CN217984500U

CN217984500U - Power supply circuit

Info

Publication number: CN217984500U
Application number: CN202221456766.7U
Authority: CN
Inventors: 温亚远; 侯佳音; 解梅; 孙九明
Original assignee: Shanghai Jusheng Technology Co Ltd
Current assignee: Shanghai Jusheng Technology Co Ltd
Priority date: 2022-06-09
Filing date: 2022-06-09
Publication date: 2022-12-06
Anticipated expiration: 2032-06-09

Abstract

A power supply circuit is disclosed. The first resistor and the controlled switch are connected in series between a first voltage source and a ground terminal to form a control signal generating circuit, the sampling circuit obtains a sampling signal, and the comparison circuit controls the controlled switch to be switched on or switched off according to the sampling signal and a reference signal so as to control the main loop switch. Therefore, when the power supply circuit is in overcurrent, the main loop switch is controlled to be switched off so as to cut off the electric connection between the power supply and the power supply equipment, the influence on the power supply circuit when the capacitor is in short circuit can be reduced, the original high-cost capacitor can be replaced by the capacitor with lower cost, and the cost of the capacitor in the circuit is reduced.

Description

Power supply circuit

Technical Field

The utility model relates to a power electronic technology field especially relates to a power supply circuit.

Background

With the development of science and technology, electronic devices play an important role in various fields such as life and production of people. Since hardware systems of electronic devices require various power sources for power supply, the design of power supply circuits is particularly important in order to improve the safety performance and the service life of the electronic devices, and the prevention of ceramic capacitor breakage is a very important design of the power supply circuits.

In the prior art, in order to prevent the ceramic capacitor from being broken, a large-capacity capacitor is generally replaced by a flexible terminal capacitor, and a small-capacity capacitor is replaced by two small capacitors connected in series. However, the cost of the flexible terminal capacitor is high, the cost is increased by replacing a large-capacity capacitor with the flexible terminal capacitor, and meanwhile, the number of capacitors is increased by replacing a small-capacity capacitor with two small capacitors connected in series, and the circuit cost is also increased.

SUMMERY OF THE UTILITY MODEL

In view of this, an object of the embodiments of the present invention is to provide a power supply circuit, which can reduce the cost of capacitors in the circuit.

In a first aspect, an embodiment of the present invention provides a power supply circuit, the power supply circuit includes:

a power source;

at least one consumer;

a main circuit switch connected between the power supply and the electric equipment; and

an overcurrent protection circuit;

wherein, the overcurrent protection circuit includes:

the control signal generating circuit comprises a first resistor and a controlled switch, wherein the first resistor and the controlled switch are connected between a first voltage source and a ground terminal in series;

a sampling circuit configured to obtain a sampled signal characterizing a current between the power source and the powered device; and

and the comparison circuit is connected with the sampling circuit and is configured to control the controlled switch to be switched on or switched off according to the sampling signal and the reference signal so as to control the control signal generation circuit to output a control signal, and the control signal is used for controlling the main loop switch.

In some embodiments, one end of the first resistor is connected to the first voltage source, the other end of the first resistor is connected to the controlled switch, and the other end of the controlled switch is grounded.

In some embodiments, the control signal generation circuit further comprises:

a control signal output terminal connected between the first resistor and the controlled switch, configured to output the control signal.

In some embodiments, the sampling circuit comprises:

a second resistor connected between the power source and the electric device; and

and the first amplifier comprises a first input end and a second input end, and the first input end and the second input end are respectively connected to two ends of the second resistor.

In some embodiments, the comparison circuit comprises:

a second amplifier comprising a first input terminal, a second input terminal, and an output terminal;

a third resistor connected between the output of the sampling circuit and the first input of the second amplifier;

a fourth resistor connected between a second voltage source and a second input terminal of the second amplifier, the second voltage source for outputting a reference signal;

a fifth resistor connected between the first input terminal and the output terminal of the second amplifier;

a sixth resistor connected between the second input terminal of the second amplifier and a ground terminal; and

and the seventh resistor is connected to the output end of the second amplifier.

In some embodiments, the second amplifier is configured to output a low level signal in response to the sampling signal being less than a first threshold, and control the controlled switch to turn off, so that the control signal generation circuit generates a first control signal to control the main loop switch to turn on.

