DC input overvoltage protection circuit

Abstract

The utility model relates to a DC input overvoltage protection circuit, and belongs to the technical field of DC input overvoltage protection of a power supply input end of a product. The protection circuit comprises a power input circuit, an input voltage detection circuit and an output voltage control circuit used for turning off the output end of the output voltage control circuit when the input voltage detection circuit detects that the input voltage is larger than a preset threshold value. Wherein the input voltage detection circuit is electrically connected with the power supply input circuit and the output voltage control circuit respectively. According to the utility model, the technical problem that the chip can be directly damaged when the input voltage is too high due to the fact that only the withstand voltage of the IC chip is depended in the prior art is effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of DC input overvoltage protection for the power input end of a product, and particularly relates to a DC input overvoltage protection circuit. Background Art

[0002] The DC input overvoltage protection circuit is mainly applied to the power input protection of products with a DC adapter. Overvoltage protection is used to protect products from using mismatched power adapters. When the input voltage is too high and exceeds the withstand voltage of the IC chip, the IC devices inside the product cannot withstand it, resulting in product damage. The overvoltage protection cooperates with the TVS tube surge protection. For corresponding products, it not only provides overvoltage protection ability but also increases the EOS protection ability.

[0003] In existing products, some circuit designs rely on the withstand voltage of the IC chip itself to resist the situation of too high input voltage. Once the withstand voltage value of the chip is insufficient, the chip will be directly damaged. Summary of the Utility Model

[0004] In view of this, it is necessary to provide a DC input overvoltage protection circuit to solve the technical problem that in the prior art, only relying on the withstand voltage of the IC chip itself causes the chip to be directly damaged when the input voltage is too high.

[0005] To solve the above problems, the utility model provides a DC input overvoltage protection circuit, including:

[0006] A power input circuit, an input voltage detection circuit, and an output voltage control circuit for turning off its own output end when the input voltage detection circuit detects that the input voltage is greater than a preset threshold;

[0007] Wherein, the input voltage detection circuit is electrically connected to the power input circuit and the output voltage control circuit respectively.

[0008] In a possible implementation manner, the power input circuit includes: a power DC plug and a TVS tube;

[0009] Wherein, the cathode of the TVS tube is electrically connected to the power DC plug, and the anode of the TVS tube is grounded.

[0010] In a possible implementation manner, the power DC plug is also electrically connected to the input voltage detection circuit.

[0011] In a possible implementation manner, the input voltage detection circuit includes: a zener diode, a triode, a first resistor, and a second resistor;

[0012] Wherein, the first resistor is in parallel with the second resistor and the triode, and the first end of the first resistor is also connected to the power DC plug, and the second end is also electrically connected to the cathode of the zener diode to form a series relationship;

[0013] The anode of the voltage stabilizing diode is grounded.

[0014] In a possible implementation, the first end of the first resistor is electrically connected to the emitter of the triode, and the second end is electrically connected to the first end of the second resistor;

[0015] The second end of the second resistor is electrically connected to the base of the triode.

[0016] In a possible implementation, the triode includes: a PNP type triode.

[0017] In a possible implementation, the output voltage control circuit includes: a MOS transistor, a capacitor, a third resistor, and a fourth resistor;

[0018] Wherein, the first end of the third resistor is electrically connected to the source electrode of the MOS transistor, the second end is electrically connected to the gate electrode of the MOS transistor, and the drain electrode of the MOS transistor serves as the output terminal of the DC input overvoltage protection circuit;

[0019] The first end of the fourth resistor is electrically connected to the gate electrode of the MOS transistor, and the second end is grounded.

[0020] In a possible implementation, the MOS transistor includes: a P-channel MOS transistor.

[0021] In a possible implementation, the input voltage detection circuit is electrically connected to the output voltage control circuit through the emitter and collector of the triode.

