A power supply output overload protection circuit, device, and system

Abstract

The embodiment of the application belongs to the technical field of power supply circuits, and relates to a power supply output overload protection circuit, device and system, which comprises a first voltage division module, a second voltage division module, a first switch module and a second switch module. The first voltage division module is connected with an internal power supply interface and a ground end respectively. The second voltage division module is connected with the first switch module, the second switch module and the internal power supply interface respectively and is used for providing a voltage division voltage for the first switch module. The first switch module is connected with the second switch module, the first voltage division module and the second voltage division module respectively and is used for turning on an external output when a normal load is connected to an external output port and turning off the external output when an abnormal load is connected to the external output port. The second switch module is connected with the first switch module, the external output port and the internal power supply interface respectively and is used for turning off or turning on according to the turning on or turning off of the first switch module. The technical scheme provided by the application can improve the safety of power supply output.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply circuit, more particularly, to a power output overload protection circuit, device and system. BACKGROUND

[0002] With the increasing variety of electronic products, many consumer electronics products have external output power interface, such as external output USB interface, which can charge external electronic devices such as mobile phones, MP3, MP4, etc. When the external device requires more power than the electronic product can output, or the external device is damaged, or the power interface is accidentally short-circuited to ground, etc., these may cause the electronic product to be damaged due to its inability to withstand the over-specification output. At the same time, the current power protection is carried out by power output protection chip, which has high cost. SUMMARY

[0003] The technical problem to be solved by the embodiments of the present application is that the external output power port of the electronic product in the related art causes abnormal operation or damage due to overload or accidental short circuit.

[0004] To solve the above technical problem, the embodiments of the present application provide a power output overload protection circuit, which adopts the following technical solution:

[0005] The first voltage dividing module, the second voltage dividing module, the first switch module and the second switch module;

[0006] The first voltage dividing module is connected to the internal power interface and the ground terminal respectively, and is used to provide a divided voltage for the first switch module;

[0007] The second voltage dividing module is connected to the first switch module, the second switch module and the internal power interface respectively, and is used to provide a divided voltage for the first switch module;

[0008] The first switch module is connected to the second switch module, the first voltage dividing module and the second voltage dividing module respectively, and is used to turn off according to the divided voltage obtained from the first voltage dividing module and the output voltage of the external output port when the external output port is connected to a normal load, and turn on the external output; when the external output port is connected to an abnormal load, it is turned on according to the divided voltage obtained from the second voltage dividing module and the power voltage of the internal power interface, and the external output is turned off;

[0009] The second switch module is connected to the first switch module, the external output port and the internal power interface respectively, and is used to turn off or turn on according to the turn-on or turn-off of the first switch module.

[0010] Further, the first switch module comprises a first triode, a second triode and a diode, wherein:

[0011] The base of the first triode is connected with the first voltage division module, the emitter of the first triode is connected with the anode of the diode, and the collector of the first triode is connected with the second voltage division module;

[0012] The base of the second triode is connected with the second voltage division module, the collector of the second triode is connected with the second switch module, and the emitter of the second triode is connected with a common connection point of the second switch module and the internal power supply interface;

[0013] The cathode of the diode is connected with a common connection point of the second switch module and the external output port.

[0014] Further, the second switch module is a MOS tube, the gate of the MOS tube is connected with the collector of the second triode, the source of the MOS tube is connected with the emitter of the second triode and the internal power supply interface respectively, and the drain of the MOS tube is connected with the cathode of the diode and the external output port respectively.

[0015] Further, the first voltage division module comprises a first voltage division resistor and a second voltage division resistor, wherein:

[0016] One end of the first voltage division resistor is connected with the internal power supply interface, the other end of the first voltage division resistor is connected with one end of the second voltage division resistor, and the other end of the second voltage division resistor is connected with a ground terminal;

[0017] A common connection point of the first voltage division resistor and the second voltage division resistor is connected with the base of the first triode.

[0018] Further, the second voltage division module comprises a third voltage division resistor and a fourth voltage division resistor;

[0019] The third voltage division resistor is connected with the collector of the first triode and the base of the second triode respectively;

[0020] One end of the fourth voltage division resistor is connected between the source of the MOS tube and the internal power supply interface, and the other end of the fourth voltage division resistor is connected between the third voltage division resistor and the base of the second triode.

[0021] Further, the power supply output overload protection circuit further comprises a first filter capacitor for filtering out interference signals.

[0022] One end of the first filter capacitor is connected between a common connection point of the first voltage dividing resistor and the second voltage dividing resistor and a base of the first transistor, and the other end of the first filter capacitor is grounded.

[0023] Further, the power output overload protection circuit further comprises a second filter capacitor connected in parallel with the fourth voltage dividing resistor.

