CN116014675A - Power supply circuit, short-circuit protection method of power supply circuit and power supply equipment - Google Patents

Abstract

The invention discloses a power supply circuit, a short-circuit protection method of the power supply circuit and power supply equipment, wherein the power supply circuit comprises a power supply circuit, a voltage detection circuit, a current detection circuit and a control circuit, and the power supply circuit comprises an output end which is used for connecting a load; the voltage detection circuit is used for detecting the output voltage of the output end; the current detection circuit is used for detecting the output current of the output end; the control circuit is connected with the current detection circuit and the voltage detection circuit and is used for carrying out short-circuit protection on the power supply circuit when the detection results of the current detection circuit and the voltage detection circuit are determined to meet the following short-circuit protection conditions when the power supply circuit supplies power to the load: the output voltage of the output end is smaller than a voltage threshold value; the output current of the output end is larger than the current threshold value, and the output current of the output end is gradually increased. The probability of false triggering of the short-circuit protection can be reduced.

Description

Power supply circuit, short-circuit protection method of power supply circuit and power supply equipment

Technical Field

The invention relates to the technical field of electronics, in particular to a power supply circuit, a short-circuit protection method of the power supply circuit and power supply equipment.

Background

In the protection mechanism of the power supply, the short-circuit protection refers to protecting the power supply (for example, turning off the power supply) in time under the condition that the output positive end of the power supply is communicated with the ground (i.e., load short circuit), so as to prevent the internal components of the power supply from being damaged by heavy current caused by the load short circuit.

Currently, in the design of short-circuit protection of a power supply, one way is to convert the output current of the power supply into voltage through a detection resistor, and judge whether the load of the power supply is short-circuited or not based on the voltage of the detection resistor; another way is to sense the output current of the power supply based on the current transformer, and determine whether the load of the power supply is shorted based on the sensing result of the current transformer. In both of these approaches, the output current of the power supply is typically sensed based on a current transformer, since the sense resistor will be lossy and unacceptable in the design of the power supply. However, in an ac scenario, a current transformer may generate large noise, which causes an inaccurate output current sensed by the current transformer, and further causes a situation that a short-circuit protection of a power supply is triggered by mistake.

Disclosure of Invention

In view of the above, embodiments of the present invention provide a power supply circuit, a short-circuit protection method for the power supply circuit, and a power supply device, which can reduce the probability of false triggering of short-circuit protection.

In one aspect, the present invention provides a power supply circuit comprising:

the power supply circuit comprises an output end, wherein the output end is used for being connected with a load;

the voltage detection circuit is used for detecting the output voltage of the output end;

the current detection circuit is used for detecting the output current of the output end;

the control circuit is connected with the current detection circuit and the voltage detection circuit and is used for carrying out short-circuit protection on the power supply circuit when the power supply circuit supplies power to the load according to detection results of the current detection circuit and the voltage detection circuit and when the following short-circuit protection conditions are met:

the output voltage of the output end is smaller than a voltage threshold value;

the output current of the output end is larger than the current threshold value, and the output current of the output end is gradually increased.

In some embodiments, the detection results of the current detection circuit include a first detection result and a second detection result, wherein the first detection result is used for representing the output current of the output terminal, and the second detection result is used for representing whether the output current of the output terminal is greater than the current threshold;

the control circuit is specifically configured to determine, based on the second detection result, whether the output current of the output terminal gradually increases according to the first detection results of a plurality of consecutive time points when it is determined that the output current of the output terminal is greater than the current threshold.

In some embodiments, the current detection circuit includes a current transformer and a rectification circuit, the current transformer is connected with the rectification circuit, the rectification circuit is connected with the control circuit, the current transformer is used for sensing the output current of the output end and outputting an alternating voltage signal corresponding to the magnitude of the output current, and the rectification circuit is used for converting the alternating voltage signal into a unidirectional voltage signal, so as to obtain the first detection result.

