Electric leakage protection circuit compatible with commercial power and ballast
By using the bandpass filter module and comparator module in the detection circuit, and utilizing the electrical signal and voltage factors between the output pins before rectification, accurate leakage current detection of the mains power and ballast is achieved. This solves the problem of leakage protection circuit failure during lamp installation and ensures operator safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technology has a problem during lamp installation, especially with dual-ended input, where the leakage protection circuit fails due to poor contact at the input end, leading to the risk of electric shock to the operator.
A leakage current protection circuit compatible with mains power and ballasts was designed. By using the bandpass filter module, comparator module and switch module in the detection circuit, the electrical signal and voltage factor between the output pins before rectification are used to achieve accurate leakage current detection and control the on/off state of the LED circuit.
It improves the accuracy and safety of leakage current detection, ensuring that leakage current can be effectively prevented under any circumstances, thus protecting the operator's safety.
Smart Images
Figure CN224068832U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to LED technical field especially, and it is a kind of leakage protection circuit compatible with city electricity and ballast. BACKGROUND
[0002] At present, lamp tube can select city electricity direct input also can select access ballast to realize power supply. Among them, when selecting city electricity input, city electricity is generally 220V / 50HZ or other voltage;And when selecting access ballast, the joint of the two ends of lamp tube has high voltage.
[0003] In the field of illumination, lamp tube is divided into single-end input and double-end input, single-end input is actually to set the joint of alternating current input end in the same end, and double-end input is to set it in the two ends of lamp tube;Because more lamp holders still retain the interface of double-end access, when replacing and installing original lamp tube, generally still adopt double-end input lamp tube.
[0004] In the process of lamp tube installation, operator generally inserts one end of lamp tube into lamp holder first, and then inserts the other end, at this time, partial connection can occur;And because operator's hand needs to be held in the end of lamp tube, if human body accidentally contacts the metal of end conduction, electric shock is easy to occur, and operation safety is affected, so it is particularly important to realize leakage protection for lamp tube.
[0005] In the prior art, mainly through the access switch tube in power input end to detect the current flowing through switch tube, to judge whether there is leakage phenomenon, to realize leakage protection. But prior art is not effective at any time, when input end contact is poor, its leakage protection circuit will fail, and operator still has the danger of electric shock. INVENTION CONTENTS
[0006] The technical problem to be solved by the utility model lies in providing a leakage protection circuit compatible with city electricity and ballast, which can realize leakage protection.
[0007] In order to solve the above technical problems, the utility model provides a kind of leakage protection circuit compatible with commercial power and ballast, comprising: power supply circuit, voltage reduction circuit, drive circuit, LED circuit and detection circuit;The input end of the power supply circuit is connected to the output pin of power supply end, and the output end of the power supply circuit is respectively connected with the input end of the voltage reduction circuit, the detection end of drive circuit and the input end of LED circuit, for rectifying the output power supply of the power supply end to the voltage reduction circuit, drive circuit and LED circuit output power supply;The input end of the drive circuit is connected with the output end of the LED circuit, for controlling the working state of the LED circuit according to the power supply;The output end of the voltage reduction circuit is connected with the detection circuit, for voltage reduction treatment to the power supply of the power supply circuit output to the detection circuit output reference voltage;The detection circuit is respectively connected with the output pin of power supply end, drive circuit and LED circuit, for controlling the working state of the drive circuit and LED circuit according to the real-time voltage between the output pin of power supply end and the reference voltage output by the voltage reduction circuit.
[0008] As an improvement of the above scheme, the detection circuit includes two band-pass filter modules, a comparison module and a switch module, the comparison module is provided with two real-time sampling ends and two reference sampling ends, the band-pass filter module, real-time sampling end, reference sampling end and two groups of output pins of the power supply end are one-to-one corresponding;The band-pass filter module is connected to the corresponding output pin, to filter the output power supply between the corresponding output pin;The real-time sampling end is connected with the corresponding band-pass filter module to detect the real-time voltage between the corresponding output pin;The reference sampling end is connected with the output end of the voltage reduction circuit to obtain reference voltage;The output end of the comparison module is connected with the switch module, for controlling the on-off state of the switch module according to the real-time voltage and reference voltage.
[0009] As an improvement of the above scheme, the band-pass filter module includes two diodes connected in anti-parallel, and the real-time sampling end of the comparison module is connected between the two diodes.
[0010] As an improvement of the above scheme, the switch module includes a first switch, the control end of the first switch is connected with the output end of the comparison module, one electrode end of the first switch is connected with the drive circuit and LED circuit, and the other electrode end of the first switch is connected with the power supply circuit.
[0011] As the improvement of the above-mentioned scheme, the comparison module comprises a first comparator, a second comparator, a second switch and a third switch; one input end of the first comparator is connected with a real-time sampling end of the comparison module, the other input end of the first comparator is connected with a reference sampling end of the comparison module, the first comparator is used for controlling the on-off state of the second switch according to the real-time voltage detected by the real-time sampling end and the reference voltage obtained by the reference sampling end; one input end of the second comparator is connected with another real-time sampling end of the comparison module, the other input end of the second comparator is connected with another reference sampling end of the comparison module, the second comparator is used for controlling the on-off state of the third switch according to the real-time voltage detected by the other real-time sampling end and the reference voltage obtained by the other reference sampling end; the second switch, the third switch and the switch module are connected in sequence, the on-off state of the second switch and the third switch controls the on-off state of the switch module, and the on-off state of the switch module controls the working state of the driving circuit and the LED circuit.
