CN213398876U - Grounding detection circuit and electrical appliance - Google Patents
Grounding detection circuit and electrical appliance Download PDFInfo
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- CN213398876U CN213398876U CN202021895302.7U CN202021895302U CN213398876U CN 213398876 U CN213398876 U CN 213398876U CN 202021895302 U CN202021895302 U CN 202021895302U CN 213398876 U CN213398876 U CN 213398876U
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Abstract
The utility model is suitable for an electronic circuit technical field provides a ground connection detection circuitry and uses electrical apparatus, and the circuit includes: the grounding detection unit is used for detecting voltage signals of the power connection end and the grounding end and correspondingly outputting a first detection signal and a second detection signal; the rectification filtering unit is used for receiving the first detection signal and the second detection signal, and outputting the first detection signal and the second detection signal after rectification filtering processing; the comparison output unit is used for receiving and comparing the first detection signal and the second detection signal which are subjected to rectification filtering processing, and outputting a comparison result to a control chip of the electric appliance; the detection power supply unit is used for converting a mains supply voltage signal input by the power connection end into a stable circuit working voltage signal and outputting the stable circuit working voltage signal to the comparison output unit. The embodiment detects the first detection signal and the second detection signal through the grounding detection unit, and compares the first detection signal and the second detection signal through the comparison output unit, so as to detect whether the electrical appliance is grounded.
Description
Technical Field
The utility model belongs to the technical field of electronic circuit, especially, relate to a ground connection detection circuitry and use electrical apparatus.
Background
Along with the increasing development of urbanization, electrical appliances become indispensable articles in family life, and along with the increasing abundance of varieties and functions of electrical appliances, places using the electrical appliances in life and work are more and more, the power consumption safety of the electrical appliances is more and more emphasized by people, and the power consumption safety of the electrical appliances is realized through the leakage protection of the electrical appliances.
The existing leakage protection of an electrical appliance is generally realized by connecting a metal shell of the electrical appliance with a power ground wire, and when leakage current occurs, the leakage protection of the electrical appliance is conducted to a common ground through the power ground wire, so that electric shock accidents to human bodies are avoided. And the leakage protection switch is arranged at the power supply inlet wire position, and when the leakage occurs, the power supply of the electrical equipment is directly cut off, so that the protection is realized.
However, these holding measures still have potential safety hazards, after the electrical appliance is used for a long time, due to reasons such as aging and loose circuit welding, poor contact can occur when the electrical appliance is connected to a public ground, the existing electrical appliance lacks a detection function for detecting whether the electrical appliance is grounded, the electrical appliance with poor grounding contact is continuously used, the potential safety hazards of electric shock accidents caused by circuit leakage exist, and the safety and reliability of the electrical appliance grounding cannot be guaranteed.
SUMMERY OF THE UTILITY MODEL
The utility model provides a ground connection detection circuitry aims at solving and detects the problem whether contact failure exists of electrical apparatus ground wire.
The utility model discloses a realize like this, a ground connection detection circuitry, include:
the grounding detection unit is connected with the power connection end and the ground wire end of the electrical appliance and used for detecting voltage signals of the power connection end and the ground wire end and correspondingly outputting a first detection signal and a second detection signal;
the rectification filtering unit is connected with the output end of the grounding detection unit and used for receiving the first detection signal and the second detection signal and outputting the first detection signal and the second detection signal after rectification filtering processing;
the comparison output unit is connected with the rectification filtering unit and used for receiving and comparing the first detection signal and the second detection signal which are subjected to rectification filtering processing, and outputting a comparison result to a control chip of the electric appliance;
and the detection power supply unit is connected with the power connection end and used for converting a voltage signal input by the power connection end into a stable circuit working voltage signal and outputting the stable circuit working voltage signal to the comparison output unit.
Still further, the ground detection circuit further includes:
and the chip power supply unit is connected with the power connection end and used for converting a voltage signal input by the power connection end into a stable chip working voltage signal and outputting the stable chip working voltage signal to the control chip.