[0024] Further, the power output overload protection circuit further comprises a protection resistor, one end of the protection resistor is connected with the collector of the second transistor and the second switch module respectively, and the other end of the protection resistor is grounded.

[0025] To solve the above technical problems, the embodiment of the present application further provides a power output overload protection device, which is the power output overload protection circuit as described above.

[0026] To solve the above technical problems, the embodiment of the present application further provides a power output overload protection system, which comprises an external device and the power output overload protection device as described above, and the device is connected with the external device through the external output port.

[0027] Compared with the prior art, the embodiment of the present application has the following beneficial effects:

[0028] The present application provides a power output overload protection circuit, which comprises a first voltage dividing module, a second voltage dividing module, a first switch module and a second switch module, the first voltage dividing module is connected with an internal power interface and a ground end respectively to provide a voltage dividing voltage for the first switch module; the second voltage dividing module is connected with the first switch module, the second switch module and the internal power interface respectively to provide a voltage dividing voltage for the first switch module; the first switch module is connected with the second switch module, the first voltage dividing module and the second voltage dividing module respectively, to turn off the external output according to the voltage dividing voltage obtained from the first voltage dividing module and the output voltage of the external output port when the external output port is connected with a normal load, and to turn on the external output according to the voltage dividing voltage obtained from the second voltage dividing module and the power voltage of the internal power interface when the external output port is connected with an abnormal load; the second switch module is connected with the first switch module, the external output port and the internal power interface respectively to turn off or turn on according to the turn on or turn off of the first switch module; the present application controls the turn on or turn off of the first switch module and the second switch module according to the connected load, and then controls the turn on or turn off of the external output, which can avoid the problems of abnormal work or damage caused by overload or accidental short circuit of the external output power port, improve the safety of power output and save cost. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the scheme in the application clearer, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0030] Figure 1 FIG. 1 is a structural schematic diagram of a power output overload protection circuit provided by an embodiment of the application. DETAILED DESCRIPTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application; the description and the drawings are to be regarded as illustrative in nature and are not intended to limit the application. The terminology used in the description of the application herein, as well as in the claims and the above description of the drawings, should not be taken to limit the scope of the application. The use of the terms "first", "second", and the like in the description of the application herein is only intended to distinguish between similar objects and not to limit the scope of the application.

[0032] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a multitude of embodiments that are of the application. It is appreciated that the embodiments described herein can be combined with other embodiments.

[0033] In order to make the scheme in the application clearer, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0034] An embodiment of the application provides a power output overload protection circuit, which comprises a first voltage division module 10, a second voltage division module 20, a first switch module 30 and a second switch module 40.

[0035] Referring to FIG. 1, the first voltage division module 10 is connected with an internal power interface VCC and a ground end respectively, and is configured to provide a voltage division voltage for the first switch module 30; the second voltage division module 20 is connected with the first switch module 30, the second switch module 40 and the internal power interface VCC respectively, and is configured to provide a voltage division voltage for the first switch module 30. Figure 1

[0036] ​The first switch module 30 is connected with the second switch module 40, the first voltage division module 10 and the second voltage division module 20 respectively, and is used for turning off according to the voltage division voltage obtained from the first voltage division module 10 and the output voltage of the external output port SYSTEM when the external output port SYSTEM is connected with normal load, and turning on the external output; turning on according to the voltage division voltage obtained from the second voltage division module 20 and the power supply voltage of the internal power supply interface VCC when the external output port SYSTEM is connected with abnormal load, and turning off the external output.

[0037] The second switch module 40 is connected with the first switch module 30, the external output port SYSTEM and the internal power supply interface VCC respectively, and is used for turning off or turning on according to the turning on or turning off of the first switch module 30.

[0038] In the embodiment, the turning on or turning off of the external output is controlled by the cooperation of the turning on or turning off between the first switch module 30 and the second switch module 40.

[0039] In the embodiment, the first switch module 30 comprises a first triode Q101, a second triode Q102 and a diode D100.

[0040] The base B of the first triode Q101 is connected with the first voltage division module 10, the emitter E of the first triode Q101 is connected with the anode of the diode D100, and the collector C of the first triode Q101 is connected with the second voltage division module 20; the base B of the second triode Q102 is connected with the second voltage division module 20, the collector C of the second triode Q102 is connected with the second switch module 40, and the emitter E of the second triode Q102 is connected to the common connection point of the second switch module 40 and the internal power supply interface VCC; the cathode of the diode D100 is connected with the common connection point of the second switch module 40 and the external output port SYSTEM.

[0041] In the embodiment, the second switch module 40 is a MOS tube Q103, the gate G of the MOS tube Q103 is connected with the collector C of the second triode Q102, the source S of the MOS tube Q103 is connected with the emitter E of the second triode Q102 and the internal power supply interface VCC respectively, and the drain D of the MOS tube Q103 is connected with the cathode of the diode D100 and the external output port SYSTEM respectively.

