Voltage reducing and stabilizing circuit and control system

Abstract

The utility model provides a voltage reducing and stabilizing circuit and a control system, and relates to the technical field of power supply circuits, the voltage reducing and stabilizing circuit comprises a first protection module, a current limiting module, a voltage stabilizing diode and a second protection module; one end of the first protection module is connected with the battery anode; the first end of the current limiting module is connected with the other end of the first protection module, and the second end of the current limiting module is connected with the microcontroller; the cathode of the voltage stabilizing diode is connected with the third end of the current limiting module; the first end of the second protection module is connected with the negative electrode of the battery, the second end of the second protection module is in common-ground connection with the positive electrode of the voltage stabilizing diode, and the third end of the second protection module is connected with the second end of the current limiting module. The current limiting module realizes preliminary attenuation of the voltage through impedance characteristics, and performs secondary clamping on the voltage in cooperation with breakdown characteristics of the voltage stabilizing diode so as to stabilize the output voltage at a target value, so that the microcontroller operates stably based on the target value, the cost of the voltage stabilizing diode and the current limiting module is low, and the preparation cost is reduced.

Description

Technical Field

[0001] This application relates to the field of power supply circuit technology, and more specifically, to a buck regulator circuit and control system. Background Technology

[0002] Microcontroller units (MCUs) are widely used as main control units in various fields (such as electronic water pumps and chips). The stability of MCU operation directly affects the performance of electronic water pumps and chips themselves.

[0003] Related technologies typically employ low dropout regulators (LDOs) to provide power to the MCU, ensuring stable operation. However, LDOs are relatively expensive. Utility Model Content

[0004] To address the aforementioned issues, this application provides a step-down voltage regulator circuit and control system, aiming to solve the problem of high cost in related technologies where LDOs provide power supply voltage to MCUs.

[0005] In a first aspect, this application provides a step-down voltage regulator circuit, including a first protection module, a current limiting module, a Zener diode, and a second protection module; one end of the first protection module is connected to the positive terminal of the battery; the first end of the current limiting module is connected to the other end of the first protection module, and the second end of the current limiting module is connected to a microcontroller; the negative terminal of the Zener diode is connected to the third end of the current limiting module, and the positive terminal of the Zener diode is grounded; the first end of the second protection module is connected to the negative terminal of the battery, the second end of the second protection module and the positive terminal of the Zener diode are connected to ground, and the controlled end of the second protection module is connected to the second end of the current limiting module.

[0006] In the above technical solution, this application utilizes the impedance characteristics of the current limiting module to initially attenuate the battery's output voltage. Combined with the characteristics of the Zener diode in the reverse breakdown region, the output voltage is further clamped, ultimately stabilizing the output voltage at the target value (i.e., the target supply voltage). Furthermore, the current limiting module enables the Zener diode to maintain this supply voltage, providing a stable supply voltage to the microcontroller. This allows the microcontroller to operate stably based on this stable supply voltage, ensuring the microcontroller's operational stability and the reliability of its load control. Compared to related technologies that use LDOs and DC-DC converters for buck and voltage regulation, this application reduces at least three power devices and two control ICs, lowering the BOM cost by approximately 40% or more, thus reducing overall manufacturing costs. Secondly, the current limiting module also limits the current flowing into the Zener diode to prevent damage due to excessive current, ensuring the Zener diode's reliability and extending its lifespan. Finally, reverse connection protection for the battery is implemented through the first and second protection modules, improving the operational reliability of the buck regulator circuit.

[0007] In conjunction with the first aspect, in some possible implementations, the step-down voltage regulator circuit further includes a first resistor and a first switch; one end of the first resistor is connected to the other end of the first protection module and the first end of the current limiting module; the controlled end of the first switch is connected to the second end of the current limiting module and the controlled end of the second protection module; the first end of the first switch is connected to the other end of the first resistor; and the second end of the first switch is connected to the microcontroller.

[0008] In the above technical solution, the first switch acts as an amplifier to amplify the current, thereby increasing the load-carrying capacity and enabling the buck regulator circuit to drive a higher-power load. Furthermore, the first switch helps maintain a stable output supply voltage, ensuring that the supply voltage remains constant even when the load current changes. This allows the microcontroller to operate stably based on the stable supply voltage, thus guaranteeing the microcontroller's operational stability and the reliability of its load control. Secondly, the first resistor acts as a current-limiting resistor, limiting the current flowing through the first switch to prevent excessive current from damaging it and avoiding the possibility of the first switch burning out due to overload. This improves the operational reliability of the first switch and extends its service life.