In some embodiments, the second amplifier is configured to output a high level signal to control the controlled switch to be turned on in response to the sampling signal increasing to be greater than or equal to a first threshold value, so that the control signal generation circuit generates a second control signal to control the main loop switch to be turned off.

In some embodiments, the second amplifier is configured to output a low level signal in response to the sampling signal decreasing to less than or equal to a second threshold, and control the controlled switch to turn off, so that the control signal generation circuit generates a first control signal to control the main loop switch to turn on;

wherein the second threshold is less than or equal to the first threshold.

In some embodiments, the power supply circuit further comprises:

the first filter circuit is connected to the output end of the power supply;

wherein the first filter circuit comprises:

the first capacitor is connected between the output end of the power supply and the grounding end;

a second capacitor; and

a third capacitor connected in series with the second capacitor between an output terminal of the power supply and a ground terminal;

wherein the first capacitor is a flexible terminal capacitor.

In some embodiments, the power supply circuit further comprises:

and the reverse connection prevention protection circuit is connected between the main loop switch and the power supply.

In some embodiments, the power supply circuit further comprises:

the second filter circuit is connected to the output end of the reverse connection prevention protection circuit;

wherein the second filter circuit comprises:

the fourth capacitor is connected between the output end of the power supply and the grounding end;

a fifth capacitor; and

the sixth capacitor is connected with the fifth capacitor in series between the output end of the power supply and the ground end;

wherein the fourth capacitor is a flexible terminal capacitor.

In some embodiments, the power supply circuit further comprises:

the third filter circuit is connected to the output end of the main loop switch;

wherein the third filter circuit comprises:

the seventh capacitor is connected between the output end of the main loop switch and the grounding end; and

the eighth capacitor is connected between the output end of the main loop switch and the grounding end;

wherein the seventh capacitor is a ceramic capacitor.

The utility model discloses technical scheme forms control signal generating circuit through first resistance and controlled switch series connection between first voltage source and earthing terminal to acquire sampling signal through sampling circuit, comparison circuit switches on or cuts off according to sampling signal and reference signal control controlled switch, with control major loop switch. Therefore, when the power supply circuit is in overcurrent, the main loop switch is controlled to be switched off so as to cut off the electric connection between the power supply and the power supply equipment, the influence on the power supply circuit when the capacitor is in short circuit can be reduced, the original high-cost capacitor can be replaced by the capacitor with lower cost, and the cost of the capacitor in the circuit is reduced.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

fig. 1 is a schematic view of a power utilization system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a prior art power supply circuit;

fig. 3 is a schematic diagram of a power supply circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a power supply circuit according to another embodiment of the present invention.

Detailed Description

The present invention will be described below based on examples, but the present invention is not limited to only these examples. In the following detailed description of the present invention, certain specific details are set forth. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details. Well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

Further, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.

Meanwhile, it should be understood that, in the following description, a "circuit" refers to a conductive loop constituted by at least one element or sub-circuit through electrical or electromagnetic connection. When an element or circuit is referred to as being "connected to" another element or element/circuit is referred to as being "connected between" two nodes, it may be directly coupled or connected to the other element or intervening elements may be present, and the connection between the elements may be physical, logical, or a combination thereof. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, it is intended that there are no intervening elements present.

Unless the context clearly requires otherwise, throughout the description, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, what is meant is "including, but not limited to".

In the description of the present invention, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

With the development of science and technology, electronic devices play an important role in various fields such as life and production of people. For example, in the field of intelligent cockpit of a vehicle, people have higher dependence on an intelligent cockpit entertainment system, and the design of cockpit host hardware is more and more important. Here, the design of the power supply is particularly important, in particular, the short-circuit phenomenon is not allowed to occur, wherein the prevention of the ceramic capacitor from breaking on the battery rail is a very important design.

Fig. 1 is a schematic diagram of an electricity utilization system according to an embodiment of the present invention. In the embodiment shown in fig. 1, the powered system comprises a power source 1, at least one primary loop and at least one powered device.

In the present embodiment, each main loop connects the power source 1 and the corresponding electric device, so that the power source 1 supplies power to each electric device through the main loop.