[0042] In the embodiment, the first voltage division module 10 comprises a first voltage division resistor R100 and a second voltage division resistor R101.

[0043] One end of the first voltage dividing resistor R100 is connected to the internal power supply interface VCC, the other end of the first voltage dividing resistor R100 is connected to one end of the second voltage dividing resistor R101, the other end of the second voltage dividing resistor R101 is connected to the ground; the common connection point of the first voltage dividing resistor R100 and the second voltage dividing resistor R101 is connected to the base B of the first triode Q101.

[0044] In some optional implementations, the second voltage dividing module 20 includes a third voltage dividing resistor R102 and a fourth voltage dividing resistor R103, wherein two ends of the third voltage dividing resistor R102 are respectively connected to the collector C of the first triode Q101 and the base B of the second triode Q102; one end of the fourth voltage dividing resistor R103 is connected between the source S of the MOS tube Q103 and the internal power supply interface VCC, the other end of the fourth voltage dividing resistor R103 is connected between the third voltage dividing resistor R102 and the base B of the second triode Q102.

[0045] In the embodiment, the internal power supply interface VCC is connected to the internal power supply output module, which is usually 5V, denoted as VCC_5V; the external output port SYSTEM is connected to the external device, the output voltage is usually 5V, denoted as SYSTEM_5V, and the two are isolated by the MOS tube Q103.

[0046] Based on the above power supply output overload protection circuit, the working principle is as follows:

[0047] When the external output port SYSTEM is connected to a normal load, the SYSTEM_5V voltage will not decrease obviously. At this time, the base B of the first triode Q101 is divided by the resistors R100 and R101, and the BE electrode of Q101 and the diode D100 (the forward voltage is usually 0.7V) also exist, so that the BE electrode voltage of Q101 is less than the conduction threshold voltage (0.7V), and it is in the cut-off state. Further, the BE electrode voltage of the second triode Q102 is less than the conduction threshold voltage (0.7V), and it is also in the cut-off state, the gate-source (GS) voltage of the MOS tube Q103 is greater than the conduction threshold voltage, and the MOS tube Q103 is in the saturated conduction state, and the external output is normal, that is, when a normal load is connected, the external output is turned on.

[0048] When the SYSTEM access to abnormal load, the SYSTEM_5V voltage will have a significant drop. At this time the base B voltage of the first transistor Q101 is equal to VCC*R101 / (R100+R101), when the external output port voltage SYSTEM_5V drops to VCC*R101 / (R100+R101)-1.4V, the first transistor Q101 starts to conduct, at this time the BE voltage of the second transistor Q102 because of the voltage division of resistor R103 and R102, so that its voltage is greater than the threshold voltage (-0.7V), the second transistor Q102 is in saturation conduction state, the CE electrode voltage drop is -0.1V~-0.2V, the SG electrode of MOS tube Q103 and the CE electrode of the second transistor Q102 are connected in parallel, resulting in the SG electrode voltage of MOS tube Q103 being less than the threshold voltage, the MOS tube Q103 is in the off state, and the external output is turned off.

[0049] When access to abnormal load, the external output is turned off, the power output circuit can be protected, avoiding damage or abnormal work, improving the safety of the circuit.

[0050] In the embodiment, the power output overload protection circuit further comprises a protection resistor R104, one end of the protection resistor R104 is connected with the collector C of the second transistor Q102 and the second switch module 40 respectively, and the other end of the protection resistor R104 is grounded.

[0051] Specifically, one end of the protection resistor R104 is connected with the collector C of the second transistor Q102 and the gate G of the MOS tube Q103 respectively, which is used to avoid the damage of the short circuit of the transistor when the second transistor Q102 is turned on.

[0052] In the embodiment, the power output overload protection circuit further comprises a first filter capacitor C100, which is used to filter out interference signals.

[0053] Specifically, one end of the first filter capacitor C100 is connected between the common connection point of the first voltage dividing resistor R100 and the second voltage dividing resistor R101 and the base B of the first transistor Q101, and the other end of the first filter capacitor C100 is grounded.

[0054] In the embodiment, the power output overload protection circuit further comprises a second filter capacitor C101, and the second filter capacitor C101 is connected in parallel with the fourth voltage dividing resistor R103. Specifically, one end of the second filter capacitor C101 is connected between the source S of the MOS tube Q103 and the internal power supply interface VCC, and the other end of the second filter capacitor C101 is connected between the third voltage dividing resistor R102 and the base B of the second transistor Q102.

[0055] In the embodiment, the first filter capacitor C100 and the second filter capacitor C101 are used to filter out interference, and can also play a certain inhibitory effect on instantaneous surge output.

