Detection circuit of grounding impedance

Abstract

The utility model provides a grounding impedance detection circuit. The detection circuit comprises a voltage input circuit, a first voltage division circuit, a to-be-detected power supply housing, a second voltage division circuit and an impedance detection circuit. The output end of the voltage input circuit is connected with the input end of the first voltage division circuit; the output end of the first voltage division circuit is connected with a to-be-tested power supply shell; the input end of the second voltage division circuit is connected with the to-be-tested power supply shell; the output end of the second voltage division circuit is connected with the input end of the impedance detection circuit; when the voltage output by the impedance detection circuit is not lower than a preset threshold value, it is determined that the to-be-detected power supply shell is not grounded; and when the voltage output by the impedance detection circuit is lower than a preset threshold value, determining that the to-be-detected power supply shell is grounded. Voltage is input through the voltage input circuit, the first voltage division circuit and the second voltage division circuit are used for voltage division, whether the to-be-detected power supply shell is grounded or not is determined according to output of the impedance detection circuit, and the purpose of effectively and accurately detecting the grounding condition of an electronic product is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power engineering, in particular to a detection circuit for grounding impedance. Background Art

[0002] With the development of society, electric power resources are widely used, and a large number of electronic products are produced and used. Therefore, effectively ensuring the safety of users' electricity consumption is of top priority. When electronic products are used irregularly, such as when the electronic products are not effectively grounded, dangers such as electric leakage are likely to occur, and it is necessary to effectively detect such irregular use in a timely manner so as to take corresponding countermeasures.

[0003] Based on this, how to quickly and accurately detect whether an electronic product is effectively grounded is a problem that needs to be solved urgently at present. Summary of the Utility Model

[0004] In view of this, an embodiment of the utility model provides a detection circuit for grounding impedance to achieve the purpose of effectively and accurately detecting the grounding condition of an electronic product.

[0005] To achieve the above purpose, the embodiment of the utility model provides the following technical solutions:

[0006] The first aspect of the utility model discloses a detection circuit for grounding impedance, and the circuit includes: a voltage input circuit, a first voltage division circuit, a power supply housing to be measured, a second voltage division circuit and an impedance detection circuit;

[0007] The output end of the voltage input circuit is connected to the input end of the first voltage division circuit; the output end of the first voltage division circuit is connected to the power supply housing to be measured;

[0008] The input end of the second voltage division circuit is connected to the power supply housing to be measured; the output end of the second voltage division circuit is connected to the input end of the impedance detection circuit;

[0009] When the voltage output by the impedance detection circuit is not lower than a preset threshold value, it is determined that the power supply housing to be measured is not grounded; when the voltage output by the impedance detection circuit is lower than the preset threshold value, it is determined that the power supply housing to be measured is grounded.

[0010] Preferably, the voltage input circuit includes: a first input circuit and a second input circuit;

[0011] One end of the first input circuit is connected to the positive terminal voltage of the first photovoltaic panel;

[0012] One end of the second input circuit is connected to the positive terminal voltage of the second photovoltaic panel;

[0013] The other end of the first input circuit is connected to the other end of the second input circuit, and the common connection end is connected to the first voltage dividing circuit.

[0014] Preferably, the first input circuit includes: a first diode and a first filter capacitor;

[0015] The positive electrode of the first diode is connected to the positive terminal voltage of the first photovoltaic panel. The first diode and the first filter capacitor are connected in parallel, and the common connection end of the parallel connection is connected to the first voltage dividing circuit.

[0016] Preferably, the second input circuit includes: a second diode and a second filter capacitor;

[0017] The positive electrode of the second diode is connected to the positive terminal voltage of the second photovoltaic panel. The second diode and the second filter capacitor are connected in parallel, and the common connection end of the parallel connection is connected to the first voltage dividing circuit.

[0018] Preferably, the first voltage dividing circuit includes: a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, and a fourth voltage dividing resistor;

[0019] One end of the first voltage dividing resistor is connected to the output end of the voltage input circuit;

[0020] The first voltage dividing resistor, the second voltage dividing resistor, the third voltage dividing resistor, and the fourth voltage dividing resistor are connected in series;

[0021] The other end of the fourth voltage dividing resistor is connected to the outer shell of the power supply to be measured.