In the embodiment shown in fig. 1, the number of the main loops may be one or multiple, and this embodiment is described by taking the number of the main loops as an example, specifically, the power utilization system includes n main loops, which are L1, L2, … …, ln respectively, where n is a positive integer greater than or equal to 2.

The number of the electric devices may be one or more, and this embodiment will be described by taking the number of the electric devices as an example. Specifically, the number of the electric devices connected to the main loop L1 is p, and the p are E1, E2, … …, ep and p are positive integers greater than or equal to 2. The number of the electric equipment connected with the main loop L2 is q, and the electric equipment is F1, F2, … …, and Fq and q are positive integers more than or equal to 2. The number of the electric equipment connected with the main loop Ln is r, and the electric equipment is G1, G2, … …, gr and r are positive integers which are more than or equal to 2.

Above-mentioned electrical system can be applicable to current various consumer or electrical system, the embodiment of the utility model provides an use the electrical system to explain for car intelligence passenger cabin as the example, wherein, the consumer is the various consumer in car intelligence passenger cabin. As a result, the number of electric devices is large in the entire electric system.

Fig. 2 is a schematic diagram of a prior art power supply circuit. In the embodiment shown in fig. 2, the power supply circuit includes a power source 11, a reverse-connection prevention protection circuit 12, a main loop switch 13, and a powered device 14. The power supply 11 supplies power to the electric equipment 14 through the reverse connection prevention protection circuit 12 and the main loop switch 13.

Further, the reverse-connection prevention protection circuit 12 is used for preventing the reverse-connection condition of the circuit.

The main circuit switch 13 is used to control the electrical connection between the power source 11 and the electrical consumer 14, i.e., to control the electrical consumer to be powered on or off. When the main circuit switch 13 is turned on, the power supply 11 supplies power to the electric equipment 14, so that the electric equipment 14 works normally, and when the main circuit switch 13 is turned off, the circuit between the power supply 11 and the electric equipment 14 is disconnected, and the electric equipment 14 stops working.

Further, the power supply circuit further comprises a plurality of capacitors.

Specifically, the capacitors Ca1, ca2, and Ca3 are used to filter the output signal of the power supply 11. The capacitor Ca1 is connected between the output terminal of the power supply 11 and the ground terminal, and the capacitors Ca2 and Ca3 are connected in series between the output terminal of the power supply 11 and the ground terminal. The capacitor Ca1 is a large capacitor of the flexible terminal, and the capacitors Ca2 and Ca3 are small capacitors.

The capacitors Cb1, cb2, and Cb3 are used to filter the output signal of the reverse connection protection circuit 12. The capacitor Cb1 is connected between the output terminal of the reverse connection prevention protection circuit 12 and the ground terminal, and the capacitors Cb2 and Cb3 are connected in series between the output terminal of the reverse connection prevention protection circuit 12 and the ground terminal. The capacitor Cb1 is a large capacitor of the flexible terminal, and the capacitors Cb2 and Cb3 are small capacitors.

The capacitors Cd1, cd2, and Cd3 are used for filtering the output signal of the main circuit switch 13. The capacitor Cd1 is connected between the output end of the main circuit switch 13 and the ground terminal, and the capacitors Cd2 and Cd3 are connected in series between the output end of the main circuit switch 13 and the ground terminal. The capacitor Cd1 is a large capacitor of a flexible terminal, and the capacitors Cd2 and Cd3 are small capacitors.

The capacitors Ca1, ca2, ca3, cb1, cb2, cb3, the reverse connection preventing circuit 12, and the main circuit switch 13 may be regarded as the main circuit switch in fig. 1.

When above-mentioned electric capacity Ca1, ca2, ca3, cb1, cb2, cb3, cd1, cd2 and Cd3 adopt ordinary ceramic capacitor, because ordinary ceramic capacitor breaks easily and the short circuit, and then lead to 11 direct grounds of power, combine the system shown in figure 1, when 11 direct grounds of power, may damage the power, or, the protection circuit who sets up in the power 11 can the output of disconnect-type power, at this moment, all consumer connected with power 11 can stop working, under some occasions, can arouse comparatively serious consequence.

Thus, in the prior art shown in fig. 2, the capacitors Ca1, cb1, and Cd1 are large capacitors with flexible terminals, so as to reduce the occurrence of capacitor rupture. Meanwhile, through the serial connection of the capacitors Ca2 and Ca3, the serial connection of the capacitors Cb2 and Cb3 and the serial connection of the capacitors Cd2 and Cd3, even if one of the capacitors is broken and short-circuited, the power supply can not be directly grounded.