In some embodiments, the current detection circuit further includes a comparison circuit including a first comparison input connected to the rectifying circuit, a second comparison input connected to the control circuit, and a comparison output for receiving a reference voltage signal indicative of the current threshold, the comparison circuit being configured to compare the unidirectional voltage signal output by the rectifying circuit with the reference voltage signal and output the second detection result.

In some embodiments, the power supply circuit includes an input terminal and a transformer, the input terminal is used for connecting with an ac power source, a primary side of the transformer is connected with the input terminal, and a secondary side of the transformer is connected with the output terminal;

the current transformer is connected with the primary side of the transformer and is used for detecting the output current of the output end by sensing the current of the primary side.

In some embodiments, the voltage detection circuit includes an amplifier, and the amplifier is connected between the output terminal and the control circuit, and is configured to amplify an output voltage of the output terminal and output the amplified output voltage to the control circuit.

The invention also provides a short-circuit protection method of the power supply circuit, wherein the power supply circuit comprises a power supply circuit, a voltage detection circuit and a current detection circuit, and the power supply circuit comprises an output end for connecting a load; the method comprises the following steps:

detecting an output voltage of the output terminal by the voltage detection circuit, and detecting an output current of the output terminal by the current detection circuit;

when the power supply circuit supplies power to the load, according to detection results of the current detection circuit and the voltage detection circuit, when the following short-circuit protection conditions are met, the power supply circuit is subjected to short-circuit protection:

the output voltage of the output end is smaller than a voltage threshold value;

the output current of the output end is larger than the current threshold value, and the output current of the output end is gradually increased.

In some embodiments, the detection results of the current detection circuit include a first detection result and a second detection result, wherein the first detection result is used for representing the output current of the output terminal, and the second detection result is used for representing whether the output current of the output terminal is greater than the current threshold; wherein:

determining whether the output current of the output terminal is greater than a current threshold based on the first detection result, and determining whether the output current of the output terminal gradually increases according to the first detection results of a plurality of continuous time points in the case that the output current of the output terminal is greater than the current threshold.

In some embodiments, the power circuit includes an input terminal for connecting to an ac power source, a transformer having a primary side connected to the input terminal, and a secondary side connected to the output terminal;

the detecting, by the current detecting circuit, the output current of the output terminal includes:

and detecting the current of the primary side of the transformer by the current detection circuit to detect the output current of the output end.

The invention also provides a power supply device comprising the power supply circuit.

In the technical solutions of some embodiments of the present application, a control circuit of a power supply circuit detects an output voltage of an output end through a voltage detection circuit, and detects an output current of the output end through a current detection circuit, where the output voltage of the output end is smaller than a voltage threshold, and the output current of the output end is larger than a current threshold, and where the output current of the output end gradually increases, short-circuit protection is performed on the power supply circuit. In the judging condition of the short-circuit protection, the threshold value judgment is carried out on the output voltage and the output current of the output end, and the change condition of the output current is judged, so that when the detected output current is larger than the current threshold value due to the superposition noise, the change condition of the output current and the magnitude of the output voltage can be combined to comprehensively judge whether the short-circuit protection is needed for the power circuit or not, and the short-circuit protection of the power circuit is prevented from being triggered by mistake when the output current is larger than the current threshold value due to the superposition noise. In summary, the power supply circuit of the present application can reduce the probability of false triggering of the short-circuit protection.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and should not be construed as limiting the invention in any way, in which:

FIG. 1 illustrates a circuit diagram of a power supply in some techniques;

FIG. 2 is a schematic diagram showing the positive voltage signal output by the rectifying circuit of FIG. 1 over time;

FIG. 3 shows a circuit block diagram of a power supply circuit provided by one embodiment of the present application;

fig. 4 shows a graph of output voltage variation trend of an output terminal when a load provided in an embodiment of the present application is shorted;

FIG. 5 shows a graph of the output current trend at the output terminal when the load provided in one embodiment of the present application is shorted;

fig. 6 shows a circuit diagram of the power supply circuit in fig. 3;

FIG. 7 is a flow chart illustrating a method of short-circuit protection according to one embodiment of the present application;

fig. 8 shows a schematic block diagram of a power supply device according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which a person skilled in the art would obtain without making any inventive effort, are within the scope of the invention.