[0009] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the current limiting module includes a current limiting resistor and a first diode; one end of the current limiting resistor serves as the first end of the current limiting module and is connected to the other end of the first protection module and one end of the first resistor; the other end of the current limiting resistor serves as the second end of the current limiting module and is connected to the controlled end of the first switch, the controlled end of the second protection module, and the microcontroller; the positive terminal of the first diode is connected to the other end of the current limiting resistor, and the negative terminal of the first diode serves as the third end of the current limiting module and is connected to the negative terminal of the Zener diode.

[0010] In the above technical solution, the current-limiting resistor, the first diode, and the Zener diode are connected in sequence, i.e., connected in series. In a series circuit, the current is the same everywhere. Therefore, the current-limiting resistor can effectively limit the current to the safe range of the first diode and the Zener diode, preventing them from being damaged due to excessive current and extending their lifespan. Secondly, the current-limiting resistor can reduce the impact of current fluctuations on the first diode and the Zener diode, making their operating state more stable and improving the voltage reduction stability and reliability of the buck regulator circuit.

[0011] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the second protection module includes a second switch, the first end of the second switch is connected to the negative terminal of the battery as the first end of the second protection module, the second end of the second switch is connected to the positive terminal of the Zener diode as the second end of the second protection module and grounded, and the controlled end of the second switch is connected to the second end of the current limiting module as the controlled end of the second protection module.

[0012] In the above technical solution, the parasitic diode between the first and second terminals of the second switch can play a simple reverse connection protection function, avoiding circuit damage caused by reverse battery polarity connection, so as to ensure the normal use of the step-down voltage regulator circuit.

[0013] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the first protection module includes a second diode, the positive terminal of the second diode is connected to the positive terminal of the battery as one end of the first protection module, and the negative terminal of the second diode is connected to the first end of the current limiting module as the other end of the first protection module.

[0014] In the above technical solution, when the anode of the second diode is connected to the positive terminal of the battery, the second diode enters the forward conduction state. At this time, the resistance of the second diode to current is very small, and the current can pass smoothly. If the battery is reverse-connected, that is, when the anode of the second diode is connected to the negative terminal of the battery, then the second diode will enter the reverse cutoff state. In this case, the PN junction inside the second diode will block most of the current to prevent the negative terminal of the battery from passing through, thus avoiding the problem of the reverse-connected battery damaging the downstream current limiting module and ensuring the normal operation of the buck regulator circuit.

[0015] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the buck regulator circuit also includes a data acquisition module. The first terminal of the data acquisition module is connected to the negative terminal of the second diode, the second terminal of the data acquisition module is connected to the microcontroller, and the third terminal of the data acquisition module is grounded. The data acquisition module is used to acquire the battery voltage and output it to the microcontroller.

[0016] In the above technical solution, the acquisition module will collect the output voltage of the battery in real time and output it to the microcontroller. When the output voltage of the battery connected to the microcontroller fluctuates greatly, the microcontroller can take corresponding protection strategies to prevent the large fluctuations from burning out the circuit board, thereby improving the operational reliability of the buck regulator circuit and extending the service life of the buck regulator circuit.

[0017] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the acquisition module includes a second resistor and a third resistor; one end of the second resistor serves as the first terminal of the acquisition module and is connected to the negative terminal of the second diode, and the other end of the second resistor serves as the second terminal of the acquisition module and is connected to the microcontroller; one end of the third resistor is connected to the other end of the second resistor, and the other end of the third resistor serves as the third terminal of the acquisition module and is grounded.

[0018] In the above technical solution, the second and third resistors are voltage divider resistors, which can convert the battery's output voltage into a voltage range that the microcontroller can acquire, thereby realizing the acquisition of the battery's output voltage. The structure is simple. Moreover, the acquisition security is high when using the second and third resistors.

[0019] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the acquisition module further includes a first capacitor and a second capacitor; the first plate of the first capacitor is connected to the negative terminal of the second diode and one end of the second resistor, and the second plate of the first capacitor is connected to the other end of the third resistor. The first plate of the second capacitor is connected to the other end of the second resistor, the microcontroller and one end of the third resistor, and the second plate of the second capacitor is grounded.