With reference to the prior art of fig. 1, each electric device needs capacitors Cd1, cd2, and Cd3 before, wherein Cd1 is a large capacitor with a flexible terminal, and the cost is high, and the capacitors Cd2 and Cd3 are small capacitors but the number of the capacitors is large, which also increases the cost. Therefore, the utility model discloses to this kind of condition, provided a can reduce the overcurrent protection circuit of electric capacity cost.

Since the power supply circuit between each powered device and the power source is substantially identical, for convenience of illustration, fig. 3 shows a schematic diagram of the power supply circuit according to an embodiment of the present invention. In the embodiment shown in fig. 2, the power supply circuit includes a power supply 1, an anti-reverse connection protection circuit 2, a main loop switch 3, a powered device 4, and an overcurrent protection circuit 5. The power supply 1 supplies power to the electric equipment 4 through the reverse connection prevention protection circuit 2 and the main loop switch 3.

In the present embodiment, the power source 1 may be various forms of power sources, such as a battery, a dry battery, an external power supply, and the like. The external power supply may be 220V or 380V ac mains, or may be various power generation devices (e.g., a solar power generator, a hydroelectric power generator, a wind power generator, etc.).

In the present embodiment, the reverse-connection prevention protection circuit 2 prevents the circuit from being reverse-connected. If the circuit is reversely connected, the situations of circuit short circuit and the like can occur, so that the circuit is damaged and unnecessary loss is brought, and therefore, the reverse connection of the circuit can be prevented through the reverse connection prevention protection circuit 2. In particular, it can be implemented by various existing methods.

For example, the reverse-connection protection circuit 2 may employ an error-proof connector to prevent the circuit from being reversed. For another example, the reverse connection protection circuit 2 may be implemented by a diode, and reverse connection protection is performed by using a unidirectional conduction characteristic of the diode, and when reverse connection occurs, the diode is turned off. For another example, the reverse connection prevention protection circuit 2 may also be implemented by a rectifier bridge, and the reverse connection protection may be implemented by the rectifier bridge, and on the other hand, the circuit can work normally regardless of whether the circuit is connected in the forward direction or in the reverse direction. Also for example, the controlled switch may be implemented by a controlled switch, and the controlled switch is reasonably arranged in the circuit, so that when the circuit is reversely connected, the controlled switch is turned off, wherein the controlled switch may be a MOSFET (Metal-Oxide-Semiconductor Transistor), a Bipolar Junction Transistor (BJT), an Insulated Gate Bipolar Transistor (IGBT), or the like.

In this embodiment, the main circuit switch 3 is connected between the power supply 1 and the electric device 4, and when the main circuit switch 3 is turned on, the power supply 1 supplies power to the electric device 4 through the reverse connection prevention protection circuit 2 and the main circuit switch 3. When the main circuit switch 3 is turned off, the power supply 1 stops supplying power to the electric device 4.

Further, the main circuit switch 3 may be implemented by various existing switching devices controlled to be turned on or off, for example, electronic elements such as MOSFET, BJT or IGBT, and also implemented by switching devices such as relay.

In this embodiment, the overcurrent protection circuit 5 is configured to obtain a sampling signal representing a current between the power supply and the electrical device, and generate a control signal according to the sampling signal and a reference signal to control the main loop switch 3 to be turned on or off.

Further, the over-current protection circuit 5 is configured to control the main loop switch 3 to be turned off to stop supplying power to the electric device 4 when the current between the power source 1 and the electric device 4 is over-current.

In this embodiment, the power supply circuit further includes a first filter circuit, a second filter circuit, and a third filter circuit.

Specifically, the first filter circuit includes a first capacitor C1, a second capacitor C2, and a third capacitor C3, and is configured to filter an output signal of the power supply 1. The first capacitor C1 is connected between the output terminal of the power supply 1 and the ground terminal, and the second capacitor C2 and the third capacitor C3 are connected in series between the output terminal of the power supply 1 and the ground terminal. The first capacitor C1 is a large capacitor of the flexible terminal, and the second capacitor C2 and the third capacitor C3 are small capacitors. Therefore, the condition that the capacitor is broken can be reduced through the large capacitor of the flexible terminal, even if one of the capacitors is broken and short-circuited in a mode of connecting the small capacitors in series, the power supply can not be directly grounded, and the influence of the broken capacitor on a circuit can be reduced.