[0012] As the improvement of the above-mentioned scheme, when the second switch and the third switch are turned on, the switch module is turned on, so that the driving circuit is not worked and the power supply circuit, the LED circuit and the detection circuit form an LED loop, and the LED circuit is worked; when the second switch and / or the third switch is turned off, the switch module is turned off, so that the LED circuit and the detection circuit are disconnected.
[0013] As the improvement of the above-mentioned scheme, the control electrode of the second switch is connected with the output end of the first comparator, the first electrode of the second switch is connected with the output end of the voltage reduction circuit, and the second electrode of the second switch is connected with the first electrode of the third switch; the control electrode of the third switch is connected with the output end of the second comparator, and the second electrode of the third switch is connected with the switch module.
[0014] As the improvement of the above-mentioned scheme, the detection circuit further comprises an anti-interference module, and the comparison module and the switch module are connected through the anti-interference module.
[0015] As the improvement of the above-mentioned scheme, when the power supply circuit is connected with the ballast, the driving circuit is not worked; when the power supply circuit is connected with the mains, the driving circuit controls the on-off state between the driving circuit and the LED circuit according to the power supply, so as to control the working state of the LED circuit.
[0016] As an improvement of the above scheme, the driving circuit comprises a driving chip, a detection pin and an open-drain pin are arranged on the driving chip, and a built-in switch is arranged in the open-drain pin; the detection pin is connected with the power supply circuit and is used for detecting a power supply output by the power supply circuit; the open-drain pin is connected with the LED circuit, and the built-in switch switches on and off according to the power supply to control the on-off state between the driving circuit and the LED circuit.
[0017] The utility model discloses have the beneficial effect in implementation:
[0018] The utility model discloses compatible leakage protection circuit of city electricity and ballast, the output pin interval electric signal before rectification is as the detection target, and the real-time voltage and reference voltage of output pin interval of power supply end are combined, and voltage factor is as the judgment basis, realizes the accurate detection of leakage from the voltage angle, and the accuracy of detection is greatly promoted, thereby effectively control LED circuit on-off state, play the role of leakage protection, guarantee the safety of people.
[0019] Further, the utility model discloses introduce comparator, switch tube and so on control element in leakage protection circuit, realized the layer layer comparison of electric signal and the flexible switching of circuit, thereby more accurate control LED circuit on-off state, high accuracy. DRAWINGS
[0020] Figure 1 It is the structure schematic diagram of leakage protection circuit of the utility model compatible city electricity and ballast.
[0021] Figure 2 It is the embodiment circuit diagram of leakage protection circuit of the utility model compatible city electricity and ballast.
[0022] Figure 3 It is one embodiment circuit diagram of step-down circuit in leakage protection circuit of the utility model compatible city electricity and ballast.
[0023] Figure 4 It is another embodiment circuit diagram of step-down circuit in leakage protection circuit of the utility model compatible city electricity and ballast.
[0024] Figure 5 It is another structure schematic diagram of leakage protection circuit of the utility model compatible city electricity and ballast. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model will be described in further detail below with reference to the drawings. Only this declaration, the up, down, left, right, front, back, inside, outside and other directions of the utility model appearing or about to appear in the text, only with the drawings of the utility model as the base, it is not the specific limitation of the utility model.
[0026] Referring to Figure 1 , Figure 1 The utility model discloses a specific structure of compatible city electricity and ballast's electric leakage protection circuit, it includes power supply circuit 1, voltage reducing circuit 2, drive circuit 5, LED circuit 3 and detection circuit 4, specifically:
[0027] The input end of power supply circuit 1 is connected to the output pin of the power supply end, and the output end of power supply circuit 1 is connected with the input end of voltage reducing circuit 2, the detection end of drive circuit 5 and the input end of LED circuit 3 respectively, for rectifying the output power supply of the power supply end to output the power supply to voltage reducing circuit 2, drive circuit 5 and LED circuit 3;
[0028] The input end of drive circuit 5 is connected with the output end of LED circuit 3, for controlling the working state of LED circuit 3 according to the power supply;
[0029] The output end of voltage reducing circuit 2 is connected with detection circuit 4, for reducing the power supply output by power supply circuit 1 to output reference voltage to detection circuit 4;
[0030] Detection circuit 4 is connected with the output pin of the power supply end, drive circuit 5 and LED circuit 3 respectively, for controlling the working state of drive circuit 5 and LED circuit 3 according to the real-time voltage between the output pin of the power supply end and the reference voltage output by voltage reducing circuit 2.
[0031] It should be noted that the utility model discloses compatible city electricity and ballast's electric leakage protection circuit can be applied in city electricity and ballast simultaneously, so the power supply end can be city electricity power supply end, also can be ballast power supply end, simultaneously, the utility model discloses electric leakage protection circuit can realize ballast and city electricity's electric leakage protection simultaneously.
