Leakage protection circuit, protection method and lighting circuit using the same
By designing a leakage protection circuit for detecting current, the problem of poor leakage protection performance when multiple lamps are connected in parallel is solved, and higher safety and accurate leakage detection are achieved.
Patent Information
- Application Number
- CN201910853398.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-09-10
- Publication Date
- 2025-03-18
- Estimated Expiration
- 2039-09-10
AI Technical Summary
The prior art has poor leakage protection performance when multiple lamps are connected in parallel, which affects operational safety.
A leakage protection circuit is designed to detect the current flowing through the first switch tube, and when the current is less than the threshold, it is characterized by leakage, and when the current is less than the threshold, it is characterized by overcurrent, and when the current is greater than the threshold, it is controlled to turn off the first switch tube.
In the case of multi-light parallel connection, the leakage protection performance and the safety of load switches are improved, and the safety during load disassembly and assembly are improved.
Smart Images
Figure CN110601133B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of power electronics, and in particular to a leakage protection circuit, a protection method and a lighting circuit using the same. Background Art
[0002] During the installation of the load, it may be partially connected. If the human body accidentally touches it, it is easy to get an electric shock, affecting the safety of operation. Figure 1 As shown, the schematic diagram of the leakage protection circuit of the prior art is illustrated. The input power supply or the input power supply after passing through the rectifier circuit, passes through the voltage divider resistors R00 and R01 to obtain the sampling signal VCS of the input voltage. The leakage protection circuit includes a resistor R1, a resistor R2 and a detection switch Q1. The first end of the detection switch Q1 is connected to the high potential output end of the rectifier circuit or one end of the input power supply through the resistor R1, and the second end of the detection switch Q1 is connected to the low potential output end of the rectifier circuit through the resistor R2. When the sampling signal VCS reaches the first threshold VREF1, the detection switch Q1 is controlled to be turned on; when the voltage at the second end of the detection switch Q1 is less than the second threshold VREF2, it indicates that the load input end is leaking, and the load switch M00 is controlled to be turned off.
[0003] When the first end of the detection switch Q1 is connected to one end of the input power supply through the resistor R1, although the setting of the resistor R1 reduces the stress of the detection switch Q1, the stress on the resistor R1 is relatively large; when the first end of the detection switch Q1 is connected to the high-potential output end of the rectifier circuit through the resistor R1, the setting of the resistor R1 will make the current flowing through the detection switch Q1 too small, and when leakage occurs, the current flowing through the detection switch Q1 becomes smaller, thereby affecting the accuracy of leakage detection. In addition, when the load switch is turned on, the load switch may be overcurrent, causing damage to the load switch. Summary of the invention
[0004] The object of the present invention is to provide a leakage protection circuit, a protection method and a lighting circuit using the same, so as to solve the problem of poor leakage protection performance when multiple lamps are connected in parallel in the prior art.
[0005] To achieve the above object, the present invention provides a leakage protection circuit, comprising a first switch tube, wherein a first end of the first switch tube is connected to a high potential output end of a rectifier circuit or one end of an AC input power supply, and a second end of the first switch tube is connected to a low potential output end of the rectifier circuit via a first resistor;
[0006] When the sampling signal of the input voltage reaches the first threshold, the current flowing through the first switch tube is detected to obtain a first current detection signal; when the first current detection signal is less than the second threshold, it indicates that the load input end is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold, it indicates that the first switch tube is overcurrent, and the first switch tube is controlled to be turned off.
[0007] Optionally, when the first current detection signal is greater than a second threshold, the current flowing through the load switch is detected to obtain a second current detection signal. When the second current detection signal is greater than a fourth threshold, it indicates that the load switch is overcurrent, and the load switch is controlled to be turned off.
[0008] Optionally, the leakage protection circuit further includes a first comparator, a second comparator and a third comparator, wherein the first input terminal of the first comparator receives a sampling signal of an input voltage, the second input terminal of the first comparator receives a first threshold value, and the first comparator outputs a first comparison signal; the first input terminal of the second comparator is connected to the second terminal of the first switch tube, the second input terminal of the second comparator receives a second threshold value, and the second comparator outputs a second comparison signal; the first input terminal of the third comparator is connected to the second terminal of the first switch tube, the second input terminal of the third comparator receives a third threshold value, and the third comparator outputs a third comparison signal;
[0009] When the sampling signal reaches a first threshold, the first comparison signal controls the first switch tube to turn on; when the first current detection signal is less than a second threshold, the second comparison signal controls the load switch to turn off or controls the load to be disabled; when the first current detection signal is greater than a third threshold, the third comparison signal controls the first switch tube to turn off.