[0020] In the above technical solution, the first and second capacitors, acting as filter capacitors, can absorb ripple and noise in the output voltage, making the voltage output to the microcontroller more stable and improving the monitoring reliability of the microcontroller. Secondly, the second plate of the second capacitor is grounded, providing a stable reference point for the capacitor, which helps eliminate high-frequency interference signals and improves the electromagnetic compatibility of the acquisition module.

[0021] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the step-down voltage regulator circuit further includes a third capacitor and a fourth capacitor; the first plate of the third capacitor is connected to the positive terminal of the battery and one end of the first protection module, the second plate of the third capacitor is connected to the first end of the second protection module and the negative terminal of the battery; the first plate of the fourth capacitor is connected to the other end of the first protection module, and the second plate of the fourth capacitor is connected to the second end of the second protection module for common ground.

[0022] In the above technical solution, the battery's output voltage may contain high-frequency noise or ripple (such as AC components during charging). In this case, the third and fourth capacitors can absorb these high-frequency components, making the voltage supplied to the subsequent circuit (such as the current limiting module) cleaner. Furthermore, by reducing high-frequency interference, the electromagnetic compatibility of the buck regulator circuit can be improved, and interference to the load can be reduced.

[0023] Secondly, embodiments of this application also provide a control system, including a battery, a microcontroller, and a buck regulator circuit as described in any optional manner in the first aspect, wherein the buck regulator circuit is connected to the battery, and the microcontroller is connected to the buck regulator circuit. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the module structure of a control system provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the circuit structure of a control system provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the circuit structure of another control system provided in an embodiment of this application;

[0027] Figure 4 This is a schematic diagram of the circuit structure of another control system provided in the embodiments of this application;

[0028] Figure 5 This is a schematic diagram of the circuit structure of another control system provided in an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of the circuit structure of another control system provided in the embodiments of this application;

[0030] Figure 7 This is a schematic diagram of the circuit structure of another control system provided in the embodiments of this application;

[0031] Figure 8 This is a schematic diagram of the circuit structure of another control system provided in the embodiments of this application.

[0032] The following are the labeling elements in the figure:

[0033] 1. Battery; 2. Buck regulator circuit; 21. First protection module; 22. Current limiting module; 23. Second protection module; 24. Data acquisition module; 3. Microcontroller;

[0034] D0, Zener diode; D1, first diode; D2, second diode; R0, current-limiting resistor; R1, first resistor; R2, second resistor; R3, third resistor; Q1, first switch; Q2, second switch; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; C5, fifth capacitor; C6, sixth capacitor; G, gate; S, source; D, drain; FB, feedback pin; VBAT+, positive terminal; VBAT-, negative terminal. Detailed Implementation

[0035] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0036] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0037] MCUs, as main control units, are widely used in various fields. For example, in the field of new energy vehicles, with the rapid development of industry, electronic water pumps are also used. The core control component of the electronic water pump is the MCU. The MCU's power supply voltage is 5V. When the power supply voltage is unstable, it will lead to poor MCU operation stability, which directly affects the performance of the electronic water pump and the chip itself. For example, electronic water pumps are usually precisely controlled by the MCU through algorithms to control parameters such as speed and flow rate. When the MCU is unstable, errors may occur in the MCU's control signals, causing the electronic water pump's speed and flow rate to fail to reach the set values, thus affecting the pump's working efficiency.

[0038] In order to enable the MCU to operate stably, LDOs are usually used to provide a stable power supply voltage to the MCU. However, LDOs are expensive, which increases the overall manufacturing cost.

[0039] To address this, this application provides a buck regulator circuit and control system. In this buck regulator circuit, a current-limiting module achieves initial voltage attenuation through impedance characteristics, and, in conjunction with the breakdown characteristics of a Zener diode, performs secondary voltage clamping to stabilize the output voltage at a target value (i.e., the target supply voltage). This allows the microcontroller to operate stably based on this stable supply voltage, thereby ensuring the operational stability of the microcontroller and the reliability of its load control. Furthermore, the Zener diode and current-limiting module have low costs, reducing the overall manufacturing cost.

[0040] In one example, such as Figure 1 As shown in the illustration, this application provides a control system including a battery 1, a buck regulator circuit 2, and a microcontroller 3. The buck regulator circuit 2 is connected to both the battery 1 and the microcontroller 3. In this example, the buck regulator circuit 2 can reduce the output voltage of the battery 1 to the supply voltage of the microcontroller 3, and it can also stabilize the output voltage of the battery 1 within the supply voltage range. This ensures the stability of the power supply from the battery 1 to the microcontroller 3 via the buck regulator circuit 2, thereby guaranteeing the operational stability of the microcontroller 3 and the reliability of its control over the load (e.g., an electronic water pump). The microcontroller 3 can be an MCU or other microcontroller unit.

