Vehicle-mounted power supply circuit and vehicle-mounted power supply PCB

Abstract

The utility model provides a vehicle-mounted power supply circuit. The vehicle-mounted power supply circuit comprises a rectification input circuit, a voltage stabilization filtering output circuit, a feedback control circuit and a direct current transformer. The output end of the rectification input circuit is connected with a primary winding of the direct-current transformer. And the direct-current transformer is provided with two secondary windings which are respectively connected with the feedback control circuit and the voltage-stabilizing filtering output circuit. The voltage-stabilizing filtering output circuit is composed of a first electronic switching tube, a first divider resistor, a first filtering capacitor and a first voltage-stabilizing diode, and voltage-stabilizing output is achieved. And the feedback control circuit comprises a second electronic switching tube, a second divider resistor and a third divider resistor and is used for controlling the output of the direct-current transformer. According to the vehicle-mounted power supply circuit, the vehicle-mounted power supply circuit can realize voltage stabilization output and feedback control without a microcontroller, so that the use cost of the vehicle-mounted power supply circuit is reduced, the circuit design is simplified, PCB printing is facilitated, the size of a PCB is reduced, and the applicability of the vehicle-mounted power supply circuit is improved.

Description

Technical Field

[0001] This disclosure relates to the technical field of vehicle-mounted cameras, and in particular to a vehicle-mounted power supply circuit and a vehicle-mounted power supply PCB board. Background Technology

[0002] Switching power supplies, as indispensable energy conversion devices in modern electronic devices, are widely used in various fields, such as communication equipment, computer equipment, and home appliances. With technological advancements, the performance requirements for switching power supplies are becoming increasingly stringent, including high efficiency, high power density, low noise, and low cost. However, traditional switching power supply designs often face the challenge of rising costs while pursuing high performance.

[0003] Specifically, in switching power supply design, the feedback circuit plays a crucial role. It monitors the output voltage or current and feeds this information back to the control circuit to adjust the operating state of the switching transistors, thereby maintaining stable output voltage or current. To achieve high-precision feedback control, modern switching power supplies typically use chips to implement the feedback circuit function. These chips integrate complex control algorithms and protection functions, enabling them to accurately monitor the output voltage or current and quickly adjust the operating state of the switching transistors based on the monitoring results.

[0004] However, while using chips to implement feedback circuits improves the performance and reliability of switching power supplies, it also increases costs. High-performance feedback control chips are often expensive, increasing the overall cost of switching power supplies, especially in large-scale production and applications where cost is a more prominent issue. Utility Model Content

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a low-cost vehicle power supply circuit and vehicle power supply PCB board.

[0006] The purpose of this disclosure is achieved through the following technical solution:

[0007] An on-board power supply circuit includes a rectifier input circuit, a voltage regulator and filter output circuit, a feedback control circuit, and a DC transformer. The input terminal of the rectifier input circuit is connected to the power supply terminal of the on-board power supply, the output terminal of the rectifier input circuit is connected to the input terminal of the primary winding of the DC transformer, the first secondary winding of the DC transformer is connected to the input terminal of the feedback control circuit, and the second secondary winding of the DC transformer is connected to the input terminal of the voltage regulator and filter output circuit.

[0008] The voltage-stabilized and filtered output circuit includes a first electronic switch, a first voltage-dividing resistor, a first filter capacitor, and a first Zener diode. The first end of the first voltage-dividing resistor is connected to the output terminal of the second secondary winding of the DC transformer. The second end of the first voltage-dividing resistor is connected to the first end of the first filter capacitor, and the second end of the first filter capacitor is grounded. The first end of the first voltage-dividing resistor is connected to the anode of the first Zener diode and the first end of the first electronic switch. The cathode of the first Zener diode is connected to the control terminal of the first electronic switch. The second end of the first electronic switch is connected to the output terminal of the voltage-stabilized and filtered output circuit.

