CN214674333U

CN214674333U - Current limiting device

Info

Publication number: CN214674333U
Application number: CN202120918001.XU
Authority: CN
Inventors: 周礼培
Original assignee: Luxshare Electronic Technology Kunshan Ltd
Current assignee: Luxshare Electronic Technology Kunshan Ltd
Priority date: 2021-04-29
Filing date: 2021-04-29
Publication date: 2021-11-09
Anticipated expiration: 2031-04-29

Abstract

The utility model discloses a current limiting device, include: the first voltage stabilizing unit is connected with a power supply end; the second voltage stabilizing unit is connected with the load end; a resistor having a first end and a grounded second end; a control unit; an integrated circuit chip unit, comprising: the input pin is connected with the first voltage stabilizing unit; the output pin is connected with the second voltage stabilizing unit; the current-limiting pin is connected with the first end of the resistor; the output overcurrent state pin is connected with the control unit, and when the current of the load end is greater than or equal to a threshold value, a low level is output to the control unit; and a ground pin. The current limiting device can protect the circuit quickly and effectively.

Description

Current limiting device

Technical Field

The utility model relates to a current limiting technical field, in particular to current limiting device.

Background

With the development of science and technology, the application of electronic technology is more and more extensive, and more electronic products appear in life and production.

In the design of the existing product, if the current is required to be limited, the current is usually limited by using a self-recovery fuse, namely when a short circuit or overload occurs to a circuit, the high current flowing through the self-recovery fuse generates heat to melt polymer resin, the volume is rapidly increased to form a high-resistance state, and the working current is rapidly reduced, so that the circuit is limited and protected; after the fault is eliminated, the self-recovery fuse is cooled and crystallized again, the volume shrinks, the conductive particles form a conductive path again, and the self-recovery fuse is recovered to be in a low-resistance state, so that the circuit is protected without manual replacement. However, the self-recovery fuse is adopted to limit the current limiting, so that the defects of low precision and slow response exist.

SUMMERY OF THE UTILITY MODEL

To the shortcoming that prior art exists, the utility model discloses a main aim at provides a current limiting device, can protect the circuit fast effectively.

In order to achieve the above object, the present invention provides a current limiting device, including: the first voltage stabilizing unit is connected with a power supply end; the second voltage stabilizing unit is connected with the load end; a resistor having a first end and a grounded second end; a control unit; an integrated circuit chip unit, comprising: the input pin is connected with the first voltage stabilizing unit; the output pin is connected with the second voltage stabilizing unit; the current-limiting pin is connected with the first end of the resistor; the output overcurrent state pin is connected with the control unit, and when the current of the load end is greater than or equal to a threshold value, a low level is output to the control unit; and a ground pin.

In the above current limiting device, the first voltage stabilizing unit includes at least one filter capacitor.

In the above-mentioned current limiting device, the first voltage stabilizing unit includes: a first filter capacitor having a first terminal and a second terminal; a second filter capacitor having a first terminal and a second terminal; the first end of the first filter capacitor is connected with the power supply end and the first end of the second filter capacitor, the first end of the second filter capacitor is connected with the input pin, and the second end of the first filter capacitor and the second end of the second filter capacitor are grounded.

In the above current limiting device, the first filter capacitor and/or the second filter capacitor is a multilayer chip ceramic capacitor.

In the above current limiting circuit, the second voltage stabilizing unit includes at least one filter capacitor.

In the above-mentioned current limiting device, the second voltage stabilizing unit includes: the third filter capacitor is provided with a first end and a second end; the fourth filter capacitor is provided with a first end and a second end; a fifth filter capacitor having a first terminal and a second terminal; a sixth filter capacitor having a first terminal and a second terminal; the first end of the third filter capacitor, the first end of the fourth filter capacitor, the first end of the fifth filter capacitor and the first end of the sixth filter capacitor are sequentially connected, the second end of the third filter capacitor, the second end of the fourth filter capacitor, the second end of the fifth filter capacitor and the second end of the sixth filter capacitor are grounded, the output pin is connected with the first end of the third filter capacitor, and the load end is connected with the first end of the third filter capacitor, the first end of the fourth filter capacitor, the first end of the fifth filter capacitor or the first end of the sixth filter capacitor.

In the above current limiting device, the third filter capacitor, the fourth filter capacitor, the fifth filter capacitor and/or the sixth filter capacitor are multilayer chip ceramic capacitors.

In the above current limiting device, the integrated circuit chip unit further includes: and the control unit controls the voltage of the enable pin to be higher or lower than a working voltage so that the integrated circuit chip unit works or does not work.

In the above current limiting device, the integrated circuit chip unit further includes: and the copper exposed pin is used for radiating the integrated circuit chip unit.

The utility model has the beneficial effects that: the current limiting device provided by the utility model has the advantages of simple realization, high precision, quick response and the like, and can quickly play the role of protecting the circuit and the load; meanwhile, the current limiting device also has the functions of active detection and error feedback, and the safety factor can be increased.

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

Drawings

Fig. 1 is a schematic block diagram of a current limiting device according to an embodiment of the present invention.