[0041] For example, assuming the output voltage of battery 1 is about 13.5V and the supply voltage of microcontroller 3 is 5V, the buck regulator circuit 2 can reduce and stabilize the input 13.5V voltage to 5V and then output it to microcontroller 3 so that microcontroller 3 can operate stably based on the 5V supply voltage.

[0042] In order for the buck regulator circuit 2 to reduce the output voltage of battery 1 to the supply voltage of microcontroller 3, in one example, such as Figure 2 As shown, the step-down voltage regulator circuit 2 includes a first protection module 21, a current limiting module 22, a Zener diode D0, and a second protection module 23. One end of the first protection module 21 is connected to the positive terminal VBAT+ of the battery 1. The first end of the current limiting module 22 is connected to the other end of the first protection module 21, and the second end of the current limiting module 22 is connected to the microcontroller 3. The negative terminal VBAT- of the Zener diode D0 is connected to the third end of the current limiting module 22, and the positive terminal VBAT+ of the Zener diode D0 is grounded. The first end of the second protection module 23 is connected to the negative terminal VBAT- of the battery 1, and the second end of the second protection module 23 is connected to the positive terminal VBAT+ of the Zener diode D0, sharing a common ground connection. The controlled terminal of the second protection module 23 is connected to the second end of the current limiting module 22.

[0043] In this example, the positive voltage of the Zener diode D0 is set to be equal to the supply voltage of the microcontroller 3. For instance, assuming the supply voltage of the microcontroller 3 is 5V, the corresponding voltage of the Zener diode D0 is 5V. In this example, the characteristics of the Zener diode D0 in its reverse breakdown region are utilized to reduce the output voltage of the battery 1 to the supply voltage of the microcontroller 3. That is, the Zener diode D0 is configured to be connected in reverse. When the output voltage of the battery 1 is higher than 5V, the Zener diode D0 begins to operate in its reverse breakdown region. At this time, regardless of how the voltage connected to the Zener diode D0 (i.e., the output voltage of the battery 1) changes, the voltage across the Zener diode D0 will remain around 5V, and this 5V voltage will be output to the microcontroller 3, enabling the microcontroller 3 to operate stably based on this 5V supply voltage. By setting the Zener diode D0, the stability of the power supply from the battery 1 to the microcontroller 3 via the Zener diode D0 can be guaranteed, thereby ensuring the operational stability of the microcontroller 3 and the reliability of its control over the load (e.g., an electronic water pump).

[0044] It is worth noting that the maximum voltage applied to the Zener diode D0 should not exceed its maximum rated voltage, in order to avoid damage to the Zener diode D0 due to excessive voltage.

[0045] Since the Zener diode D0 requires a certain current to maintain a stable voltage, but excessive current may damage it, this application includes a current limiting module 22 between the battery 1 and the Zener diode D. The current limiting module 22 restricts the current flowing into the Zener diode D0 to prevent damage due to excessive current, thus ensuring the reliability of the Zener diode D0 and consequently guaranteeing its reliable voltage reduction and regulation.

[0046] Thus, this application utilizes the impedance characteristics of the current limiting module 22 to initially attenuate the output voltage of the battery 1, and then further clamps the output voltage using the characteristics of the Zener diode D0 in the reverse breakdown region, ultimately stabilizing the output voltage at the target value (i.e., the target supply voltage). Furthermore, the current limiting module 22 enables the Zener diode D0 to maintain this supply voltage, providing a stable supply voltage to the microcontroller 3. This allows the microcontroller 3 to operate stably based on this stable supply voltage, ensuring the operational stability of the microcontroller 3 and the reliability of its load control. Compared to related technologies that use LDOs and DC-DC converters for voltage reduction and regulation, this application reduces at least three power devices and two integrated circuits (ICs), lowering the bill of materials (BOM) cost by approximately 40% or more, thereby reducing the overall manufacturing cost. Secondly, the current limiting module 22 also limits the current flowing into the Zener diode D0 to prevent damage due to excessive current, thus ensuring the reliability of the Zener diode D0 and extending its lifespan.

