CN111987692A

CN111987692A - Leakage protection circuit, control method thereof and drive circuit

Info

Publication number: CN111987692A
Application number: CN202010739509.3A
Authority: CN
Inventors: 林星宇; 叶美盼
Original assignee: Hangzhou Silan Microelectronics Co Ltd
Current assignee: Hangzhou Silan Microelectronics Co Ltd
Priority date: 2020-07-28
Filing date: 2020-07-28
Publication date: 2020-11-24
Anticipated expiration: 2040-07-28
Also published as: CN111987692B

Abstract

Disclosed is a leakage protection circuit including: the voltage sampling module is used for acquiring direct current bus voltage and sampling the direct current bus voltage to acquire sampling voltage; the leakage current control module is connected with the voltage sampling module and used for generating a sampling control signal and a leakage control signal according to the sampling voltage and the first reference voltage and generating leakage current according to the leakage control signal; and the electric leakage judging module is connected with the voltage sampling module and the electric leakage current control module and used for acquiring a first sampling voltage at a first sampling moment and a second sampling voltage at a second sampling moment according to the sampling control signal and judging whether an electric leakage phenomenon exists and generating an enabling signal according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment. The invention can avoid the problem of electric shock caused by the error contact of a human body in the process of installing the load, thereby improving the safety in the process of assembling and disassembling the load.

Description

Leakage protection circuit, control method thereof and drive circuit

Technical Field

The present disclosure relates to power electronics, and in particular, to a leakage protection circuit, a control method thereof, and a driving circuit.

Background

Fluorescent lamps are widely used in daily life, and two ends of one fluorescent lamp are respectively connected with commercial power through a zero line and a live line. When the fluorescent lamp tube is installed, one end is installed firstly, the other end is installed, if an operator carelessly touches hands or other parts of a body to the electrode at the other end when the one end is installed, the commercial power, the fluorescent lamp driving circuit, the human body and the ground form a loop, namely, the commercial power voltage is applied to the human body, the human body is paralyzed if the commercial power voltage is light, and the human body is injured by electric shock if the commercial power voltage is heavy, so that the human body is damaged, and a great potential safety hazard exists when the fluorescent lamp tube is installed.

Therefore, it is desirable to further improve the driving circuit of the fluorescent lamp to avoid the problem of electric shock caused by the accidental contact of the human body when the lamp is installed.

Disclosure of Invention

In view of the above, an object of the present invention is to provide an earth leakage protection circuit and a driving circuit, which can avoid the problem of electric shock caused by the accidental contact of a human body when a load is mounted, so as to improve the safety during the process of mounting and dismounting the load.

According to an aspect of the present invention, there is provided a leakage protection circuit, including: the voltage sampling module is used for acquiring direct-current bus voltage and sampling the direct-current bus voltage to obtain sampling voltage; the leakage current control module is connected with the voltage sampling module and used for generating a sampling control signal and a leakage control signal according to the sampling voltage and the first reference voltage and generating leakage current according to the leakage control signal; and the electric leakage judging module is connected with the voltage sampling module and the electric leakage current control module and used for acquiring a first sampling voltage at a first sampling moment and a second sampling voltage at a second sampling moment according to the sampling control signal and judging whether an electric leakage phenomenon exists and generating an enabling signal according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment.

Preferably, the leakage current control module generates a leakage current when or after the sampling voltage is greater than the first reference voltage.

Preferably, the leakage current linearly increases to a predetermined current value or linearly decreases after increasing for a predetermined time.

Preferably, the leakage current curve rises to a preset current value or the curve falls after the curve rises and is maintained for a preset time.

Preferably, the first sampling time is before the generation of the leakage current or when the generation of the leakage current starts, and the second sampling time is before the linear decrease of the leakage current.

Preferably, the first sampling time and the second sampling time are during a linear rise of the leakage current.

Preferably, when the leakage phenomenon exists, the power is not supplied to the load according to the enabling signal; and when the electric leakage phenomenon does not exist, supplying power to the load according to the enabling signal.

Preferably, when the second sampling voltage is less than or equal to the first sampling voltage, a leakage phenomenon exists; when the second sampling voltage is greater than the first sampling voltage, no leakage phenomenon exists.

Preferably, when the second sampling voltage is less than or equal to the sum of the first sampling voltage and a preset bias voltage, a leakage phenomenon exists; when the second sampling voltage is larger than the sum of the first sampling voltage and a preset bias voltage, no electric leakage phenomenon exists.

Preferably, power is supplied to the load when it is determined that there is no leakage phenomenon one or more times in succession.

Preferably, the electric leakage phenomenon is present before the continuous multiple times of judgment are not finished, and the judgment of whether the electric leakage phenomenon exists is carried out again.

Preferably, the rate of change of the sampling voltage at the time of leakage is greater than, equal to, or less than the rate of change at the time of leakage.