[0009] The feedback control circuit includes a second electronic switch, a second voltage divider resistor, and a third voltage divider resistor. The first end of the second voltage divider resistor is connected to the output end of the rectifier input circuit, the second end of the second voltage divider resistor is connected to the control end of the second electronic switch, the first end of the second electronic switch is connected to the output end of the primary winding of the DC transformer, and the second end of the second electronic switch is grounded through the third voltage divider resistor.

[0010] In one embodiment, the voltage-stabilized filter output circuit further includes a first switching diode, the anode of which is connected to the input terminal of the voltage-stabilized filter output circuit, and the cathode of which is connected to the first terminal of the first electronic switch.

[0011] In one embodiment, the voltage-regulated filter output circuit further includes a first filter capacitor, the first end of which is connected to the input terminal of the voltage-regulated filter output circuit, and the first filter capacitor is grounded.

[0012] In one embodiment, the voltage regulator output circuit further includes a fourth voltage divider resistor, the first end of which is connected to the input terminal of the voltage regulator output circuit, and the fourth voltage divider resistor is grounded.

[0013] In one embodiment, the rectifier input circuit includes a rectifier bridge circuit and a spike current suppression circuit. The spike current suppression circuit includes a second switching diode and a fifth voltage divider resistor. The input terminal of the rectifier bridge circuit is connected to the vehicle power supply terminal. The output terminal of the rectifier bridge circuit is connected to the first terminal of the fifth voltage divider resistor. The first terminal of the fifth voltage divider resistor is also connected to the first terminal of the primary winding of the DC transformer. The second terminal of the primary winding of the DC transformer is connected to the positive terminal of the second switching diode, and the negative terminal of the second switching diode is connected to the second terminal of the fifth voltage divider resistor.

[0014] In one embodiment, the rectifier input circuit further includes a fuse, the first end of which is connected to the power supply terminal of the vehicle power supply, and the second end of which is connected to the input terminal of the rectifier bridge circuit.

[0015] In one embodiment, the spike current suppression circuit further includes a second filter capacitor, the first end of which is connected to the first end of the fifth voltage divider resistor, and the second end of which is connected to the second end of the fifth voltage divider resistor.

[0016] In one embodiment, the feedback control circuit further includes a sixth voltage divider resistor, the first end of which is connected to the second end of the second voltage divider resistor, and the second end of which is connected to the control terminal of the second electronic switch.

[0017] In one embodiment, the feedback control circuit further includes a seventh voltage divider resistor, the first end of which is connected to the first end of the third voltage divider resistor, and the second end of which is connected to the ground terminal.

[0018] A vehicle power supply PCB board, comprising the vehicle power supply circuit described in any of the above claims.

[0019] Compared with the prior art, this disclosure has at least the following advantages:

[0020] 1. The above-mentioned vehicle power supply circuit, without using a microcontroller to control the circuit, can achieve the functions of voltage regulation output and feedback control, thereby reducing the cost of using the vehicle power supply circuit, simplifying the circuit design, facilitating the printing of the vehicle power supply circuit on the PCB board, and reducing the size of the PCB board, so that the PCB board of the vehicle power supply circuit can be used in more application scenarios, thereby improving the applicability of the vehicle power supply circuit. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A circuit diagram of an embodiment of an on-board power supply circuit;

[0023] Figure 2 for Figure 1 The diagram shows the PCB structure of the vehicle power supply circuit. Detailed Implementation

[0024] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0028] like Figure 1 As shown, an embodiment of the vehicle power supply circuit 10 disclosed herein includes a rectifier input circuit 100, a voltage regulator and filter output circuit 200, a feedback control circuit 300, and a DC transformer T1. The input terminal of the rectifier input circuit 100 is connected to the power supply terminal of the vehicle power supply, the output terminal of the rectifier input circuit 100 is connected to the input terminal of the primary winding of the DC transformer T1, the first secondary winding of the DC transformer T1 is connected to the input terminal of the feedback control circuit 300, and the second secondary winding of the DC transformer T1 is connected to the input terminal of the voltage regulator and filter output circuit 200.