Furthermore, the grounding detection unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first diode, a second diode, a third diode and a fourth diode;
one end of the first resistor is connected with a first power connection point of the power connection end, and the other end of the first resistor is connected to the ground wire end sequentially through a second resistor, a third resistor, a first diode and a fourth resistor which are connected in series;
the anode of the first diode is connected with one end of the fourth resistor, the cathode of the first diode is connected with the third resistor, the cathode of the first diode is also connected to the first output end through the second triode which is conducted in the forward direction, and one end of the first resistor, which is connected with the second resistor, is connected to the second output end through the third diode;
one end of the fifth resistor is connected with a second power connection point of the power connection end, the other end of the fifth resistor is connected to a line between the second resistor and the third resistor through a sixth resistor, the other end of the fifth resistor is further connected with the output end of the second circuit through a fourth diode, and one end of the sixth resistor, which is connected with the second resistor, is further connected to the ground end.
Furthermore, the rectifying and filtering unit comprises a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first capacitor and a second capacitor;
one end of the first capacitor is connected with the first output end, the other end of the first capacitor is connected with the second output end through the second capacitor, and a line between the first capacitor and the second capacitor is connected to the ground end;
one end of the seventh resistor is connected with the first path of output end, the other end of the seventh resistor is connected with the second path of output end through the eighth resistor, and a line between the seventh resistor and the eighth resistor is connected to the ground end;
one end of the ninth resistor is connected with the first output end, and the other end of the ninth resistor is connected with the first input end of the comparison output unit;
one end of the tenth resistor is connected with the second output end, and the other end of the tenth resistor is connected with the second input end of the comparison output unit.
Further, the comparison output unit includes a comparator and an eleventh resistor;
the positive input end of the comparator is used as a first input end and connected with the other end of the ninth resistor, the reverse input end of the comparator is used as a second input end and connected with the other end of the tenth resistor, the voltage end of the comparator is connected with the output end of the detection power supply unit, the grounding end of the comparator is connected to the ground end, and the output end of the comparator is connected to the control chip through the eleventh resistor.
Furthermore, the comparison output unit further comprises an optical coupling isolation module;
the positive input electrode and the eleventh resistor of the optical coupling isolation module are connected with one end, far away from the comparator, of the eleventh resistor, the negative input electrode is connected to the ground end, the positive output electrode is connected to the control chip, and the negative output electrode is grounded.
Furthermore, the detection power supply unit comprises a rectifier bridge, a third capacitor, a fourth capacitor, a fifth capacitor, a Y capacitor, a fifth diode, a switching device and a voltage chip;
the input end of the rectifier bridge is connected with the first power connection point and the second power connection point, the output end of the rectifier bridge comprises a first end and a second end, the first end is connected to the first end of a main winding of the transformer, the second end of the main winding is connected with the first pole of the switching device, the second pole of the switching device is connected with the second end, and the first end is connected with the second end through a third capacitor;
one end of the Y capacitor is connected with the second end, the other end of the Y capacitor is connected with the first end of the auxiliary winding of the transformer, the second end of the auxiliary winding is connected with the first pin of the voltage chip through a fifth diode which is conducted in the forward direction, the cathode of the fifth diode is connected to the ground end through a fourth capacitor, the other end of the Y capacitor and the second pin of the voltage chip are both connected to the ground end, the third pin of the voltage chip is connected to the ground end through the fifth capacitor, and the third pin is further connected to the comparison output unit.
Furthermore, the chip power supply unit comprises a twelfth resistor, a sixth capacitor and a sixth diode;
the anode of the sixth diode is connected with the first end of the secondary winding of the transformer, the cathode of the sixth diode is connected with the second end of the secondary winding through a sixth capacitor, the second end of the secondary winding is grounded, the cathode of the sixth diode is further connected with the output anode of the optical coupling isolation module through a twelfth resistor, and the cathode of the sixth diode is further connected with the voltage end of the control chip.
In a second aspect, the present application further provides an electrical appliance, including the ground fault detection circuit as described above.
The embodiment of the utility model provides a connect electrical terminal and ground wire end through ground connection detecting element and with electrical apparatus and be connected, thereby detect the voltage signal who connects electrical terminal and ground wire end, and will detect first detected signal and second detected signal output to rectification filter unit that generates, carry out output to comparison output unit after rectification filter processing to first detected signal and second detected signal by rectification filter unit, comparison output unit carries out comparison generation comparison result to first detected signal and second detected signal, and export comparison result to control chip, control chip judges whether ground connection with electrical apparatus according to this comparison result, thereby whether the ground wire that realizes detecting with electrical apparatus contacts badly the function.