Preferably, the voltage sampling module includes a first end to a third end, wherein the first end and the second end of the voltage sampling module are respectively connected to a first output end and a second output end of the dc bus voltage, and the third end is respectively connected to the leakage current control module and the leakage current determination module.

Preferably, the first output end and the second output end of the dc bus voltage are two ends of a dc voltage source respectively.

Preferably, the first output end and the second output end of the dc bus voltage are the first output end and the second output end of the rectifier bridge, respectively.

Preferably, the first output terminal of the dc bus voltage is connected to the input terminal of the rectifier bridge through a first diode and a second diode.

Preferably, the first diode is connected between a first input end of the rectifier bridge and a first output end of the direct current bus voltage; the second diode is connected between the second input terminal of the rectifier bridge and the first output terminal of the dc bus voltage.

Preferably, the leakage current control module includes: the judging unit is used for generating a sampling control signal and a leakage control signal according to the sampling voltage and the first reference voltage; the leakage current control unit is used for generating a reference signal according to the leakage current control signal; wherein the reference signal is a reference voltage or a reference current; and the leakage current generating unit is used for generating leakage current according to the reference signal.

Preferably, the judging unit includes a first comparator, a delay unit and a first switch; the first input end of the first comparator receives a sampling voltage, the second input end of the first comparator receives a first reference voltage, and the output end of the first comparator outputs a sampling control signal and a leakage control signal and is connected with the ground end through a first switch; the delay unit is connected between the output end of the first comparator and the control end of the first switch, and controls the on and off of the first switch.

Preferably, the leakage current generating unit includes a second operational amplifier, a feedback resistor, and a first transistor; the first input end of the second operational amplifier is connected with the leakage current control unit and receives the reference voltage, the second input end of the second operational amplifier is connected with the grounding end through the feedback resistor, and the output end of the second operational amplifier is connected with the control end of the first transistor; the first transistor and the feedback resistor are connected in series between a first output end of the direct current bus voltage and a ground end.

Preferably, the reference voltage is a voltage signal having a preset rising slope, a preset falling slope and a preset maximum voltage.

Preferably, the reference voltage is a voltage signal having a preset rising slope, a preset falling slope and a preset rising time.

Preferably, the leakage current generating unit includes a third operational amplifier, a second transistor, a third resistor, and a feedback resistor; the first input end of the third operational amplifier receives a second reference voltage, the second input end of the third operational amplifier is connected with the output end of the leakage current control unit, receives the reference current, and is connected with the ground end through a third resistor and a feedback resistor, and the output end of the third operational amplifier is connected with the control end of the second transistor; the second transistor and the feedback resistor are connected in series between a first output end of the direct current bus voltage and a ground end.

Preferably, the reference current is a current signal having a preset falling slope, a preset rising slope and a preset maximum current.

Preferably, the reference current is a current signal having a preset falling slope, a preset rising slope and a preset falling time.

Preferably, the leakage current determination module includes: the first sampling and holding unit is used for acquiring a first sampling voltage at a first sampling moment according to the sampling control signal; the second sampling and holding unit is used for acquiring a second sampling voltage at a second sampling moment according to the sampling control signal; the comparison unit is used for comparing the first sampling voltage with the second sampling voltage to obtain a comparison result so as to judge whether the electric leakage phenomenon exists or not; the counting unit is used for generating an enabling signal according to the comparison result; when the comparison result of one or more times of continuous comparison judges that the electric leakage phenomenon does not exist, the enabling signal controls the power supply to the load; when the comparison result of one or more times judges that the electric leakage phenomenon exists, the enabling signal controls not to supply power to the load, and the judgment whether the electric leakage phenomenon exists or not is restarted, and the counting unit restarts counting.

Preferably, the determining unit includes a second comparator, a delay unit, a square wave generator, a fourth switch, a fifth resistor, and a sixth resistor, wherein a first input terminal of the second comparator receives the sampling voltage, a second input terminal of the second comparator receives the first reference voltage, and an output terminal of the second comparator is connected to the ground terminal via the fifth resistor and the fourth switch, and is respectively connected to the delay unit and the square wave generator; a node between the fifth resistor and the fourth switch outputs a leakage control signal and a sampling control signal; the delay unit is connected with the grounding end through a sixth resistor and a fifth switch, and the voltage on a node between the sixth resistor and the fifth switch controls the on and off of the fourth switch; the square wave generator outputs a square wave signal to control the on and off of the fifth switch; the period of the square wave signal output by the square wave generator is at least greater than half of the power frequency period.

According to a second aspect of the present invention, there is provided a method for controlling a leakage protection circuit, comprising: acquiring direct current bus voltage, and sampling the direct current bus voltage to obtain sampling voltage; generating a sampling control signal and a leakage current control signal according to the sampling voltage and a first reference voltage, and generating leakage current according to the leakage current control signal; and acquiring a first sampling voltage at a first sampling moment and a second sampling voltage at a second sampling moment according to the sampling control signal, and judging whether a leakage phenomenon exists and generating an enable signal according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment.

