Short circuit protection circuit and LED lamp

Abstract

The utility model provides a short circuit protection circuit and an LED lamp. The short circuit protection circuit comprises a power supply input end, a first switch module, a second switch module and an AND gate module. The power input end is connected to the first end and the control end of the first switch module and the output end and the power supply end of the AND gate module. The second end of the first switch module is connected with the first input end of the AND gate module and a load circuit, the second input end of the AND gate module is used for being connected to the load circuit, the output end of the AND gate module is connected with the control end of the second switch module, and the first end of the second switch module is connected with the control end of the first switch module. The second end of the second switch module is grounded. According to the utility model, the logic function of the AND gate module is utilized, the junction voltage of the load circuit is acquired through the two input ends of the AND gate module, and the on-off of the loop of the power supply and the load circuit is controlled according to the output end of the AND gate module, so that the risk caused by short circuit in an electronic product powered by a battery can be effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, and particularly to a short - circuit protection circuit and an LED lamp. Background Technique

[0002] All kinds of portable electronic products are indispensable tools in people's work and life, bringing convenience to people's work, life and entertainment. However, many existing portable electronic products lack short - circuit protection functions, thus bringing some potential hidden dangers.

[0003] Taking a portable LED lamp as an example, the existing method is that the battery directly discharges to the LED lamp, and only a current - limiting resistor is used to limit the current in the middle. When the LED lamp is short - circuited, the battery discharges to the current - limiting resistor or even causes a short - circuit, resulting in the continuous heating of the current - limiting resistor and the battery, thus posing a safety hazard. Summary of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a short - circuit protection circuit and an LED lamp to improve the above problems.

[0005] A short - circuit protection circuit includes: a power input terminal, a first switch module, a second switch module and an AND gate module; wherein, the power input terminal is respectively connected to the first end and the control end of the first switch module, the output end and the power supply end of the AND gate module; the second end of the first switch module is connected to the first input end of the AND gate module and a load circuit, the second input end of the AND gate module is used to be connected to the load circuit, the output end of the AND gate module is connected to the control end of the second switch module, the first end of the second switch module is connected to the control end of the first switch module, and the second end of the second switch module is grounded.

[0006] Preferably, the power input terminal is connected to the control end of the first switch module through a first pull - up resistor and to the output end of the AND gate module through a second pull - up resistor.

[0007] Preferably, the first switch module is an NMOS transistor, the first end of the first switch module is the drain of the NMOS transistor, the second end is the source, and the control end is the gate.

[0008] Preferably, the second switch module is an NPN triode, the first end of the second switch module is the collector of the NPN triode, the second end is the emitter, and the control end is the base.

[0009] Preferably, it further includes a third switch module, and the third switch module is arranged between the power input terminal, the first switch module and the AND gate module.

[0010] Preferably, a current limiting module is further included, and the second end of the first switch module is connected to the load circuit through the current limiting module.

[0011] Preferably, the current limiting module is obtained by paralleling three current limiting resistors.

[0012] Preferably, a first capacitor is further included, and the power supply terminal of the AND gate module is grounded through the first capacitor.

[0013] Preferably, a current limiting resistor is further included and is disposed between the power input terminal and the power supply terminal.

[0014] An embodiment of the present invention further provides an LED lamp, which includes a power supply, an LED lamp, and the above short - circuit protection circuit, and the power supply is connected to the LED lamp through the short - circuit protection circuit.

[0015] In summary, this embodiment utilizes the logic function of the AND gate module U1, collects the voltage at the load circuit through the two input terminals of the AND gate module U1, and controls the on - off of the loop between the power supply and the load circuit according to the output terminal of the AND gate module U1, thereby effectively avoiding the risk brought by short - circuit in battery - powered electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a circuit schematic diagram of the LED lamp provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model. Therefore, the following detailed description of the embodiments of the present utility model provided in the drawings is not intended to limit the scope of the present utility model claimed, but merely represents selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0019] Please refer to Figure 1 , a short - circuit protection circuit is provided in the first embodiment of the present utility model, which includes: a power input terminal, a first switch module Q1, a second switch module Q2, and an AND - gate module U1; wherein, the power input terminal is respectively connected to the first end and the control end of the first switch module Q1, the output terminal Y of the AND - gate module U1, and the power supply terminal Vcc; the second end of the first switch module Q1 is connected to the first input terminal A of the AND - gate module U1 and the load circuit, the second input terminal B of the AND - gate module U1 is used to be connected to the load circuit, the output terminal Y of the AND - gate module U1 is connected to the control end of the second switch module Q2, the first end of the second switch module Q2 is connected to the control end of the first switch module Q1, and the second end of the second switch module Q2 is grounded.

[0020] In this embodiment, the power input terminal is used to connect to an external power supply, such as a battery, etc. The voltage generated by the power supply is provided to the load circuit through the short - circuit protection circuit, so that the load circuit enters the working state. Among them, the load circuit is an actual working electronic device, such as a chip, a buzzer, an LED lamp, etc. This embodiment takes the load circuit as an LED lamp as an example for illustration, but it should not be construed as a limitation to the present utility model.

[0021] Among them, between the power input terminal and the first switch module Q1, a third switch module S1 or a driving module, etc. can also be provided to control the power supply.