Drawings
Fig. 1 is a block diagram of an embodiment of a ground fault detection circuit provided by the present invention;
fig. 2 is a block diagram of another embodiment of a ground detection circuit according to the present invention;
fig. 3 is a schematic diagram of a specific circuit structure of an embodiment of the ground fault detection circuit provided by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention 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 invention and are not intended to limit the invention.
The existing household appliance is not grounded and is detected, potential safety hazards exist, the household appliance is connected with a power connection end and a ground wire end of the electric appliance through a ground detection unit, voltage signals of the power connection end and the ground wire end are detected, a first detection signal and a second detection signal generated by detection are output to a rectification filtering unit, the first detection signal and the second detection signal are output to a comparison output unit after being subjected to rectification filtering processing through the rectification filtering unit, the comparison output unit compares the first detection signal and the second detection signal to generate a comparison result, the comparison result is output to a control chip, and the control chip judges whether the electric appliance is grounded according to the comparison result, so that the function of detecting whether the ground wire of the electric appliance is in poor contact is achieved.
Example one
In some alternative embodiments, please refer to fig. 1, in which fig. 1 is a block diagram illustrating a grounding detection circuit according to an embodiment of the present disclosure.
As shown in fig. 1, the present application provides a ground fault detection circuit, which is characterized by comprising a ground fault detection unit 1, a rectifying and filtering unit 2, a comparison output unit 3 and a detection power supply unit.
The grounding detection unit 1 is connected with the power connection end and the ground end of the electrical appliance and used for detecting voltage signals of the power connection end and the ground end and correspondingly outputting a first detection signal and a second detection signal; the rectification filtering unit 2 is connected with the output end of the grounding detection unit 1 and is used for receiving the first detection signal and the second detection signal, and outputting the first detection signal and the second detection signal after rectification filtering processing; the comparison output unit 3 is connected with the rectification filtering unit 2 and is used for receiving and comparing the first detection signal and the second detection signal which are subjected to rectification filtering processing, and outputting a comparison result to a control chip MCU of the electric appliance; the detection power supply unit 4 is connected with the power connection end and used for converting a voltage signal input by the power connection end into a stable circuit working voltage signal and outputting the stable circuit working voltage signal to the comparison output unit 3.
When the detection device is implemented, the grounding detection unit 1 comprises a plurality of voltage dividing resistors which are connected with the power connection end and the ground wire end through the combination of the plurality of voltage dividing resistors so as to convert the voltage signals of the power connection end and the ground wire end into a first detection signal and a second detection signal; the rectification filter unit 2 rectifies and filters the first detection signal and the second detection signal, so as to reduce the output pulsation degree of the first detection signal and the second detection signal, so that the first detection signal and the second detection signal are smoother, then the first detection signal and the second detection signal are output to the comparison output unit 3, the comparison output unit 3 is powered by the detection power supply unit 4, the detection power supply unit 4 converts the mains supply voltage signal into a stable circuit working voltage signal without additionally increasing an independent power supply, the design difficulty and the input cost of the circuit are reduced, the comparison output unit 3 compares the first detection signal and the second detection signal to generate a comparison result, then the comparison result is output to a control chip MCU of the electrical appliance, the control chip MCU judges whether the grounding is poor according to the comparison result, and forbids a user to use the function of the electrical appliance when the grounding is poor, so as to protect the electric appliance and the electric safety of users.
This application is connected with the end of connecting electricity and the ground wire end of using electrical apparatus through ground connection detecting element 1, thereby detect the voltage signal who connects electricity end and ground wire end, and will detect first detected signal and second detected signal output to rectification filter unit 2 that generates, carry out rectification filter to first detected signal and second detected signal by rectification filter unit 2 and export to comparison output unit 3 after handling, comparison output unit 3 carries out comparison to first detected signal and second detected signal and generates the comparison result, and export the comparison result to control chip MCU, control chip MCU judges whether ground connection with electrical apparatus according to this comparison result, thereby realize detecting whether bad contact function with electrical apparatus's ground wire.
