CN210404715U - Leakage protection circuit and lighting circuit using same - Google Patents
Leakage protection circuit and lighting circuit using same Download PDFInfo
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- CN210404715U CN210404715U CN201921501165.1U CN201921501165U CN210404715U CN 210404715 U CN210404715 U CN 210404715U CN 201921501165 U CN201921501165 U CN 201921501165U CN 210404715 U CN210404715 U CN 210404715U
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Abstract
The utility model provides an earth leakage protection circuit and use its lighting circuit, earth leakage protection circuit includes inductive ballast detection circuitry and electric leakage detection circuitry, and inductive ballast detection circuitry detects the input current rate of change, if the input current rate of change is less than the first threshold value, the sign load input end inserts inductive ballast, controls load switch conduction or control load enable simultaneously; if the input current change rate is larger than a first threshold value, the fact that the input end of the load is not connected with the inductive ballast is represented, the electric leakage detection circuit detects whether the input end of the load leaks electricity, and if the input end of the load leaks electricity, the load switch is controlled to be turned off or the load is controlled not to be enabled; and if the load input end does not leak electricity, controlling the load switch to be conducted or controlling the load to be enabled. The utility model discloses the compatible inductive ballast of load input inserts, avoids the problem that the electric leakage misjudgement.
Description
Technical Field
The utility model relates to a power electronics field, in particular to earth leakage protection circuit and use its lighting circuit.
Background
In the process of installing the load, partial connection may occur in the process of installing the load, and if a human body is contacted carelessly at this time, electric shock is easy to occur, and the operation safety is influenced. For example, in the lighting field, the lamp tube is divided into a single-end input mode and a double-end input mode, the single-end input mode is that the connectors of the alternating current input end are arranged at the same end, the double-end input mode is arranged at two ends of the lamp tube, and because more lamp holders still keep interfaces connected with the double ends, the lamp tube with the double-end input mode is generally adopted when the original lamp tube is replaced, so that the lamp tube with the double-end input mode still has a large market.
However, especially in the case of double-ended input, one end is generally inserted into the lamp holder and then the other end, and since the operator needs to hold the end of the lamp tube by hand, the end of the lamp tube may be contacted with conductive metal, and electric shock is likely to occur. In some countries or regions, the earth leakage protection function in such a case has been taken as an essential functional module in the certification standards or specifications. In the prior art, when the load input end is connected with the inductive ballast, the inductive ballast is easily judged as the hand of an operator by mistake, so that the condition of electric leakage is judged by mistake, and an input power supply cannot normally supply power to the load.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a leakage protection circuit and use its lighting circuit for solve the electric leakage misjudgement's that prior art exists technical problem, so that input voltage can normally supply power for the load.
In order to achieve the above object, the present invention provides a leakage protection circuit, an inductive ballast detection circuit, which detects a change rate of an input current, and if the change rate of the input current is smaller than a first threshold, the inductive ballast is connected to a representation load input end, and a load switch is controlled to be turned on or a load is controlled to be enabled;
the leakage detection circuit is used for detecting whether the load input end leaks electricity or not, and controlling the load switch to be switched off or the load to be disabled if the load input end leaks electricity; and if the load input end does not leak electricity, controlling the load switch to be conducted or controlling the load to be enabled.
Optionally, the leakage protection circuit includes a logic circuit, two input ends of the logic circuit are respectively connected to the output end of the inductive ballast detection circuit and the output end of the leakage detection circuit, and the logic circuit outputs a control signal to control the on/off of the load switch or to control whether the load is enabled;
if the load input end is connected with the inductive ballast, the control signal controls the load switch to be conducted or the load to be enabled;
if the load input end is not electrified, the control signal controls the load switch to be switched on or the load to be enabled, otherwise, the control signal controls the load switch to be switched off or the load to be disabled.
Optionally, the inductive ballast detection circuit includes a current change rate detection circuit and a comparison circuit, where an input end of the current change rate detection circuit receives an input current sampling signal, detects an input current change rate, and outputs an input current change rate detection signal; the first input end of the comparison circuit is connected with the output end of the current change rate detection circuit, the second input end of the comparison circuit receives the first threshold value, and the output end of the comparison circuit is connected with one input end of the logic circuit.