[0032] In the prior art, compatible city electricity and ballast's electric leakage protection circuit detects rectified electric signal to realize electric leakage protection. Different from the prior art, the utility model discloses compatible city electricity and ballast's electric leakage protection circuit takes the electric signal before rectification (i.e. the electric signal between output pins) as the detection target, and takes voltage factor as the judgment basis, realizes the accurate detection of electric leakage from the voltage angle, and greatly improves the accuracy of detection.
[0033] The power supply circuit 1, voltage reducing circuit 2, LED circuit 3, drive circuit 5 and detection circuit 4 are described in detail as follows:
[0034] I. Power supply circuit 1
[0035] As Figure 2As shown, in the embodiment, the power supply circuit 1 comprises a first rectifier bridge BD1, a second rectifier bridge BD2, a second diode D2, a third diode D3, a seventh diode D7, an eighth diode D8, a second capacitor C2, an eighth capacitor C8, and input ports F1, F2, F3 and F4.
[0036] One AC input end of the first rectifier bridge BD1 is connected to the input port F1, the other AC input end is connected to the input port F2, the DC output negative end is connected to the voltage reduction circuit 2 and the LED circuit 3, and the DC output positive end is grounded; the positive pole of the second diode D2 is connected to the input port F1, and the negative pole is connected to the driving circuit 5; the positive pole of the third diode D3 is connected to the input port F2, and the negative pole is connected to the driving circuit 5; one end of the second capacitor C2 is connected to the input port F1, and the other end is connected to the input port F2.
[0037] Similarly, one AC input end of the second rectifier bridge BD2 is connected to the input port F3, the other AC input end is connected to the input port F4, the DC output negative end is connected to the voltage reduction circuit 2 and the LED circuit 3, and the DC output positive end is grounded; the positive pole of the seventh diode D7 is connected to the input port F3, and the negative pole is connected to the driving circuit 5; the positive pole of the eighth diode D8 is connected to the input port F4, and the negative pole is connected to the driving circuit 5; one end of the eighth capacitor C8 is connected to the input port F3, and the other end is connected to the input port F4.
[0038] When the utility model is applied to the ballast, the input ports F1, F2, F3 and F4 can be connected to four pins of the ballast.
[0039] When the utility model is applied to the commercial power, any two input ports can be selected to be connected to two pins of the commercial power, for example, the input ports F1 and F2, or the input ports F3 and F4, or the input ports F1 and F3, or the input ports F1 and F4, or the input ports F2 and F3, or the input ports F2 and F4.
[0040] Therefore, the output power supply of the power supply end can be rectified by the power supply circuit 1 to output stable power supply to the voltage reduction circuit 2 and the LED circuit 3.
[0041] II. Voltage reduction circuit 2
[0042] As shown, Figure 2As shown, in this embodiment, the step-down circuit 2 includes a voltage divider resistor group (first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, and fifth resistor R5), a first capacitor C1, and a first Zener diode D1; wherein, one end of the first resistor R1 is connected to the power supply circuit 1, and the other end is grounded through the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 in sequence. The fifth resistor R5 is connected in parallel with the first capacitor C1 and the first Zener diode D1, respectively. The positive terminal of the first Zener diode D1 is grounded, and the negative terminal is connected to the detection circuit 4.
[0043] Therefore, the step-down circuit 2 can step down the power supply output from the power supply circuit 1 and convert it into a 5V reference voltage for use by the detection circuit 4.
[0044] In other embodiments, different numbers and resistance values of resistors can be selected for voltage reduction according to actual needs.
[0045] like Figure 3 As shown, in this embodiment, the voltage divider resistor group includes four resistors connected in series (second resistor R2, third resistor R3, fourth resistor R4 and fifth resistor R5).
[0046] In other embodiments, voltage reduction can be achieved using a step-down chip.
[0047] like Figure 4 As shown, in this embodiment, the step-down circuit 2 includes a step-down chip U2, an eleventh diode D11, a twelfth diode D12, a third inductor L3, a fourth inductor L4, a sixteenth capacitor C16, a seventeenth capacitor C17, a second polarity capacitor CE2, a third polarity capacitor CE3, a fourth polarity capacitor CE4, a fortieth resistor R40, a forty-first resistor R41, and a current-limiting resistor RS1, wherein:
[0048] The ground pin GND of the step-down chip U2 is connected to the negative terminal of the twelfth diode D12. The clock pin SCL and the power supply pin VCC are respectively connected to the negative terminal of the eleventh diode D11. The open-drain pin DRAIN is connected to the power supply circuit 1 through the third inductor L3. The chip select pin CS is connected to the negative terminal of the twelfth diode D12 through the current limiting resistor RS1.
[0049] The positive terminal of the twelfth diode D12 is grounded, and the negative terminal is connected to the detection circuit 4 through the fourth inductor L4 and to the negative terminal of the eleventh diode D11 through the seventeenth capacitor C17. The positive terminal of the eleventh diode D11 is connected to the detection circuit 4.
[0050] One end of the 40th resistor R40 is connected to the detection circuit 4, and the other end is grounded. The 40th resistor R40, the 16th capacitor C16, and the second polarity capacitor CE2 are connected in parallel.
