Protection mechanism for short circuit

Abstract

The utility model discloses a circuit short circuit protection mechanism which comprises an output switch control circuit, an output short circuit detection circuit, an output open circuit detection circuit, an R1 and a chip end. The output switch control circuit, the output short circuit detection circuit, the output open circuit detection circuit and the R1 are electrically connected; the chip end comprises a 1NC, a 2FB, a 3NC, a 4LX, a 5LX, a 6NC, a 7IN, a 8OVP, a 9EN / PWM and a 10NC. The device is simple in structure and reasonable in design, the circuit can be controlled to work in a preset working voltage section, effective short-circuit protection can be realized, and the driving chip is prevented from being damaged.

Description

Technical Field

[0001] This utility model relates to the field of short circuit protection technology, and in particular to a protection mechanism for circuit short circuits. Background Technology

[0002] Some commonly used boost LED constant current driver chips on the market, such as SY7203, have overvoltage protection and constant current control functions, but because the constant current feedback pin of the component often has a low withstand voltage, when a short circuit occurs at the load end, the high voltage at the output end will directly flow into the constant current feedback pin, causing overvoltage damage to the device itself. Utility Model Content

[0003] The purpose of this invention is to provide a protection mechanism for circuit short circuits.

[0004] To achieve the above objectives, the present invention employs the following:

[0005] A circuit short-circuit protection mechanism includes: an output switch control circuit, an output short-circuit detection circuit, an output open-circuit detection circuit, resistor R1, and a chip terminal; the output switch control circuit, the output short-circuit detection circuit, the output open-circuit detection circuit, and resistor R1 are electrically connected; the chip terminal includes 1NC, 2FB, 3NC, 4LX, 5LX, 6NC, 7IN, 8OVP, 9EN / PWM, and 10NC;

[0006] The output switch control circuit includes K1, Q1, Q2, R3, R4, R7, R8 and SCP; Q1, Q2, R3, R4, R7 and R8 form the output switch control circuit, which cuts off the output by pulling down the control signal K1 when a short circuit is detected.

[0007] The output short-circuit detection circuit includes Q3, R2, R5, R6, and R9. When a short circuit occurs, R2 and R1 divide the voltage to ensure that the instantaneous voltage when a short circuit occurs under the highest operating voltage condition does not exceed the maximum allowable voltage of the FB pin. R6 and R9 set the minimum allowable operating voltage. When a short circuit occurs, the output L+ terminal voltage will be lower, Q3 will be cut off, and the SCP terminal will output a high-level indication signal. Then, a low-level signal can be output through the K1 signal to cut off the output.

[0008] The output open-circuit detection circuit includes Q4, R10, R11, R12 and OVP; the maximum allowable operating voltage is set by R10 and R11. When the set value is exceeded, Q4 is turned on, and the OVP signal terminal outputs a low level to K1, such as a microcontroller. Then, the output can be cut off by outputting a low level signal through K1.

[0009] This utility model has the following advantages:

[0010] This device has a simple structure and reasonable design. It can control the circuit to operate within a preset operating voltage range, effectively protect against short circuits, and prevent damage to the driver chip itself.

[0011] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0012] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0013] Figure 1 This is a schematic diagram of the structure of a circuit short-circuit protection mechanism of this utility model.

[0014] In the figure, the attached figures are labeled as follows:

[0015] 1-Output switch control circuit, 2-Output short circuit detection circuit, 3-Output open circuit detection circuit. Detailed Implementation

[0016] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0017] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0018] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0019] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0020] like Figure 1 As shown, a short-circuit protection mechanism includes: an output switch control circuit 1, an output short-circuit detection circuit 2, an output open-circuit detection circuit 3, an resistor R1, and a chip terminal; the output switch control circuit, the output short-circuit detection circuit, the output open-circuit detection circuit, and the resistor R1 are electrically connected; the chip terminal includes 1NC, 2FB, 3NC, 4LX, 5LX, 6NC, 7IN, 8OVP, 9EN / PWM, and 10NC;

[0021] The output switch control circuit 1 includes K1, Q1, Q2, R3, R4, R7, R8 and SCP; Q1, Q2, R3, R4, R7 and R8 form the output switch control circuit, which cuts off the output by pulling down the control signal K1 when a short circuit is detected.

[0022] The output short-circuit detection circuit 2 includes Q3, R2, R5, R6, and R9. When a short circuit occurs, R2 and R1 divide the voltage to ensure that the instantaneous voltage when a short circuit occurs under the highest operating voltage condition does not exceed the maximum allowable voltage of the FB pin. R6 and R9 set the minimum allowable operating voltage. When a short circuit occurs, the output L+ terminal voltage will be lower, Q3 will be cut off, and the SCP terminal will output a high-level indication signal. Then, a low-level signal can be output through the K1 signal to cut off the output.

[0023] The output open-circuit detection circuit 3 includes Q4, R10, R11, R12, and OVP. R10 and R11 set the maximum allowable operating voltage. When this value is exceeded, Q4 conducts, and the OVP signal terminal outputs a low level to K1. For example, a microcontroller can then output a low-level signal through K1 to cut off the output. The output open-circuit detection circuit 3 is mainly used to prevent open-circuit operation. Once open-circuit operation is allowed, a larger voltage divider resistor R2 is needed to prevent the voltage at the chip's FB terminal from exceeding the maximum allowable value when a short circuit occurs. A larger voltage divider resistor will cause greater energy consumption during operation.

[0024] K1 controls the output voltage within a reasonable range. If the voltage exceeds or falls below the preset range, an abnormal signal is output to K1 via the SCP and OVP terminals, thereby achieving shutdown control. The addition of R2 ensures that the voltage at the FB pin of the chip will not exceed the maximum allowable value when a load short circuit occurs within the reasonable operating voltage range, thus effectively protecting the driver chip.

[0025] The following is an example:

[0026]

[0027]

[0028] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0029] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A short-circuit protection mechanism, characterized in that, include: The circuit includes an output switch control circuit, an output short-circuit detection circuit, an output open-circuit detection circuit, resistor R1, and a chip terminal; the output switch control circuit, the output short-circuit detection circuit, the output open-circuit detection circuit, and resistor R1 are electrically connected; the chip terminal includes 1NC, 2FB, 3NC, 4LX, 5LX, 6NC, 7IN, 8OVP, 9EN / PWM, and 10NC. The output switch control circuit includes K1, Q1, Q2, R3, R4, R7, R8 and SCP; Q1, Q2, R3, R4, R7 and R8 form the output switch control circuit, which cuts off the output by pulling down the control signal K1 when a short circuit is detected. The output short-circuit detection circuit includes Q3, R2, R5, R6, and R9. When a short circuit occurs, R2 and R1 divide the voltage to ensure that the instantaneous voltage when a short circuit occurs under the highest operating voltage condition does not exceed the maximum allowable voltage of the FB pin. R6 and R9 set the minimum allowable operating voltage. When a short circuit occurs, the output L+ terminal voltage will be lower, Q3 will be cut off, and the SCP terminal will output a high-level indication signal. Then, a low-level signal can be output through the K1 signal to cut off the output. The output open-circuit detection circuit includes Q4, R10, R11, R12 and OVP; the maximum allowable operating voltage is set by R10 and R11. When the set value is exceeded, Q4 is turned on, and the OVP signal terminal outputs a low level to K1, such as a microcontroller. Then, the output can be cut off by outputting a low level signal through K1.

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