Example two
In some alternative embodiments, please refer to fig. 2, fig. 2 is a block diagram of another embodiment of the ground detection circuit of the present application.
As shown in fig. 2, the ground detection circuit provided by the present application further includes a chip power supply unit 5.
The chip power supply unit 5 is connected with the power connection end and used for converting a voltage signal input by the power connection end into a stable chip working voltage signal and outputting the stable chip working voltage signal to the control chip MCU.
Convert voltage signal into stable chip operating voltage signal through chip power supply unit 5, export chip operating voltage signal to control chip MCU, realize supplying power to control chip MCU, do not need individual control chip MCU to increase extra power, reduce the manufacturing cost of product.
EXAMPLE III
In some alternative embodiments, please refer to fig. 3, fig. 3 is a schematic circuit diagram of an embodiment of the ground detection circuit of the present application.
As shown in fig. 2, the ground detecting unit 1 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4;
one end of a first resistor R1 is connected with a first power connection point L of a power connection end, and the other end of the first resistor R1 is connected to a ground terminal PE through a second resistor R2, a third resistor R3, a first diode D1 and a fourth resistor R4 which are connected in series in sequence;
an anode of the first diode D1 is connected with one end of the fourth resistor R4, a cathode of the first diode D1 is connected with one end of the third resistor R3, a cathode of the first diode D1 is connected to the first output terminal Vr0 through the second triode D2 which is conducted in the forward direction, and one end of the first resistor R1, which is connected with the second resistor R2, is connected to the second output terminal Vef through the third diode D3; the cathode of the first diode D1 is connected with the anode of the second triode D2, and the cathode of the second triode is connected with the first output end Vr 0;
one end of the fifth resistor R5 is connected with the second power connection point N of the power connection end, the other end of the fifth resistor R5 is connected to a line between the second resistor R2 and the third resistor R3 through a sixth resistor R6, the other end of the fifth resistor R5 is also connected with the second power output end Vef through a fourth diode D4, and one end of the sixth resistor R6, which is connected with the second resistor R2, is also connected to the ground end Earth.
In implementation, Earth terminal Earth represents the connection with the Earth, and the first power connection point L and the second power connection point N are alternating current input terminals. Resistor R0 is the equivalent resistance of ground terminal PE to terminal N. When the voltage of the first output terminal Vr0 is lower than the voltage of the second output terminal Vef, the comparison output unit 3 outputs a high potential, which is equivalent to the voltage value of the circuit working voltage signal output by the detection power supply unit 4; when the voltage of the first output end Vr0 is higher than the voltage of the second output end Vef, the comparison output unit 3 outputs a low potential, and the control chip MCU judges whether the grounding is poor according to the level of the output signal of the comparison output unit 3.
Example four
The rectifying and filtering unit 2 comprises a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1 and a second capacitor C2;
one end of a first capacitor C1 is connected with the first output end Vr0, the other end of the first capacitor C1 is connected with the second output end Vef through a second capacitor C2, and a line between the first capacitor C1 and the second capacitor C2 is connected to a ground end Earth;
one end of a seventh resistor R7 is connected with the first path output end Vr0, the other end of the seventh resistor R7 is connected with the second path output end Vef through an eighth resistor R8, and a line between the seventh resistor R7 and the eighth resistor R8 is connected to the ground end Earth;
one end of the ninth resistor R9 is connected to the first output terminal Vr0, and the other end is connected to the first input terminal of the comparison output unit 3;
one end of the tenth resistor R10 is connected to the second output terminal Vef, and the other end is connected to the second input terminal of the comparison output unit 3.
The comparison output unit 3 includes a comparator E1 and an eleventh resistor R11;
the positive input end of the comparator E1 is used as a first input end and connected with the other end of the ninth resistor R9, the negative input end of the comparator E1 is used as a second input end and connected with the other end of the tenth resistor R10, the voltage end of the comparator E1 is connected with the output end of the detection power supply unit 4, the grounding end of the comparator E1 is connected to the Earth end Earth, and the output end of the comparator E1 is connected to the control chip MCU through the eleventh resistor R11.
