Direct current multi-input anti-reverse connection circuit and product
By using a parallel N-MOS transistor structure and voltage comparator control, the heat generation and complexity issues of diodes and rectifier bridges in high-current applications are solved, achieving a low-loss, reliable multi-input reverse connection protection circuit design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JWIPC TECH CO LTD
- Filing Date
- 2025-05-19
- Publication Date
- 2026-06-02
AI Technical Summary
In high-current applications, the conduction losses of diodes and rectifier bridges lead to severe heat generation. Existing multi-input reverse connection protection circuits are complex to design and increase costs, affecting system reliability.
By employing a parallel N-MOS transistor structure, combined with a voltage comparator and a controllable power supply module, mutual exclusion conduction and reverse connection protection of multiple input channels are achieved. The reverse connection current is blocked through the dual turn-off mechanism of the body diode of the N-MOS transistor and the voltage comparator.
It significantly reduces conduction losses, reduces heat generation, supports multi-input redundancy design, improves system reliability, simplifies circuit structure, and reduces hardware costs.
Smart Images
Figure CN224319071U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of DC input circuit technology, and more specifically, to a DC multi-input reverse connection protection circuit and product. Background Technology
[0002] Currently, industrial equipment, communication systems, and new energy products often require DC dual-input or multi-input interface designs to achieve power redundancy and improve system reliability. To prevent equipment damage caused by incorrect power connection, such circuits need to have reverse connection protection. Traditional solutions often use diodes or rectifier bridges to achieve reverse connection protection, which are simple in structure and low in cost.
[0003] Regarding the aforementioned technologies, in high-current applications, diodes and rectifier bridges, due to their large voltage drops, generate high conduction losses, leading to severe heat generation. Insufficient system heat dissipation may cause uncontrolled temperature rise, affecting circuit stability and even damaging the equipment. Furthermore, existing reverse connection protection circuits based on MOSFETs are mostly single-channel designs. Expanding to multi-input requires additional complex control circuitry to implement channel switching and mutual exclusion logic, which not only increases cost but also introduces signal interference risks, reducing overall system reliability. Utility Model Content
[0004] The present invention is mainly intended to solve the problems of voltage drop and heat generation caused by using diodes and rectifier bridges to achieve reverse connection protection. In view of the above-mentioned defects of the prior art, a DC multi-input reverse connection protection circuit is provided.
[0005] The technical solution adopted by this utility model to solve its technical problem is:
[0006] on the one hand
[0007] A DC multi-input reverse polarity protection circuit includes at least two input channels. The positive terminal of each input channel is connected in parallel to a common positive node, and the negative terminal is connected to a common negative node through the drain of an N-MOS transistor. The source of the N-MOS transistor is connected to the negative terminal of the corresponding input channel.
[0008] A voltage comparator, whose input terminals are connected to the positive and negative terminals of each input channel, and whose output terminal is connected to the gate of the corresponding N-MOS transistor;
[0009] The controllable power supply module consists of a transistor, a voltage regulator, and a capacitor. Its input is connected to a common positive node, and its output provides voltage to a voltage comparator.
[0010] The output of the voltage comparator is connected to the gate of each N-MOS transistor to control the mutual exclusion conduction of the multiple input channels.
[0011] Preferably, the Zener diode has a breakdown voltage of 10V, the transistor is an NPN type, the resistor value ranges from 1KΩ to 200KΩ, and the capacitor value ranges from 0.1uF to 10uF.
[0012] Preferably, when the input power supply is reversed, the body diode of the N-MOS transistor is reverse-cut off, causing the controllable power supply module to be unable to generate a working voltage, the voltage comparator to have no output signal, and all N-MOS transistors to remain in the off state.
[0013] Preferably, the output logic of the voltage comparator is as follows:
[0014] When an input voltage is detected to be higher than a set threshold, a high level is output to the gate of that N-MOS transistor.
[0015] Output a low level to the gate of other N-MOS transistors to ensure that the multiple input channels are mutually exclusive and conduct.