[0010] Optionally, the leakage protection circuit also includes a fourth comparator. When the first current detection signal is greater than a second threshold, the first input terminal of the fourth comparator receives the second current detection signal, the second input terminal of the fourth comparator receives a fourth threshold, and outputs a fourth comparison signal; when the second current detection signal is greater than the fourth threshold, the fourth comparison signal controls the load switch to turn off.
[0011] The present invention also provides a leakage protection circuit. When the sampling signal of the input voltage reaches a first threshold value, the current flowing through the load switch is detected to obtain a first current detection signal. When the first current detection signal is less than a second threshold value, it indicates that the load input end is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than a third threshold value, it indicates that the load switch is overcurrent, and the load switch is controlled to be turned off.
[0012] Optionally, the leakage protection circuit includes a first resistor, a first comparator and a hysteresis comparator, the first end of the load switch is connected to the load, the second end of the load switch is connected to the first end of the first resistor, the second end of the first resistor is connected to the low potential output end of the rectifier circuit, and the voltage at the first end of the first resistor is a first current detection signal; the first input end of the first comparator receives the sampling signal, the second input end of the first comparator receives the first threshold, and the first comparator outputs a first comparison signal; the first input end of the hysteresis comparator is connected to the first end of the first resistor, the second input end of the hysteresis comparator receives the second threshold, the third input end of the hysteresis comparator receives the third threshold, and the hysteresis comparator outputs a second comparison signal;
[0013] When the sampling signal reaches a first threshold, the first comparison signal controls the hysteresis comparator to work; when the first current detection signal is less than a second threshold, the second comparison signal controls the load switch to turn off or controls the load to be disabled; when the first current detection signal is greater than a third threshold, the second comparison signal controls the load switch to turn off.
[0014] The present invention also provides a lighting drive circuit, comprising any one of the leakage protection circuits and rectifier circuits described above, wherein the rectifier circuit receives an AC input and rectifies the AC input; and the leakage protection circuit detects whether leakage protection is required at the load input end.
[0015] The present invention also provides a leakage protection method, wherein a first end of a first switch tube is connected to a high potential output end of a rectifier circuit or one end of an AC input power supply, and a second end of the first switch tube is connected to a low potential output end of the rectifier circuit through a first resistor;
[0016] When the sampling signal of the input voltage reaches the first threshold, the current flowing through the first switch tube is detected to obtain a first current detection signal; when the first current detection signal is less than the second threshold, it indicates that the load input end is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold, it indicates that the first switch tube is overcurrent, and the first switch tube is controlled to be turned off.
[0017] The present invention also provides a leakage protection method. When the sampling signal of the input voltage reaches a first threshold value, the current flowing through the load switch is detected to obtain a first current detection signal. When the first current detection signal is less than the second threshold value, it indicates that the load input end is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold value, it indicates that the load input end is overcurrent, and the load switch is controlled to be turned off.
[0018] Compared with the prior art, the present invention has the following advantages: when the sampling signal of the input voltage reaches the first threshold, the current flowing through the first switch tube is detected to obtain a first current detection signal; when the first current detection signal is less than the second threshold, it indicates that the load input terminal is leaking, and the load switch is controlled to be turned off; when the first current detection signal is greater than the third threshold, it indicates that the first switch tube is overcurrent, and the first switch tube is controlled to be turned off. In the case of multiple lamps in parallel, the present invention improves the leakage protection performance and the safety of the load switch, and enhances the safety during the load disassembly and assembly process. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is the principle diagram of leakage protection circuit in the prior art;
[0020] Figure 2 This is a schematic diagram of a leakage protection circuit of the present invention;
[0021] Figure 3 Another leakage protection circuit schematic diagram of the present invention; DETAILED DESCRIPTION
[0022] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any substitution, modification, equivalent method and scheme made within the spirit and scope of the present invention.
[0023] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without these detailed descriptions.
[0024] The present 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 accompanying drawings are all simplified and not in exact proportions, in order to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.