[0047] In order for the current limiting module 22 to limit the current flowing into the Zener diode D0, in one example, such as Figure 3 As shown, the current limiting module 22 includes a current limiting resistor R0 and a first diode D1. One end of the current limiting resistor R0 serves as the first terminal of the current limiting module 22 and is connected to the other end of the first protection module 21. The other end of the current limiting resistor R0 serves as the second terminal of the current limiting module 22 and is connected to the controlled terminal of the second protection module 23 and the microcontroller 3. The anode of the first diode D1 is connected to the other end of the current limiting resistor R0, and the cathode of the first diode D1 serves as the third terminal of the current limiting module 22 and is connected to the cathode of the Zener diode D0.

[0048] Among them, such as Figure 3 As shown, the current-limiting resistor R0, the first diode D1, and the Zener diode D0 are connected in sequence, i.e., connected in series. In a series circuit, the current is the same everywhere. Therefore, the current-limiting resistor R0 effectively limits the current to the safe range of the first diode D1 and the Zener diode D0, preventing them from being damaged due to excessive current and extending their lifespan. Secondly, the current-limiting resistor R0 reduces the impact of current fluctuations on the first diode D1 and the Zener diode D0, making their operation more stable and improving the operational stability of the buck regulator circuit 2.

[0049] To improve load capacity, in one example, such as Figure 4As shown, the step-down voltage regulator circuit 2 also includes a first resistor R1 and a first switch Q1. One end of the first resistor R1 is connected to the other end of the first protection module 21 and one end of the current-limiting resistor R0. The controlled end of the first switch Q1 is connected to the other end of the current-limiting resistor R0, the controlled end of the second protection module 23, and the positive terminal of the first diode D1. The first end of the first switch Q1 is connected to the other end of the first resistor R1, and the second end of the first switch Q1 is connected to the microcontroller 3.

[0050] In this example, the first switch Q1 acts as an amplifier to amplify the current, thereby increasing its load-carrying capacity and enabling the buck regulator circuit 2 to drive a higher-power load. Furthermore, the first switch Q1 helps maintain a stable output supply voltage, ensuring that the supply voltage remains constant even when the load current changes. This allows the microcontroller 3 to operate stably based on this stable supply voltage, thus guaranteeing the operational stability of the microcontroller 3 and the reliability of its load control. Secondly, the first resistor R1 acts as a current-limiting resistor, limiting the current flowing through the first switch Q1 to prevent excessive current from damaging it and avoiding the possibility of the first switch Q1 burning out due to overload. This improves the operational reliability of the first switch Q1 and extends its service life.

[0051] For example, the diagram shows an NPN transistor as the first switch Q1. The base of the NPN transistor serves as the controlled terminal of the first switch Q1 and is connected to the other end of the current-limiting resistor R0, the controlled terminal of the second protection module 23, and the anode of the first diode D1. The collector of the NPN transistor serves as the first terminal of the first switch Q1 and is connected to the other end of the first resistor R1. The emitter of the NPN transistor serves as the second terminal of the first switch Q1 and is connected to the microcontroller 3. In the on-state, the saturation voltage drop of the NPN transistor is low, which helps to reduce the power loss and heat generation of the first switch Q1.

[0052] It's worth noting that NPN transistors have internal diodes at their base and emitter, resulting in a voltage drop. To prevent this voltage drop from affecting the supply voltage, the first diode D1 compensates for it. Specifically, assuming the positive voltage of the first diode D1 is 5.7V and the internal voltage drop of the NPN transistor is 0.7V, the first diode D1 can compensate for this 0.7V voltage drop, ensuring that the supply voltage output from the emitter of the NPN transistor remains at 5V, thus guaranteeing the stability of the output supply voltage.

[0053] Optionally, the first switch Q1 may also be an N-type metal-oxide-semiconductor (NMOS) field-effect transistor, a P-type metal-oxide-semiconductor (PMOS) field-effect transistor, an IGBT, a PNP transistor, a relay circuit, or other devices or circuits capable of switching on and off. This application does not impose specific limitations on this.

[0054] To improve the stability of the power supply voltage to microcontroller 3, in one example, such as Figure 4 As shown, the step-down voltage regulator circuit 2 also includes a fifth capacitor C5. The first plate of the fifth capacitor C5 is connected to the second terminal of the first switch Q1 and the microcontroller 3, and the second plate of the fifth capacitor C5 is grounded.

[0055] In this example, the fifth capacitor C5 acts as a filter capacitor, absorbing ripple and noise in the output voltage, making the output voltage more stable and enhancing the operational stability of the buck regulator circuit 2. Secondly, the second plate of the fifth capacitor C5 is grounded, providing a stable reference point for the capacitor, which helps eliminate high-frequency interference signals and improves the electromagnetic compatibility (EMC) of the entire buck regulator circuit 2.