Referring to fig. 1, a circuit diagram of a power supply 100 in some technologies is shown. In fig. 1, the power supply 100 includes an input 14, an output 15, and a transformer L2. Wherein the input 14 may be used for connecting to an ac power source (e.g., mains), and the output 15 may be used for connecting to a load (e.g., a server motherboard). The primary side of the transformer L2 is connected to the input terminal 14, and the secondary side is connected to the output terminal 15, for converting the electric energy provided by the ac power source into the electric energy required by the load.

Further, the power supply 100 further includes a switch 13, a comparator L1, a rectifying circuit 12, a comparator U2, and a control circuit 11. Wherein the switch 13 is connected between the input 14 and the primary side of the transformer L2. When the switch 13 is closed, the transformer L2 is communicated with the input end 14, and the transformer L2 converts the electric energy provided by the alternating current power supply into electric energy required by a load and outputs the electric energy; when the switch 13 is opened, the transformer L2 and the input terminal 14 are disconnected, and the power supply 100 stops supplying power to the load.

The current comparator L1 is connected to the primary side of the transformer L2, and can map the primary side current of the transformer L2 into a voltage signal. Meanwhile, since the primary side current and the secondary side current of the transformer L2 are in a fixed ratio, the voltage signal obtained by mapping the current transformer L1 can reflect the secondary side current of the transformer L2, and further can reflect the current output by the output end 15. Specifically, the primary side of the current transformer L1 may be connected in series between the switch 13 and the primary side of the transformer L2, so that the primary side current of the current transformer L1 is the same as the primary side current of the transformer L2. The secondary side voltage of the current comparator L1 may be positively correlated with the primary side current, i.e. also positively correlated with the secondary side current of the transformer L2, and thus also positively correlated with the current output by the output terminal 15. Therefore, the magnitude of the current output from the output terminal 15 can be determined by detecting the magnitude of the secondary side voltage of the comparator L1.

The rectifying circuit 12 may be connected between the secondary side of the comparator L1 and the comparator U2, and is configured to convert an ac voltage signal of the secondary side of the comparator L1 into a unidirectional voltage signal, and output the unidirectional voltage signal obtained by conversion to the comparator U2. Specifically, the secondary side of the comparator L1 may include a first end L11 and a second end L12, and the rectifying circuit 12 may include a capacitor C1 and rectifying diodes D1, D2, D3, D4. The capacitor C1 includes a first capacitor terminal 121 and a second capacitor terminal 122. The first capacitor terminal 121 is connected to the comparator U2, and the second capacitor terminal 122 is grounded. The anode of the rectifying diode D1 is grounded, and the cathode is connected with the first end L11 of the comparator L1; the anode of the rectifying diode D2 is connected with the first end L11 of the comparator L1, and the cathode is connected between the first capacitor end 121 and the comparator U2; the anode of the rectifying diode D3 is connected with the second end L12 of the comparator L1, and the cathode is connected between the first capacitor end 121 and the comparator U2; the anode of the rectifying diode D4 is grounded, and the cathode is connected to the second end L12 of the comparator L1. When the ac voltage signal at the secondary side of the comparator L1 is in the positive half cycle, the rectifying diodes D2 and D3 are turned on, the rectifying diodes D1 and D4 are turned off, and the voltage difference between the first capacitor terminal 121 and the second capacitor terminal 122 is positive; when the ac voltage signal on the secondary side of the comparator L1 is in the negative half cycle, the rectifying diodes D2 and D3 are turned off, and the rectifying diodes D1 and D4 are turned on, so that the voltage difference between the first capacitor terminal 121 and the second capacitor terminal 122 is positive. In this way, the voltage input to the comparator U2 is always positive, i.e. the conversion of the ac voltage signal on the secondary side of the comparator L1 into a unidirectional voltage signal is achieved. In fig. 1, the voltage signal in the single direction is a positive voltage signal having a voltage value not less than 0 v.

