Singlechip protection circuit

Abstract

The utility model discloses a single-chip microcomputer protection circuit, which relates to the field of single-chip microcomputers and comprises a power supply connector, a Zener diode D, a sampling resistor R1, a filter circuit and a voltage stabilizing chip. An external power supply is connected to the circuit through the power connector, the cathode output of the power connector is grounded, the anode output is connected with the Zener diode D, the output of the Zener diode D is connected with the sampling resistor R1, the sampling resistor is cascaded with the filter circuit, the output of the filter circuit is connected with the input end of the voltage stabilizing chip, the grounding end of the voltage stabilizing chip is grounded, and the output end of the voltage stabilizing chip is connected with the single-chip microcomputer. An input voltage is provided. According to the circuit, through the functions of high stability, low ripple output, overvoltage protection, current detection and the like, the reliability and safety of a power supply are improved, the service life of equipment is prolonged, and the equipment damage risk caused by the power supply problem of a user is reduced.

Description

Microcontroller protection circuit Technical Field

[0001] This application relates to the field of microcontrollers, and in particular to a microcontroller protection circuit. Background Technology

[0002] With the development of the times and the increasing prevalence of intelligent technology, microcontrollers are becoming increasingly important in people's lives, and are used in various fields. This has also led to an increase in the failure rate of microcontrollers in extreme environments, giving rise to microcontroller protection circuits. While these circuits can provide a certain degree of protection, they still have some problems and shortcomings. These problems and shortcomings are mainly due to the limitations of existing technology, such as the response speed, withstand voltage, and transmission delay of the protection components. To address these issues, further optimization and improvement of the design of microcontroller protection circuits are needed to enhance their protection effect and reliability. Summary of the Invention

[0003] This application provides a microcontroller protection circuit to improve the protection effect and reliability of the microcontroller. The circuit includes a power connector, a Zener diode D, a sampling resistor R1, a filter circuit, and a voltage regulator chip.

[0004] An external power supply is connected to the circuit through a power connector. The negative output of the power connector is grounded, and the positive output is connected to a Zener diode D. The output of Zener diode D is connected to a sampling resistor R1. The sampling resistor is cascaded with a filter circuit. The output of the filter circuit is connected to the input terminal of a voltage regulator chip. The ground terminal of the voltage regulator chip is grounded, and the output terminal is connected to a microcontroller to provide the input voltage.

[0005] Specifically, the voltage regulator circuit includes three parallel filter capacitors C1, C2 and C3; the positive terminals of the three filter capacitors are connected to the voltage regulator chip, and their negative terminals are grounded together.

[0006] Specifically, the power connector model is WJ500V-5.08-2P. When the positive output voltage of the power connector exceeds the Zener voltage of Zener diode D1, it will conduct and discharge the excess voltage.

[0007] Specifically, a thermistor R2 is also set between the filter circuit and the sampling resistor R1, and the temperature value in the circuit is detected by the thermistor R2.

[0008] Specifically, the sampling resistor R1 has a resistance of 300 ohms.

[0009] Specifically, capacitor C1 in the filter circuit is a 100nF ceramic capacitor used to filter out high-frequency noise in the output voltage; capacitor C2 is a 10μF electrolytic capacitor used to further stabilize the output voltage; and capacitor C3 is a 220μF electrolytic capacitor used to filter out low-frequency ripple in the output voltage to ensure the stability of the output voltage.

[0010] Specifically, the voltage regulator chip is a 78L05 three-terminal linear regulator, which converts the voltage filtered by the filter circuit into a stable 5V output voltage.

[0011] Specifically, a second filter circuit is connected after the output of the voltage regulator chip, which includes two capacitors C4 and C5 connected in parallel. Capacitor C4 is a 10μF electrolytic capacitor used to filter out low-frequency ripple in the input power supply; capacitor C6 is a 100nF ceramic capacitor used to filter out high-frequency noise in the input power supply.

[0012] Specifically, the Zener diode D1 is model BZT52B5V1. When the input voltage exceeds 5.1V, the Zener diode conducts, discharging the excess voltage to ground.

[0013] The beneficial effects of the technical solutions provided in this application include at least the following:

[0014] 1. Enhanced User Experience: Through high stability and low ripple output, overvoltage protection, current detection and other functions, the reliability and safety of the power supply are improved, the service life of the equipment is extended, and the risk of equipment damage caused by power supply problems is reduced.

[0015] 2. Efficiency Improvement: The current detection function can realize overcurrent protection and current limiting control, improve the power supply efficiency, and reduce energy waste.

[0016] 3. Easy to operate: The standard two-pin connector design simplifies the power connection process, reduces assembly and debugging time, and lowers the user's learning cost.

