Digital television signal input interface switch protection circuit

Abstract

The utility model relates to a digital television signal input interface switch protection circuit, which comprises an overvoltage / overcurrent protection circuit and a short circuit protection circuit, and is characterized in that the overvoltage / overcurrent protection circuit is used for cutting off power supply to output when input voltage is too high or output current is too high so as to protect the circuit; the short-circuit protection circuit is used for automatically cutting off current in the circuit to protect input and output when short circuit is output; when the input voltage + 5VNomal is too high or the output current is too high, the closing of the PMOS tube QT2 is controlled by controlling the conduction of the triode QT3, and then the closing of the whole circuit is controlled; and when the output is short-circuited, the PMOS tube QT5 is controlled to be closed by closing the triode QT3, so that the whole circuit is automatically closed. The circuit protection circuit has the advantages that the PMOS tubes, the triodes and the like are used as switches to control the on-off of the circuit, so that the circuit protection is realized. When abnormal conditions (such as overvoltage, overcurrent, short circuit and the like) occur in the circuit, the protection circuit can quickly respond to cut off or limit current or voltage in the circuit so as to prevent circuit elements from being damaged.

Description

Technical Field

[0001] The utility model relates to a digital television signal input interface switch protection circuit, belonging to the technical field of electronics. Background Art

[0002] The digital TV signal input interface switch protection circuit is a circuit used to protect the digital TV signal input interface, usually including overcurrent protection, overvoltage protection, short circuit protection and other functions to ensure the stability and reliability of the digital TV signal input interface.

[0003] The method of controlling the digital TV signal input interface switch protection circuit by software in the prior art has achieved flexibility and programmability, but its drawbacks are mainly reflected in the following aspects:

[0004] Increased system complexity: Relying on chip I / O and complex software programming not only prolongs the design and debugging cycle, but also requires higher technical skills from maintenance personnel. This complexity increases the probability of error, such as logical errors or improper configuration, which may cause the protection function to fail.

[0005] Response delay problem: Since software logic judgment is required, there is a natural disadvantage in processing speed compared to direct hardware control. In some time-sensitive application scenarios (such as fast channel switching or signal source switching), delays may affect the user experience.

[0006] Ongoing maintenance burden: As software is iterated and new features are added, the logic and code of the protection circuit must be adjusted accordingly, which not only increases the workload of the development team but may also introduce new errors or compatibility issues.

[0007] Resource consumption and power consumption: Software control solutions require processor resources and power, which is a disadvantage for modern electronic devices that pursue low power consumption and high efficiency, especially in mobile or battery-powered devices.

[0008] Performance limitations: Differences in TV motherboard performance may cause the protection mechanism to respond slowly when processing high-quality video streams, affecting picture quality and stability, especially when transmitting at high resolution or high frame rate.

[0009] Compatibility and standardization challenges: The diversity of different operating systems and hardware platforms requires that the software part of the protection circuit be highly adaptable, which increases development costs and makes it difficult to ensure optimal results on all platforms.

[0010] Increased security risks: The software level is easily targeted by hacker attacks. Once the protection measures are cracked or malware invades, not only will the protection function fail, but it may also bring security risks to the entire system, such as data leakage or system manipulation.

[0011] Poor environmental adaptability: External environmental factors, such as electromagnetic interference, may directly affect the stable operation of the software, thereby reducing the effectiveness of the protection circuit. This vulnerability is particularly prominent in certain harsh or unstable environments.

[0012] In summary, the traditional mechanical switch protection circuit has a slower response speed and poor control accuracy, and its reliability and adjustability need to be further improved. Utility Model Content

[0013] In order to overcome the defects of the prior art, the utility model provides a digital television signal input interface switch protection circuit. The technical solution of the utility model is:

[0014] A digital television signal input interface switch protection circuit comprises an overvoltage / overcurrent protection circuit and a short-circuit protection circuit. The overvoltage / overcurrent protection circuit is used to cut off the power supply to the output when the input voltage is too high or the output current is too high to protect the circuit; the short-circuit protection circuit is used to automatically cut off the current in the circuit to protect the input and output when the output is short-circuited; when the input voltage +5V_Nomal is too high or the output current is too high, the PMOS tube QT2 is controlled to be turned off by controlling the conduction of the triode QT3, thereby controlling the shutdown of the entire circuit; when the output is short-circuited, the PMOS tube QT5 is controlled to be turned off by turning off the triode QT3, thereby realizing automatic shutdown of the entire circuit.