[0022] In this embodiment, particularly, the first switch module Q1 is an NMOS transistor. The first end of the first switch module Q1 is the drain D, the second end is the source S, and the control end is the gate G. Of course, a PMOS transistor can also be selected as the first switch module Q1, which will not be elaborated in the present utility model.

[0023] The second switching module Q2 is an NPN transistor. The first end of the second switching module Q2 is the collector C of the NPN transistor, the second end is the emitter E of the NPN transistor, and the control end is the base B of the NPN transistor. Of course, a PNP transistor can also be selected as the second switching module Q2, which will not be elaborated in this utility model.

[0024] In this embodiment, the power input terminal is connected to the control end, i.e., the gate G, of the first switching module Q1 through a first pull-up resistor R1, and is connected to the output terminal Y of the AND gate module U1 through a second pull-up resistor R2.

[0025] In this embodiment, particularly, a current limiting module is further included. The second end of the first switching module Q1 is connected to the load circuit through the current limiting module.

[0026] In this embodiment, as Figure 1 shown, the current limiting module is formed by three current limiting resistors RS1, RS2, and RS3 connected in parallel.

[0027] In this embodiment, a first capacitor C1 is further included. The power supply terminal Vcc of the AND gate module U1 is grounded through the first capacitor C1.

[0028] In this embodiment, preferably, a current limiting resistor R3 is further included and is disposed between the power input terminal and the power supply terminal Vcc.

[0029] Among them, the function of the current limiting resistor R3 is to delay the startup of the AND gate module U1, so that the second switching module Q2 works first, and further protect the AND gate module U1.

[0030] The specific working principle of this embodiment is described in detail below:

[0031] In this embodiment, when the third switching module S1 is closed, the circuit is powered on. The second pull-up resistor R2 pulls up the base B of the second switching module Q2, making the second switching module Q2 conduct. At this time, the first switching module Q1 conducts, and the circuit is normally powered to the backend, and the LED light works normally. At this time, both input terminals A and B of the AND gate module U1 are at high level, and the output terminal Y of the AND gate module U1 outputs a high level, and the circuit works normally.

[0032] When the LED light is short-circuited, the input terminal B of the AND gate module U1 is pulled low. At this time, the output terminal Y of the AND gate module U1 will output a low level, and the second switching module Q2 is cut off. At this time, the gate G of the first switching module Q1 is pulled high by the first pull-up resistor R1, and the first switching module Q1 is turned off, and the circuit loop is cut off, thereby achieving the effect of protecting the circuit.

[0033] In summary, this embodiment utilizes the logical function of the AND gate module U1 to collect the junction voltage of the load circuit through the two input terminals of the AND gate module U1, and controls the on / off of the loop between the power supply and the load circuit according to the output terminal of the AND gate module U1, thereby effectively avoiding the risk brought by short circuits in battery-powered electronic products.

[0034] The second embodiment of the present invention further provides an LED lamp, which includes a power supply, an LED lamp, and the short-circuit protection circuit described in any of the above embodiments, and the power supply is connected to the LED lamp through the short-circuit protection circuit.

[0035] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A short circuit protection circuit, characterized in that: include: A power input terminal, a first switch module, a second switch module and an AND gate module; wherein the power input terminal is respectively connected to the first terminal and the control terminal of the first switch module, the output terminal and the power supply terminal of the AND gate module; the second terminal of the first switch module is connected to the first input terminal and the load circuit of the AND gate module, the second input terminal of the AND gate module is used to connect to the load circuit, the output terminal of the AND gate module is connected to the control terminal of the second switch module, the first terminal of the second switch module is connected to the control terminal of the first switch module, and the second terminal of the second switch module is grounded.

2. The short circuit protection circuit according to claim 1, characterized in that: The power input terminal is connected to the control terminal of the first switch module through a first pull-up resistor, and is connected to the output terminal of the AND gate module through a second pull-up resistor.

3. The short circuit protection circuit according to claim 1, characterized in that: The first switch module is an NMOS tube, the first end of the first switch module is the drain of the NMOS tube, the second end is the source, and the control end is the gate.

4. The short circuit protection circuit according to claim 1, characterized in that: The second switch module is an NPN transistor, the first end of the second switch module is the collector of the NPN transistor, the second end is the emitter of the NPN transistor, and the control end is the base of the NPN transistor.

5. The short circuit protection circuit according to claim 1, characterized in that: It also includes a third switch module, which is arranged between the power input terminal and the first switch module and the AND gate module.

6. The short circuit protection circuit according to claim 1, characterized in that: It also includes a current limiting module, and the second end of the first switch module is connected to the load circuit through the current limiting module.

7. The short circuit protection circuit according to claim 6, characterized in that: The current limiting module is obtained by connecting three current limiting resistors in parallel.

8. The short circuit protection circuit according to claim 1, characterized in that: It also includes a first capacitor, and the power supply end of the AND gate module is grounded through the first capacitor.

9. The short circuit protection circuit according to claim 1, characterized in that: It also includes a current limiting resistor arranged between the power input terminal and the power supply terminal.

10. An LED lamp, characterized in that: The invention comprises a power supply, an LED lamp and a short-circuit protection circuit as claimed in any one of claims 1 to 9, wherein the power supply is connected to the LED lamp through the short-circuit protection circuit.

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