[0025] like Figure 2As shown, a schematic diagram of a leakage protection circuit of the present invention is illustrated. The input power supply or the input power supply after passing through the rectifier circuit, passes through the voltage-dividing resistors R00 and R01 to obtain the sampling signal VCS of the input voltage. The leakage protection circuit includes a resistor R1, a resistor R2, a first switch tube Q1, a first comparator U101, a second comparator U102, a third comparator U103 and a fourth comparator U104. The first end of the first switch tube Q1 is connected to the high potential output end of the rectifier circuit U00, or one end of the input power supply AC. The second end of the first switch tube Q1 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is connected to the low potential output end of the rectifier circuit U00. The second end of the load switch M00 is connected to the low potential output end of the rectifier circuit U00 through the resistor R2, and the first end of the load switch M00 is connected to the load. The voltage at the second end of the first switch tube Q1 is the first current detection signal, and the voltage at the second end of the load switch M00 is the second current detection signal. The non-inverting input terminal of the first comparator U101 receives the first threshold VREF1, the inverting input terminal of the first comparator U101 receives the sampling signal VCS of the input voltage, and the first comparator U101 outputs the first comparison signal VC1. The non-inverting input terminal of the second comparator U102 is connected to the second end of the first switch tube Q1, the inverting input terminal of the second comparator U102 receives the second threshold VREF2, and the second comparator U102 outputs the second comparison signal VC2. The non-inverting input terminal of the third comparator U103 receives the third threshold VREF3, the inverting input terminal of the third comparator U103 is connected to the second end of the first switch tube Q1, and the third comparator U103 outputs the third comparison signal VC3. The non-inverting input terminal of the fourth comparator U104 is connected to the second end of the load switch M00, the inverting input terminal of the fourth comparator U104 receives the fourth threshold VREF4, and the fourth comparator U104 outputs the fourth comparison signal VC4.
[0026] When the sampling signal VCS reaches the first threshold VREF1, the first comparison signal VC1 controls the first switch tube Q1 to turn on. When the first current detection signal is less than the second threshold VREF2, it indicates that the load input terminal is leaking. The second comparison signal VC2 controls the load switch M00 to turn off or control the load to be disabled. When the first current detection signal is greater than the third threshold VREF3, it indicates that the first switch tube Q1 is overcurrent. To prevent the first switch tube Q1 from being damaged, the third comparison signal VC3 controls the first switch tube Q1 to turn off. When the first current detection signal is greater than the second threshold VREF2, it is determined whether the fourth threshold VREF4 is greater than the second current detection signal. When the fourth threshold VREF4 is greater than the second current detection signal, it indicates that the load switch M00 is overcurrent. To prevent the load switch M00 from being damaged, the fourth comparison signal VC4 controls the load switch M00 to turn off. In this embodiment, when the first input terminal of the first switch tube Q1 is connected to one end of the input power supply AC, the first switch tube Q1 can be protected from overcurrent. When leakage occurs, the main circuit current decreases, and the current flowing through the first switch tube Q1 decreases. There is a large difference between the current flowing through the first switch tube Q1 in the leakage and non-leakage conditions, so leakage increases the accuracy of leakage detection.
[0027] like Figure 3 As shown, another leakage protection circuit schematic diagram of the present invention is illustrated. The input power supply or the input power supply passes through the rectifier circuit U00 and then through the voltage divider resistors R00 and R01 to obtain the input voltage sampling signal VCS. The leakage protection circuit includes a first resistor R101, a first comparator U201 and a hysteresis comparator U202, a first end of a load switch M00 is connected to a load, a second end of the load switch M00 is connected to a first end of the first resistor R101, a second end of the first resistor R101 is connected to a low potential output end of a rectifier circuit U00, and a voltage at the first end of the first resistor R101 is a first current detection signal; a first input end of the first comparator U101 receives the sampling signal VCS, a second input end of the first comparator U101 receives a first threshold VREF1, and the first comparator U101 outputs a first comparison signal VC1; a first input end of the hysteresis comparator U201 is connected to a first end of the first resistor R101, a second input end of the hysteresis comparator U201 receives a second threshold VREF2, a third input end of the hysteresis comparator U201 receives a third threshold VREF3, and the hysteresis comparator outputs a second comparison signal VC2;
[0028] When the sampling signal VCS reaches the first threshold VREF1, the first comparison signal VC1 controls the hysteresis comparator U202 to work; when the first current detection signal is less than the second threshold VREF2, it indicates that the load input terminal is leaking, and the second comparison signal VC2 controls the load switch M00 to turn off or control the load to be disabled; when the first current detection signal is greater than the third threshold VREF3, it indicates that the load switch M00 is overcurrent, and the second comparison signal VC2 controls the load switch M00 to turn off.
[0029] Although the embodiments are described and illustrated separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that the embodiments can be replaced and integrated. If the content is not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.
[0030] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.