[0015] The overvoltage / overcurrent protection circuit includes capacitor CT76, capacitor CT77, resistor RT43, resistor RT44, PMOS tube QT2, resistor RT42, transistor QT3, resistor RT45, resistor RT69 and resistor RT41. The capacitor CT76 and capacitor CT77 are connected in parallel between 5V_Nomal and ground; wherein +5V_Nomal is used for input voltage, and capacitor CT76 and capacitor CT77 are used for absorbing interference signals and stabilizing voltage; the resistors RT43 and RT44 are connected in parallel between 5V_Nomal and the source of PMOS tube QT2; The resistor RT42 is connected between the base of the transistor QT3 and the source of the MOS tube QT2; the collector of the transistor QT3 is connected to 5V_Nomal, and the emitter of the transistor QT3 is connected to the source of the PMOS tube QT2, which is used to control the switch of the PMOS tube QT2; the resistor RT45 is connected between the base of the transistor QT3 and the ground; the resistor RT69 is connected between the emitter of the transistor QT3 and the source of the PMOS tube QT2; the resistor RT41 is connected between the emitter of the transistor QT3 and the ground; the drain of the PMOS tube QT2 is connected to the drain of the PMOS tube QT5, which is used for the switch of the entire circuit.

[0016] The short circuit protection circuit includes a resistor RT70, a resistor RT46, a transistor QT6, a resistor RT71, a PMOS tube QT5, a capacitor CT78, an inductor LT17 and an output ATV_in.

[0017] One end of the resistor RT70 is connected to the base of the transistor QT6, and the other end is connected to the drain of the PMOS transistor QT2 and the drain of the PMOS transistor QT5; the resistor RT46 is connected between the base of the transistor QT6 and the ground; the emitter of the transistor QT6 is grounded, and is used to control the switch of the PMOS transistor QT5; the resistor RT71 is connected between the gate and the source of the PMOS transistor QT5; the capacitor CT78 is connected between the source of the PMOS transistor QT5 and the ground, and is used for filtering the output voltage; the inductor LT17 is connected between the source of the PMOS transistor QT5 and the output ATV_in, and is used for rectifying the output voltage; the output ATV_in is used to output voltage to the RF antenna.

[0018] The advantages of the utility model are:

[0019] By using PMOS tubes, triodes, etc. as switches to control the on and off of the circuit, the circuit protection is achieved. When abnormal conditions (such as overvoltage, overcurrent, short circuit, etc.) occur in the circuit, the protection circuit will respond quickly to cut off or limit the current or voltage in the circuit to prevent the circuit components from being damaged. Compared with the traditional electronic switch protection circuit that controls the switch through software, it has the following advantages:

[0020] 1. No need for chip I / O support, compatible with any IC;

[0021] 2. Programming and configuration are simpler, reducing software development costs and the possibility of errors;

[0022] 3. It is completely controlled by hardware and does not rely on programming and code. It can work normally even if there are errors or vulnerabilities in the software;

[0023] 4. It does not require the software's logical judgment and execution process, and has a faster response speed, and can respond to emergencies more quickly;

[0024] 5. It does not need to run on the processor, reducing the system power consumption and processor resource consumption;

[0025] 6. It is not dependent on the performance and running speed of the processor and will not be affected when running multiple tasks;

[0026] 7. Better compatibility, able to be seamlessly ported to different devices or platforms;

[0027] 8. Better security. Even if there is interference from hacker attacks or malware, the protection circuit will not fail.

[0028] 9. Not affected by external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The utility model is a circuit diagram of an overvoltage / overcurrent protection circuit.

[0030] Figure 2 It is a circuit diagram of the short-circuit protection circuit of the utility model.

[0031] Figure 3 It is a schematic diagram of the connection relationship between the utility model and the RF antenna. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements fall within the scope of protection of the present invention.

[0033] See also Figures 1 to 3 The utility model relates to a digital television signal input interface switch protection circuit, including an overvoltage / overcurrent protection circuit and a short-circuit protection circuit. The overvoltage / overcurrent protection circuit is used to cut off the power supply to the output when the input voltage is too high or the output current is too high to protect the circuit; the short-circuit protection circuit is used to automatically cut off the current in the circuit to protect the input and output when the output is short-circuited; when the input voltage +5V_Nomal is too high or the output current is too high, the PMOS tube QT2 is controlled to be turned off by controlling the conduction of the transistor QT3, thereby controlling the shutdown of the entire circuit; when the output is short-circuited, the PMOS tube QT5 is controlled to be turned off by turning off the transistor QT3, thereby automatically shutting down the entire circuit.

