A protection circuit for power supply system and power supply system

Abstract

The utility model embodiment discloses a protection circuit and a power supply system of a power supply system, wherein the protection circuit comprises: a current comparison module, wherein the first input terminal of the current comparison circuit is connected to a first power supply, and the second input terminal of the current comparison circuit is connected to a reference current source; the current comparison module is configured to output a control signal in response to a first current output by the first power supply and a reference current output by the reference current source; a logic control module, wherein the signal input terminal of the logic control module is connected to the output terminal of the current comparison module, and the power input terminal of the logic control module is connected to the first power supply; the logic control module is configured to be turned on or off in response to a control signal, and the logic control module outputs a first voltage output by the first power supply when turned on. The utility model embodiment can respond to a short circuit of the power supply system in a timely manner, quickly cut off the input current, and improve the safety and reliability of the power supply system by detecting the input terminal current and controlling the energy supply of the subsequent circuit according to the input terminal current.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of electronic technology, and in particular to a protection circuit of a power supply system and a power supply system. Background Art

[0002] The stability and reliability of the power supply system are the most concerned performances in the entire design and application process. Short-circuit protection is one of the key factors affecting the stability and reliability of the system. Especially for complex power supply systems, once a short circuit occurs at the load end, if the protection is not triggered in time, it is likely to cause the entire system to be unusable or even damage the next level circuit. When a short circuit occurs at the output end of the power supply system, the system will usually detect the short circuit, then trigger the short circuit protection and shut down the power supply.

[0003] However, when a short circuit occurs at the output of the system, the input power at the input will also increase instantly, and the current at the input will overshoot. If the short circuit protection cannot be triggered in time, the excessive input current may damage the system components and cause the entire system to fail to work. However, in actual use, some short circuit protection detection points are far away from the output path, or the filtering is large, which means that it takes a certain amount of time to detect the short circuit. In this case, when the output has been short-circuited for a certain period of time, the control chip of the power supply system has not detected the abnormality and started protection. Utility Model Content

[0004] The main technical problem solved by the embodiments of the utility model is to provide a protection circuit and a power supply system for a power supply system, which can solve the problem that the short-circuit protection detection point is far away from the output end path, or the filtering is large, resulting in a certain amount of time required to detect the short circuit.

[0005] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide a protection circuit of a power supply system, the power supply system is powered by a first power supply, including: a current comparison module, the first input end of the current comparison circuit is connected to the first power supply, and the second input end of the current comparison circuit is connected to a reference current source; the current comparison module is configured to output a control signal in response to a first current output by the first power supply and a reference current output by the reference current source; a logic control module, the signal input end of the logic control module is connected to the output end of the current comparison module, and the power input end of the logic control module is connected to the first power supply; the logic control module is configured to be turned on or off in response to the control signal, and the logic control module outputs the first voltage output by the first power supply when turned on.

[0006] In some embodiments, the current comparison module includes a current comparison unit and an operational amplifier unit, the first input terminal of the current comparison unit is connected to the first power supply, and the second input terminal of the current comparison circuit is connected to the reference current source; the current comparison unit is configured to output a first signal in response to the first current and the reference current; the input terminal of the operational amplifier unit is connected to the output terminal of the current comparison unit, and the operational amplifier unit is configured to output the control signal in response to the first signal.

[0007] In some embodiments, when the control signal is at a high level, the logic control module is turned off and stops outputting the first voltage; when the control signal is at a low level, the logic control module is turned on and outputs the first voltage.

[0008] In some embodiments, when the first current is greater than the reference current, the level of the first signal is greater than 0; when the first current is equal to the reference current, the level of the first signal is equal to 0; when the first current is less than the reference current, the level of the first signal is less than 0.

[0009] In some embodiments, the current comparison unit includes a resistor R ref , resistor R in , resistor R F1 , a resistor R0 and a comparator M1, wherein the non-inverting input terminal of the comparator M1 is connected to the resistor R in The second end of the resistor R0 and the first end of the resistor R in The first end of the comparator U1 is connected to the first power supply, and the second end of the resistor R0 is grounded; the inverting input end of the comparator U1 is connected to the resistor R ref The second end and the resistor R F1 The first end of the resistor R F1 The second end of the resistor R ref The first end is connected to the reference current source.

[0010] In some embodiments, the operational amplifier unit includes a resistor R1, a resistor R2, and a resistor R F2 and an operational amplifier M2, wherein the in-phase input terminal of the operational amplifier M2 is connected to the second end of the resistor R2, and the first end of the resistor R2 is connected to the output end of the current comparison unit; the inverting input terminal of the operational amplifier M2 is connected to the first end of the resistor R1 and the resistor R F2 The first end of the resistor R F2 The second end of is connected to the output end of the operational amplifier M2, and the second end of the resistor R1 is grounded.