The comparator U2 compares the positive voltage signal output from the rectifying circuit 12 with the reference voltage signal Vref, and if the positive voltage signal is greater than the reference voltage signal Vref, outputs a first comparison result (e.g., a high level) to the control circuit 11; if the positive voltage signal is not greater than the reference voltage signal Vref, a second comparison result (e.g., low level) is output to the control circuit 11.

The control circuit 11 may be connected to the switch 13, and is configured to control on/off of the switch 13 according to a comparison result output by the comparator U2. Wherein the control circuit 11 may control the chip. Specifically, as is clear from the above description about the current comparator L1, since the magnitude of the secondary side voltage of the current comparator L1 is positively correlated with the magnitude of the current output from the output terminal 15, when the load is shorted and the current output from the output terminal 15 increases, the secondary side voltage of the current comparator L1 increases accordingly. When the secondary side voltage signal of the current comparator L1 is larger than the reference voltage signal Vref, the current of the output end 15 can be indicated to be overlarge, and a load is short-circuited; when the secondary voltage signal of the comparator L1 is not greater than the reference voltage signal Vref, it may be indicated that the current level of the output terminal 15 is within the normal range, and no short circuit occurs in the load.

In view of this, in the case that the comparator U2 outputs the first comparison result to the control circuit 11, the control circuit 11 may control the switch 13 to be turned off, so that the input terminal 14 of the power supply 100 is disconnected from the transformer L2, so as to control the power supply 100 to stop supplying power to the load for short-circuit protection; in the case that the comparator U2 outputs the second comparison result to the control circuit 11, the control circuit 11 may control the switch 13 to be connected, so that the transformer L2 converts the electric energy provided by the ac power source into the electric energy required by the load to output, and thus the load operates normally.

In the power supply 100 shown in fig. 1, since the noise of the comparator L1 is larger in the ac scene, the positive voltage signal rectified by the rectifying circuit 12 may be superimposed with the noise signal, and the positive voltage signal superimposed with the noise signal may be larger than the reference voltage signal Vref, which may cause the control circuit 11 to trigger the short-circuit protection mechanism of the power supply 100 by mistake, so that the power supply 100 is controlled to stop supplying power to the load.

For ease of understanding, please refer to fig. 2, which is a schematic diagram illustrating the change of the positive voltage signal output by the rectifying circuit 12 in fig. 1 with time. In fig. 2, the positive voltage signal within the dashed box is not greater than the reference voltage signal Vref without superimposing the noise signal, but after superimposing the noise signal, the positive voltage signal is greater than the reference voltage signal Vref. Based on the positive voltage signal on which the noise signal is superimposed, the comparator U2 outputs a first comparison result to the control circuit 11. Also, since in the power supply 100, the short-circuit protection is usually real-time protection, that is, the control circuit 11 immediately controls the switch 13 to be turned off upon receiving the first comparison result. Then, for the case in the dashed box of fig. 2, the short-circuit protection mechanism of the power supply 100 is triggered by mistake, that is, the power supply 100 is actually short-circuited in the case that the load is not short-circuited.

In view of the above, the present application provides a power supply circuit having a short-circuit protection function, and can reduce the probability of false triggering of the short-circuit protection. Referring to fig. 3, a circuit block diagram of a power supply circuit 300 according to an embodiment of the present application is provided. In fig. 3, the power supply circuit 300 includes a power supply circuit 31, a voltage detection circuit 32, a current detection circuit 33, and a control circuit 34. Wherein the power supply circuit 31 comprises an output terminal 311, the output terminal 311 being for connecting to the load 30. The power supply circuit 31 supplies power to the load 30 through the output terminal 311.

The voltage detection circuit 32 is used for detecting the output voltage of the output terminal 311, and the current detection circuit 33 is used for detecting the output current of the output terminal 311. The control circuit 34 is connected to the current detection circuit 33 and the voltage detection circuit 32, and is configured to control the power supply circuit 31 to stop supplying power to the load 30 to perform short-circuit protection on the power supply circuit 300 when the following short-circuit protection conditions are determined to be satisfied based on the detection results of the current detection circuit 33 and the voltage detection circuit 31 when the power supply circuit 31 supplies power to the load 30:

the output voltage of the output terminal 311 is less than the voltage threshold;

the output current of the output terminal 311 is greater than the current threshold, and the output current of the output terminal 311 gradually increases.