[0056] In some optional implementations, the power output overload protection circuit further includes a protection resistor R105, two ends of the protection resistor R105 are respectively connected to the external output port SYSTEM and the ground end. In order to prevent damage caused by static electricity, the unused pin cannot be suspended, and a pull-down resistor is generally connected to provide a discharge path, and the pin suspended in the air is prevented from being subjected to external electromagnetic interference.

[0057] Based on the power output overload protection circuit, the embodiment of the present application further provides a power output overload protection device, which includes the power output overload protection circuit as described above, and the device can be used as a power supply to charge the external device connected thereto.

[0058] Based on the power output overload protection device, the embodiment of the present application provides a power output overload protection system, which includes the external device and the power output overload protection device as described above, and the device is connected to the external device through the external output port SYSTEM to provide power supply for the external device.

[0059] It should be understood that the external device includes but is not limited to a smart phone, an electronic book reader, an MP3 player, an MP4 player, and the like.

[0060] Obviously, the above-described embodiments are only some of the embodiments of the present application, but not all the embodiments. The preferred embodiments of the present application are shown in the drawings, but do not limit the patent scope of the present application. The present application can be implemented in many different forms, and conversely, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some technical features. Any equivalent structure made by using the contents of the specification and drawings, directly or indirectly applied to other related technical fields, is also within the scope of the patent protection of the present application.

Claims

1. A power supply output overload protection circuit, characterized by, The power output overload protection circuit comprises: a first voltage dividing module, a second voltage dividing module, a first switch module and a second switch module; the first voltage dividing module is connected to an internal power supply interface and a ground end respectively, and is configured to provide a voltage dividing voltage for the first switch module; the second voltage dividing module is connected to the first switch module, the second switch module and the internal power supply interface respectively, and is configured to provide a voltage dividing voltage for the first switch module; the first switch module is connected to the second switch module, the first voltage dividing module and the second voltage dividing module respectively, and is configured to, when a normal load is connected to an external output port, turn off according to the voltage dividing voltage obtained from the first voltage dividing module and the output voltage of the external output port, and turn on the external output; and when an abnormal load is connected to the external output port, turn on according to the voltage dividing voltage obtained from the second voltage dividing module and the power supply voltage of the internal power supply interface, and turn off the external output; the second switch module is connected to the first switch module, the external output port and the internal power supply interface respectively, and is configured to turn off or turn on according to the turn-on or turn-off of the first switch module; the first switch module comprises a first triode, a second triode and a diode, wherein: the base of the first triode is connected to the first voltage dividing module, the emitter of the first triode is connected to the anode of the diode, and the collector of the first triode is connected to the second voltage dividing module; the base of the second triode is connected to the second voltage dividing module, the collector of the second triode is connected to the second switch module, and the emitter of the second triode is connected to a common connection point of the second switch module and the internal power supply interface; the cathode of the diode is connected to a common connection point of the second switch module and the external output port; the second switch module is a MOS tube, the gate of the MOS tube is connected to the collector of the second triode, the source of the MOS tube is connected to the emitter of the second triode and the internal power supply interface respectively, and the drain of the MOS tube is connected to the cathode of the diode and the external output port respectively; the second voltage dividing module comprises a third voltage dividing resistor and a fourth voltage dividing resistor; the two ends of the third voltage dividing resistor are connected to the collector of the first triode and the base of the second triode respectively; one end of the fourth voltage dividing resistor is connected between the source of the MOS tube and the internal power supply interface, and the other end of the fourth voltage dividing resistor is connected between the third voltage dividing resistor and the base of the second triode; the power output overload protection circuit further comprises a first filter capacitor for filtering out interference signals; one end of the first filter capacitor is connected between the common connection point of the first voltage dividing resistor and the second voltage dividing resistor and the base of the first triode, and the other end of the first filter capacitor is grounded.

2. The power supply output overload protection circuit of claim 1, wherein, the first voltage dividing module comprises a first voltage dividing resistor and a second voltage dividing resistor, wherein: One end of the first voltage dividing resistor is connected with the internal power supply interface, and the other end of the first voltage dividing resistor is connected to one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is connected to a ground terminal. A common connection point of the first voltage dividing resistor and the second voltage dividing resistor is connected with the base of the first triode.

3. The power supply output overload protection circuit of claim 1, wherein, The power output overload protection circuit further comprises a second filter capacitor connected in parallel with the fourth voltage dividing resistor.

4. The power supply output overload protection circuit according to any one of claims 1 to 3, characterized by, The power output overload protection circuit further comprises a protection resistor, one end of the protection resistor is connected with the collector of the second triode and the second switch module respectively, and the other end of the protection resistor is grounded.

5. A power supply output overload protection device, characterized by, The power output overload protection circuit comprises the power output overload protection circuit according to any one of claims 1 to 4.

6. A power supply output overload protection system characterized by, The power output overload protection device comprises an external device and the power output overload protection circuit according to claim 5, and the device is connected with the external device through the external output port.

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