Preferably, the leakage current is generated when or after the sampling voltage is greater than the first reference voltage.

Preferably, the generating of the sampling control signal and the leakage current control signal according to the sampling voltage and the first reference voltage comprises: judging whether the sampling voltage is greater than a first reference voltage or not; when the sampling voltage is greater than a first reference voltage, generating a sampling control signal and a leakage current control signal; generating a reference signal according to the leakage control signal, wherein the reference signal is a reference voltage or a reference current; generating a leakage current according to the reference signal.

According to a third aspect of the present invention, there is provided a driving circuit comprising: the leakage protection circuit described above; the driving module is connected with the electric leakage protection circuit and used for receiving an enabling signal, and when an electric leakage phenomenon exists, the driving module does not supply power to a load according to the enabling signal; and when the electric leakage phenomenon does not exist, the driving module supplies power to the load according to the enabling signal.

According to the leakage protection circuit, the control method and the driving circuit provided by the embodiment of the invention, the first sampling voltage is obtained at the first sampling moment, the second sampling voltage is obtained at the second sampling moment, and whether a leakage phenomenon exists is judged according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment, leakage protection is carried out under the condition of leakage, so that the safety in the process of disassembling and assembling a load is improved.

Furthermore, the first sampling voltage and the second sampling voltage are obtained during the rising period of the leakage current to carry out leakage judgment, and dimming data can be transmitted during the falling period of the leakage current and can be compatible with dimming.

Furthermore, the leakage current is controllable, the impact current is not large, large oscillation and large voltage mutation cannot be caused, the influence on a power grid is small, the power consumption is low, and misjudgment of leakage protection can be prevented.

Furthermore, the glitch interference is prevented by using time delay, and the DC-DC power supply, the DLT power supply and the silicon controlled rectifier power supply can be compatible.

Furthermore, the detection object is the rising edge or the falling edge of the voltage of the direct current bus, so that the detection is convenient.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 shows a schematic circuit diagram of a drive circuit to which a leakage protection circuit of an embodiment of the present invention is applied.

Fig. 2a and 2b respectively show circuit diagrams of a voltage sampling module of the leakage protection circuit according to the embodiment of the present invention.

Fig. 3 and 4 are circuit diagrams respectively showing a leakage current control module of the leakage protection circuit according to the embodiment of the present invention;

fig. 5 is a circuit diagram of a leakage determining module of the leakage protection circuit according to the embodiment of the invention;

fig. 6 and 7 show waveforms of a sampling voltage and a leakage current, respectively, according to an embodiment of the present invention.

Fig. 8 shows a circuit diagram of the determination unit in fig. 3 and 4;

fig. 9 shows a circuit diagram of the leakage current control unit in fig. 3;

fig. 10 shows a circuit diagram of the leakage current control unit in fig. 4;

fig. 11 is a signal waveform diagram of the leakage current control unit of fig. 9;

fig. 12 shows a circuit diagram of a drive circuit to which a leakage protection circuit of a second embodiment of the present invention is applied.

Fig. 13 shows a circuit diagram of a determination unit in the leakage current control module according to the second embodiment of the present invention.

Fig. 14 shows a signal waveform diagram of the determination unit in fig. 13.

Fig. 15 shows a circuit diagram of a drive circuit to which a leakage protection circuit of a third embodiment of the present invention is applied.

Fig. 16 shows a schematic circuit diagram of a driving circuit having a leakage protection circuit and a dimming circuit according to a fourth embodiment of the present invention.

FIG. 17 shows a schematic circuit diagram of the bypass module of FIG. 16;

fig. 18 is a schematic circuit diagram of a driving circuit having a leakage protection circuit and a dimming circuit according to a fifth embodiment of the present invention;

fig. 19 shows a schematic circuit diagram of the dimming circuit of fig. 18;

fig. 20 shows a schematic circuit diagram of the leakage protection circuit in fig. 18 and a schematic configuration diagram of the dimming circuit;

fig. 21 is a signal waveform diagram illustrating the driving circuit provided by the embodiment of the invention when there is no leakage phenomenon;

fig. 22 is a signal waveform diagram illustrating a leakage phenomenon occurring when a leakage protection driving circuit is connected in parallel across a normal driving circuit;

fig. 23 is a signal waveform diagram illustrating a leakage phenomenon when the driving circuit is connected in series with the dimmer according to the embodiment of the present invention;

fig. 24 shows a schematic circuit diagram of a driving device of a sixth embodiment of the invention;

fig. 25 shows a schematic circuit diagram of a driving device of a seventh embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

Fig. 1 shows a schematic circuit diagram of a drive circuit to which a leakage protection circuit of an embodiment of the present invention is applied; as shown in fig. 1, the driving circuit includes a rectifier bridge 110, a leakage protection circuit 120, and a driving module 130. The driver circuit supplies power to a load 140, wherein the load 140 may be a capacitive load or a purely resistive load, for example, the load 140 is an LED load.