[0017] 4. Cost savings: Reduces the cost of repair or replacement due to equipment damage, while the simplified design lowers production costs.

[0018] 5. High reliability: Multi-stage filtering, overvoltage protection, overtemperature protection, and high-efficiency voltage conversion improve the overall reliability of the power supply and reduce system failures caused by power supply problems. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the microcontroller protection circuit provided in this application;

[0020] Figure 2 is a schematic diagram of a microcontroller protection circuit provided in another embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0022] This application provides a microcontroller protection circuit, as shown in Figure 1, which includes a power connector, a Zener diode D, a sampling resistor R1, a filter circuit, and a voltage regulator chip. An external power supply is connected to the circuit through the power connector, providing the entire power supply. The negative output of the power connector is grounded, and the positive output is connected to the Zener diode D. The function of the Zener diode D1 is to protect the circuit; it can operate normally when the output voltage of the power connector does not exceed the safe voltage, and it will discharge voltage when the safe voltage is exceeded.

[0023] The Zener diode D output is connected to the sampling resistor R1. The sampling resistor is cascaded with a filter circuit. The output of the filter circuit is connected to the input terminal of a voltage regulator chip. The ground terminal of the voltage regulator chip is grounded, and its output is connected to a microcontroller to provide the input voltage. The sampling resistor R1 is mainly for connecting an external multimeter or other testing equipment to monitor the circuit current in real time. The filter circuit is used to filter out high and low frequency interference noise in the circuit.

[0024] In some embodiments, for power input and output, the circuit can receive external power input via a two-pin connector WJ500V-5.08-2P with a 5.08mm pitch, suitable for standard two-pin power plugs. Using an adjustable DC power supply, the input voltage is adjusted to above 7V (e.g., 9V) and connected to the IN and GND ports. The power connector conducts when the positive output voltage exceeds the Zener voltage of Zener diode D1, discharging excess voltage.

[0025] In some embodiments, the Zener diode D1 can be selected as model BZT52B5V1, a 5.1V Zener diode used for overvoltage protection. When the output voltage exceeds 5.1V, the Zener diode conducts, discharging the excess voltage to ground and preventing damage to subsequent circuits due to overvoltage.

[0026] The sampling resistor R1 measures the voltage drop across it, allowing the calculation of the current flowing through R1. For example, if the voltage drop across R1 is 200mV, the output current is 1A. A 78L05 three-terminal linear regulator can be used to convert the input voltage to a stable 5V output voltage. The output of this chip (pin 1) is connected to the OUT port to provide power to external devices.

[0027] The voltage regulator circuit includes three parallel filter capacitors C1, C2, and C3; the positive terminals of the three filter capacitors are connected to the voltage regulator chip, and their negative terminals are grounded together. In this embodiment, C1 can be a 100nF ceramic capacitor to filter out high-frequency noise in the output voltage; C2 can be a 10μF electrolytic capacitor to further stabilize the output voltage; and C3 can be a 220μF electrolytic capacitor to filter out low-frequency ripple in the output voltage, ensuring the stability of the output voltage.

[0028] In some embodiments, temperature control and secondary filtering can be added to further enhance the circuit protection effect. Referring to Figure 2, based on the circuit in Figure 1, a thermistor R2 is also placed between the filter circuit and the sampling resistor R1. The thermistor R2 detects the temperature value in the circuit. Specifically, an NCP18XH103F03RB thermistor can be selected. When the temperature reaches the Curie point, the resistance of the thermistor R2 increases sharply, thereby limiting the current flow.

[0029] For the secondary filtering part, a second filter circuit can be connected after the output of the voltage regulator chip, which includes two parallel capacitors C4 and C5. Capacitor C4 is a 10μF electrolytic capacitor used to filter out low-frequency ripple in the input power supply; capacitor C6 is a 100nF ceramic capacitor used to filter out high-frequency noise in the input power supply. After secondary filtering, a stable single-unit voltage can be obtained.

[0030] Debugging steps:

[0031] Connect to power:

[0032] • Use an adjustable DC power supply to adjust the input voltage to above 7V (e.g., 9V) and connect it to the IN port and GND port.

[0033] Measure the output voltage:

[0034] • Use a multimeter to measure the voltage at the OUT port; it should be stable at around 5V.

[0035] Test overvoltage protection:

[0036] Gradually increase the input voltage to over 7V and observe whether the Zener diode conducts and whether the output voltage remains around 5V.

[0037] Test current detection:

[0038] • Connect a known resistor (e.g., 5Ω) to the OUT port, measure the voltage drop across R1, and calculate whether the output current meets expectations.