[0022] In a possible implementation, the triode is connected in parallel with the capacitor, the third resistor, and the MOS transistor pairwise;

[0023] Wherein, the emitter of the triode is electrically connected to the first end of the capacitor, and the collector is electrically connected to the second end of the capacitor;

[0024] The first end of the third resistor is electrically connected to the source electrode of the MOS transistor, the second end is electrically connected to the gate electrode of the MOS transistor, and the drain electrode of the MOS transistor serves as the output port of the DC input overvoltage protection circuit;

[0025] The first end of the fourth resistor is electrically connected to the gate electrode of the MOS transistor, and the second end is grounded.

[0026] The beneficial effects of the present utility model are as follows. The present utility model provides a DC input overvoltage protection circuit. Through the overvoltage monitoring circuit, it prevents overvoltage input and causes damage to the product. After the monitored voltage is higher than the preset threshold, the output voltage control will control the on / off of the circuit, avoiding high voltage from entering the main board and damaging the device, thereby effectively solving the technical problem in the prior art that only relying on the withstand voltage of the IC chip itself causes the chip to be directly damaged when the input voltage is too high. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 FIG. is a schematic structural diagram of an embodiment of the DC input overvoltage protection circuit provided by the present utility model;

[0028] Figure 2 For Figure 1 schematic structural diagrams of the power input circuit, the input voltage detection circuit, and the output voltage control circuit in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0030] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present utility model.

[0031] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0032] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement them. When the combination of technical solutions appears to be contradictory or unable to be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0033] Reference to "embodiment" in this document means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present utility model. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0034] As Figure 1 shown, a specific embodiment of the present utility model discloses a DC input overvoltage protection circuit 10, including:

[0035] a power input circuit 110, an input voltage detection circuit 120, and an output voltage control circuit 130;

[0036] Among them, the input voltage detection circuit 120 is electrically connected to the power input circuit 110 and the output voltage control circuit 130 respectively.

[0037] It can be understood that the power input circuit 110 is used to provide a stable power supply interface for the device; the input voltage detection circuit 120 is used to monitor whether the input voltage exceeds a preset voltage value; the output voltage control circuit 130 is used to control the output of the voltage. When overvoltage is monitored, there is no output to protect the subsequent circuit.

[0038] Compared with the prior art, a DC input overvoltage protection circuit provided by the present utility model prevents overvoltage input and product damage through an overvoltage monitoring circuit. After the monitored voltage is higher than the preset threshold, the output voltage control will control the opening and closing of the circuit to avoid high voltage entering the main board and damaging the device, thereby effectively solving the technical problem that the prior art only relies on the withstand voltage of the IC chip itself and the chip will be directly damaged when the input voltage is too high.

[0039] As Figure 2 , in a possible implementation, the power input circuit 110 includes: a power DC plug J15 and a TVS tube D2.

[0040] In a possible implementation, the input voltage detection circuit includes: a zener diode D9, a triode Q16, a first resistor R213, and a second resistor R215.

[0041] Further, the triode Q16 is a PNP type triode.

[0042] In a possible implementation, the output voltage control circuit includes: a MOS tube Q1, a capacitor C1, a third resistor R4, and a fourth resistor R7.

[0043] Further, the MOS tube Q1 is a P-channel MOS tube.

[0044] In a possible implementation, the cathode of the TVS diode D2 is electrically connected to the power supply DC plug J15, and the anode is grounded;

[0045] The power supply DC plug J15 is also electrically connected to the input voltage detection circuit.

[0046] In a possible implementation, the first resistor R213 is connected in parallel with the second resistor and the triode Q16, and the first end of the first resistor R213 is also connected to the power supply DC plug J15, and the second end is also electrically connected to the cathode of the voltage stabilizing diode D9 to form a series relationship;

[0047] The anode of the voltage stabilizing diode D9 is grounded.

[0048] In a possible implementation, the first end of the first resistor R213 is electrically connected to the emitter of the triode Q16, and the second end is electrically connected to the first end of the second resistor R215;

[0049] The second end of the second resistor R215 is electrically connected to the base of the triode Q16.