The first input end of the rectifier bridge 110 is connected to the live line L of the ac power supply line, and the second input end is connected to the neutral line N of the ac power supply line via the fuse Rfu, for rectifying the ac input voltage. The first output terminal of the rectifier bridge 110 is connected to the second output terminal of the rectifier bridge 110 via the leakage protection circuit 120 and the driving module 130, respectively. Specifically, a first end of the leakage protection circuit 120 is connected to a first output end of the rectifier bridge 110, a second end is connected to a second output end of the rectifier bridge 110, and a third end is connected to the driving module 130; the driving module 130 is connected between the first output terminal and the second output terminal of the rectifier bridge 110, and is connected to the leakage protection circuit 120; the load 140 is connected in parallel between the first output terminal and the second output terminal of the driving module 130.

The phenomenon that a human body is electrically shocked is equivalent to the phenomenon that a resistor Rb is connected in series with a live wire L or a zero wire N of an alternating current power supply line, and the resistance Rb of the human body is more than 500 ohms generally.

In this embodiment, after the earth leakage protection module 120 starts to operate, an enable signal is sent to the driving module 130, and the enable signal controls the driving module 130 to turn off; when the leakage protection module 120 determines that the leakage phenomenon exists, the leakage determination is repeated until the leakage phenomenon is determined to not exist; when the leakage protection circuit 120 determines that there is no leakage, it sends an enable signal to the driving module 130; the enable signal at this time controls the driving module 130 to be turned on to supply power to the load 140.

In this embodiment, the leakage protection circuit 120 includes a voltage sampling module 121, a leakage current control module 122, and a leakage determining module 123.

The voltage sampling module 121 is configured to obtain a dc bus voltage VH output by the rectifier bridge 110, and sample the dc bus voltage VH to obtain a sampling voltage Vs.

In this embodiment, the voltage sampling module 121 includes a first end to a third end, wherein the first end and the second end of the voltage sampling module 121 are respectively connected to a first output end and a second output end of the rectifier bridge 110; the third end of the voltage sampling module 121 is connected to the leakage current control module 122 and the leakage judging module 123, respectively, and is configured to provide the dc bus voltage VH to the leakage current control module 122 and the leakage judging module 123.

In the present embodiment, as shown in fig. 2a, the voltage sampling module 121 includes a first resistor R1 and a second resistor R2, wherein the first resistor R1 and the second resistor R2 are connected in series between the first output terminal and the second output terminal of the rectifier bridge 110. A node between the first resistor R1 and the second resistor R2 outputs the sampled voltage Vs.

In a preferred embodiment, as shown in fig. 2b, the voltage sampling module 121 further comprises a first operational amplifier a1, wherein a first input terminal of the first operational amplifier a1 is connected to a node between the first resistor R1 and the second resistor R2, and a second input terminal of the first operational amplifier a1 is connected to an output terminal of the first operational amplifier a 1. The output of the first operational amplifier a1 outputs a sampled voltage Vs. The first input terminal of the first operational amplifier a1 is a non-inverting input terminal, and the second input terminal is an inverting input terminal, but the present invention is not limited thereto.

The leakage current control module 122 is connected to the voltage sampling module 121, and configured to generate a sampling control signal and a leakage control signal according to the sampling voltage Vs and the first reference voltage, and generate a leakage current according to the leakage control signal. Specifically, the leakage current control module 122 is electrically connected to the third terminal of the voltage sampling module 121.

In this embodiment, the rate of change of the leakage current is controllable, and the slope of the leakage current is controlled to achieve a desired value. The leakage current control module 122 may generate any leakage current, i.e. may control the slope of the leakage current. The leakage current may vary linearly or may be a gentle parabola. When the leakage current linearly changes, the leakage current linearly rises to a preset current value or linearly falls after rising and maintaining for a preset time; when the leakage current is a gentle parabola, the leakage current curve rises to a preset current value or the curve rises and maintains the curve to fall after a preset time.

The rate of change (i.e., slope) of the sampled voltage Vs in the event of leakage may be greater than, less than, or equal to the rate of change (i.e., slope) in the event of no leakage.

In this embodiment, as shown in fig. 3, the leakage current control module 122 includes a determining unit 1221, a leakage current control unit 1222, and a leakage current generating unit 1223, where the determining unit 1221 is configured to generate a sampling control signal Ctrl1 and a leakage control signal Ctrl2 according to the sampling voltage Vs and the first reference voltage; the leakage current control unit 1222 generates the reference voltage Va according to the leakage control signal Ctrl 2. The leakage current generation unit 1223 generates a leakage current Ileak according to the reference voltage Va. The leakage current generating unit 1223 includes a second operational amplifier a2, a first transistor Q1, and a feedback resistor Rcs, wherein a first input terminal of the second operational amplifier a2 receives the reference voltage Va, a second input terminal thereof is connected to a ground terminal GND through the feedback resistor Rcs, and an output terminal thereof is connected to a control terminal of the first transistor Q1. The first transistor Q1 and the feedback resistor Rcs are connected in series between the first terminal of the leakage protection circuit and the ground GND. The first input terminal of the second operational amplifier a2 is a non-inverting input terminal, and the second input terminal is an inverting input terminal, but the present invention is not limited thereto. The first transistor Q1 is an N-type transistor. When the first transistor Q1 is turned on, the current flowing through the first transistor Q1 is the leakage current Ileak.