[0022] Preferably, the second voltage dividing circuit includes: a fifth voltage dividing resistor, a sixth voltage dividing resistor, a seventh voltage dividing resistor, an eighth voltage dividing resistor, and a filtering voltage dividing circuit;

[0023] One end of the fifth voltage dividing resistor is connected to the outer shell of the power supply to be measured;

[0024] The fifth voltage dividing resistor, the sixth voltage dividing resistor, the seventh voltage dividing resistor, and the eighth voltage dividing resistor are connected in series;

[0025] The other end of the eighth voltage dividing resistor is connected to the filtering voltage dividing circuit.

[0026] Preferably, the filtering voltage dividing circuit includes: a ninth voltage dividing resistor, a tenth voltage dividing resistor, a third filter capacitor, and a fourth filter capacitor;

[0027] The ninth voltage dividing resistor and the third filter capacitor are connected in parallel. Among them, one common connection end of the parallel connection is respectively connected to the other end of the eighth voltage dividing resistor and to the tenth voltage dividing resistor; the other common connection end of the parallel connection is connected to one end of the fourth filter capacitor;

[0028] One end of the fourth filter capacitor is grounded;

[0029] The other end of the tenth voltage-dividing resistor is connected to the other end of the fourth filter capacitor, and the common connection end is connected to the input end of the impedance detection circuit.

[0030] Preferably, the impedance detection circuit includes: a fifth filter capacitor, a voltage follower, and a judgment circuit;

[0031] One end of the fifth filter capacitor is connected to pin 8 of the voltage follower, and the common connection end is connected to the positive power supply terminal; the other end of the fifth filter capacitor is connected to pin 4 of the voltage follower, and the common connection end is grounded;

[0032] The input end of the voltage follower is connected to the output end of the second voltage-dividing circuit; the output end of the voltage follower is connected to the judgment circuit.

[0033] Preferably, the judgment circuit includes: an eleventh voltage-dividing resistor, a twelfth voltage-dividing resistor, a sixth filter capacitor, and an electronic control unit;

[0034] One end of the eleventh voltage-dividing resistor is connected to the output end of the voltage follower; the other end of the eleventh voltage-dividing resistor is connected to the electronic control unit;

[0035] The twelfth voltage-dividing resistor and the sixth filter capacitor are connected in parallel, one common connection end of the parallel connection is connected to the electronic control unit, and the other common connection end of the parallel connection is grounded.

[0036] Preferably, the material of the housing of the power supply under test is metal.

[0037] Based on the above-mentioned detection circuit for grounding impedance provided by the embodiment of the present invention, the detection circuit includes: a voltage input circuit, a first voltage-dividing circuit, the housing of the power supply under test, a second voltage-dividing circuit, and an impedance detection circuit; the output end of the voltage input circuit is connected to the input end of the first voltage-dividing circuit; the output end of the first voltage-dividing circuit is connected to the housing of the power supply under test; the input end of the second voltage-dividing circuit is connected to the housing of the power supply under test; the output end of the second voltage-dividing circuit is connected to the input end of the impedance detection circuit; when the voltage output by the impedance detection circuit is not lower than the preset threshold, it is determined that the housing of the power supply under test is not grounded; when the voltage output by the impedance detection circuit is lower than the preset threshold, it is determined that the housing of the power supply under test is grounded. By inputting a voltage through the voltage input circuit, using the first voltage-dividing circuit and the second voltage-dividing circuit for voltage division, and determining whether the housing of the power supply under test is grounded according to the output of the impedance detection circuit, the purpose of effectively and accurately detecting the grounding condition of electronic products is achieved. Description of the Drawings

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0039] Figure 1 Schematic diagram of a detection circuit for grounding impedance provided by an embodiment of the present invention;

[0040] Figure 2 Schematic diagram of a voltage input circuit provided by an embodiment of the present invention;

[0041] Figure 3 Another schematic diagram of a voltage input circuit provided by an embodiment of the present invention;

[0042] Figure 4 Schematic diagram of a first voltage dividing circuit provided by an embodiment of the present invention;

[0043] Figure 5 Schematic diagram of a second voltage dividing circuit provided by an embodiment of the present invention;

[0044] Figure 6 Schematic diagram of a filtering voltage dividing circuit provided by an embodiment of the present invention;

[0045] Figure 7 Schematic diagram of an impedance detection circuit provided by an embodiment of the present invention;

[0046] Figure 8 Schematic diagram of a judgment circuit provided by an embodiment of the present invention. Detailed implementation manners

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0048] In this application, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0049] As is known from the background art, when electronic products are used in an improper manner, such as when the electronic products are not effectively grounded, dangers such as electric leakage are likely to occur, and it is necessary to effectively detect such improper use in a timely manner so as to take corresponding countermeasures.