It will be appreciated that in the event of a short circuit of load 30, the output voltage at output 311 is gradually reduced and the output current is gradually increased. See in particular fig. 4 and 5. Fig. 4 is a graph showing an output voltage variation trend of the output terminal 311 when the load 30 is shorted according to an embodiment of the present application. Fig. 5 is a graph showing the trend of the output current of the output terminal 311 when the load 30 is shorted according to one embodiment of the present application. In fig. 4 and 5, assuming that the load 30 is short-circuited from time t1, the output voltage of the output terminal 311 (shown in fig. 4) starts to decrease from time t 1. In the event that the output voltage is less than the voltage threshold, it may be determined that the load 30 is shorted. The output current of the output terminal 311 (shown in fig. 5) starts to rise from time t 1. In the event that the output current is greater than the current threshold, it may be determined that the load 30 is shorted.

It should be noted that, the voltage threshold and the current threshold may be set according to practical situations, which is not limited in this application. In general, the voltage threshold may be smaller than the normal output voltage of the output terminal 311 (the output voltage of the output terminal 311 when the load 30 is not shorted), and the current threshold may be larger than the normal output current of the output terminal 311 (the output current of the output terminal 311 when the load 30 is not shorted).

In some embodiments, in the case where the output current of the output terminal 311 is greater than the current threshold value, it may be determined whether the output current of the output terminal 311 gradually increases based on the following method:

output currents of the output terminal 311 at a plurality of time points are acquired in chronological order. If the output current at each time point is greater than the output current at a time point before the time point, it is determined that the output current of the output terminal 311 gradually increases. In other words, if the output current at the t+1th time point is greater than the output current at the t time point, it can be determined that the output current of the output terminal 311 gradually increases.

In some embodiments, in the case where the output terminal 311 outputs alternating current, the current peak value in each alternating current period may be collected in chronological order as the output current of the output terminal 311 at a plurality of time points. Of course, in other embodiments, the average value (or the effective current value) of the current in each ac power cycle may be collected as the output current of the output terminal 311 at a plurality of time points according to the time sequence.

In the present embodiment, in the case where the output current of the output terminal 311 is greater than the current threshold, the output currents of the output terminal 311 at 5 time points are collected in chronological order, and it is determined whether the output current of the output terminal 311 gradually increases based on the output currents at the 5 time points.

In some embodiments, the control circuit 34 may be a control chip. The control circuit 34 is provided with a voltage abnormality flag and a current abnormality flag. When the output voltage of the output terminal 311 is less than the voltage threshold, setting the voltage abnormality flag to a value (e.g., 1) indicating voltage abnormality; when the output current of the output terminal 311 is greater than the current threshold and the output current of the output terminal 311 gradually increases, the current abnormality flag is set to a value (e.g., 1) representing the current abnormality. When the voltage abnormality flag and the current abnormality flag are both abnormal (e.g., 1), the control circuit 34 may perform short-circuit protection on the power circuit 300.

In this embodiment, when it is determined that the output voltage and the output current of the output terminal 311 satisfy the above-described conditions for short-circuit protection of the power supply circuit 300, the control circuit 34 may control the power supply circuit 31 to stop supplying power to the load 30, so as to perform short-circuit protection on the power supply circuit 300, and prevent the power supply circuit 300 from being damaged by a large current generated by the short-circuit of the load 30. It will be appreciated that the manner of short-circuit protection of the power circuit 300 includes, but is not limited to, stopping the power to the load 30 as described above, and the particular manner of short-circuit protection is not limited in this application.

