CN217789541U - Power supply circuit and power supply device - Google Patents

Abstract

The application discloses a power supply circuit and power supply equipment, wherein the power supply circuit comprises a voltage conversion circuit, a first EMI filter circuit, a first switch circuit, a second EMI filter circuit, a second switch circuit and a first capacitor; the output end of the first EMI filter circuit is connected with the voltage conversion circuit through the first switch circuit, the input end of the second EMI filter circuit is connected with the voltage conversion circuit through the second switch circuit, and the grounding end of the second EMI filter circuit is connected with the grounding end of the first EMI filter circuit in a common ground manner; the first capacitor is connected in parallel with the output end of the second EMI filter circuit, and the capacitance value of the first capacitor is larger than that of the capacitor in the second EMI filter circuit. Through parallelly connected a great electric capacity that increases at the output side of second EMI filter circuit, the residual voltage of reduction output side that can be fine prevents the potential safety hazard and reduces the electric quantity loss.

Description

Power supply circuit and power supply device

Technical Field

The application relates to the technical field of power supplies, in particular to a power supply circuit and power supply equipment.

Background

In the device that needs to be charged and discharged (such as a portable power source/a charger), a bidirectional charging and discharging circuit is usually adopted, that is, the charging circuit and the discharging circuit share the same circuit structure by controlling a switch circuit. However, during the charging process, the discharging interface of these devices may have residual voltage (e.g., about 10V), that is, the output terminal has residual power. Although the residual power is within the safe voltage range, the residual power still has safety hazards and generates loss of power.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a power supply circuit and power supply equipment, can reduce the incomplete electricity of output, prevents the potential safety hazard.

A first aspect of an embodiment of the present application provides a power supply circuit, including a voltage conversion circuit, a first EMI filter circuit, a first switch circuit, a second EMI filter circuit, a second switch circuit, and a first capacitor;

the voltage conversion circuit is used for realizing bidirectional voltage conversion;

the output end of the first EMI filter circuit is connected with the voltage conversion circuit through the first switch circuit, and the input end of the first EMI filter circuit is used for being connected with a charging interface;

the input end of the second EMI filter circuit is connected with the voltage conversion circuit through the second switch circuit, and the output end of the second EMI filter circuit is used for connecting a discharging interface; the grounding end of the second EMI filter circuit is connected with the grounding end of the first EMI filter circuit in a common ground mode;

the first capacitor is connected in parallel with the output end of the second EMI filter circuit, and the capacitance value of the first capacitor is larger than that of the capacitor in the second EMI filter circuit.

A second aspect of embodiments of the present application provides a power supply apparatus including:

the aforementioned power supply circuit;

the battery module is used for storing electric quantity;

the charging interface is used for connecting a power supply circuit;

the discharging interface is used for connecting a load circuit;

and the voltage conversion circuit in the power supply circuit is used for converting the voltage input by the charging interface and then charging the battery module, and/or converting the voltage output by the battery module and then discharging the voltage from the discharging interface.

According to the power supply circuit and the power supply equipment provided by the embodiment of the application, the power supply circuit comprises a voltage conversion circuit, a first EMI filter circuit, a first switch circuit, a second EMI filter circuit, a second switch circuit and a first capacitor; the output end of the first EMI filter circuit is connected with the voltage conversion circuit through the first switch circuit, the input end of the second EMI filter circuit is connected with the voltage conversion circuit through the second switch circuit, and the grounding end of the second EMI filter circuit is connected with the grounding end of the first EMI filter circuit in a common ground mode; the first capacitor is connected in parallel with the output end of the second EMI filter circuit, and the capacitance value of the first capacitor is larger than that of the capacitor in the second EMI filter circuit. Through parallelly connected a great electric capacity that increases at the output side of second EMI filter circuit, the residual voltage of reduction output side that can be fine prevents the potential safety hazard and reduces the electric quantity loss.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

FIG. 1 is a schematic diagram of a prior art power supply circuit;

FIG. 2 is a schematic diagram of a variation of the power supply circuit of FIG. 1;