[0050] Therefore, an embodiment of the present utility model provides a detection circuit for grounding impedance. The detection circuit includes: a voltage input circuit, a first voltage dividing circuit, a power supply housing to be measured, a second voltage dividing circuit, and an impedance detection circuit; an output end of the voltage input circuit is connected to an input end of the first voltage dividing circuit; an output end of the first voltage dividing circuit is connected to the power supply housing to be measured; an input end of the second voltage dividing circuit is connected to the power supply housing to be measured; an output end of the second voltage dividing circuit is connected to an input end of the impedance detection circuit; when the voltage output by the impedance detection circuit is not lower than a preset threshold value, it is determined that the power supply housing to be measured is not grounded; when the voltage output by the impedance detection circuit is lower than the preset threshold value, it is determined that the power supply housing to be measured is grounded. By inputting a voltage through the voltage input circuit, performing voltage division by using the first voltage dividing circuit and the second voltage dividing circuit, and determining whether the power supply housing to be measured is grounded according to the output of the impedance detection circuit, the purpose of effectively and accurately detecting the grounding condition of the electronic product is achieved.

[0051] See Figure 1 , which shows a schematic diagram of a detection circuit for grounding impedance provided by an embodiment of the present utility model. The detection circuit is applied to the circuit of a photovoltaic micro-inverter and is mainly used to detect the grounding condition of the power supply housing of an electronic product.

[0052] The detection circuit for grounding impedance includes: a voltage input circuit 1, a first voltage dividing circuit 2, a power supply housing to be measured PE, a second voltage dividing circuit 3, and an impedance detection circuit 4.

[0053] It should be noted that the power supply housing to be measured PE is the housing of the electronic product to be tested, and the material of the power supply housing to be measured PE is metal.

[0054] Specifically, as Figure 1As shown, the output terminal of the voltage input circuit 1 is connected to the input terminal of the first voltage dividing circuit 2; the output terminal of the first voltage dividing circuit 2 is connected to the outer shell PE of the power supply under test; the input terminal of the second voltage dividing circuit 3 is connected to the outer shell PE of the power supply under test; the output terminal of the second voltage dividing circuit 3 is connected to the input terminal of the impedance detection circuit 4.

[0055] It should be noted that one end of the impedance detection circuit 4 is connected to the 5V positive terminal voltage (such as Figure 1 the +5V_IC shown); the other end of the impedance detection circuit 4 is grounded (such as Figure 1 the AGND_P shown).

[0056] It can be understood that the voltage input circuit 1 inputs the positive terminal voltage of the photovoltaic panel, and the voltage input circuit 1 is connected to the outer shell PE of the power supply under test through the first voltage dividing circuit 2. Among them, the first voltage dividing circuit 2 is used for voltage division.

[0057] Furthermore, the outer shell PE of the power supply under test is connected to the impedance detection circuit 4 through the second voltage dividing circuit 3. Among them, the second voltage dividing circuit 3 is used for voltage division; the impedance detection circuit 4 is used to detect whether the outer shell PE of the power supply under test is grounded.

[0058] It can be understood that when the outer shell PE of the power supply under test is well grounded, the voltage at the outer shell PE of the power supply under test is close to zero, and the voltage output by the impedance detection circuit 4 should be lower than the preset threshold; when the outer shell PE of the power supply under test is not grounded or the grounding impedance is large, the voltage at the outer shell PE of the power supply under test is high, and the voltage output by the impedance detection circuit 4 is not lower than the preset threshold.