The voltage signals of the first output end Vr0 and the second output end Vef are rectified and filtered through the rectifying and filtering unit 2, and the rectified and filtered voltage signals are output to the comparator E1 to be compared, for example, when the level of the first output end Vr0 is higher than that of the second output end Vef, the comparator E1 outputs a low level to the control chip MCU, when the level of the first output end Vr0 is lower than that of the second output end Vef, the comparator E1 outputs a high level to the control chip MCU, the control chip MCU judges whether the ground wire is in poor contact according to the level of the electric signal output by the comparator E1, for example, when the comparator E1 outputs a high level to the control chip MCU, the ground wire is judged to be in good contact, and when the comparator E1 outputs a low level to the control chip MCU, the ground wire is judged to be in poor contact. Of course, in implementation, the positive input end and the negative input end of the comparator E1 may be connected to the other ends of the tenth resistor R10 and the ninth resistor R9, respectively, and in this case, the control logic of the control chip MCU is opposite to the above, so that the detection of the poor ground may be achieved.
EXAMPLE five
The comparison output unit 3 further comprises an optical coupling isolation module;
the positive input pole of the optical coupling isolation module is connected with one end, far away from the comparator E1, of the eleventh resistor R11, the negative input pole of the optical coupling isolation module is connected to Earth end Earth, the positive output pole of the optical coupling isolation module is connected to the control chip MCU, and the negative output pole of the optical coupling isolation module is grounded. Data transmission is carried out through the optical coupling isolation module, so that the high-voltage end of a mains supply and the low-voltage end of the chip are isolated, and the safety of a circuit is protected.
EXAMPLE six
The detection power supply unit 4 comprises a rectifier bridge E2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a Y capacitor CY1, a fifth diode D5, a switching device Q1 and a voltage chip U1;
an input end of a rectifier bridge E2 is connected with an L end and an N end, an output end of the rectifier bridge E2 comprises a first end El1 and a second end El2, the first end El1 is connected with a first end of a main winding of a transformer T1, the second end of the main winding is connected with a first pole of a switching device Q1, a second pole of the switching device Q1 is connected with a second end El2, and a first end El1 is connected with a second end El2 through a third capacitor C3; in practice, the switching device Q1 is an electronic component capable of opening a circuit, interrupting a current, or making the current flow to other circuits, the switching device Q1 includes but is not limited to a MOS transistor, a triode, a power transistor, etc., a first pole, a second pole, and a third pole of the switching device Q1 are three pins of the switching device Q1, the switching device Q1 is an MOS transistor, and a first pole, a second pole, and a third pole of the switching device Q1 are a drain, a source, and a gate of the MOS transistor, respectively, where the third pole of the switching device Q1 is connected to a switching power supply control chip, and the third pole of the switching device Q1 is connected to the switching power supply control chip as a prior art, which will not be described herein.
One end of a Y capacitor CY1 is connected to the second end El2, the other end is connected to the first end of the auxiliary winding of the transformer T1, the second end of the auxiliary winding is connected to the first pin of the voltage chip U1 through a forward conducting fifth diode D5, the cathode of the fifth diode D5 is further connected to the ground end Earth through a fourth capacitor C4, the other end of the Y capacitor CY1 and the second pin of the voltage chip U1 are both connected to the ground end Earth, the third pin of the voltage chip U1 is connected to the ground end Earth through a fifth capacitor C5, and the third pin is further connected to the comparison output unit. The first pin of the voltage chip U1 is an input pin Vin, the second pin of the voltage chip U1 is a ground pin GND, and the third pin of the voltage chip U1 is an output pin Vout.
During implementation, the Y capacitor CY1 is a safety capacitor, the Y capacitor CY1 cannot cause electric shock after the capacitor fails, personal safety is not damaged, the output voltage of the auxiliary winding of the switching power supply is stabilized by using the Y capacitor CY1, the voltage output from the power supply unit 4 to the comparison output unit 3 is further stably detected, the circuit stability can be effectively improved, and the accuracy of ground wire detection is provided.
EXAMPLE seven
The chip power supply unit 5 includes a twelfth resistor R12, a sixth capacitor C6, and a sixth diode D6;
an anode of the sixth diode D6 is connected to a first end of the secondary winding of the transformer T1, a cathode of the sixth diode D6 is connected to a second end of the secondary winding through a sixth capacitor C6, the second end of the secondary winding is grounded, a cathode of the sixth diode D6 is further connected to an output anode of the opto-coupler isolation module through a twelfth resistor R12, and a cathode of the sixth diode D6 is further connected to a voltage end of the control chip MCU. The power supply unit 5 supplies power to the control chip MCU, and a power supply is not required to be additionally arranged on the control chip MCU, so that the circuit structure is simplified, and the production cost is reduced.