FIG. 3 is a schematic diagram of the power supply circuit of FIG. 1 with the power supply reversed;

FIG. 4 is a schematic diagram of a power circuit according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a variation of the power circuit of FIG. 4;

FIG. 6 is a schematic diagram of a power supply circuit designed to be grounded in one embodiment;

FIG. 7 is a schematic diagram of waveforms of different power circuit residual voltages in one embodiment;

FIG. 8 is a schematic diagram of the power supply reverse connection of the power supply circuit of FIG. 4;

FIG. 9 is a waveform illustrating the residual voltage of different power circuits when the power is reversed in one embodiment;

FIG. 10 is a schematic diagram of a power supply circuit in one embodiment;

FIG. 11 is a schematic diagram of a power supply circuit in another embodiment;

fig. 12 is a schematic structural diagram of a power supply device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It should be noted that, if not conflicted, the individual features of the embodiments of the present application can be combined with one another within the scope of protection of the present application. Additionally, while functional block divisions are performed in the device diagrams, with logical sequences shown in the flowcharts, in some cases, the steps shown or described may be performed in a different order than the block divisions in the device diagrams, or the flowcharts.

Fig. 1 is a schematic diagram of a power supply circuit, which may be used in a device that needs to be charged and discharged, such as a mobile power supply/a charger, or other electronic devices with an energy storage function, where the voltage conversion circuit 10 may employ a bidirectional charging and discharging circuit, for example, by controlling a switch circuit in the voltage conversion circuit 10, so that the voltage conversion circuit can implement bidirectional voltage conversion, that is, the charging circuit and the discharging circuit share the same circuit structure.

As shown in fig. 1, the charging interface 21 and the discharging interface 31 are both connected to the voltage converting circuit 10, and normally, during charging, the switch K1 and the switch K2 are closed and the switch K3 is kept open, and during discharging, the switch K1 and the switch K2 are opened and the switch K3 is kept closed, so that it is ensured that the unused interface is not charged.

When the Power circuit works in a UPS (Uninterruptible Power Supply) mode, the switch K1, the switch K2, and the switch K3 are turned on, and the electric Power accessed from the charging interface 21 supplies Power to the electric equipment connected to the discharging interface 31, and when the electric Power is cut off, the electric energy stored in the energy storage device such as a battery is directly processed by the voltage conversion circuit 10 and then the electric equipment is supplied Power through the discharging interface 31.

The inventor of the present application has found that when the power circuit is subjected to a charging test and the power circuit is not operated in the UPS mode, the measurement discharge interface 31 has a residual voltage, for example, about 10V, that is, the output terminal has residual power. Although the residual power is within the safe voltage range, the residual power still has safety hazards and generates loss of power.

Referring to fig. 1 and 2, fig. 2 is an equivalent schematic diagram of the circuit on the left side of fig. 1, and the left side of fig. 2 is a charging interface 21 and a corresponding first filter circuit 20, which are connected to a second filter circuit 30 and a discharging interface 31 on the right side through a ground terminal PE1.

During charging, the switch K1 and the switch K2 are closed, and the voltage difference between the CHG-L (live wire) and the CHG-N (zero wire) is input voltage. The first filter circuit 20, which is composed of a resistor R1, a capacitor C2, a capacitor C3, a capacitor C4, and the like, is used to filter the input voltage. When the switch K2 is closed, the zero line CHG-N of the charging interface 21 is communicated with the zero line OUT-N of the discharging interface. The second filter circuit 30, which is composed of a resistor R2, a capacitor C5, a capacitor C6, a capacitor C7, and the like, is used for filtering the voltage output from the voltage conversion circuit 10 to the discharge interface 31. All grounds in the energy storage device are generally connected to the common ground, specifically, the ground terminal PE1 of the first filter circuit 20 is connected to the ground terminal PE2 of the second filter circuit 30, so the ground terminal PE1 between the capacitor C3 and the capacitor C4 and the ground terminal PE2 between the capacitor C6 and the capacitor C7 are the same potential point. As shown in FIG. 2, when the entire device is not grounded, the impedance between the ground terminals PE1 and CHG-L divides the input voltage, so that the ground terminal PE1 is at the voltage between CHG-L and CHG-N, and the voltage of the ground terminal PE1 is coupled to the ground terminal PE2, i.e. the voltage exists at the ground terminal PE2, so that the voltage between the ground terminals PE2 and OUT-N becomes the excitation source, thereby causing the voltage to exist between OUT-L and OUT-N of the discharge interface 31, and the detected residual power depends on the divided voltage of the impedance between the capacitor C7 and OUT-L and OUT-N.

