Low-loss backward voltage protection circuit

Abstract

The utility model provides a low-loss backward voltage protection circuit, which comprises a filtering noise reduction circuit and a one-way conduction circuit, the input end of the filtering noise reduction circuit is connected with an OTG 5V output interface of a tablet computer, and the output end of the filtering noise reduction circuit is connected with the input end of the one-way conduction circuit. The output end of the one-way conduction circuit is connected with the OTG USB interface of the tablet computer, and the whole one-way conduction circuit can replace an independent diode to prevent reverse voltage input. The reverse voltage protection circuit has the advantages that the whole one-way conduction circuit can replace an independent diode to prevent reverse voltage input, the resistance value of the whole one-way conduction circuit is far lower than that of the diode, and heat generated by the reverse voltage protection circuit is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a low-loss reverse voltage protection circuit. Background Art

[0002] In many smart electronic devices, such as tablet computers, some customized products require an additional OTG USB interface to be independently designed. The main TYPE C interface is responsible for connecting to the computer and has a charging function, while the additional OTG USB interface is responsible for connecting an external mouse, keyboard or other peripherals.

[0003] Since this additional OTG USB interface is directly connected to the outside, a reverse voltage protection circuit is generally designed to prevent the internal components from being damaged by high voltage or surge input due to the wrong power supply. In existing tablet computers, a common reverse protection circuit is to design a diode to achieve reverse protection, but this circuit has a major disadvantage, that is, there is a large voltage difference. The input voltage needs to be increased to meet the output of 5V. Due to the voltage difference, the voltage will also fluctuate to a certain extent when the current is different, which leads to the generation of higher additional heat. Utility Model Content

[0004] In order to solve the problems in the prior art, the utility model provides a low-loss reverse voltage protection circuit. By arranging a filtering noise reduction circuit and a unidirectional conduction circuit that cooperate with each other in the low-loss reverse voltage protection circuit, the unidirectional conduction circuit as a whole can replace a single diode to prevent reverse voltage input, and the overall resistance of the unidirectional conduction circuit is much lower than that of the diode, which can reduce the voltage difference between the two ends of the unidirectional conduction circuit and reduce the heat generated by the reverse voltage protection circuit, thereby solving the problem in the prior art that the reverse voltage protection circuit uses a diode with a large voltage difference and generates higher additional heat.

[0005] The utility model provides a low-loss reverse voltage protection circuit, which is arranged between the OTG5V output interface of a tablet computer and the OTG USB interface of the tablet computer, and comprises a filtering noise reduction circuit and a unidirectional conduction circuit, wherein the input end of the filtering noise reduction circuit is connected to the OTG5V output interface of the tablet computer, the output end of the filtering noise reduction circuit is connected to the input end of the unidirectional conduction circuit, the output end of the unidirectional conduction circuit is connected to the OTG USB interface of the tablet computer, and the unidirectional conduction circuit as a whole can replace a single diode to prevent voltage reverse input.

[0006] The utility model is further improved, the unidirectional conduction circuit is provided with a field effect tube Q1, a resistor R2, a resistor R3 and a diode D1, wherein the gate of the field effect tube Q1 is connected to one end of the resistor R2 and one end of the resistor R3, the drain of the field effect tube Q1 is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering noise reduction circuit, and the positive electrode of the diode D1, the source of the field effect tube Q1 is connected to the other end of the resistor R3 and the OTG USB interface of the tablet computer, and the other end of the resistor R2 is connected to the negative electrode of the diode D1.

[0007] The utility model is further improved, the unidirectional conduction circuit is further provided with a transistor Q2, a resistor R4, a resistor R5 and a resistor R6, wherein the base of the transistor Q2 is connected to one end of the resistor R4 and one end of the resistor R6, the other end of the resistor R4 is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering noise reduction circuit, the positive electrode of the diode D1, and the drain of the field effect transistor Q1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the gate of the field effect transistor Q1, one end of the resistor R2, and one end of the resistor R3, and the other end of the resistor R6 and the emitter of the transistor Q2 are grounded.

