A main single-chip microcomputer power supply circuit based on a DC-DC converter

Abstract

The utility model discloses a kind of main single-chip power supply circuit based on DC-DC converter, it is related to power management technical field, to solve the low efficiency of existing linear voltage stabilizer, heat, poor adaptability, and part DC-DC scheme component complex, the problem of incomplete protection function.Circuit includes input power interface, DC-DC converter module, protection circuit, filter circuit and main single-chip load interface;Input interface is connected with chip VIN pin, chip FB pin is connected with R21, R56 ground, EN pin is started and stopped by high-low level control, SW pin is connected with load interface through filter circuit (including inductance, capacitor, freewheeling diode), and it provides stable 5V voltage for main single-chip.Protection circuit contains high-temperature thermal shutdown, 150 ℃ shutdown, 120 ℃ recovery, undervoltage lock and surge suppression function.Circuit conversion efficiency is greater than or equal to 90%, output ripple is less than or equal to 50mV, protection is comprehensive and miniaturization, applicable to portable electronic equipment, small embedded system.

Description

Technical Field

[0001] This utility model relates to the field of power management technology, specifically to a main microcontroller power supply circuit based on a DC-DC converter. Background Technology

[0002] In embedded systems and Internet of Things (IoT) applications, the microcontroller (MCU) serves as the core control unit, requiring extremely high stability of the power supply voltage and power conversion efficiency.

[0003] Existing voltage regulators mostly use linear regulators. Although their circuit structure is simple, they reduce the voltage by dividing the voltage through series resistors. Excess energy is dissipated as heat. Especially when the input-output voltage difference is large or the load current is high, the efficiency is low. At the same time, the large amount of heat generated by the low efficiency requires additional heat dissipation design, which increases the system size. Long-term high temperature can affect the life of components. It is difficult to meet the requirements of a wide input voltage range and cannot be compatible with various external power supplies.

[0004] Therefore, it is necessary to provide a main microcontroller power supply circuit based on a DC-DC converter to solve the above-mentioned problems. Utility Model Content

[0005] To address the aforementioned technical problems, a main microcontroller power supply circuit based on a DC-DC converter is provided. This technical solution solves the problems of existing DC-DC converter power supply schemes mentioned in the background, which, although improving efficiency, suffer from complex peripheral components, incomplete protection functions (such as lack of high-temperature thermal shutdown and undervoltage lockout), and low output voltage regulation accuracy, making it difficult to balance stability, safety, and miniaturization requirements.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A main microcontroller power supply circuit based on a DC-DC converter includes an input power interface, a DC-DC converter module, a protection circuit, a filter circuit, and a main microcontroller load interface; The input power interface is electrically connected to the voltage input terminal of the DC-DC converter module. The DC-DC converter module uses an asynchronous buck converter chip. The third pin of the asynchronous buck converter chip is used as the feedback terminal, which is connected in series with the twenty-first voltage divider resistor and the fifty-sixth voltage divider resistor and grounded. Its fourth pin is used as the enable terminal, which is connected to a high level to start and to a low level to turn off. The sixth pin of the asynchronous buck converter chip in the DC-DC converter module is used as a switch output terminal and connected to the main microcontroller load interface after passing through a filter circuit. The main microcontroller load interface is used to connect to the main microcontroller and provide it with a stable operating voltage. The protection circuit is integrated inside the DC-DC converter module and implemented in conjunction with external components.

[0007] In an optional embodiment, the protection circuit includes a high-temperature thermal shutdown unit that shuts down the power device when the temperature of the asynchronous buck chip is greater than or equal to 150°C and restores the output when the temperature is less than or equal to 120°C.

[0008] In an optional embodiment, a thirteenth filter capacitor is connected in parallel between the input power interface and the fifth pin of the asynchronous buck chip, thereby forming a surge suppression unit of the protection circuit. The protection circuit also includes an undervoltage lockout unit to prevent the power device from operating when the input voltage is too low.

[0009] In an optional embodiment, the filtering circuit includes a third inductor and an eleventh filter capacitor. The third inductor is connected in series between the sixth pin of the asynchronous buck converter chip and the output terminal of the DC-DC converter module, and the eleventh filter capacitor is connected in parallel between the output terminal of the DC-DC converter module and ground.

[0010] In an optional embodiment, the filtering circuit further includes a fourteenth diode and a fourteenth filter capacitor, wherein the fourteenth diode is connected in parallel between the sixth pin of the asynchronous buck converter chip and ground, and the fourteenth filter capacitor is connected in parallel between the output of the DC-DC converter module and ground.