Referring to fig. 1 and 3, in use, the live wire and the neutral wire are often connected in an opposite manner, and even if the neutral wire is connected to the ground wire, the voltage coupled to the discharging interface 31 will be greatly increased. Specifically, after grounding, the grounding terminals PE1 and PE2 are connected to the live line, so that the voltages at the grounding terminals PE1 and PE2 are greatly increased, and the voltage coupled at the discharge interface 31 may also be higher, for example, up to 36V.

The inventor of the application finds that the existing power supply circuit has the problems, improves the power supply circuit, can reduce the residual electricity at the output end of the power supply circuit, and prevents potential safety hazards.

Referring to fig. 4, an embodiment of the present application provides a power circuit 100. The power supply circuit 100 can be used for a power supply device, for example. For example, the power supply device may or may not include an energy storage device, such as a rechargeable battery. The power supply device can obtain electric energy from the outside, for example, obtain electric energy from a power grid, a generator, an energy storage device connected with the power supply device, a solar battery and the like, and can store the obtained electric energy to the energy storage device.

The power supply circuit 100 includes: a voltage conversion circuit 110, a first EMI filter circuit 120, a first switch circuit 130, a second EMI filter circuit 140, a second switch circuit 150, and a first capacitor C1.

Illustratively, the voltage conversion circuit 110 is used to implement bidirectional voltage conversion, such as AC-DC conversion and DC-AC conversion, low voltage to high voltage and high voltage to low voltage. For example, the voltage conversion circuit 110 includes a BUCK circuit (also referred to as a step-down circuit) and/or a BOOST circuit (also referred to as a step-up circuit), and a driving circuit, and the driving circuit adjusts an electrical parameter such as an output voltage of the voltage change circuit by controlling a duty ratio of a switching transistor of the BUCK circuit and/or the BOOST circuit. Needless to say, the voltage conversion circuit 110 includes a rectifier circuit, an inverter circuit, and a bidirectional DC-DC conversion circuit. The bidirectional DC-DC conversion circuit can be composed of a BUCK circuit and a BOOST circuit. The control of the operating mode and the output voltage of the voltage conversion circuit 110 can be realized by controlling the switching tubes in the inverter circuit and the bidirectional DC-DC conversion circuit.

As shown in fig. 4, the output terminal of the first EMI filter circuit 120 is connected to the voltage converter circuit 110 through the first switch circuit 130, and the input terminal of the first EMI filter circuit 120 is connected to the charging interface 101, so as to perform EMI (Electro Magnetic Interference) -filtering on the input voltage of the charging interface 101, so as to improve EMC (Electro Magnetic Compatibility) performance; and the input end of the second EMI filter circuit 140 is connected to the voltage converting circuit 110 through the second switch circuit 150, and the output end of the second EMI filter circuit 140 is used for connecting to the discharge interface 102, so as to perform high-frequency filtering on the voltage output by the voltage converting circuit 110 to the discharge interface 102, so as to improve EMC performance.

In some embodiments, the power circuit 100 further includes a control circuit (not shown). For example, the control circuit may control the first switch circuit 130 to be connected, and the power source may supply power to the voltage conversion circuit 110 through the first EMI filter circuit 120, for example, to enable the voltage conversion circuit 110 to charge an energy storage device such as a battery. And the control circuit may control the second switch circuit 150 to be connected, and the voltage conversion circuit 110 may convert the electric energy stored in the energy storage device and output the converted electric energy through the second EMI filter circuit 140.