Specifically, the leakage current control unit 1222 generates the reference voltage Va as a voltage signal having a preset rising slope, a preset falling slope and a preset maximum voltage Vref. I.e. from 0 to the preset maximum voltage Vref within time t 1; and then linearly decreases from the preset maximum voltage Vref to 0 within time t 2.

In a preferred embodiment, the reference voltage Va generated by the leakage current control unit 1222 is a voltage signal having a preset rising slope, a preset falling slope and a preset rising time. I.e., rises from 0 with a preset rising slope and is maintained for a preset rising time t1, and then linearly falls to 0 with a preset falling slope within a time t 2.

In the present embodiment, as shown in fig. 8, the determining unit 1221 includes a first comparator U1, a Delay unit Delay, and a first switch S1, wherein a first input terminal of the first comparator U1 receives the sampling voltage Vs, a second input terminal thereof receives the reference voltage Vref1, and an output terminal thereof is connected to the Delay unit Delay and connected to the ground GND via the first switch S1; the Delay unit Delay controls the on and off of the first switch S1. When the sampling voltage Vs is higher than the first reference voltage Vref1, the output leakage control signal Ctrl2 is active (i.e., high), and then remains active for a time t_delayAnd then outputs an inactive level (i.e., a low level). The first input terminal of the first comparator U1 is a non-inverting input terminal, and the second input terminal is an inverting input terminal, but the present invention is not limited thereto.

As shown in fig. 9, the leakage current control unit 1222 includes a first current source Io1, a second current source Io2, an inverter INV, a first capacitor C1, and a second switch S2 and a third switch S3; the first current source Io1, the second switch S2, the third switch S3 and the second current source Io2 are connected in series between the power voltage VDD and the ground terminal GND; a node between the second switch S2 and the third switch S3 outputs the reference voltage Va, and is connected to the ground GND through the first capacitor C1. The control end of the second switch S2 receives the leakage control signal Ctrl 2; the control terminal of the third switch S3 receives the leakage control signal Ctrl2 via the inverter INV. That is, the second switch S2 is controlled to be turned on and off by the leakage control signal Ctrl2 of the determination unit 1221; the third switch S3 is controlled to be turned on and off by the reverse signal of the leakage control signal Ctrl2 of the determination unit 1221.

Referring to fig. 11, the control signal of the second switch S2 is in phase with the leakage control signal Ctrl 2; the control signal of the third switch S3 is inverse to the leakage control signal Ctrl2, the leakage current Ileak rises linearly when the leakage control signal Ctrl2 is at the active level, and the time t1 of the linear rise and the time t of the active level holding t_delayThe same is true.

In a preferred embodiment, as shown in fig. 4, the leakage current control module 222 includes a determining unit 2221, a leakage current control unit 2222, and a leakage current generating unit 2223, wherein the determining unit 2221 is configured to generate a sampling control signal Ctrl1 and a leakage control signal Ctrl2 according to the sampling voltage Vs and a first reference voltage; the leakage current control unit 2222 generates the reference current Ia according to the leakage control signal Ctrl 2; the leakage current generating unit 2223 generates a leakage current Ileak according to the reference current Ia. The leakage current generating unit 2223 includes a third operational amplifier a3, a second transistor Q2, a third resistor R3, and a feedback resistor Rcs, wherein a first input terminal of the third operational amplifier a3 receives a second reference voltage Vref2, a second input terminal receives the reference current Ia, and is connected to a ground terminal GND through the third resistor R3 and the feedback resistor Rcs; the output terminal is connected to the control terminal of the second transistor Q2. The second transistor Q2 and the feedback resistor Rcs are connected in series between the first terminal of the leakage protection circuit 120 and the ground GND. The linear decrease of the leakage current Ileak is started after the leakage current Ileak linearly rises to a preset current or rises for a preset time. The first input terminal of the third operational amplifier a3 is a non-inverting input terminal, and the second input terminal is an inverting input terminal, but the present invention is not limited thereto. The second transistor Q2 is an N-type transistor.

Specifically, the reference current Ia generated by the leakage current control unit 2222 is a current signal having a preset falling slope, a preset rising slope and a preset maximum current Iref. I.e. from the preset maximum current Iref to 0 during time t 1; then rises linearly from 0 to a preset maximum current Iref within time t 2. The second reference voltage Vref2 is Iref R3.