[0059] Based on this principle, when the voltage output by the impedance detection circuit 4 is not lower than the preset threshold, it is determined that the grounding impedance of the outer shell PE of the power supply under test is large and the outer shell PE of the power supply under test is not grounded; when the voltage output by the impedance detection circuit 4 is lower than the preset threshold, it is determined that the grounding impedance of the outer shell PE of the power supply under test is small and the outer shell PE of the power supply under test is well grounded. Among them, the preset threshold can be determined according to the actual situation and is not specifically limited here.

[0060] The following will respectively be based on Figure 2 、 Figure 4 、 Figure 5 and Figure 7 , explain and illustrate the voltage input circuit 1, the first voltage dividing circuit 2, the second voltage dividing circuit 3 and the impedance detection circuit 4.

[0061] Refer to Figure 2 the content shown to further explain the voltage input circuit 1.

[0062] Specifically, the voltage input circuit 1 includes a first input circuit 11 and a second input circuit 12. Among them, one end of the first input circuit 11 is connected to the positive terminal voltage of the first photovoltaic panel (such as Figure 2As shown in Figure 2 the positive terminal voltage of the second photovoltaic panel (+PV2 as shown in

[0063] It should be noted that isolation is provided between +PV1 and +PV2.

[0064] Next, in combination with Figure 3 the content shown, a detailed explanation of the first input circuit 11 and the second input circuit 12 will be given:

[0065] Refer to Figure 3 the content shown. The first input circuit 11 includes a first diode (such as Figure 3 the D61 diode shown in Figure 3 and a first filter capacitor (such as

[0066] the C227 capacitor shown in

[0067] Specifically, the positive electrode of the first diode is connected to the positive terminal voltage of the first photovoltaic panel. The first diode and the first filter capacitor are connected in parallel, and the common terminal of the parallel connection is connected to the first voltage dividing circuit.

[0068] That is to say, the A pole of the D61 diode is connected to +PV1, one end of the C227 capacitor is connected to the A pole of the D61 diode, and the other end of the C227 capacitor is connected to the K pole of the D61 diode.

[0069] It should be noted that the second input circuit 12 includes a second diode (such as Figure 3 the D62 diode shown in Figure 3 and a second filter capacitor (such as

[0070] the C236 capacitor shown in

[0071] Specifically, the positive electrode of the second diode is connected to the positive terminal voltage of the second photovoltaic panel. The second diode and the second filter capacitor are connected in parallel, and the common terminal of the parallel connection is connected to the first voltage dividing circuit.

[0072] That is to say, the anode of the D62 diode is connected to +PV2, one end of the C236 capacitor is connected to the anode of the D62 diode, and the other end of the C236 capacitor is connected to the cathode of the D62 diode. The cathode of the D61 diode and the cathode of the D62 diode are connected to each other, and the common connection end is connected to the first voltage dividing circuit 2.

[0073] Refer to Figure 4 the content shown in

[0074] It should be noted that the first voltage dividing circuit 2 includes: a first voltage dividing resistor (such as Figure 4 the R279 resistor shown in Figure 4 ), a second voltage dividing resistor (such as Figure 4 the R271 resistor shown in Figure 4 ), a third voltage dividing resistor (such as

[0075] the R268 resistor shown in

[0076] ), and a fourth voltage dividing resistor (such as

[0077] the R276 resistor shown in

[0078]

[0079] Figure 5 Refer to the content shown in

[0080] Figure 5 It should be noted that the second voltage dividing circuit 3 includes: a fifth voltage dividing resistor (such as Figure 5 the R280 resistor shown in Figure 5 ), a sixth voltage dividing resistor (such as Figure 5 the R269 resistor shown in Figure 5 ), a seventh voltage dividing resistor (such as Figure 5 the R272 resistor shown in Figure 5 ), an eighth voltage dividing resistor (such as Figure 5 the R277 resistor shown in Figure 5 ), and a filtering voltage dividing circuit 31.

[0081] It can be understood that the specific parameters of the resistors R280, R269, R272 and R277 are all 105AR, wherein 105 is the resistance value of the resistors R280, R269, R272 and R277.

[0082] Specifically, one end of the fifth voltage-dividing resistor is connected to the power supply housing PE to be tested; the fifth voltage-dividing resistor, the sixth voltage-dividing resistor, the seventh voltage-dividing resistor and the eighth voltage-dividing resistor are connected in series; the other end of the eighth voltage-dividing resistor is connected to the filtering voltage-dividing circuit 31 .