The ground terminal PE2 of the second EMI filter circuit 140 is connected to the ground terminal PE1 of the first EMI filter circuit 120 in common. Referring to fig. 4 to 5, the ground terminal PE1 of the first EMI filter circuit 120 is connected to the ground terminal PE2 of the second EMI filter circuit 140, so that the ground terminal PE1 and the ground terminal PE2 have the same potential point.

Specifically, referring to fig. 5, the first capacitor C1 is connected in parallel to the output end of the second EMI filter circuit 140, and the capacitance of the first capacitor C1 is greater than the capacitance of the capacitor in the second EMI filter circuit 140.

By connecting a large capacitor in parallel between the second EMI filter circuit 140 and the discharge interface 102, the residual current at the output terminal of the power circuit 100 can be reduced, and the potential safety hazard can be prevented.

Specifically, according to the impedance calculation formula of the capacitor, the impedance Zc = 1/(jwC), which is inversely proportional to the capacitance value of the capacitor C, and by connecting a large capacitor in parallel between the second EMI filter circuit 140 and the discharge interface 102, the divided voltage of the excitation source formed by the voltage between the ground terminals PE2 and OUT-N at the output side of the second EMI filter circuit 140 can be reduced, so as to reduce the residual voltage at the discharge interface 102, i.e., between OUT-L and OUT-N.

In some embodiments, the relationship between the residual voltage at the discharge interface 102 and the capacitance value of the first capacitor C1 is shown in table 1:

TABLE 1 relationship between residual voltage at discharge interface and capacitance of first capacitor

Without increasing C1	33nF	66nF	99nF	132nF	220nF
						10.9V	2.4V	1.3V	0.88V	0.67V	0.26V

As can be seen from table 1, the residual voltage at the discharge interface 102 is inversely proportional to the capacitance value of the first capacitor C1. It is understood that the capacitance value of the first capacitor C1 may be set according to requirements, such as set between 80nF and 250nF, and specifically may be set to 220nF.

In some embodiments, the capacitance of the first capacitor C1 is 10 to 100 times the capacitance of the capacitor in the second EMI filter circuit 140. Optionally, the capacitance of the first capacitor C1 is 100 times that of the capacitor in the second EMI filter circuit 140.

It should be noted that, in some embodiments, the capacitance of the first capacitor C1 is too large, which may result in a degradation of the output dynamic response of the power circuit 100.

In some embodiments, the capacitance of the capacitors in the first EMI filter circuit 120 and the second EMI filter circuit 140 needs to be determined according to the EMC performance of the circuit, and is typically a small capacitor (1 to 10 nF), for example, 2.2nF, to achieve better filtering of high frequencies. It should be noted that, if the capacitance in the EMI filter circuit is directly replaced by a capacitance with a larger capacitance value, the EMC filtering effect of the EMI filter circuit is affected, because the larger the capacitance value of the capacitance is, the lower the filtering frequency is. Therefore, a person skilled in the art will usually set a capacitor with a smaller capacitance value according to the filtering effect of EMI during circuit design, and will not adopt the solution of the present application.

When the first capacitor C1 is connected in parallel between the second EMI filter circuit 140 and the discharge interface 102, since the second EMI filter circuit 140 filters out the high frequency interference, the high frequency interference does not affect the subsequent circuit. Meanwhile, the added first capacitor C1 is connected to the second EMI filter circuit 140 by a wire, and does not affect the filtering function of the second EMI filter circuit 140.