In the technical solutions of some embodiments of the present application, the control circuit 34 of the power circuit 300 detects the output voltage of the output terminal 311 through the voltage detection circuit 32, and detects the output current of the output terminal 311 through the current detection circuit 33, where the output voltage of the output terminal 311 is smaller than the voltage threshold, and the output current of the output terminal 311 is greater than the current threshold, and the output current of the output terminal 311 gradually increases, the power circuit 300 is short-circuited. Since the output voltage and the output current of the output terminal 311 are simultaneously determined as the threshold value and the change condition of the output current are determined in the determination condition of the short-circuit protection, in this way, when the detected output current is greater than the current threshold value due to the superposition noise, the change condition of the output current and the magnitude of the output voltage can be combined to comprehensively determine whether the short-circuit protection needs to be performed on the power circuit 300, so as to prevent the short-circuit protection of the power circuit 300 from being triggered by mistake when the output current is greater than the current threshold value due to the superposition noise. In summary, the power circuit 300 of the present application can reduce the probability of false triggering of the short-circuit protection.

For example, referring to fig. 4 and 5, the output current detected at time t2 is greater than the current threshold due to the superimposed noise. In the solution shown in fig. 1, the short-circuit protection of the power supply circuit is triggered immediately at time t 2. As can be seen from the relevant description of fig. 1, this is a false-triggered short-circuit protection. In the technical scheme of the application, at the time t2, since the output voltage is not smaller than the voltage threshold and the output current is not gradually increased, even if the detected output current is larger than the current threshold, the short-circuit protection of the power circuit 300 is not triggered, and the probability of false triggering of the short-circuit protection in the power circuit 300 is further reduced.

Specifically, please refer to fig. 6, which is a circuit diagram of the power circuit 300 in fig. 3. In some embodiments, the power supply circuit 31 includes an input 312 and a transformer L32. The input end 312 is used for connecting to an ac power source (such as a mains supply), the primary side of the transformer L32 is connected to the input end 312, and the secondary side of the transformer L32 is connected to the output end 311. The working principle of the transformer L32 is similar to that of fig. 1 and is not described here again.

In some embodiments, the detection results of the current detection circuit 33 include a first detection result and a second detection result, wherein the first detection result is used to represent the output current of the output terminal 311, and the second detection result is used to represent whether the output current of the output terminal 311 is greater than a current threshold. The control circuit 34 is specifically configured to determine whether the output current of the output terminal 311 gradually increases according to the first detection results at a plurality of consecutive time points in a case where it is determined that the output current of the output terminal 311 is greater than the current threshold based on the second detection result.

Specifically, the current detection circuit 33 includes a current transformer L31, a rectifying circuit 33, and a comparing circuit U32. The current transformer L31 is connected to the rectifying circuit 331, the rectifying circuit 331 is connected to the control circuit 34, the current transformer L31 is configured to sense an output current of the output terminal 311, and output an ac voltage signal corresponding to the output current, and the rectifying circuit 331 is configured to convert the ac voltage signal into a unidirectional voltage signal, so as to obtain a first detection result. The comparison circuit U32 includes a first comparison input terminal a, a second comparison input terminal B, and a comparison output terminal C, where the first comparison input terminal a is connected to the rectification circuit 33, the comparison output terminal C is connected to the control circuit 34, the second comparison input terminal B is configured to receive a reference voltage signal representing a current threshold, and the comparison circuit U32 is configured to compare the unidirectional voltage signal output by the rectification circuit 33 with the reference voltage signal, and output a second detection result. The current transformer L31 may include a current transformer. The principle of the current transformer L31 detecting the output current, the rectification principle of the rectification current 331, and the comparison principle of the comparison circuit U32 are similar to those of fig. 1, and are not repeated here.

The main difference of the current detection circuit 33 in fig. 6 compared to fig. 1 is that: the first capacitor terminal 332 of the capacitor C31 is connected to the first comparison input terminal a of the control circuit 34 and the comparison circuit U32 at the same time, and is configured to output a first detection result to the control circuit 34 and the comparison circuit U32 at the same time, so that the control circuit 34 determines whether the output current of the output terminal 311 gradually increases based on the first detection result, and the comparison circuit U32 compares the first detection result with the reference voltage signal and outputs a second detection result.