[0016] Preferably, a logic isolation circuit is provided between the output terminal of the voltage comparator and the gate of each N-MOS transistor to prevent signal interference.
[0017] Preferably, the voltage comparator integrates a priority control function, which sets the priority order of the input channels through an external adjustable resistor. When a high-priority input is active, a low-priority channel is automatically blocked.
[0018] Preferably, the circuit further includes a fault detection module, which acquires the output voltage of the controllable power module through an ADC and triggers an LED alarm signal when the input is reversed or the power supply is abnormal.
[0019] on the other hand
[0020] An electronic product, wherein any of the aforementioned DC multiple input reverse polarity protection circuits is integrated on the electronic product.
[0021] The beneficial effects of this utility model are as follows:
[0022] 1. By using N-MOS transistors instead of traditional diodes and rectifier bridges, the low on-resistance characteristics of N-MOS transistors significantly reduce voltage drop, power consumption and heat generation, making them suitable for high-current scenarios.
[0023] 2. Supports multi-input redundancy design, and achieves mutual exclusion conduction of channels through the logic control of voltage comparators to ensure seamless switching between main and backup power supplies and improve system reliability;
[0024] 3. By using the dual turn-off mechanism of the N-MOS transistor's body diode and voltage comparator, reverse current is blocked to prevent equipment damage;
[0025] 4. The controllable power supply module, priority control module, and fault detection module can be flexibly expanded to adapt to different application requirements;
[0026] 5. Simplify the circuit, eliminating the complex circuitry required for multi-channel control, and achieve the function using only N-MOS transistors and general-purpose components, thereby reducing hardware costs. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the multi-input circuit of a preferred embodiment of the present invention. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, of the embodiments of this utility model. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0030] Example 1
[0031] The preferred embodiment of this utility model is as follows: Figure 1 As shown, a DC multi-input reverse connection protection circuit includes at least two input channels, with the positive terminal of each input channel connected in parallel to a common positive node, and the negative terminal connected to a common negative node through the drain of an N-MOS transistor.
[0032] The source of the N-MOS transistor is connected to the negative terminal of the corresponding input channel;
[0033] A voltage comparator has its input terminals connected to the positive and negative terminals of each input channel, and its output terminal connected to the gate of the corresponding N-MOS transistor. The output of the voltage comparator is connected to the gate of each N-MOS transistor to control the mutual exclusion conduction of the multiple input channels. The output logic of the voltage comparator is as follows:
[0034] When an input voltage is detected to be higher than a set threshold, a high level is output to the gate of that N-MOS transistor; a low level is output to the gates of other N-MOS transistors to ensure that multiple input channels are mutually exclusive and can be turned on.
[0035] The controllable power supply module consists of transistors, Zener diodes, resistors, and capacitors. The input terminal of the controllable power supply module is connected to a common positive node, and the output terminal provides voltage to the voltage comparator.
[0036] The Zener diode has a breakdown voltage of 10V, the transistor is NPN type, the resistor value ranges from 1KΩ to 200KΩ, and the capacitor value ranges from 0.1uF to 10uF.
[0037] When the input power is reversed, the body diode of the N-MOS transistor is reversed and cut off, causing the controllable power module to be unable to generate the working voltage, the voltage comparator to have no output signal, and all N-MOS transistors to remain in the off state.
[0038] A logic isolation circuit is provided between the output of the voltage comparator and the gate of each N-MOS transistor to prevent signal interference.
[0039] The voltage comparator integrates priority control functionality, allowing the priority order of input channels to be set via an external adjustable resistor. When a high-priority input is active, low-priority channels are automatically disabled.
[0040] The circuit also includes a fault detection module, which acquires the output voltage of the controllable power supply module through an ADC and triggers an LED alarm signal when the input is reversed or the power supply is abnormal.