[0056] Under normal circumstances, the positive terminal VBAT+ of battery 1 should be connected to the positive terminal of the buck regulator circuit 2, while the negative terminal VBAT- of battery 1 should be connected to the negative terminal of the buck regulator circuit 2. If the positive terminal VBAT+ of battery 1 is connected to the negative terminal of the buck regulator circuit 2, and the negative terminal VBAT- of battery 1 is connected to the positive terminal of the buck regulator circuit 2, this indicates that battery 1 is reverse-connected. Reverse connection of battery 1 will damage the subsequent buck regulator circuit 2 and affect its normal operation. This application prevents reverse connection of battery 1 through the first protection module 21 and the second protection module 23. In one example, such as Figure 5 As shown, the first protection module 21 includes a second diode D2. The positive terminal of the second diode D2 is connected to the positive terminal VBAT+ of the battery 1 as one end of the first protection module 21, and the negative terminal of the second diode D2 is connected to the first end of the current limiting module 22 as the other end of the first protection module 21.

[0057] The second diode D2 is an electronic component with unidirectional conductivity. When the power supply is connected in the correct direction, the second diode D2 is in a forward bias state, allowing current to flow. However, when the battery is connected in reverse, the second diode D2 is in a reverse bias state, almost not conducting, thus preventing current from flowing in the opposite direction. In this example, when the anode of the second diode D2 is connected to the positive terminal VBAT+ of battery 1, the second diode D2 enters the forward conduction state. At this time, the resistance of the second diode D2 to the current is very small, and the current can flow smoothly. If the battery is connected in reverse, that is, when the anode of the second diode D2 is connected to the negative terminal VBAT- of battery 1, then the second diode D2 will enter the reverse cutoff state. In this case, the PN junction inside the second diode D2 will block most of the current, preventing the negative terminal VBAT- of battery 1 from flowing through, avoiding the problem of the reverse connection of battery 1 damaging the downstream current limiting module 22, and ensuring the normal operation of the buck regulator circuit 2.

[0058] In one example, such as Figure 5 As shown, the second protection module 23 includes a second switch Q2. The first end of the second switch Q2 is connected to the negative terminal VBAT- of the battery 1 as the first end of the second protection module 23. The second end of the second switch Q2 is connected to the positive terminal of the Zener diode D0 as the second end of the second protection module 23. The controlled end of the second switch Q2 is connected to the second end of the current limiting module 22 as the controlled end of the second protection module 23.

[0059] The diagram illustrates a MOS transistor as an example of a second switch Q2. The drain (D) of the MOS transistor serves as the first terminal of the second switch Q2, connected to the negative terminal VBAT- of battery 1. The source (S) of the MOS transistor serves as the second terminal of the second switch Q2, connected to the positive terminal of the Zener diode D0, and grounded. The gate (G) of the MOS transistor serves as the controlled terminal of the second switch Q2, connected to the second terminal of the current limiting module 22. A parasitic diode exists between the drain (D) and source (S) of the MOS transistor. This diode is formed by the PN junction during the manufacturing process. In the case of reverse power connection, the parasitic diode inside the MOS transistor prevents current from flowing from the drain (D) to the source (S). It can be understood that even if a positive voltage is applied to the drain (D), the current will not flow through the drain (D) to the source (S) due to the presence of the parasitic diode, thus protecting the subsequent circuit from the effects of reverse power connection. In this way, the parasitic diode built into the MOS transistor provides a simple reverse connection protection function, preventing circuit damage caused by reverse polarity connection of battery 1, and ensuring the normal operation of the buck regulator circuit 2.

[0060] In this example, the anode of the first diode D1 is connected to the gate of the MOS transistor to turn on the MOS transistor with a stable 5.7V, preventing damage to the MOS transistor. In one example, such as... Figure 6As shown, the step-down voltage regulator circuit 2 also includes a sixth capacitor C6. The first plate of the sixth capacitor C6 is connected to the second terminal of the second switch Q2 and the positive terminal of the Zener diode D0. The second plate of the sixth capacitor C6 is connected to the controlled terminal of the second switch Q2 and the second terminal of the current limiting module 22.