In some embodiments, the voltage detection circuit 32 is connected to the output terminal 311 of the power supply circuit 31 for detecting the output voltage of the output terminal 311. The power supply circuit 31 may include a power supply capacitor C32 and a diode D1, and the output terminal 311 may include a first output terminal P1 and a second output terminal P2. The first end of the supply capacitor C32 is connected to the first output terminal P1 through the diode D1, and the second end of the supply capacitor C32 and the second output terminal P2 are grounded. A load may be connected between the first output terminal P1 and the second output terminal P2. Specifically, the first terminal of the power supply capacitor C32 may be connected to the anode of the diode D1, and the first output terminal P1 may be connected to the cathode of the diode D1. The voltage detection circuit 32 may detect the cathode voltage of the diode D1 as the output voltage of the power supply terminal 311. When the load is short-circuited, the cathode of the diode D1 is grounded, and the voltage gradually drops to 0; when the load is not shorted, the cathode of diode D1 is grounded through the load and the voltage may be above the voltage threshold. It is possible to determine whether the load is shorted by detecting whether the cathode voltage of the diode D1 is less than the voltage threshold.

In some embodiments, the voltage detection circuit 32 includes an amplifier U31, where the amplifier U31 is connected between the output terminal 311 and the control circuit 34, and is configured to amplify the output voltage of the output terminal 311 and output the amplified output voltage to the control circuit 34. Specifically, the positive input end of the amplifier U31 may be connected to the anode of the diode D1, the negative input end may be connected to the cathode of the diode D1, and the output end may be connected to the control circuit 34, so as to amplify the output voltage of the output end 311 and output the amplified output voltage to the control circuit 34.

In some embodiments, the power supply circuit 31 includes a switch 313. Switch 313 is connected between input 312 and the primary side of transformer L32. The control circuit 34 is connected to the switch 313. When the control circuit 34 determines that the output current and the output voltage of the output terminal 311 satisfy the above-described short-circuit protection condition, the control switch 313 is turned off to stop the power supply circuit 31 from supplying power to the load.

Corresponding to the power circuit 300, the present application also provides a short-circuit protection method of the power circuit 300. The short circuit protection method may be applied to the control circuit 34 of the power supply circuit 300. Referring to fig. 7, a flow chart of a short-circuit protection method according to an embodiment of the present application is shown.

In step S71, the output voltage of the output terminal 311 is detected by the voltage detection circuit 32, and the output current of the output terminal 311 is detected by the current detection circuit 33.

In some embodiments, the output current of output terminal 311 may be detected by current detection circuit 33 detecting the current at the primary side of transformer L32.

In step S72, when the power supply circuit 31 supplies power to the load 30, the power supply circuit 300 is short-circuited when it is determined that the following short-circuit protection conditions are satisfied based on the detection results of the current detection circuit 33 and the voltage detection circuit 32:

the output voltage of the output terminal 311 is less than the voltage threshold;

the output current of the output terminal 311 is greater than the current threshold, and the output current of the output terminal 311 gradually increases.

In some embodiments, the detection results of the current detection circuit 32 include a first detection result and a second detection result, wherein the first detection result is used for representing the output current of the output terminal 311, and the second detection result is used for representing whether the output current of the output terminal 311 is greater than a current threshold; wherein:

it may be determined whether the output current of the output terminal 311 is greater than a current threshold based on the first detection result, and in the case where the output current of the output terminal 311 is greater than the current threshold, it is determined whether the output current of the output terminal 311 gradually increases according to the first detection results at a plurality of consecutive time points.

For a description of the principle of the short-circuit protection method, reference may be made to the related description of the power supply circuit 300, which is not repeated here.

Referring to fig. 8, a schematic block diagram of a power supply apparatus 800 according to an embodiment of the present application is provided. The power supply apparatus 800 includes the above-described power supply circuit 300. For a description of the beneficial effects of the power supply device 800, reference may be made to the related description of the power supply circuit 300, which is not repeated here.

Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.