In a preferred embodiment, the reference current Ia generated by the leakage current control unit 2222 is a current signal having a preset falling slope, a preset rising slope and a preset falling time. I.e. falls to 0 within a preset falling time t1 from following a preset falling slope, and then rises linearly from 0 following a preset rising slope within a time t 2.

As shown in fig. 10, the leakage control unit 2222 includes a first current source Io1, a second current source Io2, a third current source Io3, an inverter INV, a first capacitor C1, a second switch S2, a third switch S3, a fourth operational amplifier a4, third to seventh transistors (Q3-Q7), a fourth resistor R4; the first current source Io1, the second switch S2, the third switch S3 and the second current source Io2 are connected in series between the power voltage VDD and the ground terminal GND; a first input end of the fourth operational amplifier a4 is connected to a node between the second switch S2 and the third switch S3, a second input end is connected to a ground end GND through a fourth resistor R4, and an output end is connected to a control end of the third transistor Q3; the fourth transistor Q4, the third transistor Q3, and the fourth resistor R4 are connected in series between the power supply voltage VDD and the ground GND; the fifth transistor Q5 and the sixth transistor Q6 are connected in series between the power supply voltage VDD and the ground terminal GND; the third current source Io3 and the seventh transistor Q7 are connected in series between the power supply voltage VDD and the ground GND; a node between the third current source Io3 and the seventh transistor Q7 outputs the reference current Ia. The control terminal of the fourth transistor Q4 is connected to the drain thereof, and is connected to the control terminal of the fifth transistor Q5; the control terminal of the sixth transistor Q6 is connected to its drain and to the control terminal of the sixth transistor Q4. The control end of the second switch S2 receives the leakage control signal Ctrl 2; the control terminal of the third switch S3 receives the leakage control signal Ctrl2 via the inverter INV. That is, the second switch S2 is controlled to be turned on or off by the leakage control signal Ctrl2 of the determination unit 2221; the third switch S3 is controlled to be turned on and off by the reverse signal of the leakage control signal Ctrl2 of the determination unit 2221.

Specifically, the source of the fourth transistor Q4 receives the power supply voltage VDD, and the drain thereof is connected to the drain of the third transistor Q3; the source of the third transistor Q3 is connected to the ground GND via the fourth resistor R4; a source of the fifth transistor Q5 receives the power supply voltage VDD, and a drain thereof is connected to the drain of the sixth transistor Q6; the source of the sixth transistor Q6 is connected to the ground GND; the drain of the seventh transistor Q7 is connected to the third current source Io3, and the source is connected to the ground GND.

The third transistor Q3, the sixth transistor Q6, and the seventh transistor Q7 are N-type transistors; the fourth transistor Q4 and the fifth transistor Q5 are P-type transistors.

The first input terminal of the fourth operational amplifier a4 is a non-inverting input terminal, and the second input terminal is an inverting input terminal, but the present invention is not limited thereto.

The leakage determining module 123 is connected to the leakage control module 122 and the voltage sampling module 121, respectively, obtains sampling voltages Vs at different times according to the sampling control signal, and determines whether a leakage phenomenon exists by comparing the sampling voltages Vs at different times.

The leakage determining module 123 is configured to obtain a first sampling voltage Vs1 at a first sampling time and a second sampling voltage Vs2 at a second sampling time according to the sampling control signal Ctrl1, and determine whether a leakage phenomenon exists according to the first sampling voltage Vs1 and the second sampling voltage Vs 2. Wherein the first sampling instant is earlier than the second sampling instant, and the first sampling instant and the second sampling instant are before the end of the leakage current Ileak. In this embodiment, the first sampling time is before the generation of the leakage current Ileak or when the generation of the leakage current Ileak is started, and the second sampling time is before the linear decrease of the leakage current Ileak.

In a preferred embodiment, the first sampling time and the second sampling time are during the linear rising of the leakage current Ileak, and the first sampling time is earlier than the second sampling time.

Specifically, when there is no leakage phenomenon, the leakage human body resistance Rb is 0 ohm, when Vs2 > Vs 1; when the leakage phenomenon exists, the leakage human body resistance 101 is larger than 500 ohms, and Vs2 is smaller than or equal to Vs 1. Therefore, whether the leakage phenomenon exists can be judged by comparing the magnitudes of the first sampling voltage Vs1 and the second sampling voltage Vs2, namely when Vs2 > Vs1, the leakage phenomenon does not exist; when Vs2 is less than or equal to Vs1, a leakage phenomenon exists.

When no current leaks, the waveform of the leakage current Ileak is the same.

The leakage determining module 123 is further configured to generate an enable signal; the enable signal is used to control the driving module 130 to be turned on and off. When the electric leakage phenomenon is judged to exist, the enabling signal controls the driving module 130 to be turned off; when it is determined that there is no leakage, the enable signal controls the driving module 130 to be turned on.

