 and capacitor C2 are both grounded.

[0023] It can be understood that capacitors C1 and C2 are filter capacitors.

[0024] See Figure 2 In one embodiment, the step-down module 200 includes a chip U1 and a resistor R2. The chip U1 is electrically connected to the first end of the capacitor C1 and the first end of the capacitor C2, respectively. The first end of the resistor R2 is electrically connected to the chip U1, and the second end of the resistor R2 is grounded.

[0025] It should be noted that the chip U1 can be model RT7272B, and resistor R2 is a current-limiting resistor.

[0026] See Figure 2 In one embodiment, the step-down module 200 further includes a capacitor C7 and a resistor R3. The first end of the capacitor C7 is electrically connected to the chip U1, the second end of the capacitor C7 is electrically connected to the first end of the resistor R3, and the second end of the resistor R3 is grounded.

[0027] It should be noted that capacitor C7 and resistor R3 form an RC network, which plays a role in suppressing noise interference.

[0028] See Figure 2 In one embodiment, the step-down module 200 further includes a capacitor C3, the first end of which is electrically connected to the chip U1.

[0029] It is understandable that capacitor C3 is a bootstrap capacitor.

[0030] See Figure 2 In one embodiment, the step-down module 200 further includes an inductor L1, a resistor R1, and a resistor R4. The first terminal of inductor L1 is electrically connected to the second terminal of capacitor C3, the second terminal of inductor L1 is electrically connected to the first terminal of resistor R1, the second terminal of resistor R1 is electrically connected to the first terminal of resistor R4, and the second terminal of resistor R4 is grounded. Specifically, the step-down module 200 also includes a capacitor C4. The first terminal of capacitor C4 is electrically connected to the second terminal of inductor L1, the second terminal of capacitor C4 is electrically connected to chip U1, and the first terminal of inductor L2 is electrically connected to the first terminal of capacitor C4.

[0031] It should be noted that capacitor C4 is a feedforward capacitor. It samples the BL_FB feedback signal through the node voltage between the resistors. Combined with the feedforward capacitor C4, it forms the zero and pole of the circuit. The high-frequency signal output by chip U1 can be quickly transmitted to the 5-pin input through the feedforward capacitor. It is connected to the inverting terminal of the built-in reference voltage comparator and compared with the reference voltage. This allows chip U1 to respond quickly to changes in the load of the downstream stage and control the voltage output of chip U1, thereby limiting the fluctuation range of the output voltage.

[0032] The circuit principle of this application is explained below: First, the external VCC voltage is filtered to ground by capacitors C1 and C2 to remove interference noise from the input voltage. Capacitor C1 has a larger capacitance and presents a lower impedance to low-frequency signals, thus absorbing low-frequency interference signals. Capacitor C2 has a smaller capacitance and presents an even lower impedance to high-frequency signals, thus filtering out high-frequency ripple interference signals. Subsequently, the VCC voltage provides the 8-pin input startup voltage to chip U1, connecting to the power regulator input terminal of the built-in circuit.

[0033] After the 8-pin connector of chip U1 is powered on, the central control motherboard of the laptop outputs the BL_EM control signal, which is connected to the 3-pin enable input of chip U1. The signal is compared with the operational amplifier of the built-in circuit to ensure that the enable pin of chip U1 is in a low-level state when it is powered on, so as to prevent the built-in circuit of chip U1 from being started to work by mistake. The chip U1 will start the built-in circuit to work only after the input voltage of 8-pin is stable. The 7-pin external resistor R2 connected to ground of chip U1, along with the built-in circuit, sets the maximum output current, thus limiting the current and preventing overload damage to the chip or load circuit. Meanwhile, the 6-pin external capacitor C7 and resistor R3, connected in series to ground, provide loop compensation to the output of the built-in reference voltage comparator. This stabilizes the control feedback loop, adjusts the frequency response, and suppresses noise interference. The RC network alters the phase and gain margins of the built-in circuit, ensuring the stability of the control feedback loop in both high and low frequency bands and preventing oscillations due to insufficient phase. Simultaneously, the RC series circuit has low impedance characteristics to high-frequency noise, filtering out high-frequency interference in the control signal and improving the anti-interference capability of chip U1. Furthermore, it accelerates the response speed of chip U1 to changes in input voltage or load and suppresses voltage overshoot and ringing.