[0034] The overvoltage / overcurrent protection circuit includes capacitor CT76, capacitor CT77, resistor RT43, resistor RT44, PMOS tube QT2, resistor RT42, transistor QT3, resistor RT45, resistor RT69 and resistor RT41. The capacitor CT76 and capacitor CT77 are connected in parallel between 5V_Nomal and ground; wherein +5V_Nomal is used for input voltage, and capacitor CT76 and capacitor CT77 are used for absorbing interference signals and stabilizing voltage; the resistors RT43 and RT44 are connected in parallel between 5V_Nomal and the source of PMOS tube QT2 to prevent excessive current from damaging the devices in the circuit; the resistor RT42 is connected between the base of transistor QT3 and the source of MOS tube QT2 to prevent excessive current from damaging the circuit The device in the circuit; the collector of the transistor QT3 is connected to 5V_Nomal, and the emitter of the transistor QT3 is connected to the source of the PMOS tube QT2, which is used to control the switch of the PMOS tube QT2; the resistor RT45 is connected between the base of the transistor QT3 and the ground, which is used to help the transistor QT3 to be reliably cut off when there is no input voltage and to help accelerate the discharge of the charge stored in the PN junction capacitor of the transistor QT3; the resistor RT69 is connected between the emitter of the transistor QT3 and the source of the PMOS tube QT2, which is used to prevent the voltage between the source and the gate of the PMOS tube QT2 from being too high and being damaged; the resistor RT41 is connected between the emitter of the transistor QT3 and the ground, which is used to prevent the device from being damaged by excessive current in the circuit; the drain of the PMOS tube QT2 is connected to the drain of the PMOS tube QT5, which is used for the switch of the entire circuit.

[0035] The short circuit protection circuit includes a resistor RT70, a resistor RT46, a transistor QT6, a resistor RT71, a PMOS tube QT5, a capacitor CT78, an inductor LT17 and an output ATV_in.

[0036] One end of the resistor RT70 is connected to the base of the transistor QT6, and the other end is connected to the drain of the PMOS transistor QT2 and the drain of the PMOS transistor QT5, so as to prevent the device from being damaged by excessive current in the circuit; the resistor RT46 is connected between the base of the transistor QT6 and the ground, so as to help the transistor QT6 to be reliably cut off when there is no input voltage and to help accelerate the discharge of the charge stored in the PN junction capacitor of the transistor QT6; the emitter of the transistor QT6 is grounded, so as to control the switch of the PMOS transistor QT5; the resistor RT71 is connected between the gate and the source of the PMOS transistor QT5, so as to prevent the voltage between the source and the gate of the PMOS transistor QT2 from being damaged due to excessively high voltage; the capacitor CT78 is connected between the source of the PMOS transistor QT5 and the ground, so as to filter the output voltage; the inductor LT17 is connected between the source of the PMOS transistor QT5 and the output ATV_in, so as to rectify the output voltage; the output ATV_in is used to output voltage to the RF antenna.

[0037] The working principle of the utility model is:

[0038] When the circuit works normally, the transistor QT3 is not turned on, the resistor RT69 and the resistor RT41 divide the voltage, the voltage Vsg2 between the source and the gate of the PMOS tube QT2 is equal to the voltage across the resistor RT69 and is greater than 0, and the PMOS tube QT2 is turned on. At the same time, the resistor RT70 and the resistor RT46 divide the voltage, the voltage Vbe6 between the base and the emitter of the transistor QT6 is equal to the voltage across the resistor RT46 and is greater than its switching voltage, the transistor QT6 is turned on, the voltage Vsg5 between the source and the gate of the PMOS tube QT5 is greater than its switching voltage, the PMOS tube QT5 is turned on, and the voltage of the output terminal ATV_in is about 5V.

[0039] Short circuit protection: When the output terminal ATV_in is short-circuited, the source potential of the PMOS tube QT5 drops to 0, Vsg5 = 0V, the PMOS tube QT5 is turned off, and the circuit is disconnected.