In some embodiments, referring to fig. 4, the first EMI filter circuit 120 includes a second capacitor C2, a third capacitor C3, and a fourth capacitor C4; the second capacitor C2 is connected in parallel between the live line input end and the neutral line input end of the first EMI filter circuit 120; one end of the third capacitor C3 is connected to the live wire output end of the first EMI filter circuit 120, and the other end is connected to the ground end PE1 of the first EMI filter circuit 120; one end of the fourth capacitor C4 is connected to the zero line output end of the first EMI filter circuit 120, and the other end is connected to the ground end PE1 of the first EMI filter circuit 120. In this embodiment, the input end and the output end are determined according to the current flowing direction on the live wire and the neutral wire, so that the end of the live wire CHG-L close to the charging interface 101 is taken as the input end, the end close to the voltage conversion circuit 110 is taken as the output end, and similarly, the end of the live wire OUT-L close to the voltage conversion circuit 110 is taken as the input end, and the end close to the discharging interface 102 is taken as the output end.

Illustratively, the second capacitor C2 is used for filtering out differential mode interference, and the third capacitor C3 and the fourth capacitor C4 are used for filtering out common mode interference. Of course, the structure of the first EMI filter circuit 120 is not limited thereto, and as shown in fig. 5, the first EMI filter circuit 120 may not include the second capacitor C2.

Referring to fig. 4 to 5, the first EMI filter circuit 120 further includes a first resistor R1, the first resistor R1 is connected in parallel between the live input terminal and the neutral input terminal of the first EMI filter circuit 120, and as shown in fig. 4, the first resistor R1 is connected in parallel with the second capacitor C2. The first resistor R1 may be used to discharge the second capacitor C2.

In some embodiments, referring to fig. 4-5, the second EMI filter circuit 140 includes a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7; the fifth capacitor C5 is connected in parallel between the live wire output end and the zero wire output end of the second EMI filter circuit 140; one end of the sixth capacitor C6 is connected to the live wire input end of the second EMI filter circuit 140, and the other end is connected to the ground end PE2 of the second EMI filter circuit 140; one end of the seventh capacitor C7 is connected to the zero line input end of the second EMI filter circuit 140, and the other end is connected to the ground terminal PE2 of the second EMI filter circuit 140. Illustratively, the fifth capacitor C5 is used for filtering out differential mode interference, and the sixth capacitor C6 and the seventh capacitor C7 are used for filtering out common mode interference. Although the structure of the second EMI filter circuit 140 is not limited thereto, for example, the first EMI filter circuit 120 may not include the second capacitor C2.

Illustratively, the second EMI filter circuit 140 further includes a second resistor R2, and referring to fig. 4, the second resistor R2 is connected in parallel with the fifth capacitor C5. The second resistor R2 may be used to discharge the fifth capacitor C5.

In some embodiments, the capacitance of the first capacitor C1 is 10 to 100 times the capacitance of the sixth capacitor C6 in the second EMI filter circuit 140. Optionally, the capacitance value of the first capacitor C1 is 100 times that of the sixth capacitor C6.

For example, referring to fig. 5, according to the circuit connection relationship, the first capacitor C1 is connected in parallel with the sixth capacitor C5, and the second resistor R2 is connected in series with the sixth capacitor C6 between the zero line OUT-N and the ground terminal PE2, so as to form a voltage division of the voltage (i.e., the voltage across the seventh capacitor C7). Because the capacitance value of the first capacitor C1 is greater than the capacitance value of the sixth capacitor C6, and the impedance of the first capacitor C1 is less than the impedance of the sixth capacitor C6, the voltage division of the first capacitor C1 is smaller, and the voltage division of the first capacitor C1 is also the voltage between OUT-L and OUT-N, that is, the voltage division at the output side of the second EMI filter circuit 140 can be reduced, so that the residual voltage at the discharge interface 102, that is, between OUT-L and OUT-N, is reduced.