[0051] The forty-first resistor R41 is connected in parallel with the third inductor L3; the positive terminal of the fourth polarity capacitor CE4 is connected to the open-drain pin DRAIN, and the negative terminal is grounded; the positive terminal of the third polarity capacitor CE3 is connected to power supply circuit 1, and the negative terminal is grounded.
[0052] It should be noted that when connected to mains power, whether it is a single-ended input to input ports F1 and F2, a single-ended input to input ports F3 and F4, or a dual-ended input, the voltage after rectification by the first rectifier bridge DB1 and the second rectifier bridge DB2 is 310VDC, which is consistent with the working state of the step-down chip U2. Therefore, the step-down chip U2 can work normally, playing the role of step-down constant current, and supplying a constant reference voltage to the detection circuit 4.
[0053] Therefore, in applications, different step-down circuits 2 can be used to step down the power output of power supply circuit 1 according to actual needs, and no restrictions are imposed here.
[0054] III. LED Circuit 3
[0055] like Figure 2 As shown, in this embodiment, the LED circuit 3 includes a plurality of light-emitting diodes (LED1...LEDN) connected in series.
[0056] IV. Drive Circuit 5
[0057] This utility model's leakage protection circuit, compatible with both mains power and ballasts, can be applied to both mains power and ballasts. When the power supply circuit 1 is connected to the ballast, the drive circuit 5 does not work. When the power supply circuit 1 is connected to mains power, the drive circuit 5 controls the on / off state between the drive circuit 5 and the LED circuit 3 according to the power supply, thereby controlling the working state of the LED circuit 3.
[0058] For example, when the driving circuit 5 does not detect leakage, the driving circuit 5 is connected to the LED circuit 3, and the driving circuit 5 drives the LED circuit 3, thereby ensuring the constant current power supply of the LED circuit 3.
[0059] For example, when the driving circuit 5 detects leakage, the driving circuit 5 disconnects from the LED circuit 3, and the LED circuit 3 is open-circuited.
[0060] In some embodiments, the driving circuit 5 includes a driving chip U1, which has a detection pin REC and an open-drain pin DRAIN. The open-drain pin DRAIN has a built-in switch. The detection pin REC is connected to the power supply circuit 1 and is used to detect the power supply output by the power supply circuit 1. The open-drain pin DRAIN is connected to the LED circuit 3, and the built-in switch switches between on and off states according to the power supply to control the on / off state between the driving circuit 5 and the LED circuit 3.
[0061] like Figure 2As shown, in this embodiment, the driving circuit 5 includes a driving chip U1, a first transformer coil T1, a sixth diode D6, a Zener diode TVS1, a first polarized capacitor CE1, a seventh capacitor C7, a ninth capacitor C9, a tenth capacitor C10, an eighth resistor R8, a ninth resistor R9, an eleventh resistor R11, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a seventeenth resistor R17, and an eighteenth resistor R18. The open-drain pin DRAIN of the driving chip U1 is connected to the negative terminal of the LED circuit 3 through the first transformer coil T1; the compiler pin ISP is grounded through the seventeenth resistor R17 and the eighteenth resistor R18; the ground pin GND is grounded and connected to the positive terminal of the sixth diode D6 through the ninth capacitor C9. The cathode of the sixth diode D6 is connected to the anode of LED circuit 3; the detection pin REC is connected to power supply circuit 1 through the fourteenth resistor R14 and the thirteenth resistor R13, and grounded through the Zener diode TVS1 and the fifteenth resistor R15 respectively; the power supply pin VIN is connected to the anode of LED circuit 3 through the eighth resistor R8; one end of the tenth capacitor C10 is grounded, and the other end is connected to the cathode of detection circuit 4 and LED circuit 3 respectively; one end of the ninth resistor R9 is connected to the anode of LED circuit 3, and the other end is connected to the open-drain pin DRAIN through the seventh capacitor C7; one end of the first polarized capacitor CE1 is connected to the anode of LED circuit 3, and the other end is connected to the cathode of LED circuit 3; the eleventh resistor R11 is connected in parallel with the first polarized capacitor CE1.
[0062] It should be noted that the detection pin REC of the driver chip U1 has an input current detection function; when the power supply is greater than 72mA, the driver chip U1 turns on the built-in switch of the open-drain pin DRAIN; when the power supply is less than 72mA, the driver chip U1 turns off the built-in switch of the open-drain pin DRAIN. Preferably, the driver chip U1 can be JW1830, JW1831, JW1832 or other similar solutions, but this is not a limitation.
[0063] V. Detection Circuit 4
[0064] like Figure 2 As shown, the detection circuit 4 includes two bandpass filter modules 41, a comparison module 42 and a switch module 43. The comparison module 42 is provided with two real-time sampling terminals and two reference sampling terminals. The two sets of output pins of the bandpass filter module 41, the real-time sampling terminal, the reference sampling terminal and the power supply terminal correspond one-to-one.
[0065] The bandpass filter module 41 is connected to a corresponding set of output pins to filter the output power supply between the corresponding set of output pins;
[0066] The real-time sampling terminal is connected to the corresponding bandpass filter module 41 to detect the real-time voltage between a set of corresponding output pins;
[0067] The reference sampling end is connected with the output end of the voltage reduction circuit 2 to obtain the reference voltage;
[0068] The output end of the comparison module 42 is connected with the switch module 43 to control the on-off state of the switch module 43 according to the real-time voltage and the reference voltage.