[0083] That is, one end of the resistor R280 is connected to the power supply housing PE to be tested; the resistor R280, the resistor R269, the resistor R272 and the resistor R277 are connected in series; and the other end of the resistor R277 is connected to the filter voltage divider circuit 31.

[0084] It should be noted that the resistors R280, R269, R272 and R277 form a series voltage divider.

[0085] Combine the following Figure 6 The content shown explains the filter voltage divider circuit 31 in detail:

[0086] See also Figure 6 The content shown in the figure, the filter voltage divider circuit 31 includes: a ninth voltage divider resistor (such as Figure 6 The R283 resistor shown in the figure), the tenth voltage resistor (such as Figure 6 The R278 resistor shown in the figure), the third filter capacitor (such as Figure 6 The C232 capacitor shown in FIG. 1 and the fourth filter capacitor (as shown in FIG. Figure 6 The C233 capacitor shown in Figure 1).

[0087] It can be understood that the specific parameter of the R283 resistor is 304CR, where 304 is the resistance value of the R283 resistor. The specific parameter of the R278 resistor is 102FR, where 102 is the resistance value of the R278 resistor. The specific parameter of the C232 capacitor is 103CEX, where 103 is the capacitance value of the C232 capacitor. The specific parameter of the C233 capacitor is 103CEX, where 103 is the capacitance value of the C233 capacitor.

[0088] Specifically, the ninth voltage-dividing resistor and the third filter capacitor are connected in parallel, wherein one common end of the parallel connection is respectively connected to the other end of the eighth voltage-dividing resistor and the tenth voltage-dividing resistor; the other common end of the parallel connection is connected to one end of the fourth filter capacitor; one end of the fourth filter capacitor is grounded; the other end of the tenth voltage-dividing resistor is connected to the other end of the fourth filter capacitor, and the connected common end is connected to the input end of the impedance detection circuit 4.

[0089] That is to say, resistor R283 and capacitor C232 are in parallel, and a common terminal of the parallel connection is connected to the other end of resistor R277 and one end of resistor R278. The other common terminal of the parallel connection is connected to one end of capacitor C233; one end of capacitor C233 is grounded (specifically as Figure 7 shown); the other end of resistor R278 is connected to the other end of capacitor C233, and the common terminal of the connection is connected to the input end of impedance detection circuit 4.

[0090] It should be particularly noted that resistor R283 and resistor R278 are connected in series to form the second voltage division circuit 3 for series voltage division. Capacitors C232 and C233 respectively play a role in smoothing and filtering on their branches.

[0091] Refer to Figure 7 the content shown to further illustrate impedance detection circuit 4.

[0092] It should be noted that impedance detection circuit 4 includes: a fifth filter capacitor (such as Figure 7 capacitor C235 shown in Figure 7 ), a voltage follower (such as

[0093] voltage follower U25A shown in

[0094] ), and a judgment circuit 41.

[0095] It can be understood that the specific parameters of capacitor C235 are 104CFXC, where 104 is the capacitance value of capacitor C235; voltage follower U25A is specifically a voltage follower of model SGM8252, which is composed of an operational amplifier, and the output voltage of voltage follower U25A follows the change of the input voltage.

[0096] Specifically, one end of the fifth filter capacitor is connected to pin 8 of the voltage follower, and the common terminal of the connection is connected to the positive power supply terminal; the other end of the fifth filter capacitor is connected to pin 4 of the voltage follower, and the common terminal of the connection is grounded; the input end of the voltage follower is connected to the output end of the second voltage division circuit; the output end of the voltage follower is connected to judgment circuit 41.

[0095] That is to say, one end of capacitor C235 is connected to pin 8 of voltage follower U25A, and the common terminal of the connection is connected to the positive power supply +5V_IC; the other end of capacitor C235 is connected to pin 4 of voltage follower U25A, and the common terminal of the connection is grounded (i.e., connected to AGND_P); pin 3 of voltage follower U25A is connected to the other end of resistor R278, and pin 2 of voltage follower U25A is connected to the output end of voltage follower U25A (i.e., pin 1); the output end of voltage follower U25A is connected to judgment circuit 41.

[0096] It should be particularly noted that capacitor C235 plays a role in smoothing and filtering on its branch.