[0011] In some embodiments, the level of the first signal is calculated according to the following formula:

[0012] U0=R F1 / R ref *(U in -U ref ),

[0013] Among them, U in =I in *R in , I in is the first current; U ref =I ref *R ref , I ref is the reference current.

[0014] In some embodiments, the level of the control signal is calculated according to the following formula:

[0015] U1=(1+R F2 / R1)*U0,

[0016] Among them, U0 is the first signal.

[0017] In order to solve the above technical problems, another technical solution adopted by the present invention is: to provide a power supply system, comprising: a first power supply; a reference current source; and a protection circuit of the power supply system as described above.

[0018] In some embodiments, the power supply system also includes: a voltage conversion module, the input end of the voltage conversion module is connected to the output end of the protection circuit of the power supply system, and the output end of the voltage conversion module is connected to the load; the voltage conversion module is configured to output a second voltage in response to a first voltage output by the protection circuit of the power supply system to power the load.

[0019] The beneficial effects of the embodiments of the utility model are as follows: different from the prior art, the embodiments of the utility model can respond to power supply system short circuit in a timely manner, quickly cut off input current, and improve the safety and reliability of the power supply system by detecting input current and controlling the energy supply of the subsequent circuit according to the input current. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a protection circuit of a power supply system provided by an embodiment of the utility model;

[0021] Figure 2 It is a structural schematic diagram of a current comparison module provided by an embodiment of the utility model;

[0022] Figure 3It is a circuit structure diagram of a current comparison unit and an operational amplifier unit provided in an embodiment of the utility model;

[0023] Figure 4 It is a structural schematic diagram of a power supply system provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the utility model, the utility model is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0026] The embodiment of the present application provides a protection circuit for a power supply system, and its structural schematic diagram is as follows: Figure 1 As shown, the power supply system is powered by a first power supply 20 , and the protection circuit includes a current comparison module 110 and a logic control module 120 .

[0027] Among them, the first input end of the current comparison module 110 is connected to the first power supply 20, and the second input end of the current comparison circuit 110 is connected to the reference current source 30; the signal input end of the logic control module 120 is connected to the output end of the current comparison module 110, and the power input end of the logic control module 120 is connected to the first power supply 20.

[0028] Specifically, the current comparison module 110 is configured to output a control signal in response to the first current output by the first power source 20 and the reference current output by the reference current source 30 .

[0029] The logic control module 120 is configured to be turned on or off in response to the control signal. When the logic control module 120 is turned on, it outputs the first voltage output by the first power supply. When the logic control module 120 is turned off, it stops outputting the first voltage.

[0030] In some embodiments, the control signal is an analog signal, which generally has two states: a high level (generally represented as HIGH or 1) and a low level (generally represented as LOW or 0).

[0031] The output end of the logic control module 120 is connected to a device that requires electrical energy. When the control signal is at a high level (or a low level), the switch inside the logic control module 120 is turned on, allowing the first voltage to pass through, and the output end outputs the first voltage; when the control signal is at a low level (or a high level), the switch inside the logic control module 110 is turned off, preventing the first voltage from passing through, and the output end does not output the first voltage.

[0032] In the embodiment of the present application, when the control signal is at a high level, the logic control module is turned off and stops outputting the first voltage; when the control signal is at a low level, the logic control module is turned on and outputs the first voltage.

[0033] The core of the logic control module 120 is a logic gate circuit, such as an AND gate, an OR gate, a NOT gate, etc., which determines whether to allow the electric energy (i.e., the first voltage) to pass according to the state of the control signal. The logic control module 120 can also be implemented using a microcontroller (MCU), which has more complex logic processing capabilities and can perform more complex logic control tasks.

[0034] In some embodiments of the present application, a current comparison module is provided, and its structural diagram is as follows: Figure 2 As shown, the current comparison module 110 includes a current comparison unit 111 and an operational amplifier unit 112 .

[0035] The first input terminal of the current comparison unit 111 is connected to the first power supply 20 , the second input terminal of the current comparison unit 111 is connected to the reference current source 30 , and the input terminal of the operational amplifier unit 112 is connected to the output terminal of the current comparison unit 111 .

[0036] Specifically, the current comparison unit 111 is configured to output a first signal in response to the first current and the reference current; the operational amplifier unit 112 is configured to output a control signal in response to the first signal.