Optionally, the leakage detection circuit includes a current detection module and a first comparator, a first input end of the first comparator receives a sampling signal of an input voltage, a second input end of the first comparator receives a second threshold, and the first comparator outputs a first comparison signal; the first end of the current detection module is connected with the high potential output end of the rectifying circuit or one end of the input power supply through a first resistor, the second end of the current detection module is connected with the low potential output end of the rectifying circuit, and the control end of the current detection module receives the first comparison signal; when the sampling signal of the input voltage reaches a second threshold value, the current detection module detects current flowing through the second resistor to obtain a current detection signal, and if the current detection signal is lower than a third threshold value, the current detection signal represents the electric leakage of the input end of the load.
Optionally, the current detection module includes a first switching tube and a second comparator, a first end of the first switching tube is connected to the high potential output end of the rectification circuit or one end of the input power supply through a first resistor, and a second end of the first switching tube is connected to the low potential output end of the rectification circuit through a second resistor; a first input end of the second comparator is connected with a second end of the first switch tube, the second end of the second comparator receives a third threshold value, the voltage of the second end of the first switch tube is the current detection signal, and an output signal of the second comparator is used as an output signal of the electric leakage detection circuit; and when the sampling signal of the input voltage reaches a second threshold value, the first comparison signal controls the first switch tube to be conducted.
The utility model also provides a lighting circuit, including any one of the above-mentioned earth leakage protection circuit, rectifier circuit, the rectifier circuit receives the alternating current input, and rectifies the alternating current input; the leakage protection circuit detects whether the input end of the load needs to be subjected to leakage protection; and when the load input end is connected with the inductive ballast or the load input end is not electrified, controlling the load switch to be conducted or controlling the load to be enabled.
Compared with the prior art, the utility model has the advantages of it is following: detecting the change rate of the input current, if the change rate of the input current is smaller than a first threshold value, representing that the input end of the load is connected with the inductive ballast, and simultaneously controlling the load switch to be conducted or controlling the load to be enabled; if the input current change rate is larger than a first threshold value, representing that the load input end is not connected with the inductive ballast, and simultaneously detecting whether the load input end leaks electricity or not, if the load input end leaks electricity, controlling a load switch to be switched off or controlling the load not to be enabled; and if the load input end does not leak electricity, controlling the load switch to be conducted or controlling the load to be enabled. The utility model discloses can compatible inductive ballast insert, avoid being the human body with inductive ballast misjudgement for input power supply can normally give the load power supply, the utility model discloses can also play earth leakage protection effect, promote the security of load dismouting in-process.
Drawings
Fig. 1 is a schematic diagram of the leakage protection circuit of the present invention;
FIG. 2 is a schematic diagram of the leakage detecting circuit of the present invention;
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to only these embodiments. The present invention covers any alternatives, modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.
In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention, and it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are simplified and in non-precise proportion, so as to facilitate and clearly assist in explaining the embodiments of the present invention.