[0061] In one example, such as Figure 6 As shown, the step-down voltage regulator circuit 2 also includes a third capacitor C3 and a fourth capacitor C4. The first plate of the third capacitor C3 is connected to the positive terminal VBAT+ of the battery 1 and one end of the first protection module 21, and the second plate of the third capacitor C3 is connected to the first end of the second protection module 23 and the negative terminal VBAT- of the battery 1. The first plate of the fourth capacitor C4 is connected to the other end of the first protection module 21, and the second plate of the fourth capacitor C4 is connected to the second end of the second protection module 23 via a common ground connection.

[0062] The output voltage of battery 1 may contain high-frequency noise or ripple (such as AC components during charging). In this case, the third capacitor C3 and the fourth capacitor C4 can absorb these high-frequency components, making the voltage supplied to the subsequent circuit (such as the current limiting module 22) cleaner. Furthermore, by reducing high-frequency interference, the electromagnetic compatibility of the buck regulator circuit 2 can be improved, and interference to the load can be reduced.

[0063] To monitor the output voltage of battery 1 in real time, in one example, such as Figure 7 As shown, the step-down voltage regulator circuit 2 also includes a data acquisition module 24. The first terminal of the data acquisition module 24 is connected to the negative terminal of the second diode D2, the second terminal of the data acquisition module 24 is connected to the microcontroller 3, and the third terminal of the data acquisition module 24 is grounded. The data acquisition module 24 is used to acquire the voltage of the battery 1 and output it to the microcontroller 3. It is worth noting that the second terminal of the data acquisition module 24 is connected to the feedback pin FB of the microcontroller 3.

[0064] In this example, the acquisition module 24 will acquire the output voltage of battery 1 in real time and output it to microcontroller 3. When the output voltage of battery 1 connected to microcontroller 3 fluctuates greatly, microcontroller 3 can take corresponding protection strategies to prevent the large fluctuation from burning the circuit board, thereby improving the operational reliability of buck regulator circuit 2 and extending the service life of buck regulator circuit 2.

[0065] For example, such as Figure 8 As shown, the acquisition module 24 includes a second resistor R2 and a third resistor R3. One end of the second resistor R2 serves as the first terminal of the acquisition module 24 and is connected to the negative terminal of the second diode D2. The other end of the second resistor R2 serves as the second terminal of the acquisition module 24 and is connected to the microcontroller 3. One end of the third resistor R3 is connected to the other end of the second resistor R2, and the other end of the third resistor R3 serves as the third terminal of the acquisition module 24 and is grounded.

[0066] In this example, the second resistor R2 and the third resistor R3 are voltage divider resistors, which can convert the output voltage of battery 1 into a voltage range that the microcontroller 3 can acquire, thereby realizing the acquisition of the output voltage of battery 1. The structure is simple. Moreover, the acquisition security is relatively high when acquiring data through the second resistor R2 and the third resistor R3.

[0067] To improve the stability of the voltage output to microcontroller 3, in one example, such as Figure 8 As shown, the acquisition module 24 also includes a first capacitor C1 and a second capacitor C2. The first plate of the first capacitor C1 is connected to the negative terminal of the second diode D2 and one end of the second resistor R2, and the second plate of the first capacitor C1 is connected to the other end of the third resistor R3. The first plate of the second capacitor C2 is connected to the other end of the second resistor R2, the microcontroller 3, and one end of the third resistor R3, and the second plate of the second capacitor C2 is grounded.

[0068] In this example, the first capacitor C1 and the second capacitor C2 act as filter capacitors, absorbing ripple and noise in the output voltage, making the voltage output to the microcontroller 3 more stable and improving the monitoring reliability of the microcontroller 3. Secondly, the second plate of the second capacitor C2 is grounded, providing a stable reference point for the capacitor, which helps eliminate high-frequency interference signals and improves the electromagnetic compatibility of the acquisition module 24.

[0069] In summary, this application utilizes the impedance characteristics of the current limiting module 22 to initially attenuate the output voltage of the battery 1, and then further clamps the output voltage using the characteristics of the Zener diode D0 in the reverse breakdown region, ultimately stabilizing the output voltage at the target value (i.e., the target supply voltage). Furthermore, the current limiting module 22 enables the Zener diode D0 to maintain this supply voltage, providing a stable supply voltage to the microcontroller 3. This allows the microcontroller 3 to operate stably based on this stable supply voltage, ensuring the operational stability of the microcontroller 3 and the reliability of its load control. Compared to related technologies that use LDOs and DC-DC converters for voltage reduction and regulation, this application reduces at least three power devices and two control ICs, lowering the BOM cost by approximately 40% or more, thus reducing the overall manufacturing cost. Secondly, the current limiting module 22 also limits the current flowing into the Zener diode D0 to prevent damage due to excessive current, thereby ensuring the reliability of the Zener diode D0 and extending its lifespan. Secondly, reverse connection protection for battery 1 is achieved through the first protection module 21 and the second protection module 23, thereby improving the operational reliability of the step-down voltage regulator circuit 2.