In some embodiments, the zero line input terminal of the first EMI filter circuit 120 or the zero line output terminal of the first EMI filter circuit 120 is further configured to be connected to the ground terminal PE1 of the first EMI filter circuit 120, that is, the zero line input terminal of the first EMI filter circuit 120 or the zero line output terminal of the first EMI filter circuit 120 is also grounded. In some embodiments, the zero line input terminal of the second EMI filter circuit 140 or the zero line output terminal of the second EMI filter circuit 140 is further configured to be connected to the ground terminal PE2 of the second EMI filter circuit 140, that is, the zero line input terminal of the second EMI filter circuit 140 or the zero line output terminal of the second EMI filter circuit 140 is also grounded. Referring to fig. 6, the ground terminal PE1 of the first EMI filter circuit 120 is connected to the zero line input terminal CHG-N of the first EMI filter circuit 120, optionally, through a smaller resistor, such as a resistor R3 and/or a resistor R4 with 10 ohms, that is, the resistor R3 and/or the resistor R4 is connected in parallel with the capacitor C4, but is not limited thereto. The connection mode of the zero line and the ground terminal can be called as a grounding design, that is, all the ground terminals are connected in common ground only by grounding corresponding points. When the zero line end (CHG-N/OUT-N) and the grounding end (PE 1/PE 2) are both grounded, the zero line end and the grounding end are both at ground potential, and the potential difference between the zero line end and the grounding end is basically 0, so that the partial voltage on the output side of the second EMI filter circuit 140 can be further reduced or eliminated through the grounding design, and the residual voltage at the discharge interface 102, namely between OUT-L and OUT-N, is reduced or eliminated.

In some embodiments, fig. 7 is a waveform diagram illustrating the residual voltage of the discharge interface 102 of the three power supply circuits. Curve A1 in fig. 7 corresponds to the current power circuit in fig. 1, and the residual voltage is about 10V; curve A2 corresponds to the power circuit 100 in fig. 4, and the residual voltage is about 0.295V; curve A3 corresponds to the power circuit 100 in fig. 6, and the residual voltage is about 0.0003V. That is, in this embodiment, the residual voltage of the output terminal can be significantly reduced by adding the first capacitor, and the residual voltage of the output terminal can be further ensured to be kept within a more ideal range by performing a grounding design on the basis of adding the first capacitor.

The power supply circuit provided by the application can also realize the effect of reducing the residual voltage of the output end when the power supply is reversely connected (namely CHG-L and CHG-N are reversely connected), and the specific analysis is as follows:

fig. 8 is a schematic diagram of the power circuit 100 according to the embodiment of the present application when the live line CHG-L and the neutral line CHG-N are connected in reverse. Fig. 9 is a schematic diagram showing waveforms of residual voltages of two power circuits when the live line and the neutral line are connected reversely. Curve A4 in fig. 9 corresponds to the current power circuit in fig. 1, and the residual voltage of the discharging interface 102 can be as high as 36V; curve A5 corresponds to the power circuit 100 in fig. 4 and fig. 8, and when the first capacitor C1 with 220nF is connected in parallel at the discharge interface 102, the residual voltage coupled at the discharge interface 102 is reduced to 1.2V. It can be determined that, in the power supply circuit 100 according to the embodiment of the present application, after a capacitor is added in parallel to the output side of the second EMI filter circuit 140, the residual voltage on the output side can be well reduced, for example, stabilized below 1.2V, regardless of whether the live line and the neutral line are connected in a positive or a reverse manner.

In some embodiments, as shown in fig. 4, the first switching circuit 130 includes a first switching element K1 and a second switching element K2; a first end of the first switching element K1 is connected to the live wire output end of the first EMI filter circuit 120, and a second end of the first switching element K1 is connected to the positive connection end of the voltage conversion circuit 110; a first end of the second switching element K2 is connected to the zero line output end of the first EMI filter circuit 120, and a second end of the second switching element K2 is connected to the negative connection end of the voltage conversion circuit 110.

For example, when the voltage conversion circuit 110 is charged to an energy storage device such as a battery, the control circuit may control the first switching element K1 and the second switching element K2 to be turned on, and the first EMI filter circuit 120 filters the input voltage of the charging interface 101.

In some embodiments, as shown in fig. 4, the second switching circuit 150 includes a third switching element K3, a first terminal of the third switching element K3 is connected to the live input terminal of the second EMI filter circuit 140, and a second terminal of the third switching element K3 is connected to the second terminal of the first switching element K1. When the control circuit controls the third switching element K3 to be turned on, the voltage conversion circuit 110 may convert the electric energy stored in the energy storage device and output the converted electric energy to the discharge interface 102 through the second switching circuit 150 and the second EMI filter circuit 140, and the second EMI filter circuit 140 may perform high-frequency filtering on the voltage output by the voltage conversion circuit 110.