[0008] The utility model is further improved, the filtering and noise reduction circuit is provided with a resistor R1 and a capacitor C1, wherein one end of the resistor R1 is connected to one end of the capacitor C1, the drain of the field effect tube Q1, the OTG 5V output interface of the tablet computer, the positive electrode of the diode D1, and the drain of the field effect tube Q1, and the other end of the resistor R1 and the other end of the capacitor C1 are grounded.

[0009] The utility model is further improved in that the field effect tube Q1 is a P-type MOS tube.

[0010] Compared with the prior art, the beneficial effects of the utility model are: providing a low-loss reverse voltage protection circuit, by arranging a filtering noise reduction circuit and a unidirectional conduction circuit that cooperate with each other in the low-loss reverse voltage protection circuit, the unidirectional conduction circuit as a whole can replace a single diode to prevent reverse voltage input, and the overall resistance of the unidirectional conduction circuit is much lower than that of the diode, which can reduce the voltage difference between the two ends of the unidirectional conduction circuit and reduce the heat generated by the reverse voltage protection circuit, solving the problem in the prior art that the reverse voltage protection circuit uses a diode with a large voltage difference and generates higher additional heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0012] Figure 1 This is a principle block diagram of a low-loss reverse voltage protection circuit of the utility model;

[0013] Figure 2 The utility model is a circuit diagram of a low-loss reverse voltage protection circuit. DETAILED DESCRIPTION

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present utility model; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model; the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present utility model or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order.

[0015] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0016] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings.

[0017] like Figure 1-2As shown, a low-loss reverse voltage protection circuit provided by the utility model is arranged between the OTG 5V output interface of the tablet computer and the OTG USB interface of the tablet computer, including a filtering noise reduction circuit and a unidirectional conduction circuit, the input end of the filtering noise reduction circuit is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering noise reduction circuit is connected to the input end of the unidirectional conduction circuit, and the output end of the unidirectional conduction circuit is connected to the OTG USB interface of the tablet computer; the unidirectional conduction circuit is provided with a field effect transistor Q1, a resistor R2, a resistor R3 and a diode D1, wherein the gate of the field effect transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3, the drain of the field effect transistor Q1 is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering noise reduction circuit, and the positive electrode of the diode D1, and the source of the field effect transistor Q1 is connected to the other end of the resistor R3 and the OTG The unidirectional conduction circuit is further provided with a transistor Q2, a resistor R4, a resistor R5 and a resistor R6, wherein the base of the transistor Q2 is connected to one end of the resistor R4 and one end of the resistor R6, the other end of the resistor R4 is connected to the OTG 5V output interface of the tablet computer, the output end of the filter noise reduction circuit, the positive electrode of the diode D1, and the drain of the field effect transistor Q1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the gate of the field effect transistor Q1, one end of the resistor R2, and one end of the resistor R3, and the other end of the resistor R6 and the emitter of the transistor Q2 are grounded; wherein the field effect transistor Q1 is a P-type MOS tube, which plays the role of a switch, and the diode D1 has a unidirectional conduction function to prevent the OTGUSB interface of the tablet computer, that is, the USB_VBUS power supply from leaking to the drain of the field effect transistor Q1. In this embodiment, the unidirectional conduction circuit as a whole can replace a single diode to prevent reverse voltage input. When the OTG 5V output interface of the tablet computer is connected to a high level, the field effect tube Q1 is turned on, and the OTG 5V output interface of the tablet computer is connected to the OTG USB interface of the tablet computer and works normally; when the OTG USB interface of the tablet computer is connected to a high level, the field effect tube Q1 is cut off, and the OTG 5V output interface of the tablet computer and the OTG USB interface of the tablet computer are not connected, and do not work; and because the resistance of the field effect tube Q1 is very low, the resistance of the unidirectional conduction circuit as a whole is much lower than that of a single diode. A single diode generally has a resistance of 0.3Ω and generates high heat. Therefore, the field effect tube Q1 can reduce the voltage difference between the two ends of the unidirectional conduction circuit and reduce the heat generated by the reverse voltage protection circuit.