[0029] The voltage regulator and filter output circuit 200 includes a first electronic switch Q5, a first voltage divider resistor R25, a first filter capacitor C10, and a first Zener diode Z4. The first end of the first voltage divider resistor R25 is connected to the output terminal of the second secondary winding of the DC transformer T1, and the second end of the first voltage divider resistor R25 is connected to the first end of the first filter capacitor C10. The second end of the first filter capacitor C10 is grounded. The first end of the first voltage divider resistor R25 is connected to the positive terminal of the first Zener diode Z4 and the first end of the first electronic switch Q5. The negative terminal of the first Zener diode Z4 is connected to the control terminal of the first electronic switch Q5. The second end of the first electronic switch Q5 is connected to the output terminal of the voltage regulator and filter output circuit 200.

[0030] The feedback control circuit 300 includes a second electronic switch Q1, a second voltage divider resistor R2, and a third voltage divider resistor RS1. The first end of the second voltage divider resistor R2 is connected to the output end of the rectifier input circuit 100, the second end of the second voltage divider resistor R2 is connected to the control end of the second electronic switch Q1, the first end of the second electronic switch Q1 is connected to the output end of the primary winding of the DC transformer T1, and the second end of the second electronic switch Q1 is grounded through the third voltage divider resistor RS1.

[0031] In this embodiment, when the output voltage of the vehicle power supply terminal reaches the rectifier input circuit 100, the current is rectified and output as DC to the input terminal of the primary winding of the DC transformer T1. At the same time, the DC also flows through the second voltage divider resistor R2, and then the current flows to the control terminal of the second electronic switch Q1, so that the voltage at the control terminal of the second electronic switch Q1 is greater than its conduction threshold voltage, thereby turning on the second electronic switch Q1. Meanwhile, since the first terminal of the second electronic switch Q1 is connected to the primary winding of the DC transformer T1, the current can form a current loop through the second electronic switch Q1 and the third voltage divider resistor RS1 with the ground terminal, thereby enabling the DC transformer T1 to work normally, so that the first secondary winding and the second secondary winding of the DC transformer T1 can obtain induced current through electromagnetic induction. On the other hand, the induced current is transmitted through the second secondary winding of the DC transformer T1 to the first voltage divider resistor R25 and the first terminal of the first electronic switch Q5. Then, the current flows through the first voltage divider resistor R25 to the control terminal of the first electronic switch Q5, making the voltage at the control terminal of the first electronic switch Q5 greater than its conduction threshold voltage, thereby turning on the first electronic switch Q5 and outputting current to the load. In addition, since the cathode of the first Zener diode Z4 is connected to the control terminal of the first electronic switch Q5, the control terminal of the first electronic switch Q5 maintains a stable conducting state after obtaining a sufficient conduction threshold voltage.

[0032] The aforementioned vehicle power supply circuit 10 achieves voltage regulation and feedback control without using a microcontroller, thus reducing its cost and simplifying its design. This facilitates PCB printing and reduces the PCB size, making the PCB suitable for a wider range of applications and improving its overall applicability. Specific PCB design diagrams can be found in [reference needed]. Figure 2 As shown.

[0033] like Figure 1 As shown, in one embodiment, the voltage regulator and filter output circuit 200 further includes a first switching diode. The anode of the first switching diode is connected to the input terminal of the voltage regulator and filter output circuit 200, and the cathode of the first switching diode is connected to the first terminal of the first electronic switch Q5. In this embodiment, when the vehicle power supply provides power and passes through the rectifier input circuit 100, DC power is delivered to the primary winding of the DC transformer T1, thereby generating an induced current in the secondary winding through electromagnetic induction. This induced current then flows through the first voltage divider resistor R25. After being divided, a portion of the current flows to the control terminal of the first electronic switch Q5, and the other portion of the current flows through the first switching diode to the first terminal of the first electronic switch Q5. When the circuit is working normally, the first switching diode is forward-biased, allowing the current output from the second secondary winding of the DC transformer T1 to flow to the first electronic switch Q5. When the voltage at the control terminal of the first electronic switch Q5 reaches the conduction threshold, the first electronic switch Q5 is turned on, transferring current to the load. The forward conduction state of the first switching diode helps ensure that current can flow smoothly through the first electronic switching transistor Q5, thereby avoiding interruption or damage to the voltage regulation and filtering output circuit 200.