[0011] Compared with the prior art, the beneficial effects of this utility model are: This solution proposes a main microcontroller power supply circuit based on a DC-DC converter, which uses the ZCC5145 DC-DC converter. This improves power conversion efficiency, significantly reduces energy loss and circuit heat generation, and eliminates the need for additional heat dissipation design. At the same time, the circuit integrates multiple protection functions such as high-temperature thermal shutdown, undervoltage lockout, and surge suppression to prevent circuit damage due to abnormal operating conditions (high temperature, low voltage, surge), thereby improving system reliability. Through high-precision voltage divider resistors and voltage feedback loops, the output voltage error is reduced, meeting the stringent requirements of the microcontroller for power supply stability. Attached Figure Description

[0012] Figure 1 This is a circuit diagram of the DC-DC converter module of this utility model; Figure 2 This is a circuit diagram of the main microcontroller of this utility model. Detailed Implementation

[0013] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0014] Reference Figure 1-2As shown, a main microcontroller power supply circuit based on a DC-DC converter includes an input power interface, a DC-DC converter module, a protection circuit, a filter circuit, and a main microcontroller load interface. The input power interface is electrically connected to the voltage input terminal (pin VIN) of the DC-DC converter module. The DC-DC converter module uses a non-synchronous buck converter chip. Pin FB of the non-synchronous buck converter chip is used as the feedback terminal, connected in series with the 21st voltage divider resistor R21 and the 56th voltage divider resistor R56 and grounded. Its fourth pin EN is used as the enable terminal, connected to a high level to start and connected to a low level to turn off. In the DC-DC converter module, the sixth pin SW of the asynchronous step-down chip is used as a switch output terminal and connected to the main microcontroller load interface after passing through the filter circuit. The main microcontroller load interface is used to connect to the main microcontroller and provide it with a stable operating voltage. The protection circuit is integrated inside the DC-DC converter module and implemented in conjunction with external components.

[0015] Furthermore, the protection circuit includes a high-temperature thermal shutdown unit, which shuts down the power devices when the temperature of the asynchronous buck chip is greater than or equal to 150°C, and restores the output when the temperature is less than or equal to 120°C.

[0016] Furthermore, a thirteenth filter capacitor C13 is connected in parallel between the input power interface and the fifth pin VIN of the asynchronous buck chip, thus forming the surge suppression unit of the protection circuit. The protection circuit also includes an undervoltage lockout unit to prevent the power device from operating when the input voltage is too low.

[0017] Furthermore, the filter circuit includes a third inductor L3 and an eleventh filter capacitor C11. The third inductor L3 is connected in series between the sixth pin SW of the asynchronous buck converter chip and the output terminal of the DC-DC converter module, and the eleventh filter capacitor C11 is connected in parallel between the output terminal of the DC-DC converter module and ground.

[0018] Furthermore, the filter circuit also includes a fourteenth diode D14 and a fourteenth filter capacitor C14. The fourteenth diode D14 is connected in parallel between the sixth pin SW of the asynchronous buck converter chip and ground, and the fourteenth filter capacitor C14 is connected in parallel between the output terminal of the DC-DC converter module and ground.

[0019] Specifically, the main microcontroller uses the MC51F003, with an operating voltage range of 4.5V-5.5V, matching the 5V output of the circuit, making it suitable for low-power embedded scenarios. The asynchronous step-down DC-DC converter is the ZCC5145, with an input voltage range of 4V-45V, a maximum output current of 600mA, and a switching frequency of 1.2MHz, meeting the 5V / maximum 200mA power supply requirements of the microcontroller (MC51F003). The 21st voltage divider resistor R21 has a resistance of 120KΩ (1% accuracy), and the 56th voltage divider resistor R56 has a resistance of 22KΩ (1% accuracy). The output voltage is set to 5V using the formula VOUT = 0.8V × (1 + R21 / R56). Substituting the values ​​into the formula, R21 / R56 ≈ 5.25. Therefore, R21 = 120KΩ (1% accuracy) and R56 = 22KΩ (1% accuracy) are selected to ensure an output voltage error ≤1%. The microcontroller load interface outputs 5V with a maximum output current of 600mA, and is compatible with the VDD (pin 9) and VSS (pin 7) pins of the MC51F003 microcontroller. The circuit's power conversion efficiency is ≥90%, output voltage ripple is ≤50mV, and standby current is ≤3µA. The input power interface is compatible with 4V-45V input voltages and supports battery, external power adapter (e.g., 12V / 3A) power supply methods. The circuit is integrated on a single PCB board and is suitable for portable electronic devices, small embedded systems, or IoT terminal devices. Input capacitor C13 is a 4.7uF / 50VX5R ceramic capacitor (low ESR, wide temperature range), output capacitor C11 is a 10uF / 16VX7R ceramic capacitor, and auxiliary filter capacitor C14 is a 101 / 50V (0.01uF) ceramic capacitor, collectively suppressing switching noise and voltage ripple. The fourteenth diode, D14, is a Schottky diode with a low forward voltage drop (≤0.4V), reducing freewheeling losses.