Fig. 2 is a schematic circuit diagram of a current limiting device according to an embodiment of the present invention.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided in conjunction with the accompanying drawings and specific embodiments for further understanding the objects, aspects and functions of the present invention, but not for limiting the scope of the appended claims.

Where certain terms are used in the specification and following claims to refer to particular components or features, those skilled in the art will understand that various terms or numbers may be used by a skilled user or manufacturer to refer to the same component or feature. This specification and the claims that follow do not intend to distinguish between components or features that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. In addition, the term "connected" is intended to encompass any direct or indirect electrical connection. Indirect electrical connection means include connection by other means.

Fig. 1 is a schematic block diagram of a current limiting device according to an embodiment of the present invention; fig. 2 is a schematic circuit diagram of a current limiting device according to an embodiment of the present invention.

Referring to fig. 1, a current limiting device 100 according to an embodiment of the present invention includes a first voltage stabilizing unit 10, an integrated circuit chip unit 20, and a second voltage stabilizing unit 30, wherein the first voltage stabilizing unit 10 connects a power source terminal with the integrated circuit chip unit 20, so that the first voltage stabilizing unit 10 can stably output a voltage that the power source terminal can deliver to the integrated circuit chip unit 20; the integrated circuit chip unit 20 is connected with the second voltage stabilizing unit 30, the control unit 40 and the resistor 50; the second voltage stabilization unit 30 is connected to a load terminal. In the application scenario of the current limiting device provided in the present invention, for example, DVDD _ USB is a power source end connected to the first voltage stabilizing unit 10 of the current limiting device 100, and the current limiting device 100 is, for example, a circuit device that converts dc from dc to dc, for example, 12V to 5V, so that a load end connected to the second voltage stabilizing unit 30 can be 5V _ USB, and mainly supplies power to a load, such as a mobile hard disk, a USB disk, and the like; under normal conditions, the power source terminal DVDD _ USB has a voltage output, which is typically 5V/2A, and after passing through the current limiting device 100, the load terminal 5V _ USB outputs 5V/0.9A, so that when the load current exceeds 0.9A, the ic chip unit 20 will detect that the load current is too large to cut off the output, thereby protecting the front and rear two stages of circuits.

Referring to fig. 2, the first voltage stabilization unit 10 includes at least one filter capacitor; in this embodiment, specifically, the first voltage stabilizing unit 10 includes a first filter capacitor C1 and a second filter capacitor C2, where the first filter capacitor C1 and the second filter capacitor C2 are connected in parallel, that is, a first end of the first filter capacitor C1 is connected to a first end of the second filter capacitor C2, a second end of the first filter capacitor C1 is connected to a second end of the second filter capacitor C2 and grounded, and a first end of the first filter capacitor C1 is connected to a power supply terminal; it should be noted that, the present invention does not limit the number of the filter capacitors of the first voltage stabilizing unit 10, and can be adjusted according to actual situations; in addition, the filter capacitor constituting the first voltage stabilization unit 10 may be, for example, a multilayer chip ceramic capacitor (MLCC).

Referring to fig. 2, the integrated circuit chip unit 20 employs, for example, a TPS series power management chip U1; the chip U1 is provided with an input pin IN, an output pin OUT, a current limiting pin ILIM, an output overcurrent state pin FAULT and a grounding pin GND; the input pin IN is connected to the first end of the second filter capacitor C2 of the first voltage stabilization unit 10 and receives the stable point voltage input by the first voltage stabilization unit 10 to ensure that the chip U1 works normally; the output pin OUT outputs a voltage to the second voltage stabilization unit 30; the current limiting pin ILIM is connected to a first end of the resistor R4, while a second end of the resistor R4 is grounded, the resistor R4 is, for example, an adjustable resistor, the resistance value of the adjustable resistor R4 can have different voltages, and the limitation of different current magnitudes can be realized through ohm's law conversion; the output overcurrent state pin FAULT is connected to the control unit 40 (for example, a micro control unit, MCU), the output overcurrent state pin FAULT is at a high level under normal conditions, and when the current at the load terminal is too large (for example, greater than a threshold), the output overcurrent state pin FAULT is output to the control unit for prompting, for example, the output overcurrent state pin FAULT can be connected to an input/output pin (IO pin) of the MCU, the IO pin can be an interrupt pin, if there is a level change, a response is triggered, the load current condition can be clearly known to the MCU, so as to make an accurate judgment to respond to the relevant work, specifically, an operational amplifier and a current detection module are provided inside the chip U1, the current magnitude is judged through feedback of the IO pin, when the load current is too large, the circuit is protected to be cut off, so that there is no large current flowing back to the load to damage the load, when the chip U1 has work protection, the low level is output to the MCU unit through the output overcurrent state pin FAULT, and the MCU unit detects the low level, so that the overcurrent phenomenon at the load end can be known, and a user can be informed through a loudspeaker or other modes, so that the user can know the load condition more simply and clearly; the ground pin GND is grounded, so that the whole chip U1 has a return path to ensure that the chip U1 works normally. Preferably, the chip U1 may further have an enable pin EN, and the potential of the enable pin EN is higher than 1.2V (for example, working voltage) to enable the chip U1, and the chip U1 does not work when the potential of the enable pin EN is lower than 1.2V, and by connecting the enable pin EN to an IO pin of the MCU unit, the enable control of the chip U1 may be implemented through the IO pin, and then the chip U1 may be turned off under low power consumption to achieve the effect of reducing power consumption and reduce energy consumption; preferably, the chip U1 may also have exposed copper PADs, which may be used to facilitate heat dissipation from the chip U1.