[0069] Therefore, through the cooperation among the band-pass filtering module 41, the comparison module 42 and the switch module 43, the switch module 43 can accurately switch on and off according to the real-time voltage between the output pins and the reference voltage of the voltage reduction circuit 2, and the accuracy is high.
[0070] The band-pass filtering module 41, the comparison module 42 and the switch module 43 will be described in detail as follows:
[0071] (1) Band-pass filtering module
[0072] The band-pass filtering module 41 includes two diodes connected in opposite directions, and the real-time sampling end of the comparison module 42 is connected between the two diodes.
[0073] As shown in Figure 2 In this embodiment, one band-pass filtering module 41 includes the fourth diode D4 and the fifth diode D5, and the other band-pass filtering module 42 includes the ninth diode D9 and the twelfth diode D10.
[0074] The positive pole of the fourth diode D4 is connected with the input port F1, the negative pole of the fourth diode D4 is connected with the negative pole of the fifth diode D5, and the positive pole of the fifth diode D5 is connected with the input port F2.
[0075] Similarly, the positive pole of the ninth diode D9 is connected with the input port F3, the negative pole of the ninth diode D9 is connected with the negative pole of the twelfth diode D10, and the positive pole of the twelfth diode D10 is connected with the input port F4.
[0076] During operation, a real-time sampling end A can be arranged between the fourth diode D4 and the fifth diode D5, and another real-time sampling end B can be arranged between the ninth diode D9 and the twelfth diode D10.
[0077] Therefore, through the arrangement of the real-time sampling ends A and B, the real-time voltage between the output pins can be effectively detected, and the power state between the output pins can be obtained in real time.
[0078] (2) Comparison module
[0079] As shown in Figure 2As shown, in the embodiment, the comparison module 42 comprises a first comparator U1A, a second comparator UIB, a second switch Q2 and a third switch Q3; one input terminal of the first comparator U1A is connected with a real-time sampling terminal of the comparison module 42, the other input terminal of the first comparator U1A is connected with a reference sampling terminal of the comparison module 42, the first comparator U1A is used for controlling the on-off state of the second switch Q2 according to the real-time voltage detected by the real-time sampling terminal and the reference voltage obtained by the reference sampling terminal; one input terminal of the second comparator UIB is connected with another real-time sampling terminal of the comparison module 42, the other input terminal of the second comparator UIB is connected with another reference sampling terminal of the comparison module 42, the second comparator UIB is used for controlling the on-off state of the third switch Q3 according to the real-time voltage detected by the other real-time sampling terminal and the reference voltage obtained by the other reference sampling terminal; the second switch Q2, the third switch Q3 and the switch module 43 are connected in sequence, the on-off state of the second switch Q2 and the third switch Q3 controls the on-off state of the switch module 43, and the on-off state of the switch module 43 controls the working state of the driving circuit 5 and the LED circuit 3.
[0080] It should be noted that when the second switch Q2 and the third switch Q3 are turned on, the switch module 43 is turned on, so that the driving circuit 5 does not work and the power supply circuit 1, the LED circuit 3 and the detection circuit 4 form an LED loop, and the LED circuit 3 works; when the second switch Q2 and / or the third switch Q3 are turned off, the switch module 43 is turned off, so that the LED circuit 3 is disconnected with the detection circuit 4.
[0081] Further, referring to Figure 5 , the control electrode of the second switch Q2 is connected with the output terminal of the first comparator U1A, the first electrode of the second switch Q2 is connected with the output terminal of the voltage reduction circuit 2, and the second electrode of the second switch Q2 is connected with the first electrode of the third switch Q3; the control electrode of the third switch Q3 is connected with the output terminal of the second comparator UIB, and the second electrode of the third switch Q3 is connected with the switch module 43.
[0082] For example, when the first comparator U1A and the second comparator UIB both output low level, the second switch Q2, the third switch Q3 and the switch module 43 are turned on, so that the power supply circuit 1, the LED circuit 3 and the detection circuit 4 form an LED loop, and the LED circuit 3 works;
[0083] When the first comparator U1A outputs high level and the second comparator UIB outputs low level, the second switch Q2 is turned off, the third switch Q3 is turned on, and the switch module 43 is turned off, so that the LED circuit 3 is disconnected with the detection circuit 4;
[0084] When the first comparator U1A outputs a low level and the second comparator UIB outputs a high level, the second switch Q2 is turned on, the third switch Q3 is turned off, and the switch module 43 is turned off, so that the LED circuit 3 is disconnected from the detection circuit 4.
[0085] When both the first comparator U1A and the second comparator UIB output a high level, the second switch Q2, the third switch Q3, and the switch module 43 are disconnected, so that the LED circuit 3 is disconnected from the detection circuit 4.
[0086] It should be noted that the output levels of the first comparator U1A and the second comparator UIB can affect the on / off states of the second switch Q2 and the third switch Q3, but the specific logic can be set according to the actual situation. For example, it can be set so that the second switch Q2 is turned on when the first comparator U1A outputs a low level; or it can be set so that the second switch Q2 is turned on when the first comparator U1A outputs a high level.