[0050] In a possible implementation, the triode Q16 is connected in parallel with the capacitor C1, the third resistor R4, and the MOS transistor Q1 in pairs;

[0051] Among them, the emitter of the triode Q16 is electrically connected to the first end of the capacitor C1, and the collector is electrically connected to the second end of the capacitor C1;

[0052] The first end of the third resistor R4 is electrically connected to the source of the MOS transistor Q1, the second end is electrically connected to the gate of the MOS transistor Q1, and the drain of the MOS transistor Q1 serves as the output port of the DC input overvoltage protection circuit;

[0053] The first end of the fourth resistor R7 is electrically connected to the gate of the MOS transistor Q1, and the second end is grounded.

[0054] It should be noted that assuming the rated input voltage of the device is DC12V, when the device is powered by a 24V power adapter, if no protection is added at this time, the main board may be directly burned out. When the monitored voltage is higher than 13.7V, the output voltage control circuit 130 will control the MOS transistor Q1 to turn off, thereby preventing high voltage from entering the main board and damaging the device.

[0055] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A DC input overvoltage protection circuit, characterized in that, Comprising: A power input circuit, an input voltage detection circuit, and an output voltage control circuit for turning off its own output terminal when the input voltage detection circuit detects that the input voltage is greater than a preset threshold; Wherein, the input voltage detection circuit is electrically connected to the power input circuit and the output voltage control circuit respectively.

2. The DC input overvoltage protection circuit according to claim 1, wherein The power input circuit includes: a power DC plug and a TVS tube; Wherein, the cathode of the TVS tube is electrically connected to the power DC plug, and the anode of the TVS tube is grounded.

3. The DC input overvoltage protection circuit according to claim 2, wherein The power DC plug is also electrically connected to the input voltage detection circuit.

4. The DC input overvoltage protection circuit according to claim 3, wherein The input voltage detection circuit includes: a zener diode, a triode, a first resistor, and a second resistor; Wherein, the first resistor is in parallel with the second resistor and the triode, and the first end of the first resistor is also connected to the power DC plug, and the second end is also electrically connected to the cathode of the zener diode to form a series relationship; The anode of the zener diode is grounded.

5. The DC input overvoltage protection circuit according to claim 4, characterized in that, The first end of the first resistor is electrically connected to the emitter of the triode, and the second end is electrically connected to the first end of the second resistor; The second end of the second resistor is electrically connected to the base of the triode.

6. The DC input overvoltage protection circuit according to claim 4, wherein, The triode includes: a PNP type triode.

7. The DC input overvoltage protection circuit according to claim 4, wherein The output voltage control circuit includes: a MOS tube, a capacitor, a third resistor, and a fourth resistor; Wherein, the first end of the third resistor is electrically connected to the source of the MOS tube, the second end is electrically connected to the gate of the MOS tube, and the drain of the MOS tube serves as the output terminal of the DC input overvoltage protection circuit; The first end of the fourth resistor is electrically connected to the gate of the MOS tube, and the second end is grounded.

8. The DC input overvoltage protection circuit according to claim 7, characterized in that, The MOS tube includes: a P-channel MOS tube.

9. The DC input overvoltage protection circuit according to claim 6, wherein The input voltage detection circuit is electrically connected to the output voltage control circuit through the emitter and collector of the triode.

10. The DC input overvoltage protection circuit according to claim 9, wherein The triode is in parallel with the capacitor, the third resistor, and the MOS tube pairwise; Wherein, the emitter of the triode is electrically connected to the first end of the capacitor, and the collector is electrically connected to the second end of the capacitor; The first end of the third resistor is electrically connected to the source of the MOS tube, the second end is electrically connected to the gate of the MOS tube, and the drain of the MOS tube serves as the output port of the DC input overvoltage protection circuit; The first end of the fourth resistor is electrically connected to the gate of the MOS tube, and the second end is grounded.

Images