Specifically, the second filter capacitor includes a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6, and is configured to filter the output signal of the reverse connection protection circuit 2. The fourth capacitor C4 is connected between the output end of the reverse connection prevention protection circuit 2 and the ground end, and the fifth capacitor C5 and the sixth capacitor C6 are connected between the output end of the reverse connection prevention protection circuit 2 and the ground end in series. The fourth capacitor C4 is a large capacitor of the flexible terminal, and the fifth capacitor C5 and the sixth capacitor C6 are small capacitors. Therefore, the condition that the capacitor is broken can be reduced through the large capacitor of the flexible terminal, even if one of the capacitors is broken and short-circuited in a mode of connecting the small capacitors in series, the power supply can not be directly grounded, and the influence of the broken capacitor on a circuit can be reduced.

The seventh capacitor C7 and the eighth capacitor C8 are used for filtering the output signal of the main circuit switch 3. The seventh capacitor C7 is connected between the output terminal of the main circuit switch 3 and the ground terminal, and the eighth capacitor C8 is connected in series between the output terminal of the main circuit switch 3 and the ground terminal. The seventh capacitor C7 is a common large-capacity capacitor, and the eighth capacitor C8 is a small capacitor.

In some embodiments, to further save cost, for the capacitors C4, C5 and C6, the capacitor C4 may be replaced by a common large-capacity capacitor, and the series circuit of C5 and C6 may be replaced by a small-capacity capacitor.

Further, the utility model discloses ordinary large capacity electric capacity can be ceramic capacitor etc..

Further, the reverse connection prevention protection circuit 2, the main circuit switch 3, and the overcurrent protection circuit 5 and the capacitors C1, C2, C3, C4, C5, and C6 in fig. 3 may be regarded as the main circuit in fig. 1.

Therefore, the capacitor in front of the electric equipment is replaced by the common large-capacity capacitor from the large capacitor of the flexible terminal, and the capacitor cost can be reduced by replacing the mode of connecting two small capacitors in series by one small capacitor. Meanwhile, by arranging the protection circuit, when the overcurrent of the current between the power supply and the electric equipment is detected, the main loop switch is controlled to be turned off so as to stop supplying power to the electric equipment. Therefore, only the power supply of the main loop is short-circuited, and the electric equipment connected with other main loops can still work normally, thereby providing the safety performance of the system.

The embodiment of the utility model provides a through setting up protection circuit for when protection circuit current between power and consumer overflows, control major loop switch turn-offs, in order to stop to supply power for the consumer. The capacitor in front of the electric equipment can be made to be a common large-capacity capacitor, and the circuit cost can be reduced by reducing the number of small-capacity capacitors.

Further, fig. 4 is a schematic diagram of a power supply circuit according to another embodiment of the present invention. In the embodiment shown in fig. 4, the power supply circuit includes a power supply 1, an anti-reverse connection protection circuit 2, a main loop switch 3, a powered device 4 and an overcurrent protection circuit 5. The power supply 1 supplies power to the electric equipment 4 through the reverse connection prevention protection circuit 2 and the main loop switch 3.

In this embodiment, the specific implementation manners of the power supply 1, the reverse connection protection circuit 2, the main circuit switch 3 and the electric device 4 can be described with reference to fig. 3, and the embodiment of the present invention is not described herein again.

In the present embodiment, the overcurrent protection circuit 5 includes a sampling circuit 51, a comparison circuit 52, and a control signal generation circuit 53. Wherein the sampling circuit is configured to obtain a sampled signal that is used to characterize a current between the power source and the powered device. The comparison circuit 52 is connected to the sampling circuit 51, and configured to control the controlled switch to be turned on or off according to the sampling signal and the reference signal, so as to control the control signal generation circuit 53 to output a control signal, where the control signal is used to control the main loop switch 3.

In this embodiment, the sampling circuit includes a second resistor R2 and a first amplifier U1. The second resistor R2 is connected in the main loop and is used for obtaining the current of the main loop. In the embodiment shown in fig. 2, the main loop current is the current between the power source 1 and the consumer 4.