[0087] Furthermore, the comparison module 42 also includes a first voltage divider resistor group 421, a second voltage divider resistor group 422, a third voltage divider resistor group 423, and a fourth voltage divider resistor group 424; one input terminal of the first comparator U1A is connected to a real-time sampling terminal of the comparison module 42 through the first voltage divider resistor group 421, and the other input terminal of the first comparator U1A is connected to a reference sampling terminal of the comparison module 42 through the second voltage divider resistor group 422; one input terminal of the second comparator UIB is connected to another real-time sampling terminal of the comparison module 42 through the third voltage divider resistor group 423, and the other input terminal of the second comparator UIB is connected to another reference sampling terminal of the comparison module 42 through the fourth voltage divider resistor group 424.
[0088] It should be noted that in practical applications, different numbers and resistance values of voltage divider resistors can be set according to requirements to form the first voltage divider resistor group 421, the second voltage divider resistor group 422, the third voltage divider resistor group 423 and the fourth voltage divider resistor group 424.
[0089] like Figure 2 As shown, in this embodiment, the first voltage divider resistor group 421 includes the twenty-sixth resistor R26 and the twenty-seventh resistor R27 connected in series; the second voltage divider resistor group 422 includes the twenty-fifth resistor R25 and the twenty-ninth resistor R29 connected in series; the third voltage divider resistor group 423 includes the thirty-seventh resistor R37 and the thirty-eighth resistor R38 connected in series; and the fourth voltage divider resistor group 424 includes the twenty-fourth resistor R24 and the twenty-eighth resistor R28 connected in series.
[0090] (3) Switching module
[0091] like Figure 2As shown in the embodiment, the switch module 43 comprises a first switch Q1, a control end of the first switch Q1 is connected with the output end of the comparison module 42, one electrode end of the first switch Q1 is connected with the driving circuit 5 and the LED circuit 3, and the other electrode end of the first switch Q1 is connected with the power supply circuit 1.
[0092] Therefore, when the first switch Q1 is turned on, the power supply circuit 1, the LED circuit 3 and the detection circuit 4 form an LED loop, and the LED circuit 3 works; when the first switch Q1 is turned off, the LED circuit 3 is disconnected with the detection circuit 4.
[0093] As can be seen from the circuit structure of the integrated band-pass filter module 41, the comparison module 42 and the switch module 43, Figure 2 As shown in the embodiment,
[0094] The non-inverting input end of the first comparator U1A is connected with the step-down circuit 2 through the twenty-fifth resistor R25 and grounded through the twenty-ninth resistor R29, the inverting input end of the first comparator U1A is connected with a real-time sampling end A through the twenty-sixth resistor R26 and grounded through the twenty-seventh resistor R27, and the output end of the first comparator U1A is connected with the gate of the second switch Q2.
[0095] The non-inverting input end of the second comparator U1B is connected with the step-down circuit 2 through the twenty-fourth resistor R24 and grounded through the twenty-eighth resistor R28, the inverting input end of the second comparator U1B is connected with another real-time sampling end B through the thirty-seventh resistor R37 and grounded through the thirty-eighth resistor R38, and the output end of the second comparator U1B is connected with the gate of the third switch Q3.
[0096] The source of the second switch Q2 is connected with the step-down circuit 2, the drain of the second switch Q2 is connected with the source of the third switch Q3, the drain of the third switch Q3 is connected with the control end of the first switch Q1, one output end of the first switch Q1 is connected with the LED circuit 3, and the other end is grounded.
[0097] Further, the detection circuit 4 further comprises an anti-interference module 44, and the comparison module 42 and the switch module 43 are connected through the anti-interference module 44.
[0098] As shown in the embodiment, Figure 2 As shown in the embodiment, the anti-interference module 44 comprises a thirtieth resistor R30, a thirty-second resistor R32 and an RC circuit (a thirty-third resistor R33 and a thirteenth capacitor C13 connected in parallel with each other); the thirtieth resistor R30 is connected in series between the comparison module 42 and the switch module 43; one end of the thirty-second resistor R32 is connected with the switch module 43, and the other end is connected with the power supply circuit (i.e. grounded); one end of the RC circuit is connected with the comparison module 42, and the other end is connected with the power supply circuit (i.e. grounded).
[0099] Therefore, the isolation between the comparison module 42 and the switch module 43 can be realized by the anti-interference module 44, interference on the switch module 43 is avoided, and accuracy of the switch module 43 is improved.
[0100] Further, the utility model discloses a leakage protection circuit of compatible city electricity and ballast still includes filter circuit 6, the input of filter circuit 6 is connected with the output of power supply circuit 1, and the output of filter circuit 6 is connected with drive circuit 5 and LED circuit 3 respectively.