Claims
1. A leakage protection circuit, characterized in that: It includes a first switch tube, wherein a first end of the first switch tube is directly connected to a high potential output end of a rectifier circuit or one end of an AC input power supply, and a second end of the first switch tube is connected to a low potential output end of the rectifier circuit via a first resistor; When the sampling signal of the input voltage reaches the first threshold, the current flowing through the first switch tube is detected to obtain a first current detection signal; when the first current detection signal is less than the second threshold, it indicates that the load input terminal is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold, it indicates that the first switch tube is overcurrent, and the first switch tube is controlled to be turned off; The leakage protection circuit also includes a first comparator, a second comparator and a third comparator, wherein the first input terminal of the first comparator receives a sampling signal of an input voltage, the second input terminal of the first comparator receives a first threshold value, and the first comparator outputs a first comparison signal; the first input terminal of the second comparator is connected to the second terminal of the first switch tube, the second input terminal of the second comparator receives a second threshold value, and the second comparator outputs a second comparison signal; the first input terminal of the third comparator is connected to the second terminal of the first switch tube, the second input terminal of the third comparator receives a third threshold value, and the third comparator outputs a third comparison signal; When the sampling signal reaches a first threshold, the first comparison signal controls the first switch tube to turn on; when the first current detection signal is less than a second threshold, the second comparison signal controls the load switch to turn off or controls the load to be disabled; when the first current detection signal is greater than a third threshold, the third comparison signal controls the first switch tube to turn off.
2. The leakage protection circuit according to claim 1, characterized in that: When the first current detection signal is greater than the second threshold, the current flowing through the load switch is detected to obtain a second current detection signal. When the second current detection signal is greater than the fourth threshold, it indicates that the load switch is overcurrent, and the load switch is controlled to be turned off.
3. The leakage protection circuit according to claim 2, characterized in that: The leakage protection circuit also includes a fourth comparator. When the first current detection signal is greater than a second threshold, the first input terminal of the fourth comparator receives the second current detection signal, the second input terminal of the fourth comparator receives a fourth threshold, and the fourth comparator outputs a fourth comparison signal; when the second current detection signal is greater than the fourth threshold, the fourth comparison signal controls the load switch to turn off.
4. A leakage protection circuit, characterized in that: When the sampling signal of the input voltage reaches the first threshold, the current flowing through the load switch is detected to obtain a first current detection signal. When the first current detection signal is less than the second threshold, it indicates that the load input terminal is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold, it indicates that the load switch is overcurrent, and the load switch is controlled to be turned off; The leakage protection circuit includes a first resistor, a first comparator and a hysteresis comparator, wherein the first end of the load switch is connected to the load, the second end of the load switch is connected to the first end of the first resistor, the second end of the first resistor is connected to the low potential output end of the rectifier circuit, and the voltage at the first end of the first resistor is a first current detection signal; the first input end of the first comparator receives the sampling signal, the second input end of the first comparator receives the first threshold, and the first comparator outputs a first comparison signal; the first input end of the hysteresis comparator is connected to the first end of the first resistor, the second input end of the hysteresis comparator receives the second threshold, the third input end of the hysteresis comparator receives the third threshold, and the hysteresis comparator outputs a second comparison signal; When the sampling signal reaches a first threshold, the first comparison signal controls the hysteresis comparator to work; when the first current detection signal is less than a second threshold, the second comparison signal controls the load switch to turn off or controls the load to be disabled; when the first current detection signal is greater than a third threshold, the second comparison signal controls the load switch to turn off.
5. A lighting drive circuit, characterized in that: It comprises any one of the leakage protection circuit and rectification circuit described in claims 1-4, wherein the rectification circuit receives an AC input and rectifies the AC input; and the leakage protection circuit detects whether leakage protection is required at the load input end.
6. A leakage protection method, using the leakage protection circuit as claimed in claim 1, characterized in that: The first end of the first switch tube is directly connected to the high potential output end of the rectifier circuit or one end of the AC input power supply, and the second end of the first switch tube is connected to the low potential output end of the rectifier circuit through the first resistor; When the sampling signal of the input voltage reaches the first threshold, the current flowing through the first switch tube is detected to obtain a first current detection signal; when the first current detection signal is less than the second threshold, it indicates that the load input end is leaking, and the load switch is controlled to be turned off or the load is disabled; when the first current detection signal is greater than the third threshold, it indicates that the first switch tube is overcurrent, and the first switch tube is controlled to be turned off.
7. A leakage protection method, using the leakage protection circuit as claimed in claim 4, characterized in that: When the sampling signal of the input voltage reaches a first threshold value, the current flowing through the load switch is detected to obtain a first current detection signal. When the first current detection signal is less than the second threshold value, it indicates that the load input terminal is leaking, and the load switch is controlled to be turned off or the load is disabled; or, when the first current detection signal is greater than the third threshold value, it indicates that the load input terminal is overcurrent, and the load switch is controlled to be turned off.
Citation Information
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