In this embodiment, as shown in fig. 5, the leakage determining module 123 includes a first sample-and-hold unit 1231, a second sample-and-hold unit 1232, a comparing unit 1233, and a counting unit 1234. The first sample-and-hold unit 1231 obtains a first sampled voltage Vs1 according to the sampling control signal Ctrl1 and the sampled voltage Vs; the second sample-and-hold unit 1232 obtains a second sampled voltage Vs2 according to the sampling control signal Ctrl1 and the sampled voltage Vs; the comparison unit 1233 receives the first sampled voltage Vs1 and the second sampled voltage Vs2, compares the magnitudes of the first sampled voltage Vs1 and the second sampled voltage Vs2, determines whether a leakage phenomenon exists according to the comparison result, and does not exist when Vs2 > Vs 1; when Vs2 is less than or equal to Vs1, a leakage phenomenon exists. The counting unit 1234 is configured to count the number of times that there is a leakage phenomenon, and generate an enable signal EN according to a comparison result; when the comparison result obtained for one or more times continuously determines that the leakage phenomenon does not exist, the enable signal controls the driving module 130 to be turned on. Specifically, when it is determined that there is no leakage phenomenon one or more times continuously, the enable signal sent to the driving module 130 controls the driving module 130 to be turned on. When the electric leakage phenomenon is continuously judged for a plurality of times, whether the electric leakage phenomenon exists is judged again, and counting is restarted.

As shown in fig. 6 and 7, during the rising period of the leakage current Ileak, if there is a leakage phenomenon, the sampling voltage Vs will drop, and referring to the solid line part in the figure, Vs2 ≦ Vs1, it is determined that there is a leakage phenomenon. If there is no leakage, the sampling voltage Vs will still rise or not change, and as shown by the dotted line in the figure, Vs2 > Vs1, it is determined that there is no leakage.

In a preferred embodiment, when the second sampled voltage Vs2 is less than or equal to the superimposed value of the first sampled voltage Vs1 and the preset bias voltage, it is determined that the leakage phenomenon exists; on the contrary, when the second sampling voltage Vs2 is greater than the superimposed value of the first sampling voltage Vs1 and the preset bias voltage, it is determined that the leakage phenomenon does not exist. The preset bias voltage may be less than zero, equal to zero, or greater than zero.

When the power is on, the electric leakage determining module 123 sends an enable signal EN to the driving module 130, and controls the driving module 130 to turn off; the electric leakage judging module 123 starts to judge whether an electric leakage phenomenon exists, when the electric leakage judging module 123 judges that the electric leakage phenomenon exists, the enabling signal EN still controls the driving module 130 to be turned off, and whether the electric leakage phenomenon exists or not is repeatedly judged until the electric leakage phenomenon does not exist; when the leakage determining module 123 determines that there is no leakage, the enable signal EN controls the driving module 130 to be turned on to supply power to the load 140.

According to the leakage protection circuit, the control method and the driving circuit thereof, the first sampling voltage obtained at the first sampling time and the second sampling voltage obtained at the second sampling time are compared, wherein the first sampling time is earlier than the second sampling time, and the first sampling time and the second sampling time are before the leakage current is finished, whether a leakage phenomenon exists is judged, and leakage protection is performed under the condition of leakage, so that the safety in the process of assembling and disassembling a load is improved.

Furthermore, the leakage current is controllable, the impact current is not large, large oscillation and large voltage sudden change cannot be caused, the influence on a power grid is small, meanwhile, the power consumption is low, and misjudgment of leakage protection can be prevented.

Fig. 12 is a schematic circuit diagram showing a driving circuit of a leakage protection circuit according to a second embodiment of the present invention. Compared with the driving circuit of the leakage protection circuit shown in fig. 1, the determining unit in the leakage current control module has a DC determining function, and can be applied to determine leakage under two conditions of DC power supply and ac power supply, in this embodiment, a DC input is taken as an example, and the leakage protection circuit 120 is directly connected to a DC power supply DC. The rest of the driving circuit in the second embodiment is the same as that in the first embodiment, and is not described herein again.

In the present embodiment, as shown in fig. 13, the determining unit 3221 includes a second comparator U2, a Delay unit Delay, a square wave generator U3, a fourth switch S4, a fifth switch S5, a fifth resistor R5 and a sixth resistor R6, wherein a first input terminal of the second comparator U2 receives the sampling voltage Vs, a second input terminal thereof receives the first reference voltage Vref1, and an output terminal thereof is connected to the ground terminal GND via the fifth resistor R5 and the fourth switch S4 and is respectively connected to the Delay unit Delay and the square wave generator; a node between the fifth resistor R5 and the fourth switch S4 outputs a leakage control signal Ctrl2 and a sampling control signal Ctrl 1; the Delay unit Delay is connected to the ground GND via a sixth resistor R6 and a fifth switch S5, and a signal at a node between the sixth resistor R6 and the fifth switch S5 controls on and off of the fourth switch S4; the output of the square wave generator U3 controls the turning on and off of the fifth switch S5.