[0101] As Figure 2 In the embodiment, the filter circuit 6 includes a first inductor L1, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a fifteenth capacitor C15 and a thermistor RV1; wherein the supply pin VCC of the drive chip U1 is grounded through the fifth capacitor C5; one end of the thermistor RV1 is connected to the positive pole of the LED circuit 3, and the other end is grounded; one end of the third capacitor C3 is connected to the power supply circuit 1, and the other end is grounded; one end of the fourth capacitor C4 is connected to the positive pole of the LED circuit 3, and the other end is grounded; one end of the first inductor L1 is connected to the power supply circuit 1, and the other end is connected to the positive pole of the LED circuit 3; and the fifteenth capacitor C15 is connected in parallel with the first inductor L1.
[0102] Therefore, the filter circuit 6 can filter the power supply voltage output by the power supply circuit 1 to supply power to the drive circuit 5 and the LED circuit 3.
[0103] The leakage detection principle of the embodiment shown in the following is further described. Figure 2 Figure 2
[0104] I. Access ballast
[0105] When the ballast input, the input port F1 and F2 exist real-time voltage difference, the real-time voltage is divided by the twenty-sixth resistance R26 and the twenty-seventh resistance R27, and is greater than the 5V voltage of the first comparator U1A (wherein 5V is a fuzzy concept, and the voltage can be changed according to the change of the output power supply of the power supply end), the first comparator U1A outputs low level, so that the second switch Q2 is turned on; similarly, the input port F3 and F4 exist real-time voltage difference, the real-time voltage is divided by the thirty-seventh resistance R37 and the thirty-eighth resistance R38, and is greater than the 5V voltage of the second comparator U1B, the second comparator U1B outputs low level, so that the third switch Q3 is turned on; the 5V voltage enters the control electrode of the first switch Q1 through the second switch Q2 and the third switch Q3, at this time the first switch Q1 is turned on, so that the output power supply of the power supply circuit 1 flows from the DC output negative terminal of the first rectifier bridge BD1 and the second rectifier bridge BD2 to the LED circuit 3, the first switch Q1, and finally returns to the DC output positive terminal of the first rectifier bridge BD1 and the second rectifier bridge BD2, to form an LED loop, so that the LED circuit 3 is lit. At this time, the negative electrode of the LED circuit 3 is pulled to the ground by the first switch Q1, and the open-drain pin DRAIN of the driving chip U1 is equivalent to the ground at this time, so that the driving chip U1 does not meet the working condition and does not participate in the work.
[0106] When one end of the lamp tube is off, there is no voltage difference between the input port F1 and F2, or F3 and F4, at this time the second switch Q2 or the third switch Q3 is not turned on; because one of them is not turned on, the control electrode of the first switch Q1 at this time is without voltage and current, and the first switch Q1 is in the off state, so that the LED loop of the circuit is cut off, so that the installer is safe to touch the other end, and the function of preventing electric leakage is achieved.
[0107] II. Access to city power
[0108] When the city power is accessed, the single-ended or double-ended of the power supply circuit 1 can work normally. When the input port F1 and F2, or F3 and F4 input the city power, the input voltage is subject to the actual scheme, which can be wide voltage, narrow voltage, single voltage, etc., and the following describes the working principle with 220V / 50HZ:
[0109] When accessing the mains, the voltage input is through the input port F1 and F2, or the input port F3 and F4, or the input port F1, F2 and F3, F4 permutation and combination (such as, from F1 and F3, or F1 and F4, or F2 and F3, or F2 and F4 input); but no matter which way is two feet input, at this time the second switch Q2 or the third switch Q3 is not conductive; because of a non-conducting, the control electrode of the first switch Q1 at this time has no voltage and current, the first switch Q1 is in the off state, so that the first switch Q1 does not work, does not affect the work of the driving chip U1, so that the output power supply of the power supply circuit 1 is sequentially from the DC output negative terminal of the first rectifier bridge BD1 and the second rectifier bridge BD2, through the first inductor L1, the LED circuit 3, the open drain pin DRAIN, the driving chip U1 and the compile pin ISP, and finally returns to the DC output positive terminal of the first rectifier bridge BD1 and the second rectifier bridge BD2, to form an LED loop, so that the LED circuit 3 is normally lit.
[0110] At this time, when one foot input is disconnected from the human body, because the internal resistance of the human body is greater than 500Ω, the detection pin REC equivalent to the driving chip U1 is connected to a resistor at this time, the current of the detection pin REC will decrease, so that the state of more than 72MA before changes to less than 72MA, at this time the built-in switch of the open drain pin DRAIN is closed, so that the LED loop is cut off, and the function of the leakage protection is realized.
[0111] In summary, the leakage protection circuit compatible with the mains and the ballast of the utility model takes the output pin interval electrical signal before rectification as the detection target, and combines the real-time voltage and the reference voltage between the output pins of the power supply end, takes the voltage factor as the judgment basis, realizes the accurate detection of the leakage from the voltage angle, greatly improves the accuracy of the detection, thereby effectively controls the on-off state of the LED circuit, plays the role of preventing leakage, and ensures the safety of the human body; further, the leakage protection circuit of the utility model introduces the comparator, the switch tube and other control elements, realizes the layer-by-layer comparison of the electrical signal and the flexible switching of the circuit, thereby more accurately controls the on-off state of the LED circuit, and the accuracy is high.