[0040] Overvoltage protection: Resistors RT42, RT43 and RT44 are connected between the base and emitter of transistor QT3. When the voltage at the input terminal +5V_Normal is too high, the voltage is higher, and the voltage Veb3 between the base and emitter of transistor QT3 is greater than its conduction voltage, and transistor QT3 is turned on. The gate of PMOS tube QT2 is connected to the collector of transistor QT3 (the emitter of transistor QT3 is connected to the input terminal +5V_Normal), the potential rises rapidly, Vsg2 drops to 0 quickly, PMOS tube QT2 is turned off, and the circuit is disconnected.

[0041] Overcurrent protection: When the current is too high, according to the formula U=IR, the voltage across resistors RT43 and RT44 is greater, and transistor QT3 is turned on. The gate of PMOS tube QT2 is connected to the collector of transistor QT3 (the emitter of transistor QT3 is connected to the input terminal +5V_Normal), the potential rises rapidly, Vsg2 drops to 0 quickly, PMOS tube QT2 is turned off, and the circuit is disconnected.

[0042] like Figure 3 As shown, the +5V_Normal voltage converted by the mainboard is output to the RF antenna through the digital TV signal input interface switch protection circuit of the utility model, thereby protecting the RF antenna.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A digital television signal input interface switch protection circuit, characterized in that: It includes an overvoltage / overcurrent protection circuit and a short-circuit protection circuit. The overvoltage / overcurrent protection circuit is used to cut off the power supply to the output when the input voltage is too high or the output current is too high to protect the circuit; The short-circuit protection circuit can automatically cut off the current in the circuit to protect the input and output when the output is short-circuited; when the input voltage +5V_Nomal is too high or the output current is too high, the PMOS tube QT2 is controlled to be turned off by controlling the conduction of the transistor QT3, thereby controlling the shutdown of the entire circuit; when the output is short-circuited, the PMOS tube QT5 is controlled to be turned off by turning off the transistor QT3, thereby automatically shutting down the entire circuit.

2. The digital television signal input interface switch protection circuit according to claim 1, characterized in that: The overvoltage / overcurrent protection circuit includes capacitor CT76, capacitor CT77, resistor RT43, resistor RT44, PMOS tube QT2, resistor RT42, transistor QT3, resistor RT45, resistor RT69 and resistor RT41. The capacitor CT76 and capacitor CT77 are connected in parallel between 5V_Nomal and ground; wherein +5V_Nomal is used for input voltage, capacitor CT76 and capacitor CT77 are used for absorbing interference signals and stabilizing voltage; the resistors RT43 and RT44 are connected in parallel between 5V_Nomal and ground. mal and the source of the PMOS tube QT2; the resistor RT42 is connected between the base of the transistor QT3 and the source of the MOS tube QT2; the collector of the transistor QT3 is connected to 5V_Nomal, and the emitter of the transistor QT3 is connected to the source of the PMOS tube QT2, which is used to control the switch of the PMOS tube QT2; the resistor RT45 is connected between the base of the transistor QT3 and the ground; the resistor RT69 is connected between the emitter of the transistor QT3 and the source of the PMOS tube QT2; the resistor RT41 is connected between the emitter of the transistor QT3 and the ground; The drain of the PMOS tube QT2 is connected to the drain of the PMOS tube QT5 and is used for switching of the entire circuit.

3. The digital television signal input interface switch protection circuit according to claim 2, characterized in that: The short-circuit protection circuit includes a resistor RT70, a resistor RT46, a transistor QT6, a resistor RT71, a PMOS transistor QT5, a capacitor CT78, an inductor LT17 and an output ATV_in. One end of the resistor RT70 is connected to the base of the transistor QT6, and the other end is connected to the drain of the PMOS transistor QT2 and the drain of the PMOS transistor QT5; the resistor RT46 is connected between the base of the transistor QT6 and the ground; the emitter of the transistor QT6 is grounded, and is used to control the switch of the PMOS transistor QT5; the resistor RT71 is connected between the gate and the source of the PMOS transistor QT5; the capacitor CT78 is connected between the source of the PMOS transistor QT5 and the ground, and is used for filtering the output voltage; the inductor LT17 is connected between the source of the PMOS transistor QT5 and the output ATV_in, and is used for rectifying the output voltage; the output ATV_in is used to output voltage to the RF antenna.

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