[0034] like Figure 1As shown, in one embodiment, the voltage regulator output circuit 200 further includes a first filter capacitor C10. The first terminal of the first filter capacitor C10 is connected to the input terminal of the voltage regulator output circuit 200, and the first filter capacitor C10 is grounded. In this embodiment, when the vehicle power supply supplies power and passes through the rectifier input circuit 100 and the DC transformer T1, the induced current generated in the second secondary winding flows through the first voltage divider resistor R25. Part of it flows to the control terminal of the first electronic switch Q5 to control its conduction; the other part flows through the first switching diode to the first terminal of the first electronic switch Q5, and is finally transferred to the load. In this process, the first filter capacitor C10 and the first voltage divider resistor R25 are connected in parallel to filter and regulate the induced current. During transient circuit response or load changes, the first filter capacitor C10 can quickly release or absorb charge to maintain the stability of the output voltage. Its energy storage characteristics help the circuit maintain a stable output voltage when the load suddenly increases or decreases, thereby improving the stability of the voltage regulator output circuit 200 and ensuring that the load obtains a stable operating voltage.

[0035] like Figure 1 As shown, in one embodiment, the voltage regulator output circuit 200 further includes a fourth voltage divider resistor R10. The first end of the fourth voltage divider resistor R10 is connected to the input terminal of the voltage regulator output circuit 200, and the fourth voltage divider resistor R10 is grounded. In this embodiment, when the vehicle power supply supplies power and passes through the rectifier input circuit 100 and the DC transformer T1, the induced current generated by the second secondary winding first flows through the fourth voltage divider resistor R10. Furthermore, since the fourth voltage divider resistor R10 acts as a voltage divider, it can reduce the high-voltage portion of the induced current to a voltage range suitable for subsequent circuit processing, thereby protecting the components in the circuit from high-voltage damage. On the other hand, the voltage divider circuit formed between the fourth voltage divider resistor R10 and ground constitutes a simple low-pass filter, which can filter out high-frequency noise and interference in the induced current, thereby making the output current of the voltage regulator output circuit 200 smoother and more stable.

[0036] like Figure 1As shown, in one embodiment, the rectifier input circuit 100 includes a rectifier bridge circuit 110 and a spike current suppression circuit 120. The spike current suppression circuit 120 includes a second switching diode D3 and a fifth voltage divider resistor R8. The input terminal of the rectifier bridge circuit 110 is connected to the vehicle power supply terminal, and the output terminal of the rectifier bridge circuit 110 is connected to the first terminal of the fifth voltage divider resistor R8. The first terminal of the fifth voltage divider resistor R8 is also connected to the first terminal of the primary winding of the DC transformer T1. The second terminal of the primary winding of the DC transformer T1 is connected to the positive terminal of the second switching diode D3, and the negative terminal of the second switching diode D3 is connected to the second terminal of the fifth voltage divider resistor R8. In this embodiment, since the input terminal of the rectifier bridge circuit 110 is connected to the vehicle power supply terminal, it can form a bridge connection through its four internal diodes to convert the AC power supplied by the vehicle power supply into DC power, and provide a stable DC power supply for subsequent circuits. A spike current suppression circuit 120 is connected between the output terminal of the rectifier bridge circuit 110 and the primary winding of the DC transformer T1, thereby suppressing spike currents and voltage overshoots generated during rectification, and protecting the DC transformer T1 and the components in the circuit from damage. Specifically, when the DC output of the rectifier bridge circuit 110 contains spike currents, the spike current is directed through the second switching diode D3 to the fifth voltage divider resistor R8 to suppress and absorb the spike currents and convert them into heat dissipation, thus avoiding the impact of spike currents and voltage overshoots on the circuit components.