Example eight
In a second aspect, the present application further provides an electrical appliance, including the ground fault detection circuit as described above.
When the detection circuit is implemented, the power connection end of an electric appliance is connected with a live wire and a zero line of commercial power, the ground wire end is grounded, and the ground detection unit 1 of the ground detection circuit is connected with the power connection end and the ground wire end, so that voltage signals of the power connection end and the ground wire end are converted into a first detection signal and a second detection signal; the rectification filtering unit 2 carries out rectification filtering processing on the first detection signal and the second detection signal, so that the output pulsation degree of the first detection signal and the second detection signal is reduced, the first detection signal and the second detection signal are smoother, then the first detection signal and the second detection signal are output to the comparison output unit 3, the comparison output unit 3 compares the first detection signal and the second detection signal to generate a comparison result, then the comparison result is output to a control chip MCU of an electrical appliance, the control chip MCU judges whether the electrical appliance is in poor ground connection according to the comparison result, and the function of the electrical appliance is forbidden to be used by a user when the electrical appliance is in poor ground connection, so that the electrical appliance and the power utilization safety of the user are protected.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. A ground detection circuit, comprising:
the grounding detection unit (1) is connected with a power connection end and a grounding end (PE) of an electrical appliance and is used for detecting voltage signals of the power connection end and the grounding end (PE) and correspondingly outputting a first detection signal and a second detection signal;
the rectification filtering unit (2) is connected with the output end of the grounding detection unit (1) and is used for receiving the first detection signal and the second detection signal, and outputting the first detection signal and the second detection signal after rectification filtering processing;
the comparison output unit (3) is connected with the rectification filtering unit (2) and is used for receiving and comparing the first detection signal and the second detection signal which are subjected to rectification filtering processing, and outputting a comparison result to a control chip (MCU) of an electric appliance;
and the detection power supply unit (4) is connected with the power connection end and is used for converting a voltage signal input by the power connection end into a stable circuit working voltage signal and outputting the stable circuit working voltage signal to the comparison output unit (3).
2. The ground detection circuit of claim 1, further comprising:
and the chip power supply unit (5) is connected with the power connection end and used for converting a voltage signal input by the power connection end into a stable chip working voltage signal and outputting the stable chip working voltage signal to the control chip (MCU).
3. The ground detection circuit according to claim 2, characterized in that the ground detection unit (1) comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a first diode (D1), a second diode (D2), a third diode (D3), and a fourth diode (D4);
one end of the first resistor (R1) is connected with a first power connection point (L) of the power connection end, and the other end of the first resistor (R1) is connected to the ground terminal (PE) through the second resistor (R2), the third resistor (R3), the first diode (D1) and the fourth resistor (R4) which are connected in series in sequence;
the anode of the first diode (D1) is connected with one end of the fourth resistor (R4), the cathode of the first diode is connected with the third resistor (R3), the cathode of the first diode is also connected to the first output end (Vr0) through the second diode (D2) which is conducted in the forward direction, and one end of the first resistor (R1) connected with the second resistor (R2) is connected to the second output end (Vef) through the third diode (D3);
one end of the fifth resistor (R5) is connected with a second power connection point (N) of the power connection end, the other end of the fifth resistor (R5) is connected to a line between the second resistor (R2) and the third resistor (R3) through the sixth resistor (R6), the other end of the fifth resistor (R5) is connected with the second power output end (Vef) through the fourth diode (D4), and one end of the sixth resistor (R6) connected with the second resistor (R2) is further connected to a ground end (Earth).