Alternatively, as shown in fig. 10, the number of the third switching elements K3 is plural; the plurality of third switching elements K3 are arranged in parallel. The plurality of third switching elements K3 are arranged in parallel, so that the current flowing through each third switching element K3 can be reduced, the performance requirement on high-voltage resistance and high current of a single third switching element K3 is further reduced, and the reduction of the production cost is facilitated.

Optionally, as shown in fig. 11, the second switch circuit 150 further includes a fourth switch element K4, a first end of the fourth switch element K4 is connected to the zero line input end of the second EMI filter circuit 140, and a second end of the fourth switch element K4 is connected to a second end of the second switch element K2. When the power supply supplies power to the voltage conversion circuit 110 through the charging interface 101, the third switching element K3 and the fourth switching element K4 may be controlled to be turned off, and the problem of the residual power at the discharging interface 102 may also be solved, but the cost may be increased. Optionally, a plurality of fourth switching elements K4 are provided; the plurality of fourth switching elements K4 are arranged in parallel. The plurality of fourth switching elements K4 are arranged in parallel, so that the current flowing through each fourth switching element K4 can be reduced, the performance requirement on the high-voltage resistance and large current of the single fourth switching element K4 is further reduced, and the reduction of the production cost is facilitated.

The power supply circuit provided by the embodiment of the application comprises a voltage conversion circuit, a first EMI filter circuit, a first switch circuit, a second EMI filter circuit, a second switch circuit and a first capacitor; the output end of the first EMI filter circuit is connected with the voltage conversion circuit through the first switch circuit, the input end of the second EMI filter circuit is connected with the voltage conversion circuit through the second switch circuit, and the grounding end of the second EMI filter circuit is connected with the grounding end of the first EMI filter circuit in a common ground manner; the first capacitor is connected in parallel with the output end of the second EMI filter circuit, and the capacitance value of the first capacitor is larger than that of the capacitor in the second EMI filter circuit. Through parallelly connected increase a great electric capacity in the output side of second EMI filter circuit, the residual voltage of reduction output side that can be fine, no matter the power of the interface that charges is just connecing or the reverse connection, for example can all stabilize residual voltage below 1.2V, prevent the potential safety hazard and reduce the electric quantity loss.

Referring to fig. 12 in conjunction with the foregoing embodiments, fig. 12 is a schematic block diagram of a power supply apparatus 200 according to an embodiment of the present application.

As shown in fig. 12, the power supply apparatus 200 includes:

the aforementioned power supply circuit 100;

a battery module 210 for storing electric power; alternatively, the battery module 210 may be detachably disposed or integrally disposed.

A charging interface 101 for connecting a power supply circuit; the power supply circuit can obtain electric energy from a power grid, a generator, an energy storage device, a solar battery and the like;

a discharge interface 102 for connecting a load circuit;

the voltage conversion circuit in the power circuit 100 is used for converting the voltage input by the charging interface 101 and then charging the battery module 210, and/or converting the voltage output by the battery module 210 and then discharging the voltage to the outside through the discharging interface 102.

The power supply equipment that this application embodiment provided, through parallelly connected increase a great electric capacity in power supply circuit's output side, the residual voltage of interface that discharges that reduces that can be fine, no matter the power of the interface that charges is just connecing or the transposition, for example can all be with residual voltage stable below 1.2V, prevent the potential safety hazard and reduce the electric quantity loss.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It should also be understood that the term "and/or" as used in this application and the appended claims refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or substitutions within the technical scope of the present application, and these modifications or substitutions should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A power supply circuit is characterized by comprising a voltage conversion circuit, a first EMI filter circuit, a first switch circuit, a second EMI filter circuit, a second switch circuit and a first capacitor;

the voltage conversion circuit is used for realizing bidirectional voltage conversion;