[0037] like Figure 1 As shown, in one embodiment, the rectifier input circuit 100 further includes a fuse F1. The first end of fuse F1 is connected to the power supply terminal of the vehicle power supply, and the second end of fuse F1 is connected to the input terminal of the rectifier bridge circuit 110. In this embodiment, when the vehicle power supply terminal provides voltage to the vehicle power circuit 10, the current first flows through fuse F1 and then to the rectifier bridge circuit 110. Because fuse F1 contains a specially designed metal wire or sheet, it can quickly melt and break the circuit when the current is too large or a short circuit occurs, thereby preventing the current from continuing to flow. This protects other components in the circuit from damage caused by excessive current, thus avoiding more serious malfunctions or safety accidents. Specifically, under normal operating conditions, fuse F1 allows current to flow smoothly without affecting the normal operation of the rectifier bridge circuit 110. The rectifier bridge circuit 110 converts the AC power supplied by the vehicle power supply into DC power and outputs it to the subsequent circuits. When an abnormality occurs in the circuit and the current increases sharply, the fuse F1 will immediately melt and cut off the circuit, thereby effectively preventing further increase in current from damaging the circuit components.

[0038] like Figure 1As shown, in one embodiment, the spike current suppression circuit 120 further includes a second filter capacitor C6. The first terminal of the second filter capacitor C6 is connected to the first terminal of the fifth voltage divider resistor R8, and the second terminal of the second filter capacitor C6 is connected to the second terminal of the fifth voltage divider resistor R8. In this embodiment, when the rectifier bridge circuit 110 converts AC to DC, high-frequency noise and ripple voltage may be generated. Since the second filter capacitor C6 can effectively absorb and smooth these high-frequency noises and ripple voltages, and the second filter capacitor C6 is connected in parallel across the fifth voltage divider resistor R8, the function of the spike current suppression circuit 120 is enhanced, thereby improving the stability and reliability of the entire vehicle power supply circuit 10. Specifically, when the DC output of the rectifier bridge circuit 110 contains high-frequency noise or ripple voltage, these fluctuations will first pass through the fifth voltage divider resistor R8. At this time, due to its energy storage characteristics, the second filter capacitor C6 will quickly absorb the energy in these fluctuations and convert it into electric field energy stored inside the capacitor. When the voltage fluctuation in the circuit decreases, the second filter capacitor C6 will release the stored energy in a timely manner to replenish the electrical energy in the circuit, thereby maintaining the relative stability of the output voltage.

[0039] like Figure 1 As shown, in one embodiment, the feedback control circuit 300 further includes a sixth voltage divider resistor R3. The first end of the sixth voltage divider resistor R3 is connected to the second end of the second voltage divider resistor R2, and the second end of the sixth voltage divider resistor R3 is connected to the control terminal of the second electronic switch Q1. In this embodiment, the sixth voltage divider resistor R3 and the second voltage divider resistor R2 together form a voltage divider network for the output voltage of the rectifier bridge circuit 110. When the rectifier bridge circuit 110 converts AC power to DC power and outputs it, the DC voltage is first divided by the second voltage divider resistor R2, and then a portion of the voltage signal is transmitted to the sixth voltage divider resistor R3. The sixth voltage divider resistor R3 further divides this voltage signal, and finally transmits the adjusted voltage signal to the control terminal of the second electronic switch Q1, making the monitoring of the output voltage of the rectifier bridge circuit 110 by the feedback control circuit 300 more accurate. By adjusting the resistance value of the sixth voltage divider resistor R3, the magnitude of the voltage signal transmitted to the control terminal of the second electronic switch Q1 can be precisely controlled, thereby achieving precise control of the conduction state of the second electronic switch Q1.