[0034] Chip U1 outputs voltage via its built-in DC-DC step-down logic drive circuit through its 1-pin pin. This voltage is then connected to one end of inductor L1 to suppress current surges, mitigating the current surge during switching of the built-in MOSFET and reducing the stress on subsequent circuit components. An external bootstrap capacitor C3, connected to pin 2, is electrically connected to pin 1 of chip U1 to cancel out ripple and pulse interference signals. The other end of inductor L1 is connected to feedback resistors R1 and R4 and feedforward capacitor C4. The BL_FB feedback signal is sampled through the node voltage between the resistors. Combined with the feedforward capacitor C4, this forms the zero and pole of the circuit, allowing the high-frequency signal output by chip U1 to be quickly transmitted to the 5-pin input via the feedforward capacitor. This input is connected to the inverting terminal of the built-in reference voltage comparator and compared with the reference voltage. This enables chip U1 to quickly respond to changes in the load of subsequent stages, controlling the voltage output of chip U1 and thus limiting the fluctuation range of the output voltage.

[0035] After chip U1 outputs voltage through one end of inductor L1, it connects to a π-type ripple suppression circuit composed of capacitors C5 and C6 and inductor L2. The voltage first passes through capacitor C1 for charging and filtering, removing ripple interference signals from the output voltage of chip U1. After capacitor C1 is fully charged, it discharges to one end of inductor L2. At this time, the impedance of the DC voltage across inductor L2 is very small, and the voltage drop and loss generated by the voltage passing through inductor L2 are also very small. Therefore, the output voltage of inductor L2 is the same as the output voltage. Subsequently, the other end of inductor L2 is connected to capacitor C6 for secondary filtering, further suppressing high-frequency noise and filtering out low-frequency ripple. This ensures that both the input and output of the π-type ripple suppression circuit are in a low-impedance state, reducing mutual influence between the preceding and following stages and ensuring the integrity of the output voltage. Finally, the π-type ripple suppression circuit outputs the BL_VCC voltage, providing an efficient and stable operating voltage for the laptop display.

[0036] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs. The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A ripple suppression circuit for a notebook computer display, characterized in that, include: Input module; The step-down module is electrically connected to the input module; The suppression module includes capacitor C5, inductor L2 and capacitor C6. One end of capacitor C5 is electrically connected to the step-down module, and the second end of capacitor C5 is grounded. The first end of inductor L2 is electrically connected to the first end of capacitor C5, and the second end of inductor L2 is electrically connected to the first end of capacitor C6. The second end of capacitor C6 is grounded.

2. The ripple suppression circuit for a notebook computer display according to claim 1, characterized in that, The input module includes capacitor C1 and capacitor C2. The first end of capacitor C1 is electrically connected to the first end of capacitor C2, and the second ends of capacitor C1 and capacitor C2 are both grounded.

3. The ripple suppression circuit for a notebook computer display according to claim 2, characterized in that, The step-down module includes a chip U1 and a resistor R2. The chip U1 is electrically connected to the first terminal of the capacitor C1 and the first terminal of the capacitor C2, respectively. The first terminal of the resistor R2 is electrically connected to the chip U1, and the second terminal of the resistor R2 is grounded.

4. The ripple suppression circuit for a notebook computer display according to claim 3, characterized in that, The step-down module also includes a capacitor C7 and a resistor R3. The first end of the capacitor C7 is electrically connected to the chip U1, the second end of the capacitor C7 is electrically connected to the first end of the resistor R3, and the second end of the resistor R3 is grounded.

5. The ripple suppression circuit for a notebook computer display according to claim 3, characterized in that, The step-down module also includes a capacitor C3, the first end of which is electrically connected to the chip U1.

6. The ripple suppression circuit for a notebook computer display according to claim 5, characterized in that, The step-down module also includes an inductor L1, a resistor R1, and a resistor R4. The first end of the inductor L1 is electrically connected to the second end of the capacitor C3, the second end of the inductor L1 is electrically connected to the first end of the resistor R1, the second end of the resistor R1 is electrically connected to the first end of the resistor R4, and the second end of the resistor R4 is grounded.

7. The ripple suppression circuit for a notebook computer display according to claim 6, characterized in that, The step-down module also includes a capacitor C4, the first end of which is electrically connected to the second end of the inductor L1, the second end of which is electrically connected to the chip U1, and the first end of the inductor L2 is electrically connected to the first end of the capacitor C4.

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