[0018] like Figure 1As shown, the filter noise reduction circuit is provided with a resistor R1 and a capacitor C1, wherein one end of the resistor R1 is connected to one end of the capacitor C1, the drain of the field effect transistor Q1, the OTG 5V output interface of the tablet computer, the positive electrode of the diode D1, and the drain of the field effect transistor Q1, and the other end of the resistor R1 and the other end of the capacitor C1 are grounded. In this embodiment, the filter noise reduction circuit is used to reduce noise interference in the reverse voltage protection circuit and improve the stability of the reverse voltage protection circuit.

[0019] From the above, it can be seen that the utility model provides a low-loss reverse voltage protection circuit. By arranging a filtering noise reduction circuit and a unidirectional conduction circuit that cooperate with each other in the low-loss reverse voltage protection circuit, the unidirectional conduction circuit as a whole can replace a single diode to prevent reverse voltage input, and the overall resistance of the unidirectional conduction circuit is much lower than that of the diode, which can reduce the voltage difference between the two ends of the unidirectional conduction circuit and reduce the heat generated by the reverse voltage protection circuit, thereby solving the problem in the prior art that the reverse voltage protection circuit uses a diode with a large voltage difference and generates higher additional heat.

[0020] The specific implementation methods described above are preferred implementation methods of the present utility model, and are not intended to limit the specific implementation scope of the present utility model. The scope of the present utility model includes but is not limited to the specific implementation methods. All equivalent changes made in accordance with the present utility model are within the protection scope of the present utility model.

Claims

1. A low-loss reverse voltage protection circuit is provided between the OTG 5V output interface of a tablet computer and the OTG USB interface of the tablet computer, characterized in that: It includes a filtering and noise reduction circuit and a unidirectional conduction circuit, wherein the input end of the filtering and noise reduction circuit is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering and noise reduction circuit is connected to the input end of the unidirectional conduction circuit, and the output end of the unidirectional conduction circuit is connected to the OTG USB interface of the tablet computer. The unidirectional conduction circuit as a whole can replace a single diode to prevent reverse voltage input.

2. The low-loss reverse voltage protection circuit according to claim 1, characterized in that: The unidirectional conduction circuit is provided with a field effect transistor Q1, a resistor R2, a resistor R3 and a diode D1, wherein the gate of the field effect transistor Q1 is connected to one end of the resistor R2 and one end of the resistor R3, the drain of the field effect transistor Q1 is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering noise reduction circuit, and the positive electrode of the diode D1, the source of the field effect transistor Q1 is connected to the other end of the resistor R3 and the OTG USB interface of the tablet computer, and the other end of the resistor R2 is connected to the negative electrode of the diode D1.

3. The low-loss reverse voltage protection circuit according to claim 2, characterized in that: The unidirectional conduction circuit is further provided with a transistor Q2, a resistor R4, a resistor R5 and a resistor R6, wherein the base of the transistor Q2 is connected to one end of the resistor R4 and one end of the resistor R6, the other end of the resistor R4 is connected to the OTG 5V output interface of the tablet computer, the output end of the filtering and noise reduction circuit, the positive electrode of the diode D1, and the drain of the field effect transistor Q1, the collector of the transistor Q2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the gate of the field effect transistor Q1, one end of the resistor R2, and one end of the resistor R3, and the other end of the resistor R6 and the emitter of the transistor Q2 are grounded.

4. The low-loss reverse voltage protection circuit according to claim 3, characterized in that: The filtering and noise reduction circuit is provided with a resistor R1 and a capacitor C1, wherein one end of the resistor R1 is connected to one end of the capacitor C1, the drain of the field effect transistor Q1, the OTG 5V output interface of the tablet computer, the positive electrode of the diode D1, and the drain of the field effect transistor Q1, and the other end of the resistor R1 and the other end of the capacitor C1 are grounded.

5. The low-loss reverse voltage protection circuit according to claim 4, characterized in that: The field effect transistor Q1 is a P-type MOS tube.

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