the output end of the first EMI filter circuit is connected with the voltage conversion circuit through the first switch circuit, and the input end of the first EMI filter circuit is used for being connected with a charging interface;

the input end of the second EMI filter circuit is connected with the voltage conversion circuit through the second switch circuit, and the output end of the second EMI filter circuit is used for connecting a discharging interface; the grounding end of the second EMI filter circuit is connected with the grounding end of the first EMI filter circuit in a common ground manner;

the first capacitor is connected in parallel with the output end of the second EMI filter circuit, and the capacitance value of the first capacitor is larger than that of the capacitor in the second EMI filter circuit.

2. The power supply circuit of claim 1, wherein the first EMI filter circuit comprises a second capacitor, a third capacitor, and a fourth capacitor; the second capacitor is connected in parallel between the live wire input end and the zero line input end of the first EMI filter circuit; one end of the third capacitor is connected to the live wire output end of the first EMI filter circuit, and the other end of the third capacitor is connected to the grounding end of the first EMI filter circuit; one end of the fourth capacitor is connected to the zero line output end of the first EMI filter circuit, and the other end of the fourth capacitor is connected to the grounding end of the first EMI filter circuit;

the second EMI filter circuit comprises a fifth capacitor, a sixth capacitor and a seventh capacitor; the fifth capacitor is connected in parallel between the live wire output end and the zero line output end of the second EMI filter circuit; one end of the sixth capacitor is connected to the live wire input end of the second EMI filter circuit, and the other end of the sixth capacitor is connected to the grounding end of the second EMI filter circuit; one end of the seventh capacitor is connected to the zero line input end of the second EMI filter circuit, and the other end of the seventh capacitor is connected to the grounding end of the second EMI filter circuit.

3. The power circuit of claim 2, wherein the zero line input of the first EMI filter circuit or the zero line output of the first EMI filter circuit is further configured to connect to a ground terminal of the first EMI filter circuit; or alternatively

And the zero line input end of the second EMI filter circuit or the zero line output end of the second EMI filter circuit is also used for being connected with the grounding end of the second EMI filter circuit.

4. The power supply circuit according to claim 2, wherein a capacitance value of the first capacitor is 10 times to 100 times a capacitance value of the sixth capacitor.

5. The power supply circuit according to claim 4, wherein a capacitance value of the first capacitor is 100 times a capacitance value of the sixth capacitor.

6. The power supply circuit of claim 2, wherein the first EMI filter circuit further comprises a first resistor connected in parallel with the second capacitor;

the second EMI filter circuit further comprises a second resistor connected in parallel with the fifth capacitor.

7. The power supply circuit according to claim 2, wherein the first switching circuit includes a first switching element and a second switching element; the first end of the first switching element is connected with the live wire output end of the first EMI filter circuit, and the second end of the first switching element is connected with the positive connecting end of the voltage conversion circuit; the first end of the second switching element is connected with the zero line output end of the first EMI filter circuit, and the second end of the second switching element is connected with the negative connecting end of the voltage conversion circuit; the second switching circuit comprises a third switching element, a first end of the third switching element is connected with the live wire input end of the second EMI filtering circuit, and a second end of the third switching element is connected with a second end of the first switching element.

8. The power circuit of claim 7, wherein the second switching circuit further comprises a fourth switching element, a first terminal of the fourth switching element being connected to the neutral input of the second EMI filter circuit, a second terminal of the fourth switching element being connected to the second terminal of the second switching element.

9. The power supply circuit according to claim 7, wherein the third switching element is plural; a plurality of the third switching elements are arranged in parallel.

10. A power supply apparatus, characterized by comprising:

the power supply circuit of any one of claims 1-9;

the battery module is used for storing electric quantity;

the charging interface is used for connecting a power supply circuit;

the discharging interface is used for connecting a load circuit;

and the voltage conversion circuit in the power supply circuit is used for converting the voltage input by the charging interface and then charging the battery module, and/or converting the voltage output by the battery module and then discharging the voltage from the discharging interface.

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