[0097] Next, in combination with Figure 8The content shown explains the judgment circuit 41 in detail:

[0098] Referring to Figure 8 the content shown, the judgment circuit 41 includes the eleventh voltage-dividing resistor (such as Figure 8 the R282 resistor shown in Figure 8 ), the twelfth voltage-dividing resistor (such as Figure 8 the R281 resistor shown in Figure 8 ), the sixth filter capacitor (such as

[0099] the C234 capacitor shown in

[0100] ), and the electronic control unit (such as

[0101] the MCU shown in

[0102] ). It can be understood that the specific parameter of the R282 resistor is 102FR, where 102 is the resistance value of the R282 resistor; the specific parameter of the R281 resistor is 102FR, where 102 is the resistance value of the R281 resistor; the specific parameter of the C234 capacitor is 103CEX, where 103 is the capacitance value of the C234 capacitor. Specifically, one end of the eleventh voltage-dividing resistor is connected to the output end of the voltage follower; the other end of the eleventh voltage-dividing resistor is connected to the electronic control unit; the twelfth voltage-dividing resistor and the sixth filter capacitor are connected in parallel, and a common end of the parallel connection is connected to the electronic control unit, and the other common end of the parallel connection is grounded. That is to say, one end of the R282 resistor is connected to the output end (i.e., pin 1) of the U25A voltage follower; the other end of the R282 resistor is connected to the MCU; the R281 resistor and the C234 capacitor are connected in parallel, and a common end of the parallel connection is connected to the MCU, and the other common end of the parallel connection is grounded (i.e., connected to AGND_P). It should be noted that the C234 capacitor plays a role of smoothing and filtering in its branch. The R282 resistor and the R281 resistor form a series voltage division. It can be understood that when the PE of the power supply under test is well grounded, the voltage at the PE is pulled down, and the U25A voltage follower outputs a voltage lower than the preset threshold. Based on this, the MCU electronic control unit determines that the PE of the power supply under test is well grounded. On the other hand, when the PE of the power supply under test is not grounded or has a large grounding impedance, the voltage at the PE is high, and the U25A voltage follower outputs a voltage not lower than the preset threshold. Based on this, the MCU electronic control unit determines that the PE of the power supply under test is not grounded and determines that the grounding impedance of the PE of the power supply under test is large.

[0103] It can be understood that when the PE of the power supply under test is well grounded, the voltage at the PE is pulled down, and the U25A voltage follower outputs a voltage lower than the preset threshold. Based on this, the MCU electronic control unit determines that the PE of the power supply under test is well grounded.

[0104] On the other hand, when the PE of the power supply under test is not grounded or has a large grounding impedance, the voltage at the PE is high, and the U25A voltage follower outputs a voltage not lower than the preset threshold. Based on this, the MCU electronic control unit determines that the PE of the power supply under test is not grounded and determines that the grounding impedance of the PE of the power supply under test is large.

[0105] It should be specifically noted that the specific models and parameters of components such as diodes, capacitors, resistors, and voltage followers listed in the above embodiments of the present utility model are only for illustrative purposes and can be determined according to actual situations during application, and no specific limitations are made in the embodiments of the present utility model.

[0106] In the embodiments of the present utility model, a voltage is input through a voltage input circuit, voltage division is performed using a first voltage division circuit and a second voltage division circuit, the outer shell of the power supply to be tested is connected to a voltage follower through a series resistor, and the voltage follower outputs a voltage to an electronic control unit for judgment to determine whether the outer shell of the power supply to be tested is grounded, achieving the purpose of effectively and accurately detecting the grounding condition of electronic products.

[0107] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for a system or system embodiment, since it is basically similar to the method embodiment, it is described relatively simply, and the relevant parts can refer to the partial description of the method embodiment. The systems and system embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0108] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present utility model.

[0109] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A detection circuit for grounding impedance, characterized in that, The circuit includes: a voltage input circuit, a first voltage dividing circuit, the housing of the power supply under test, a second voltage dividing circuit, and an impedance detection circuit; The output terminal of the voltage input circuit is connected to the input terminal of the first voltage dividing circuit; the output terminal of the first voltage dividing circuit is connected to the housing of the power supply under test; The input terminal of the second voltage dividing circuit is connected to the housing of the power supply under test; the output terminal of the second voltage dividing circuit is connected to the input terminal of the impedance detection circuit; When the voltage output by the impedance detection circuit is not lower than a preset threshold, it is determined that the housing of the power supply under test is not grounded; when the voltage output by the impedance detection circuit is lower than the preset threshold, it is determined that the housing of the power supply under test is grounded.