[0039] In summary, the technical effects brought about by the circuit structure of this application include the following:

[0040] 1. High stability and low ripple output: The circuit uses multi-stage filtering capacitors (C1, C2, C3, C4, C5), including electrolytic capacitors and ceramic capacitors. Electrolytic capacitors are used to filter out low-frequency ripple, and ceramic capacitors are used to filter out high-frequency noise. This multi-stage filtering design ensures the stability of the output voltage, reduces voltage fluctuations, and is suitable for devices with high power supply stability requirements. It effectively reduces ripple in the output voltage, improves power quality, and reduces interference to subsequent circuits.

[0041] 2. Overvoltage Protection: The circuit uses a Zener diode D1 (BZT52B5V1) for overvoltage protection. This provides high safety. When the output voltage exceeds 5.1V for any reason (such as excessively high input voltage or a short circuit), the Zener diode conducts, discharging the excess voltage to ground and preventing damage to subsequent circuits due to overvoltage. The overvoltage protection function reduces the risk of equipment damage caused by abnormal voltage, improving system reliability and reducing the cost of repair or replacement due to equipment failure.

[0042] 3. Current Detection Function: A sampling resistor R1 (300Ω) is used in the circuit for current detection. By detecting the output current, real-time monitoring and control of the load current can be achieved, ensuring that the circuit operates within a safe range. The current detection function can be used to implement overcurrent protection, current limiting control, and other functions, improving the efficiency of the power supply. Users can understand the actual operating status of the power supply through the current detection function, facilitating troubleshooting and maintenance.

[0043] 4. Over-temperature protection function: The circuit uses a thermistor R2. When the temperature reaches the Curie point, the resistance value increases sharply, thereby limiting the current flow.

[0044] 5. High-efficiency and stable voltage conversion utilizes the 78L05 voltage regulator chip. The 78L05 is a common three-terminal regulator with high conversion efficiency and stability. This chip has been extensively verified, demonstrating good reliability and stability, reducing power supply problems caused by chip failure. The three-terminal regulator has a simple design, small footprint, and is suitable for compact devices.

[0045] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A microcontroller protection circuit, characterized in that, It includes a power connector, a Zener diode D, a sampling resistor R1, a filter circuit, and a voltage regulator chip. The external power supply is connected to the circuit through the power connector. The negative output of the power connector is grounded, and the positive output is connected to the Zener diode D. The output of the Zener diode D is connected to the sampling resistor R1. The sampling resistor is cascaded with a filter circuit. The output of the filter circuit is connected to the input terminal of the voltage regulator chip. The ground terminal of the voltage regulator chip is grounded, and the output terminal is connected to the microcontroller to provide the input voltage.

2. The microcontroller protection circuit according to claim 1, characterized in that, The voltage regulator circuit includes three parallel filter capacitors C1, C2 and C3; the positive terminals of the three filter capacitors are connected to the voltage regulator chip, and their negative terminals are grounded together.

3. The microcontroller protection circuit according to claim 1, characterized in that, The power connector model is WJ500V-5.08-2P. When the positive output voltage of the power connector exceeds the Zener voltage of Zener diode D1, it will conduct and discharge the excess voltage.

4. The microcontroller protection circuit according to claim 1, characterized in that, A thermistor R2 is also placed between the filter circuit and the sampling resistor R1 to detect the temperature value in the circuit.

5. The microcontroller protection circuit according to claim 4, characterized in that, The sampling resistor R1 has a resistance of 300 ohms.

6. The microcontroller protection circuit according to claim 2, characterized in that, The filter circuit uses a 100nF ceramic capacitor C1 to filter out high-frequency noise in the output voltage; a 10μF electrolytic capacitor C2 to further stabilize the output voltage; and a 220μF electrolytic capacitor C3 to filter out low-frequency ripple in the output voltage and ensure the stability of the output voltage.

7. The microcontroller protection circuit according to claim 1, characterized in that, The voltage regulator chip is a 78L05 three-terminal linear regulator, which converts the voltage filtered by the filter circuit into a stable 5V output voltage.

8. The microcontroller protection circuit according to claim 7, characterized in that, A second filter circuit is connected after the output of the voltage regulator chip, which includes two capacitors C4 and C5 connected in parallel. Capacitor C4 is a 10μF electrolytic capacitor used to filter out low-frequency ripple in the input power supply; capacitor C6 is a 100nF ceramic capacitor used to filter out high-frequency noise in the input power supply.

9. The microcontroller protection circuit according to claim 3, characterized in that, The Zener diode D1 is model BZT52B5V1. When the input voltage exceeds 5.1V, the Zener diode conducts, discharging the excess voltage to ground.

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