4. The ground detection circuit according to claim 3, characterized in that the rectifying-filtering unit (2) comprises a seventh resistor (R7), an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R10), a first capacitor (C1) and a second capacitor (C2);
one end of the first capacitor (C1) is connected with the first output end (Vr0), the other end of the first capacitor (C1) is connected with the second output end (Vef) through the second capacitor (C2), and a line between the first capacitor (C1) and the second capacitor (C2) is connected to the ground end (Earth);
one end of the seventh resistor (R7) is connected with the first output end (Vr0), the other end of the seventh resistor (R7) is connected with the second output end (Vef) through the eighth resistor (R8), and a line between the seventh resistor (R7) and the eighth resistor (R8) is connected to the ground (Earth);
one end of the ninth resistor (R9) is connected with the first path output end (Vr0), and the other end of the ninth resistor is connected with the first input end of the comparison output unit (3);
one end of the tenth resistor R10(10) is connected with the second output end (Vef), and the other end is connected with the second input end of the comparison output unit (3).
5. The ground detection circuit according to claim 4, characterized in that the comparison output unit (3) comprises a comparator (E1) and an eleventh resistor (R11);
the positive input end of the comparator (E1) is used as the first input end and connected with the other end of the ninth resistor (R9), the reverse input end is used as the second input end and connected with the other end of the tenth resistor (R10), the voltage end is connected with the output end of the detection power supply unit (4), the grounding end is connected to the ground end (Earth), and the output end is connected to the control chip (MCU) through the eleventh resistor (R11).
6. The ground detection circuit according to claim 5, characterized in that the comparison output unit (3) further comprises an opto-isolator module;
the positive input electrode of the optical coupling isolation module is connected with one end, far away from the comparator (E1), of the eleventh resistor (R11), the negative input electrode of the optical coupling isolation module is connected to the ground end (Earth), the positive output electrode of the optical coupling isolation module is connected to the control chip (MCU), and the negative output electrode of the optical coupling isolation module is grounded.
7. The ground detection circuit according to claim 6, characterized in that the detection power supply unit (4) comprises a rectifier bridge (E2), a third capacitor (C3), a fourth capacitor (C4), a fifth capacitor (C5), a Y capacitor (CY1), a fifth diode (D5), a switching device (Q1) and a voltage chip (U1);
an input end of the rectifier bridge (E2) is connected to the first power connection point (L) and the second power connection point (N), an output end of the rectifier bridge (E2) includes a first end (El1) and a second end (El2), the first end (El1) is connected to a first end of a main winding of a transformer (T1), the second end of the main winding is connected to a first pole of the switching device (Q1), a second pole of the switching device (Q1) is connected to the second end (El2), and the first end (El1) is connected to the second end (El2) through the third capacitor (C3);
one end of the Y capacitor (CY1) is connected to the second end (El2), the other end of the Y capacitor is connected to the first end of the auxiliary winding of the transformer (T1), the second end of the auxiliary winding is connected to the first pin of the voltage chip (U1) through the forward conducting fifth diode (D5), the cathode of the fifth diode (D5) is further connected to the ground (Earth) through the fourth capacitor (C4), the other end of the Y capacitor (CY1) and the second pin of the voltage chip (U1) are both connected to the Earth (Earth), the third pin of the voltage chip (U1) is connected to the Earth (Earth) through the fifth capacitor (C5), and the third pin is further connected to the comparison output unit (3).
8. The ground detection circuit according to claim 7, characterized in that the chip power supply unit (5) comprises a twelfth resistor (R12), a sixth capacitor (C6) and a sixth diode (D6);
the positive pole of sixth diode (D6) is connected the first end of the secondary winding of transformer (T1), the negative pole passes through sixth electric capacity (C6) with the second end of secondary winding is connected, the second end ground connection of secondary winding, the negative pole of sixth diode (D6) still passes through twelfth resistance (R12) with the output positive pole of opto-coupler isolation module is connected, the negative pole of sixth diode (D6) still with the voltage end connection of control chip (MCU).
9. An electrical consumer, characterized in that it comprises a ground detection circuit as claimed in any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021895302.7U CN213398876U (en) | 2020-09-02 | 2020-09-02 | Grounding detection circuit and electrical appliance |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021895302.7U CN213398876U (en) | 2020-09-02 | 2020-09-02 | Grounding detection circuit and electrical appliance |
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| CN213398876U true CN213398876U (en) | 2021-06-08 |
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| CN202021895302.7U Active CN213398876U (en) | 2020-09-02 | 2020-09-02 | Grounding detection circuit and electrical appliance |
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| CN (1) | CN213398876U (en) |
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