[0040] like Figure 1As shown, in one embodiment, the feedback control circuit 300 further includes a seventh voltage divider resistor RS2. The first terminal of the seventh voltage divider resistor RS2 is connected to the first terminal of the third voltage divider resistor RS1, and the second terminals of both the seventh voltage divider resistor RS2 and the third voltage divider resistor RS1 are connected to the ground terminal. In this embodiment, when the second electronic switch Q1 is in the on state, the DC current, through the parallel network composed of the third voltage divider resistor RS1 and the seventh voltage divider resistor RS2, divides the voltage and affects the potential of the second terminal of the second electronic switch Q1, thereby enhancing the feedback control capability of the on state of the second electronic switch Q1. Specifically, the introduction of the seventh voltage divider resistor RS2 provides an additional voltage divider path for the circuit. It, together with the third voltage divider resistor RS1, shares the voltage difference between the second terminal of the second electronic switch Q1 and the ground terminal. By adjusting the resistance value of the seventh voltage divider resistor RS2, the voltage division ratio of the parallel voltage divider network can be further fine-tuned, thereby affecting the voltage at the control terminal of the second electronic switch Q1, and thus achieving fine control of the on state of the second electronic switch Q1.

[0041] A vehicle power supply PCB board includes the vehicle power supply circuit 10 of any of the above-mentioned embodiments. In this embodiment, when the output voltage of the vehicle power supply terminal reaches the rectifier input circuit 100, the current is rectified and output as DC to the input terminal of the primary winding of the DC transformer T1. At the same time, the DC also flows through the second voltage divider resistor R2, and then the current flows to the control terminal of the second electronic switch Q1, so that the voltage at the control terminal of the second electronic switch Q1 is greater than its conduction threshold voltage, thereby turning on the second electronic switch Q1. Meanwhile, since the first terminal of the second electronic switch Q1 is connected to the primary winding of the DC transformer T1, the current can form a current loop through the second electronic switch Q1 and the third voltage divider resistor RS1 and the ground terminal, thereby enabling the DC transformer T1 to work normally, so that the first secondary winding and the second secondary winding of the DC transformer T1 can obtain induced current through electromagnetic induction. On the other hand, the induced current is transmitted through the second secondary winding of the DC transformer T1 to the first voltage divider resistor R25 and the first terminal of the first electronic switch Q5. Then, the current flows through the first voltage divider resistor R25 to the control terminal of the first electronic switch Q5, making the voltage at the control terminal of the first electronic switch Q5 greater than its conduction threshold voltage, thereby turning on the first electronic switch Q5 and outputting current to the load. In addition, since the cathode of the first Zener diode Z4 is connected to the control terminal of the first electronic switch Q5, the control terminal of the first electronic switch Q5 maintains a stable conducting state after obtaining a sufficient conduction threshold voltage.

[0042] Compared with the prior art, this disclosure has at least the following advantages:

[0043] 1. The above-mentioned vehicle power supply circuit 10 can achieve the functions of voltage regulation output and feedback control without using a microcontroller to control the circuit, thereby reducing the cost of using the vehicle power supply circuit 10 and simplifying the circuit design. This is beneficial for the printing of the vehicle power supply circuit 10 on the PCB board and reduces the size of the PCB board, so that the PCB board of the vehicle power supply circuit 10 can be used in more application scenarios, thereby improving the applicability of the vehicle power supply circuit 10.