[0020] Circuit operation: During power-on startup: An external power supply (such as a 12V / 3A adapter) is connected to the VIN pin (pin 5) of the asynchronous buck converter chip through the input power interface. After the EN pin (pin 4) is connected to a high level, the asynchronous buck converter chip starts working. Then, through the internal MOSFET high-frequency switch (1.2MHz), a pulse voltage is output from the SW pin (pin 3). After energy storage by inductor L3 and filtering by capacitor C11, it is converted into a stable 5V DC voltage, thus achieving voltage conversion. Then, the output voltage is acquired in real time by the FB pin (pin 2) of the asynchronous buck converter chip and compared with the internal 0.8V reference voltage. By adjusting the duty cycle of the SW pin, the output voltage is ensured to remain stable at 5V, unaffected by input voltage fluctuations or load changes. This achieves feedback regulation.

[0021] The protection triggering process is as follows: if the circuit temperature is too high (junction temperature of the non-synchronous buck chip ≥150℃), the thermal shutdown function is activated to shut down the power device; once the temperature drops to 120℃, the output is automatically restored; if the input voltage is too low (below the UVLO threshold), the undervoltage lockout function is triggered to prevent the non-synchronous buck chip from working and avoid damage to the device under low voltage.

[0022] The main microcontroller is powered by a stable 5V voltage connected to the VDD pin of the main microcontroller through the microcontroller load interface, providing the microcontroller with operating power. At the same time, C14 further filters out high-frequency noise to ensure stable operation of the microcontroller.

[0023] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A main microcontroller power supply circuit based on a DC-DC converter, characterized in that, Includes input power interface, DC-DC converter module, protection circuit, filter circuit and main microcontroller load interface; The input power interface is electrically connected to the voltage input terminal of the DC-DC converter module. The DC-DC converter module uses an asynchronous buck converter chip. The third pin of the asynchronous buck converter chip is used as the feedback terminal, which is connected in series with the twenty-first voltage divider resistor and the fifty-sixth voltage divider resistor and grounded. Its fourth pin is used as the enable terminal, which is connected to a high level to start and to a low level to turn off. The sixth pin of the asynchronous buck converter chip in the DC-DC converter module is used as a switch output terminal and connected to the main microcontroller load interface after passing through a filter circuit. The main microcontroller load interface is used to connect to the main microcontroller and provide it with a stable operating voltage. The protection circuit is integrated inside the DC-DC converter module and implemented in conjunction with external components.

2. The main microcontroller power supply circuit based on a DC-DC converter according to claim 1, characterized in that: The protection circuit includes a high-temperature thermal shutdown unit, which shuts down the power device when the temperature of the asynchronous step-down chip is greater than or equal to 150°C, and restores the output when the temperature is less than or equal to 120°C.

3. The main microcontroller power supply circuit based on a DC-DC converter according to claim 1, characterized in that: A thirteenth filter capacitor is connected in parallel between the input power interface and the fifth pin of the asynchronous step-down chip, thus forming a surge suppression unit of the protection circuit. The protection circuit also includes an undervoltage lockout unit to prevent the power device from operating when the input voltage is too low.

4. The main microcontroller power supply circuit based on a DC-DC converter according to claim 1, characterized in that: The filtering circuit includes a third inductor and an eleventh filter capacitor. The third inductor is connected in series between the sixth pin of the asynchronous buck converter chip and the output terminal of the DC-DC converter module, and the eleventh filter capacitor is connected in parallel between the output terminal of the DC-DC converter module and ground.

5. The main microcontroller power supply circuit based on a DC-DC converter according to claim 1, characterized in that: The filtering circuit also includes a fourteenth diode and a fourteenth filter capacitor. The fourteenth diode is connected in parallel between the sixth pin of the asynchronous step-down chip and ground, and the fourteenth filter capacitor is connected in parallel between the output terminal of the DC-DC converter module and ground.

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