Further, a second resistor R2 is connected between the power supply 1 and the reverse connection prevention protection circuit 2.

It should be understood that the embodiment of the present invention does not limit the connection position of the second resistor R2, and the second resistor R2 may also be connected at other positions of the main circuit, for example, the second resistor R2 may be connected between the reverse connection prevention protection circuit 2 and the main circuit switch 3.

Further, the non-inverting input terminal of the first amplifier U1 is connected between the second resistor R2 and the power supply 1, and the inverting input terminal of the first amplifier U1 is connected between the second resistor R2 and the reverse protection circuit 2. That is, the input signals of the non-inverting input terminal and the inverting input terminal of the first amplifier U1 are the voltages at the two ends of the second resistor R2, respectively. Since the output signal of the operational amplifier is proportional to the difference between the signal voltages of the two input terminals, the output signal of the first amplifier U1 is proportional to the current flowing through the second resistor R2. Therefore, a signal proportional to the main loop current, i.e., the sampling signal Vs, can be obtained through the second resistor R2 and the first amplifier U1.

In this embodiment, the comparison circuit 52 is a hysteresis comparison circuit, and is configured to control the controlled switch to be turned on or off according to the sampling signal Vs and the reference signal V2, so as to control the control signal generation circuit 53 to output a control signal Vc, where the control signal Vc is used for controlling the main loop switch 3. The comparison circuit 52 includes a second amplifier U2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a second voltage source 52a. The control signal Vc includes a first control signal Vc1 and a second control signal Vc2, the first control signal Vc1 is a low-level signal, and the second control signal Vc2 is a high-level signal.

Further, the second amplifier U2 is configured to output a low level signal in response to the sampling signal Vs being smaller than the first threshold Vh1, and control the controlled switch Q1 to be turned off, so that the control signal generating circuit 53 generates the first control signal Vc1 to control the main loop switch 3 to be turned on. The first control signal Vc1 is a low level signal.

The second amplifier U2 is further configured to output a high level signal in response to the sampling signal Vs increasing to be greater than or equal to the first threshold Vh1, and control the controlled switch Q1 to be turned on, so that the control signal generating circuit 53 generates a second control signal Vc2 to control the main loop switch 3 to be turned off.

The second amplifier U2 is further configured to output a low level signal in response to the sampling signal Vs decreasing to be less than or equal to a second threshold Vh2, and control the controlled switch Q1 to turn off, so that the control signal generating circuit 53 generates a first control signal Vc1 to control the main loop switch 3 to turn on.

The first threshold is an upper threshold, the second threshold is a lower threshold, and the second threshold is smaller than or equal to the first threshold.

Specifically, the second amplifier U2 includes a first input, a second input, and an output. In fig. 4, the first input terminal is a non-inverting input terminal, and the second input terminal is an inverting input terminal.

A third resistor R3 is connected between the output of the sampling circuit 51 and the first input of the second amplifier U2.

A fourth resistor R4 is connected between the second voltage source 52a and the second input of said second amplifier U2.

The second voltage source 52a is used to output the reference signal V2.

In some embodiments, the second voltage source 52a may be implemented by a DC-DC (direct current-direct current) converter, which converts the output signal of the power supply 1 into the reference voltage V2.

The sixth resistor R6 is connected between the second input terminal of the second amplifier U2 and the ground terminal, and forms a series circuit with the fourth resistor R4, and the voltage value input to the second input terminal of the second amplifier U2 can be adjusted by setting the resistance values of the fourth resistor R4 and the sixth resistor R6.

A fifth resistor R5 is connected between the first input and the output of the second amplifier.

The sixth resistor R6 is connected between the second input terminal of the second amplifier and ground.

A seventh resistor R7 is connected to the output of the second amplifier.

Therefore, the second amplifier U2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the second voltage source 52a form a hysteretic comparator, when the reference signal Vs gradually increases or decreases, two unequal thresholds exist, and the transmission characteristic has the shape of a hysteretic curve, so that the power amplifier has strong interference resistance. For the comparison circuit in fig. 4, the first threshold and the second threshold are respectively:

where Uh1 is the first threshold and Uref is the input voltage of the second input of the second amplifier U2.