2. The circuit according to claim 1, wherein The voltage input circuit includes: a first input circuit and a second input circuit; One end of the first input circuit is connected to the positive terminal voltage of the first photovoltaic panel; One end of the second input circuit is connected to the positive terminal voltage of the second photovoltaic panel; The other end of the first input circuit is connected to the other end of the second input circuit, and the connected common terminal is connected to the first voltage dividing circuit.

3. The circuit according to claim 2, wherein The first input circuit includes: a first diode and a first filter capacitor; The positive electrode of the first diode is connected to the positive terminal voltage of the first photovoltaic panel, the first diode and the first filter capacitor are connected in parallel, and the connected common terminal is connected to the first voltage dividing circuit.

4. The circuit according to claim 2, wherein The second input circuit includes: a second diode and a second filter capacitor; The positive electrode of the second diode is connected to the positive terminal voltage of the second photovoltaic panel, the second diode and the second filter capacitor are connected in parallel, and the connected common terminal is connected to the first voltage dividing circuit.

5. The circuit according to claim 1, characterized in that, The first voltage dividing circuit includes: a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, and a fourth voltage dividing resistor; One end of the first voltage dividing resistor is connected to the output terminal of the voltage input circuit; The first voltage dividing resistor, the second voltage dividing resistor, the third voltage dividing resistor, and the fourth voltage dividing resistor are connected in series; The other end of the fourth voltage dividing resistor is connected to the housing of the power supply under test.

6. The circuit according to claim 1, wherein The second voltage dividing circuit includes: a fifth voltage dividing resistor, a sixth voltage dividing resistor, a seventh voltage dividing resistor, an eighth voltage dividing resistor, and a filter voltage dividing circuit; One end of the fifth voltage dividing resistor is connected to the housing of the power supply under test; The fifth voltage dividing resistor, the sixth voltage dividing resistor, the seventh voltage dividing resistor, and the eighth voltage dividing resistor are connected in series; The other end of the eighth voltage dividing resistor is connected to the filter voltage dividing circuit.

7. The circuit according to claim 6, wherein The filter voltage dividing circuit includes: a ninth voltage dividing resistor, a tenth voltage dividing resistor, a third filter capacitor, and a fourth filter capacitor; The ninth voltage dividing resistor and the third filter capacitor are connected in parallel, wherein one common terminal of the parallel connection is respectively connected to the other end of the eighth voltage dividing resistor and to the tenth voltage dividing resistor; the other common terminal of the parallel connection is connected to one end of the fourth filter capacitor; One end of the fourth filter capacitor is grounded; The other end of the tenth voltage dividing resistor is connected to the other end of the fourth filter capacitor, and the connected common terminal is connected to the input terminal of the impedance detection circuit.

8. The circuit according to claim 1, wherein The impedance detection circuit includes: a fifth filter capacitor, a voltage follower, and a judgment circuit; One end of the fifth filter capacitor is connected to pin 8 of the voltage follower, and the common connection end is connected to the positive power supply terminal; the other end of the fifth filter capacitor is connected to pin 4 of the voltage follower, and the common connection end is grounded. The input end of the voltage follower is connected to the output end of the second voltage dividing circuit; the output end of the voltage follower is connected to the judgment circuit.

9. The circuit according to claim 8, characterized in that, The judgment circuit includes: an eleventh voltage dividing resistor, a twelfth voltage dividing resistor, a sixth filter capacitor, and an electronic control unit. One end of the eleventh voltage dividing resistor is connected to the output end of the voltage follower; the other end of the eleventh voltage dividing resistor is connected to the electronic control unit. The twelfth voltage dividing resistor and the sixth filter capacitor are in parallel, one common connection end of the parallel connection is connected to the electronic control unit, and the other common connection end of the parallel connection is grounded.

10. The circuit according to claim 1, wherein The material of the housing of the power supply under test is metal.

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