Claims (10)

1. A power supply circuit, the power supply circuit comprising:

the power supply circuit comprises an output end, wherein the output end is used for being connected with a load;

the voltage detection circuit is used for detecting the output voltage of the output end;

the current detection circuit is used for detecting the output current of the output end;

the control circuit is connected with the current detection circuit and the voltage detection circuit and is used for carrying out short-circuit protection on the power supply circuit when the power supply circuit supplies power to the load according to detection results of the current detection circuit and the voltage detection circuit and when the following short-circuit protection conditions are met:

the output voltage of the output end is smaller than a voltage threshold value;

the output current of the output end is larger than the current threshold value, and the output current of the output end is gradually increased.

2. The circuit of claim 1, wherein the detection results of the current detection circuit comprise a first detection result and a second detection result, wherein the first detection result is used for representing the output current magnitude of the output terminal, and the second detection result is used for representing whether the output current of the output terminal is greater than the current threshold;

the control circuit is specifically configured to determine, based on the second detection result, whether the output current of the output terminal gradually increases according to the first detection results of a plurality of consecutive time points when it is determined that the output current of the output terminal is greater than the current threshold.

3. The circuit of claim 2, wherein the current detection circuit comprises a current transformer and a rectification circuit, the current transformer is connected with the rectification circuit, the rectification circuit is connected with the control circuit, the current transformer is used for sensing the output current of the output end and outputting an alternating voltage signal corresponding to the output current, and the rectification circuit is used for converting the alternating voltage signal into a unidirectional voltage signal to obtain the first detection result.

4. A circuit as claimed in claim 3, wherein the current detection further circuit comprises a comparison circuit comprising a first comparison input connected to the rectifying circuit, a second comparison input connected to the control circuit, and a comparison output for receiving a reference voltage signal indicative of the current threshold, the comparison circuit being arranged to compare the unidirectional voltage signal output by the rectifying circuit with the reference voltage signal and to output the second detection result.

5. A circuit as claimed in claim 3, wherein the power supply circuit comprises an input for connection to an ac power source and a transformer, the primary side of the transformer being connected to the input and the secondary side of the transformer being connected to the output;

the current transformer is connected with the primary side of the transformer and is used for detecting the output current of the output end by sensing the current of the primary side.

6. The circuit of claim 1, wherein the voltage detection circuit comprises an amplifier connected between the output terminal and the control circuit for amplifying the output voltage of the output terminal and outputting the amplified output voltage to the control circuit.

7. The short-circuit protection method of the power supply circuit is characterized in that the power supply circuit comprises a power supply circuit, a voltage detection circuit and a current detection circuit, and the power supply circuit comprises an output end for connecting a load; the method comprises the following steps:

detecting an output voltage of the output terminal by the voltage detection circuit, and detecting an output current of the output terminal by the current detection circuit;

when the power supply circuit supplies power to the load, according to detection results of the current detection circuit and the voltage detection circuit, when the following short-circuit protection conditions are met, the power supply circuit is subjected to short-circuit protection:

the output voltage of the output end is smaller than a voltage threshold value;

the output current of the output end is larger than the current threshold value, and the output current of the output end is gradually increased.

8. The method of claim 7, wherein the detection results of the current detection circuit comprise a first detection result and a second detection result, wherein the first detection result is used to characterize the output current magnitude of the output terminal, and the second detection result is used to characterize whether the output current of the output terminal is greater than the current threshold; wherein:

determining whether the output current of the output terminal is greater than a current threshold based on the first detection result, and determining whether the output current of the output terminal gradually increases according to the first detection results of a plurality of continuous time points in the case that the output current of the output terminal is greater than the current threshold.

9. The method of claim 7, wherein the power circuit comprises an input terminal for connection to an ac power source and a transformer, a primary side of the transformer being connected to the input terminal, a secondary side of the transformer being connected to the output terminal;

the detecting, by the current detecting circuit, the output current of the output terminal includes:

and detecting the current of the primary side of the transformer by the current detection circuit to detect the output current of the output end.

10. A power supply apparatus, characterized in that the power supply apparatus comprises the power supply circuit as claimed in any one of claims 1 to 6.

Images