[0041] When power is applied to any of the paths, the body diode inside the N-MOS transistor is in a conducting state at the instant of power-on, thus forming a loop. In this loop, a controllable power supply is generated through the transistor, Zener resistor, and capacitor. This generated power supply then powers a voltage comparator. After being powered on, the voltage comparator outputs a high-level or low-level signal to the gate and source terminals of the corresponding N-MOS transistor based on the power-on state of the comparator circuit. The high-level signal must be greater than the N-MOS transistor's turn-on threshold, and the low-level signal must be less than the N-MOS transistor's turn-on threshold. Upon receiving the high-level output signal, the N-MOS transistor turns on, the power supply loop for the subsequent load is formed, and the circuit begins normal operation.
[0042] When the positive and negative terminals of the power input are reversed, the body diode inside the N-MOS transistor is in the cutoff state, and a circuit cannot be formed. The transistor and Zener diode cannot generate power to supply the voltage comparator, and the voltage comparator cannot work. At this time, the N-MOS transistor cannot be turned on, the load circuit cannot be formed, the device does not work, and the system circuit will not be damaged.
[0043] When any one or more inputs are connected to the power supply, there is no interference between them because each input is separated by an N-MOS transistor and controlled independently.
[0044] Example 2
[0045] An electronic product that integrates any of the DC multiplexer reverse polarity protection circuits as described in Example 1.
[0046] The implementation principle of this application embodiment is as follows: when any input power supply is normally connected, the body diode of the N-MOS transistor is turned on, the controllable power module generates a working voltage to drive the voltage comparator, the voltage comparator outputs a high level to the gate of the corresponding N-MOS transistor according to the detected input voltage, turns on the N-MOS transistor, and forcibly turns off other N-MOS transistors through logic control, ensuring that multiple input channels are mutually exclusive and conducting, solving the problem of voltage drop and heat generation caused by using diodes and rectifier bridges to prevent reverse connection, while also meeting the requirements of multiple inputs.
[0047] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A DC multi-input reverse polarity protection circuit, comprising at least two input channels, characterized in that, The positive terminal of each input channel is connected in parallel to a common positive node, and the negative terminal is connected to a common negative node through the drain of an N-MOS transistor. The source of the N-MOS transistor is connected to the negative terminal of the corresponding input channel; A voltage comparator, whose input terminals are connected to the positive and negative terminals of each input channel, and whose output terminal is connected to the gate of the corresponding N-MOS transistor; The controllable power supply module consists of transistors, Zener diodes, resistors, and capacitors. The input terminal of the controllable power supply module is connected to a common positive node, and the output terminal provides voltage to a voltage comparator. The output of the voltage comparator is connected to the gate of each N-MOS transistor to control the mutual exclusion conduction of the multiple input channels.
2. The DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, The Zener diode has a breakdown voltage of 10V, the transistor is NPN type, the resistor value ranges from 1KΩ to 200KΩ, and the capacitor value ranges from 0.1uF to 10uF.
3. The DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, When the input power is reversed, the body diode of the N-MOS transistor is reversed and cut off, causing the controllable power module to be unable to generate a working voltage, the voltage comparator to have no output signal, and all N-MOS transistors to remain in the off state.
4. The DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, The output logic of the voltage comparator is as follows: When an input voltage is detected to be higher than a set threshold, a high level is output to the gate of that N-MOS transistor. Output a low level to the gate of other N-MOS transistors to ensure that the multiple input channels are mutually exclusive and conduct.
5. A DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, A logic isolation circuit is provided between the output terminal of the voltage comparator and the gate of each N-MOS transistor to prevent signal interference.
6. The DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, The voltage comparator integrates a priority control function, which sets the priority order of the input channels through an external adjustable resistor. When a high-priority input is valid, the low-priority channel is automatically blocked.
7. A DC multi-input reverse polarity protection circuit according to claim 1, characterized in that, The circuit also includes a fault detection module, which acquires the output voltage of the controllable power module through an ADC and triggers an LED alarm signal when the input is reversed or the power supply is abnormal.
8. An electronic product, characterized in that, The electronic product integrates a DC multiple input reverse connection protection circuit as described in any one of claims 1-7.