Referring to fig. 2, the second voltage stabilizing unit 30 includes at least one filter capacitor; in this embodiment, specifically, the second voltage stabilizing unit 30 includes a third filter capacitor C3, a fourth filter capacitor C4, a fifth filter capacitor C5 and a sixth filter capacitor C6, where the third filter capacitor C3, the fourth filter capacitor C4, the fifth filter capacitor C5 and the sixth filter capacitor C6 are connected in parallel, that is, a first end of the third filter capacitor C3, a first end of the fourth filter capacitor C4, a first end of the fifth filter capacitor C5 and a first end of the sixth filter capacitor C6 are sequentially connected, a second end of the third filter capacitor C3, a second end of the fourth filter capacitor C4, a second end of the fifth filter capacitor C5 and a second end of the sixth filter capacitor C6 are sequentially connected and grounded, and a first end of the third filter capacitor C3 is connected to the output pin OUT of the chip U1 and receives the output voltage thereof; the first end of the third filter capacitor C3, the first end of the fourth filter capacitor C4, the first end of the fifth filter capacitor C5 or the first end of the sixth filter capacitor C6 are connected to the load end and provide a stable voltage output thereto; it should be noted that, the present invention does not limit the number of the filter capacitors of the second voltage stabilizing unit 30, and can be adjusted according to actual situations; in addition, the filter capacitor constituting the second voltage stabilization unit 30 may be, for example, a multilayer chip ceramic capacitor (MLCC).

In summary, the current limiting device provided by the utility model has the advantages of simple realization, high precision, fast response and the like, and can play the role of protecting the circuit and the load quickly; meanwhile, the current limiting device also has the functions of active detection and error feedback, and the safety factor can be increased.

Naturally, the present invention can be embodied in many other forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be made by one skilled in the art without departing from the spirit or essential attributes thereof, and it is intended that all such changes and modifications be considered as within the scope of the appended claims.

Claims

1. A current limiting device, comprising:

the first voltage stabilizing unit is connected with a power supply end;

the second voltage stabilizing unit is connected with a load end;

a resistor having a first end and a second end grounded;

a control unit;

an integrated circuit chip unit, comprising:

the input pin is connected with the first voltage stabilizing unit;

the output pin is connected with the second voltage stabilizing unit;

the current-limiting pin is connected with the first end of the resistor;

the output overcurrent state pin is connected with the control unit and outputs a low level to the control unit when the current of the load end is greater than or equal to a threshold value;

a ground pin.

2. The current-limiting device of claim 1, wherein the first voltage stabilization unit comprises at least one filter capacitor.

3. The current-limiting apparatus of claim 2, wherein the first voltage stabilization unit comprises:

a first filter capacitor having a first terminal and a second terminal;

a second filter capacitor having a first terminal and a second terminal;

the first end of the first filter capacitor is connected with the power supply end and the first end of the second filter capacitor, the first end of the second filter capacitor is connected with the input pin, and the second end of the first filter capacitor and the second end of the second filter capacitor are grounded.

4. The current-limiting device of claim 3, wherein the first filter capacitor and/or the second filter capacitor is a multilayer chip ceramic capacitor.

5. The current-limiting device of claim 1, wherein the second voltage stabilization unit comprises at least one filter capacitor.

6. The current-limiting apparatus of claim 5, wherein the second voltage stabilization unit comprises:

a third filter capacitor having a first terminal and a second terminal;

a fourth filter capacitor having a first terminal and a second terminal;

a fifth filter capacitor having a first terminal and a second terminal;

a sixth filter capacitor having a first terminal and a second terminal;

the first end of the third filter capacitor, the first end of the fourth filter capacitor, the first end of the fifth filter capacitor and the first end of the sixth filter capacitor are sequentially connected, the second end of the third filter capacitor, the second end of the fourth filter capacitor, the second end of the fifth filter capacitor and the second end of the sixth filter capacitor are grounded, the output pin is connected with the first end of the third filter capacitor, and the load end is connected with the first end of the third filter capacitor, the first end of the fourth filter capacitor, the first end of the fifth filter capacitor or the first end of the sixth filter capacitor.

7. The current-limiting device of claim 6, wherein the third filter capacitor, the fourth filter capacitor, the fifth filter capacitor, and/or the sixth filter capacitor is a multilayer chip ceramic capacitor.

8. The current-limiting device of claim 1, wherein the integrated circuit chip unit further comprises:

and the control unit controls the voltage of the enable pin to be higher or lower than a working voltage so that the integrated circuit chip unit works or does not work.

9. The current-limiting device of claim 1, wherein the integrated circuit chip unit further comprises:

and the copper-exposed pin is used for radiating the heat of the integrated circuit chip unit.