[0037] In an embodiment of the present application, when the first current is greater than the reference current, the level of the first signal is greater than 0; when the first current is equal to the reference current, the level of the first signal is equal to 0; when the first current is less than the reference current, the level of the first signal is less than 0.

[0038] In some embodiments, the current comparison unit 111 can be implemented based on the following technologies: using two resistor networks, one connected in series with the first power source 20, and the other connected in series with the reference current source 30. When the voltage difference between the two resistor networks exceeds a threshold, the comparison unit outputs a signal; using an operational amplifier to amplify the voltage difference between the two resistor networks and output a signal through a comparator.

[0039] In some embodiments, the implementation of the operational amplifier unit 112 can be based on the following technologies: using an operational amplifier to amplify the signal output by the current comparison unit 111 to meet the amplitude requirement of the control signal; if the control signal needs to be converted into another type (such as a digital signal), the operational amplifier unit 112 may include a converter, such as a combination of a comparator and a Schmitt trigger, to convert the analog signal into a digital signal.

[0040] In some embodiments of the present application, a current comparison unit and an operational amplifier unit are provided, respectively, and their circuit structure diagrams are shown in FIG. Figure 3 As shown:

[0041] The current comparison unit 111 includes a resistor R ref , resistor R in , resistor R F1 , resistor R0 and comparator M1. The non-inverting input of comparator M1 is connected to resistor R in The second end of the resistor R0 and the first end of the resistor R in The first end of the resistor R0 is connected to the first power supply, and the second end of the resistor R0 is grounded; the inverting input end of the comparator M1 is connected to the resistor R ref The second end and resistor R F1 The first end of the resistor R F1 The second end of the resistor R is connected to the output end of the comparator M1 and the input end of the operational amplifier unit. ref The first end is connected to a reference current source.

[0042] The level of the first signal is calculated according to the following formula:

[0043] U0=R F1 / R ref *(U in -U ref ),

[0044] Among them, U in =I in *R in , I in is the first current; U ref =I ref *R ref , I ref is the reference current.

[0045] The operational amplifier unit 112 includes a resistor R1, a resistor R2, and a resistor R F2 The in-phase input terminal of the operational amplifier M2 is connected to the second end of the resistor R2, and the first end of the resistor R2 is connected to the output end of the current comparison unit; the inverting input terminal of the operational amplifier M2 is connected to the first end of the resistor R1 and the resistor R F2 The first end of the resistor R F2 The second end of is connected to the output end of the operational amplifier M2, and the second end of the resistor R1 is grounded.

[0046] The level of the control signal is calculated according to the following formula:

[0047] U1=(1+R F2 / R1)*U0,

[0048] Among them, U0 is the first signal.

[0049] Specifically, when a short circuit occurs at the output end of the power supply system, the input power at the input end will also increase instantly, and the current at the input end will overshoot. The input end current is the current source current I in , I in With reference current I ref The first signal U0 is obtained through the comparator M1, and the first signal U0 is amplified to finally obtain the control signal U1.

[0050] The logic control module 120 operates according to the level of the control signal U1. When the control signal U1 is equal to or less than 0, it is in a low level state, and the logic control module 120 does not work, remains turned on, and supplies power to the subsequent modules. When the control signal U1 is greater than 0, it is in a high level state, the logic control module 120 works, disconnects the power supply, and the subsequent modules have no power supply and are forced to shut down.

[0051] Different from the prior art, the embodiments of the utility model can respond to power supply system short circuit in time, quickly cut off input current, and improve the safety and reliability of the power supply system by detecting input current and controlling the energy supply of the subsequent circuit according to the input current.

[0052] Based on the protection circuit provided in the above embodiment, the embodiment of the present application also provides a power supply system, whose structural diagram is as follows: Figure 4 As shown, the power supply system includes a first power supply 20, a reference current source 30, a protection circuit 10 of the power supply system and a voltage conversion module 40.

[0053] Among them, the first input end of the current comparison module 110 in the protection circuit 10 of the power supply system is connected to the first power supply 20, and the second input end of the current comparison circuit 110 is connected to the reference current source 30; the signal input end of the logic control module 120 in the protection circuit 10 of the power supply system is connected to the output end of the current comparison module 110, and the power input end of the logic control module 120 is connected to the first power supply 20.

[0054] The input end of the voltage conversion module 40 is connected to the output end of the protection circuit 10 of the power supply system (ie Figure 4 The output end of the voltage conversion module 40 is connected to the load 50. The voltage conversion module 40 is configured to output a second voltage to power the load 50 in response to the first voltage output by the protection circuit 10 of the power supply system.