As shown in fig. 1, the schematic diagram of the leakage protection circuit of the present invention is illustrated, and ac voltage or ac voltage passes through the rectifier circuit and then passes through the divider resistors R00 and R01 to obtain the sampling signal VCS of the input voltage. The leakage protection circuit comprises an inductive ballast detection circuit U01, a leakage detection circuit U02 and a logic circuit U03. The inductive ballast detection circuit U01 detects the input current change rate, if the input current change rate is smaller than a first threshold value VREF1, the input end of the representation load is connected with the inductive ballast, and meanwhile, the load switch M00 is controlled to be conducted or the load is controlled to be enabled; if the input current change rate is greater than a first threshold value VREF1, indicating that the input end of the load is not connected with the inductive ballast, detecting whether the input end of the load is in electric leakage or not by the electric leakage detection circuit U02, and if the input end of the load is in electric leakage, controlling the load switch M00 to be turned off or controlling the load not to be enabled; if the load input end does not leak electricity, the load switch M00 is controlled to be conducted or the load is controlled to be enabled. The inductive ballast detection circuit U01 includes a current rate of change detection circuit that receives an input current detection signal (the input current is the main loop current) and outputs an input current rate of change detection signal Vrate and a comparison circuit. The comparison circuit respectively receives the detection signal Vrate and a first threshold value VREF1, the output end of the comparison circuit is connected with one input end of a logic circuit U03, when the detection signal Vrate is smaller than the first threshold value VREF1, the detection signal Vrate represents that the input end of the load is connected with the inductive ballast, and when the detection signal Vrate is larger than the first threshold value VREF1, the detection signal Vrate represents that the input end of the load is not connected with the inductive ballast. The leakage detection circuit U02 receives the sampling signal VCS, and has an output terminal connected to another input terminal of the logic circuit U03. The logic circuit U03 outputs a control signal to control the on-off of the load switch or control whether the load is enabled, if the load input end is connected to the inductive ballast or the load is not electrified, the control signal controls the on-off of the load switch or the load is enabled; and if the load leaks electricity, the control signal controls the load switch to be switched off or the load is not enabled.
The inductance ballast equivalent model is big inductance series connection big resistance, the utility model discloses be 1H inductance series 100 omega resistance with the inductance ballast equivalence. Assuming that the parasitic resistance in the circuit is 860 Ω, the object access resistance in leakage is 500 Ω. In the case of an inductive ballast, it is,
for leakage, assuming dt is 100uS, then
In the case of no electrical leakage, the power supply is,
in summary, no matter leakage or no leakage occurs, when the load input end is connected to the inductive ballast, the input current change rate is smaller than that when the load input end is not connected to the inductive ballast.
As shown in fig. 2, the schematic diagram of the leakage detection circuit of the present invention is illustrated, including a first comparator U201, a current detection module U202 and a first resistor R1, wherein a first input terminal of the first comparator U201 receives a sampling signal VCS of an input voltage, a second input terminal of the first comparator U201 receives a second threshold VREF2, and the first comparator U201 outputs a first comparison signal; the first end of the current detection module U202 is connected to the high-potential output end of the rectifying circuit U00 or one end of the ac input power supply through a first resistor R1, the second end of the current detection module U202 is connected to the low-potential output end of the rectifying circuit U00, and the control end of the current detection module U202 receives the first comparison signal VC 1; when the sampling signal VCS of the input voltage reaches the second threshold VREF2, the current detection module U202 detects the current flowing through the first resistor R1 to obtain a current detection signal VC2, and when the current detection signal VC2 is lower than the third threshold VREF3, it is determined that a leakage phenomenon exists in the circuit. The current detection module U202 includes a second comparator U2022, a first switch Q1, and a second resistor R2. A first end of the first switching tube Q1 is connected with a high-potential output end of the rectifying circuit U00 or one end of an alternating-current input power supply through a first resistor R1, and a second end of the first switching tube Q1 is connected with a low-potential output end of the rectifying circuit U00 through a second resistor R2; the first input end of the second comparator U2022 is connected to the second end of the first switch Q1, the second end of the second comparator U2022 receives a third threshold VREF3, the voltage at the second end of the first switch Q1 is the current detection signal, and the output signal of the second comparator U2022 is the output signal of the leakage detection circuit. The first comparison signal VC1 controls the on/off of the first switch tube Q1, and when the sampling signal VCs of the input voltage reaches the second threshold VREF2, the first comparison signal VC1 controls the on/off of the first switch tube Q1.
Although the embodiments have been described and illustrated separately, it will be apparent to those skilled in the art that some common techniques may be substituted and integrated between the embodiments, and reference may be made to one of the embodiments not explicitly described, or to another embodiment described.
The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.
Claims (6)
1. An earth leakage protection circuit, characterized in that: comprises that
The inductive ballast detection circuit detects the change rate of the input current, if the change rate of the input current is smaller than a first threshold value, the inductive ballast is connected to the input end of the characterization load, and meanwhile, the load switch is controlled to be conducted or the load is controlled to be enabled;
the leakage detection circuit is used for indicating that the input end of the load is not connected with the inductive ballast if the change rate of the input current is greater than a first threshold value, detecting whether the input end of the load leaks electricity or not, and controlling the load switch to be switched off or the load to be disabled if the input end of the load leaks electricity; and if the load input end does not leak electricity, controlling the load switch to be conducted or controlling the load to be enabled.