[0112] The above is the preferred embodiment of the utility model, and it should be pointed out that for ordinary technical personnel in the technical field, without departing from the principle of the utility model, a number of improvements and refinements can be made, and these improvements and refinements are also regarded as the protection range of the utility model.
Claims
1. A ground fault protection circuit compatible with both a mains supply and a ballast, characterized in that, The power supply circuit, the voltage reduction circuit, the driving circuit, the LED circuit and the detection circuit are included. The input end of the power supply circuit is connected to the output pin of the power supply end, and the output end of the power supply circuit is connected to the input end of the voltage reduction circuit, the detection end of the driving circuit and the input end of the LED circuit respectively, for rectifying the output power supply of the power supply end to output the power supply to the voltage reduction circuit, the driving circuit and the LED circuit. The input end of the driving circuit is connected to the output end of the LED circuit, for controlling the working state of the LED circuit according to the power supply. The output end of the voltage reduction circuit is connected to the detection circuit, for reducing the power supply output by the power supply circuit to output the reference voltage to the detection circuit. The detection circuit is connected to the output pin of the power supply end, the driving circuit and the LED circuit respectively, for controlling the working state of the driving circuit and the LED circuit according to the real-time voltage between the output pins of the power supply end and the reference voltage output by the voltage reduction circuit.
2. The line and ballast compatible ground fault protection circuit of claim 1, wherein, The detection circuit includes two band-pass filter modules, a comparison module and a switch module, the comparison module is provided with two real-time sampling ends and two reference sampling ends, and the band-pass filter modules, the real-time sampling ends, the reference sampling ends and the two groups of output pins of the power supply end are one-to-one corresponding. The band-pass filter module is connected to a corresponding group of output pins to filter the output power between the corresponding group of output pins. The real-time sampling end is connected to the corresponding band-pass filter module to detect the real-time voltage between the corresponding group of output pins. The reference sampling end is connected to the output end of the voltage reduction circuit to obtain the reference voltage. The output end of the comparison module is connected to the switch module to control the on-off state of the switch module according to the real-time voltage and the reference voltage.
3. The line and ballast compatible ground fault protection circuit of claim 2, wherein, The band-pass filter module includes two diodes connected in anti-series, and the real-time sampling end of the comparison module is connected between the two diodes.
4. The line and ballast compatible ground fault protection circuit of claim 2, wherein, The switch module includes a first switch, the control end of the first switch is connected to the output end of the comparison module, one electrode end of the first switch is connected to the driving circuit and the LED circuit, and the other electrode end of the first switch is connected to the power supply circuit.
5. The line and ballast compatible ground fault protection circuit of claim 2, wherein, The comparison module includes a first comparator, a second comparator, a second switch and a third switch. One input end of the first comparator is connected to one real-time sampling end of the comparison module, the other input end of the first comparator is connected to one reference sampling end of the comparison module, and the first comparator is used for controlling the on-off state of the second switch according to the real-time voltage detected by one real-time sampling end and the reference voltage obtained by one reference sampling end. One input end of the second comparator is connected to the other real-time sampling end of the comparison module, the other input end of the second comparator is connected to the other reference sampling end of the comparison module, and the second comparator is used for controlling the on-off state of the third switch according to the real-time voltage detected by the other real-time sampling end and the reference voltage obtained by the other reference sampling end. The second switch, the third switch and the switch module are connected in sequence, the on-off state of the second switch and the third switch controls the on-off state of the switch module, and the on-off state of the switch module controls the working state of the driving circuit and the LED circuit.
6. The leakage protection circuit compatible with the commercial power supply and the ballast according to claim 5, wherein, When the second switch and the third switch are turned on, the switch module is turned on, so that the driving circuit is not worked and the power supply circuit, the LED circuit and the detection circuit form an LED loop, and the LED circuit is worked; When the second switch and / or the third switch is turned off, the switch module is turned off, so that the LED circuit and the detection circuit are disconnected.
7. The leakage protection circuit compatible with the commercial power supply and the ballast according to claim 5, wherein, the control electrode of the second switch is connected to the output end of the first comparator, the first electrode of the second switch is connected to the output end of the voltage reduction circuit, and the second electrode of the second switch is connected to the first electrode of the third switch; the control electrode of the third switch is connected to the output end of the second comparator, and the second electrode of the third switch is connected to the switch module.
8. The line and ballast compatible ground fault protection circuit of claim 2, wherein, The detection circuit further comprises an anti-interference module, and the comparison module and the switch module are connected through the anti-interference module.
9. The line and ballast compatible ground fault protection circuit of claim 1, wherein, When the power supply circuit is connected to the ballast, the driving circuit is not worked; When the power supply circuit is connected to the commercial power supply, the driving circuit controls the on-off state between the driving circuit and the LED circuit according to the power supply, so as to control the working state of the LED circuit.
10. The line and ballast compatible ground fault protection circuit of claim 1 or 9, wherein, The driving circuit comprises a driving chip, the driving chip is provided with a detection pin and an open-drain pin, and the open-drain pin is provided with an internal switch; the detection pin is connected to the power supply circuit and is used for detecting the power supply output by the power supply circuit; the open-drain pin is connected to the LED circuit, and the internal switch switches the on-off state according to the power supply, so as to control the on-off state between the driving circuit and the LED circuit.