[0070] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0071] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A step-down voltage regulator circuit, applied to a microcontroller, characterized in that, The step-down regulator circuit includes: The first protection module, one end of which is connected to the positive terminal of the battery; A current limiting module, wherein a first end of the current limiting module is connected to the other end of the first protection module, and a second end of the current limiting module is connected to the microcontroller; A Zener diode, the negative terminal of which is connected to the third terminal of the current limiting module, and the positive terminal of which is grounded; and, The second protection module has a first terminal connected to the negative terminal of the battery, a second terminal connected to the positive terminal of the Zener diode and grounded, and a controlled terminal connected to the second terminal of the current limiting module.

2. The step-down voltage regulator circuit according to claim 1, characterized in that, The step-down voltage regulator circuit also includes: A first resistor, one end of which is connected to the other end of the first protection module and the first end of the current limiting module; and... A first switch, the controlled terminal of the first switch is connected to the second terminal of the current limiting module and the controlled terminal of the second protection module, the first terminal of the first switch is connected to the other end of the first resistor, and the second terminal of the first switch is connected to the microcontroller.

3. The step-down voltage regulator circuit according to claim 2, characterized in that, The current limiting module includes: A current-limiting resistor, one end of which serves as the first terminal of the current-limiting module and is connected to the other terminal of the first protection module and one end of the first resistor; the other end of which serves as the second terminal of the current-limiting module and is connected to the controlled terminal of the first switch, the controlled terminal of the second protection module, and the microcontroller; and, The first diode has its anode connected to the other end of the current-limiting resistor, and its cathode is connected to the cathode of the Zener diode as the third terminal of the current-limiting module.

4. The step-down voltage regulator circuit according to claim 1, characterized in that, The second protection module includes: The second switch has a first terminal connected to the negative terminal of the battery as the first terminal of the second protection module, a second terminal connected to the positive terminal of the Zener diode as the second terminal of the second protection module, and a controlled terminal connected to the second terminal of the current limiting module as the controlled terminal of the second protection module.

5. The step-down voltage regulator circuit according to claim 1, characterized in that, The first protection module includes: The second diode has its positive terminal connected to the positive terminal of the battery as one end of the first protection module, and its negative terminal connected to the first end of the current limiting module as the other end of the first protection module.

6. The step-down voltage regulator circuit according to claim 5, characterized in that, The step-down voltage regulator circuit also includes: The acquisition module has a first terminal connected to the negative terminal of the second diode, a second terminal connected to the microcontroller, and a third terminal grounded. The acquisition module is used to acquire the voltage of the battery and output it to the microcontroller.

7. The step-down voltage regulator circuit according to claim 6, characterized in that, The acquisition module includes: A second resistor, one end of which serves as the first terminal of the acquisition module and is connected to the negative terminal of the second diode, and the other end of which serves as the second terminal of the acquisition module and is connected to the microcontroller; and, The third resistor has one end connected to the other end of the second resistor, and the other end of the third resistor serves as the third terminal of the acquisition module for grounding.

8. The step-down voltage regulator circuit according to claim 7, characterized in that, The acquisition module also includes: A first capacitor, wherein the first plate of the first capacitor is connected to the negative terminal of the second diode and one end of the second resistor, and the second plate of the first capacitor is connected to ground along with the other end of the third resistor; and... The second capacitor has its first plate connected to the other end of the second resistor, the microcontroller, and one end of the third resistor, and its second plate is grounded.

9. The step-down voltage regulator circuit according to any one of claims 1-8, characterized in that, The step-down voltage regulator circuit also includes: A third capacitor, wherein the first plate of the third capacitor is connected to the positive terminal of the battery and one end of the first protection module, and the second plate of the third capacitor is connected to the first end of the second protection module and the negative terminal of the battery; and, The fourth capacitor has its first plate connected to the other end of the first protection module, and its second plate connected to the second end of the second protection module.

10. A control system, characterized in that, include: Battery; The buck regulator circuit as described in any one of claims 1-9, wherein the buck regulator circuit is connected to the battery; and, A microcontroller is connected to the buck regulator circuit.

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