Where Uh1 is the second threshold and Uref is the input voltage at the second input of the second amplifier U2.

The aforementioned Uol and Uoh are determined by the parameters of the second amplifier and the input voltage. Specifically, assuming that the output swing of the second amplifier is 0V to (Vcc-1.5V) and the input voltage Vcc of the second amplifier is 6V, uol is 0V and Uoh is (Vcc-1.5V) equal to 4.5V.

The input voltage Uref at the second input terminal of the second amplifier U2 is determined according to the reference voltage V2, the fourth resistor R4 and the sixth resistor R6, and the specific calculation formula is as follows:

wherein, V2 is the reference voltage output by the second voltage source.

Therefore, as can be seen from the above formula, the first threshold value and the second threshold value are related to the resistance values of the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6, and therefore, the first threshold value and the second threshold value can be adjusted to reasonable values by adjusting the resistance values of the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6.

When the voltage value of the sampling signal Vs gradually changes from large to small, the second amplifier output is switched from a high level to a low level when the sampling signal Vs decreases to Uh2. When the voltage value of the sampling signal Vs changes gradually from small to large, the second amplifier output is switched from low level to high level when the sampling signal Vs increases to Uh 1. Wherein Uh1 is greater than or equal to Uh2. When Uh1 is greater than Uh2, a threshold interval (Uh 2, uh 1) is formed in which the output signal of the second amplifier is kept constant, thereby preventing repeated false triggering.

Specifically, the current in the main loop is zero before the power supply circuit starts to operate. When the power supply circuit starts to work, the current in the main loop is gradually increased, and when the sampling signal Vs is increased to Uh1, the output of the second amplifier is switched from low level to high level. That is, the second amplifier U2 is configured to output a low level signal in response to the sampling signal Vs being less than the first threshold Vh1, and to output a high level signal in response to the sampling signal Vs increasing to be greater than or equal to the first threshold Vh 1. Thus, when the power supply circuit is subjected to an overcurrent due to a short circuit or the like, the second amplifier U2 outputs a high level signal in response to the increase of the sampling signal Vs to be greater than or equal to the first threshold Vh1, and controls the controlled switch Q1 to be turned on, so that the control signal generation circuit 53 generates the second control signal Vc2 to control the main loop switch 3 to be turned off. At this time, since the main circuit switch 3 is turned off, the current in the main circuit gradually decreases, and when the current decreases to be less than or equal to the second threshold Vh2, a low level signal is output to control the controlled switch Q1 to be turned off, so that the control signal generating circuit 53 generates the first control signal Vc1 to control the main circuit switch 3 to be turned on.

In this embodiment, the control signal generating circuit 53 includes a first voltage source 53a, a first resistor R1, and a controlled switch Q1, and the first resistor R1 and the controlled switch Q1 are connected in series between the first voltage source 53a and the ground.

The first voltage source 53a is used to output a first voltage V1.

In some embodiments, the first voltage source 53a may be implemented by a DC-DC (direct current-direct current) converter, which converts the output signal of the power supply 1 into the first voltage V1.

In some embodiments, to further reduce the components of the circuit, saving cost, the first voltage source 53a and the second voltage source 52a may be the same voltage source. Further, the first voltage source 53a and the second voltage source 52a may be power supply voltage sources of respective modules in the circuit, for example, the first voltage source 53a and the second voltage source 52a may be power supply voltage sources of an MCU (micro controller Unit), which may be 3.3V, 5V, 12V, or the like.

Further, the controlled switch Q1 is configured to be turned on when the input signal is at a high level and turned off when the input signal is at a low level.

Specifically, the present embodiment is described by taking the controlled switch Q1 as a MOSFET (Metal-Oxide-Semiconductor Transistor) as an example. It should be understood that a Bipolar Junction Transistor (BJT) or an Insulated Gate Bipolar Transistor (IGBT) may also be applicable to the technical solution of the embodiments of the present invention.

Further, the control signal generating circuit 53 further includes a control signal output terminal P connected between the first resistor R1 and the controlled switch Q1, and configured to output the control signal Vc.

In the present embodiment, the main circuit switch 3 is configured to be turned on at a high level.