2. The earth leakage protection circuit of claim 1, wherein: the leakage protection circuit further comprises a logic circuit, two input ends of the logic circuit are respectively connected with the output end of the inductive ballast detection circuit and the output end of the leakage detection circuit, and the logic circuit outputs a control signal;
if the load input end is connected with the inductive ballast, the control signal controls the load switch to be conducted or the load to be enabled;
when the load input end is not connected with the inductive ballast, if the load input end is not electrified, the control signal controls the load switch to be switched on or the load to be enabled, otherwise, the control signal controls the load switch to be switched off or the load to be disabled.
3. The earth leakage protection circuit of claim 2, wherein: the inductive ballast detection circuit comprises a current change rate detection circuit and a comparison circuit, wherein the input end of the current change rate detection circuit receives an input current sampling signal, detects the input current change rate and outputs an input current change rate detection signal; the first input end of the comparison circuit is connected with the output end of the current change rate detection circuit, the second input end of the comparison circuit receives the first threshold value, and the output end of the comparison circuit is connected with one input end of the logic circuit.
4. The earth leakage protection circuit of any one of claims 1, 2 or 3, wherein: the leakage detection circuit comprises a current detection module and a first comparator, wherein a first input end of the first comparator receives a sampling signal of an input voltage, a second input end of the first comparator receives a second threshold value, and the first comparator outputs a first comparison signal; the first end of the current detection module is connected with the high potential output end of the rectifying circuit or one end of the input power supply through a first resistor, the second end of the current detection module is connected with the low potential output end of the rectifying circuit, and the control end of the current detection module receives the first comparison signal; when the sampling signal of the input voltage reaches a second threshold value, the current detection module detects current flowing through the second resistor to obtain a current detection signal, and if the current detection signal is lower than a third threshold value, the current detection signal represents the electric leakage of the input end of the load.
5. The leakage protection circuit of claim 4, wherein: the current detection module comprises a first switching tube and a second comparator, wherein the first end of the first switching tube is connected with the high-potential output end of the rectification circuit or one end of the input power supply through a first resistor, and the second end of the first switching tube is connected with the low-potential output end of the rectification circuit through a second resistor; a first input end of the second comparator is connected with a second end of the first switch tube, the second end of the second comparator receives a third threshold value, the voltage of the second end of the first switch tube is the current detection signal, and an output signal of the second comparator is used as an output signal of the electric leakage detection circuit; and when the sampling signal of the input voltage reaches a second threshold value, the first comparison signal controls the first switch tube to be conducted.
6. A lighting driving circuit, characterized in that: the leakage protection circuit comprises any one of the leakage protection circuit and the rectifying circuit, wherein the rectifying circuit receives an alternating current input and rectifies the alternating current input; the leakage protection circuit detects whether the input end of the load needs to be subjected to leakage protection; and when the load input end is connected with the inductive ballast or the load input end is not electrified, controlling the load switch to be conducted or controlling the load to be enabled.
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| CN201921501165.1U CN210404715U (en) | 2019-09-10 | 2019-09-10 | Leakage protection circuit and lighting circuit using same |
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| CN201921501165.1U CN210404715U (en) | 2019-09-10 | 2019-09-10 | Leakage protection circuit and lighting circuit using same |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110601134A (en) * | 2019-09-10 | 2019-12-20 | 杰华特微电子（杭州）有限公司 | Leakage protection circuit, protection method and lighting circuit applying leakage protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110601134A (en) * | 2019-09-10 | 2019-12-20 | 杰华特微电子（杭州）有限公司 | Leakage protection circuit, protection method and lighting circuit applying leakage protection circuit |
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Address after: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee after: Jiehuate Microelectronics Co.,Ltd. Address before: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee before: JOULWATT TECHNOLOGY (HANGZHOU) Co.,Ltd. |
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