[0044] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A vehicle-mounted power supply circuit, comprising a rectifier input circuit, a voltage regulator and filter output circuit, a feedback control circuit, and a DC transformer, wherein the input terminal of the rectifier input circuit is connected to the power supply terminal of the vehicle-mounted power supply, the output terminal of the rectifier input circuit is connected to the input terminal of the primary winding of the DC transformer, the first secondary winding of the DC transformer is connected to the input terminal of the feedback control circuit, and the second secondary winding of the DC transformer is connected to the input terminal of the voltage regulator and filter output circuit, characterized in that... The voltage-stabilized and filtered output circuit includes a first electronic switch, a first voltage-dividing resistor, a first filter capacitor, and a first Zener diode. The first end of the first voltage-dividing resistor is connected to the output terminal of the second secondary winding of the DC transformer. The second end of the first voltage-dividing resistor is connected to the first end of the first filter capacitor. The second end of the first filter capacitor is grounded. The first end of the first voltage-dividing resistor is connected to the anode of the first Zener diode and the first end of the first electronic switch. The cathode of the first Zener diode is connected to the control terminal of the first electronic switch. The second end of the first electronic switch is connected to the output terminal of the voltage-stabilized and filtered output circuit. The feedback control circuit includes a second electronic switch, a second voltage divider resistor, and a third voltage divider resistor. The first end of the second voltage divider resistor is connected to the output end of the rectifier input circuit, the second end of the second voltage divider resistor is connected to the control end of the second electronic switch, the first end of the second electronic switch is connected to the output end of the primary winding of the DC transformer, and the second end of the second electronic switch is grounded through the third voltage divider resistor.

2. The vehicle power supply circuit according to claim 1, characterized in that, The voltage-stabilized filter output circuit further includes a first switching diode, the positive terminal of which is connected to the input terminal of the voltage-stabilized filter output circuit, and the negative terminal of which is connected to the first terminal of the first electronic switch.

3. The vehicle power supply circuit according to claim 2, characterized in that, The voltage regulator and filter output circuit further includes a first filter capacitor, the first end of which is connected to the input terminal of the voltage regulator and filter output circuit, and the first filter capacitor is grounded.

4. The vehicle power supply circuit according to claim 1, characterized in that, The voltage regulator and filter output circuit also includes a fourth voltage divider resistor, the first end of which is connected to the input terminal of the voltage regulator and filter output circuit, and the fourth voltage divider resistor is grounded.

5. The vehicle power supply circuit according to claim 1, characterized in that, The rectifier input circuit includes a rectifier bridge circuit and a spike current suppression circuit. The spike current suppression circuit includes a second switching diode and a fifth voltage divider resistor. The input terminal of the rectifier bridge circuit is connected to the vehicle power supply terminal. The output terminal of the rectifier bridge circuit is connected to the first terminal of the fifth voltage divider resistor. The first terminal of the fifth voltage divider resistor is also connected to the first terminal of the primary winding of the DC transformer. The second terminal of the primary winding of the DC transformer is connected to the positive terminal of the second switching diode. The negative terminal of the second switching diode is connected to the second terminal of the fifth voltage divider resistor.

6. The vehicle power supply circuit according to claim 5, characterized in that, The rectifier input circuit also includes a fuse, the first end of which is connected to the power supply terminal of the vehicle power supply, and the second end of which is connected to the input terminal of the rectifier bridge circuit.

7. The vehicle power supply circuit according to claim 5, characterized in that, The peak current suppression circuit further includes a second filter capacitor, the first end of which is connected to the first end of the fifth voltage divider resistor, and the second end of which is connected to the second end of the fifth voltage divider resistor.

8. The vehicle power supply circuit according to claim 1, characterized in that, The feedback control circuit further includes a sixth voltage divider resistor, the first end of which is connected to the second end of the second voltage divider resistor, and the second end of which is connected to the control terminal of the second electronic switch.

9. The vehicle power supply circuit according to claim 8, characterized in that, The feedback control circuit further includes a seventh voltage divider resistor, the first end of which is connected to the first end of the third voltage divider resistor, and the second end of which is connected to the ground terminal.

10. A vehicle-mounted power supply PCB board, characterized in that, The vehicle power supply circuit includes any one of claims 1 to 9.

Images