Thus, the current in the main loop is zero before the power supply circuit starts to operate. When the power supply circuit starts to work, the current in the main loop is gradually increased, when the power supply circuit normally works, the current in the main loop is always smaller than a first threshold Vh1, the output signal of the second amplifier is low level, at the moment, the controlled switch Q1 is turned off, the first voltage output by the first voltage source is output to the control signal output end P through the first resistor R1, at the moment, the control signal Vc output by the control signal output end P is high level, the main loop switch 3 is turned on, and the power supply 1 normally supplies power for the electric equipment 4. When the current of the main circuit increases due to a short circuit or the like, the sampling signal Vs output by the first amplifier also increases, and when Vs increases to the upper threshold Uh1, the output signal of the second amplifier switches from a low level to a high level. At this time, the controlled switch Q1 is turned on, the control signal output end P is grounded, the output control signal Vc is at a low level, the main circuit switch 3 is turned off, and the power supply 1 is cut off to supply power to the electric equipment 4.

Therefore, when the power supply circuit is in overcurrent, the overcurrent protection circuit disconnects the main loop switch to stop the power supply to supply power to the electric equipment, so that the influence on the power supply circuit when the capacitor is short-circuited can be reduced, the original high-cost capacitor can be replaced by the capacitor with lower cost, and the cost of the capacitor in the circuit is reduced.

The embodiment of the utility model provides a form control signal generating circuit through first resistance and controlled switch series connection between first voltage source and earthing terminal to acquire sampling signal through sampling circuit, comparison circuit switches on or cuts off according to sampling signal and the controlled switch of reference signal control, with control major loop switch. Therefore, when the power supply circuit is in overcurrent, the main loop switch is controlled to be switched off so as to cut off the electric connection between the power supply and the power supply equipment, the influence on the power supply circuit when the capacitor is in short circuit can be reduced, the original high-cost capacitor can be replaced by the capacitor with lower cost, and the cost of the capacitor in the circuit is reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A power supply circuit, characterized in that the power supply circuit comprises:

a power source;

at least one consumer;

an overcurrent protection circuit;

wherein, the overcurrent protection circuit includes:

and the comparison circuit is connected with the sampling circuit and is configured to control the controlled switch to be switched on or switched off according to the sampling signal and a reference signal so as to control the control signal generation circuit to output a control signal, and the control signal is used for controlling the main loop switch.

2. The power supply circuit of claim 1, wherein one end of the first resistor is connected to the first voltage source, the other end of the first resistor is connected to the controlled switch, and the other end of the controlled switch is grounded.

3. The power supply circuit of claim 2, wherein the control signal generation circuit further comprises:

4. The power supply circuit of claim 1, wherein the sampling circuit comprises:

5. The power supply circuit of claim 1, wherein the comparison circuit comprises:

6. The power supply circuit of claim 5, wherein the second amplifier is configured to output a low level signal in response to the sampling signal being less than a first threshold, and to control the controlled switch to turn off, such that the control signal generation circuit generates a first control signal to control the main loop switch to turn on.

7. The power supply circuit of claim 5, wherein the second amplifier is configured to output a high level signal to control the controlled switch to turn on in response to the sampling signal increasing to be greater than or equal to a first threshold value, so that the control signal generation circuit generates a second control signal to control the main loop switch to turn off.

8. The power supply circuit according to claim 5 or 6, wherein the second amplifier is configured to output a low level signal in response to the sampling signal decreasing to be less than or equal to a second threshold value, and control the controlled switch to be turned off, so that the control signal generating circuit generates a first control signal to control the main loop switch to be turned on;

wherein the second threshold is less than or equal to the first threshold.

9. The power supply circuit of claim 1, further comprising:

the first filter circuit is connected to the output end of the power supply;

wherein the first filter circuit comprises:

a second capacitor; and

the third capacitor is connected with the second capacitor in series between the output end of the power supply and the ground end;

wherein the first capacitor is a flexible terminal capacitor.

10. The power supply circuit of claim 1, further comprising:

11. The power supply circuit of claim 10, further comprising:

wherein the second filter circuit comprises:

a fifth capacitor; and

the sixth capacitor and the fifth capacitor are connected between the output end of the power supply and the ground end in series;

wherein the fourth capacitor is a flexible terminal capacitor.

12. The power supply circuit of claim 1, further comprising:

wherein the third filter circuit comprises:

wherein the seventh capacitor is a ceramic capacitor.