[0055] Several implementations of the voltage conversion module 40 are listed below:

[0056] A linear regulator chip including its peripheral circuits is used to convert a first voltage into a stable second voltage.

[0057] A switching regulator chip including its peripheral circuit is used to convert a first voltage into a second voltage lower than the first voltage.

[0058] A boost regulator chip including its peripheral circuits is used to convert a first voltage into a second voltage higher than the first voltage.

[0059] When selecting the implementation method of the voltage conversion module, factors such as input voltage range, output voltage accuracy, conversion efficiency, output current capability, size, cost, etc. need to be considered to ensure that the voltage conversion module can meet the application requirements.

[0060] Different from the prior art, the embodiments of the utility model can respond to power supply system short circuit in time, quickly cut off input current, and improve the safety and reliability of the power supply system by detecting input current and controlling the energy supply of the subsequent circuit according to the input current.

[0061] It should be noted that the preferred embodiments of the utility model are given in the specification and drawings of the utility model, but the utility model can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not used as additional restrictions on the content of the utility model. The purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the description of the utility model; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the scope of protection of the claims attached to the utility model.

Claims

1. A protection circuit for a power supply system, wherein the power supply system is powered by a first power supply, characterized in that: include: A current comparison module, wherein a first input terminal of the current comparison module is connected to the first power supply, and a second input terminal of the current comparison module is connected to a reference current source; The current comparison module is configured to output a control signal in response to a first current output by the first power supply and a reference current output by the reference current source; A logic control module, wherein a signal input terminal of the logic control module is connected to an output terminal of the current comparison module, and an electric energy input terminal of the logic control module is connected to the first power supply; The logic control module is configured to be turned on or off in response to the control signal, and the logic control module outputs the first voltage output by the first power supply when turned on.

2. The circuit according to claim 1, characterized in that The current comparison module includes a current comparison unit and an operational amplifier unit. The first input terminal of the current comparison unit is connected to the first power supply, and the second input terminal of the current comparison unit is connected to the reference current source; The current comparison unit is configured to output a first signal in response to the first current and the reference current; An input terminal of the operational amplifier unit is connected to an output terminal of the current comparison unit, and the operational amplifier unit is configured to output the control signal in response to the first signal.

3. The circuit according to claim 1, characterized in that When the control signal is at a high level, the logic control module is turned off and stops outputting the first voltage; When the control signal is at a low level, the logic control module is turned on to output the first voltage.

4. The circuit according to claim 2, characterized in that When the first current is greater than the reference current, the level of the first signal is greater than 0; When the first current is equal to the reference current, the level of the first signal is equal to 0; When the first current is less than the reference current, the level of the first signal is less than 0.

5. The circuit according to claim 2, characterized in that The current comparison unit includes a resistor R ref , resistor R in , resistor R F1 , resistor R0 and comparator M1, The non-inverting input terminal of the comparator M1 is connected to the resistor R in The second end of the resistor R0 and the first end of the resistor R in The first end of the resistor R0 is connected to the first power supply, and the second end of the resistor R0 is grounded; The inverting input terminal of the comparator M1 is connected to the resistor R ref The second end and the resistor R F1 The first end of the resistor R F1 The second end of the resistor R ref The first end is connected to the reference current source.

6. The circuit according to claim 2, characterized in that The operational amplifier unit includes a resistor R1, a resistor R2, and a resistor R F2 and operational amplifier M2, The in-phase input terminal of the operational amplifier M2 is connected to the second end of the resistor R2, and the first end of the resistor R2 is connected to the output end of the current comparison unit; The inverting input terminal of the operational amplifier M2 is connected to the first terminal of the resistor R1 and the resistor R F2 The first end of the resistor R F2 The second end of is connected to the output end of the operational amplifier M2, and the second end of the resistor R1 is grounded.

7. The circuit according to claim 5, characterized in that The level of the first signal is calculated according to the following formula: U0=R F1 / R ref *(U in -U ref ), Among them, U in =I in *R in , I in is the first current; U ref =I ref *R ref , I ref is the reference current.

8. The circuit according to claim 6, characterized in that The level of the control signal is calculated according to the following formula: U1=(1+R F2 / R1)*U0, Among them, U0 is the first signal.

9. A power supply system, characterized in that: include: First power source; Reference current source; A protection circuit for a power supply system as claimed in any one of claims 1 to 8.

10. The system according to claim 9, characterized in that Also includes: A voltage conversion module, wherein an input end of the voltage conversion module is connected to an output end of the protection circuit of the power supply system, and an output end of the voltage conversion module is connected to a load; The voltage conversion module is configured to output a second voltage to power the load in response to a first voltage output by the protection circuit of the power supply system.

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