Referring to fig. 14, when the sampling voltage Vs is less than the first reference voltage Vref1, the second comparator U2 outputs a low level, the Delay unit Delay outputs a low level, and the square wave generator U3 outputs a low level; when the sampling voltage Vs is greater than or equal to the first reference voltage Vref1, the second comparator U2 outputs a high level, the Delay unit Delay still outputs a low level, the fourth switch S4 is turned off, the leakage control signal Ctrl2 is a high level, when the Delay unit Delay jumps to a high level after a certain time, at this time, the fourth switch S4 is turned on, and the leakage control signal Ctrl2 jumps to a low level; when the output of the square wave generator U3 is at a high level, the fifth switch S5 is turned on, the fourth switch S4 is turned off, and the leakage control signal Ctrl2 jumps to a high level again. The determining unit 3221 generates a periodic leakage control signal, that is, the leakage control signal Ctrl2 toggles to a high level every time interval t3, and the time t3 needs to be at least greater than one ac cycle.

Fig. 15 shows a schematic circuit diagram of a driving circuit of a leakage protection circuit provided by a third embodiment of the present invention. Compared with the driving circuit of the leakage protection circuit shown in fig. 1, the first terminal of the leakage protection circuit 120 is connected to the input terminal of the rectifier bridge 110 through the first diode D1 and the second diode D2. The rest of the driving circuit in the third embodiment is the same as that in the first embodiment, and is not described again here.

Specifically, the first diode D1 is connected between a first input terminal of the rectifier bridge 110 and a first terminal of the leakage protection circuit 120; the second diode D2 is connected between the second input terminal of the rectifier bridge 110 and the first terminal of the leakage protection circuit 120.

The leakage protection circuit in the first to third embodiments of the present invention can be compatible with the dimming circuit, and performs leakage detection on the rising edge of the dc bus voltage, and performs leakage protection when there is a leakage phenomenon; and when the leakage phenomenon does not exist, dimming data and power are transmitted to realize dimming, wherein the dimming data are transmitted at the falling edge of the direct current bus voltage.

Fig. 16 shows a schematic circuit diagram of a drive circuit of a fourth embodiment of the present invention. Compared to the first embodiment of the present invention, the driving circuit further includes a dimming circuit 150 and a dimmer 160. The dimmer 160 obtains an Ac input voltage from a power supply (i.e., Ac input power Ac) and outputs the Ac input voltage with dimming data based on a dimming operation. The rectifier bridge 110 rectifies the ac input voltage with the dimming data to output a dc bus voltage VH with the dimming data. The dimming circuit 150 performs dimming according to the dc bus voltage VH with dimming data, and the driving module 130 steps down the dc bus voltage VH to obtain a dc output voltage, thereby driving the external load 140, such as an LED lamp.

In the present embodiment, the dimmer 160 includes a first input terminal connected to the live line L of the ac power supply line and a first output terminal for generating the ac input voltage with the dimming data based on the dimming operation. The rectifier bridge 110 is, for example, a full-wave rectifier circuit, and rectifies an ac input voltage into a dc bus voltage VH. A first input of the rectifier bridge 110 is connected to a first output of the dimmer 160, and a second input is connected to the neutral line N of the ac supply line.

As shown in fig. 16, the leakage protection circuit 120 detects whether there is a leakage phenomenon and generates an enable signal; the dimming circuit 150 is connected to the leakage protection circuit 120, receives the enable signal, and when there is no leakage, the enable signal controls the dimming circuit 150 to start dimming, and when there is leakage, the enable signal controls the dimming circuit 150 to stop dimming.

Specifically, the leakage protection circuit 120 is connected between the first output terminal and the second output terminal of the rectifier bridge 110. The leakage protection circuit 120 generates a leakage detection signal according to the dc bus voltage VH with the dimming data and determines whether there is a leakage phenomenon according to the dc bus voltage VH. The driving module 130 is configured to step down the dc bus voltage VH to obtain a dc output voltage. A first input terminal of the driving module 130 is connected to a first output terminal of the rectifier bridge 110, a second input terminal of the driving module 130 is connected to a second output terminal of the rectifier bridge 110, and the driving module 130 is configured to supply power to an external load 140 (e.g., an LED lamp). The driving module 130 may be implemented by a switching power supply or a linear constant current control circuit. For example, the driving module 130 may be implemented by using a switching power supply with various topologies, such as a Buck-BOOST (Buck) topology, a FLYBACK (FLYBACK) topology, and the like.

The dimming circuit 150 is connected between the first output terminal and the second output terminal of the rectifier bridge 110, and is connected to the leakage current protection circuit 120, and generates a leakage current according to a leakage detection signal when leakage detection is performed or a leakage phenomenon exists, and parses dimming data from the dc bus voltage VH when no leakage phenomenon exists, and generates a pulse width modulation signal PWM according to the dimming data, and generates a bypass control signal according to the dc bus voltage VH. In this embodiment, the leakage current linearly increases to a predetermined current value or linearly decreases after the leakage current increases for a predetermined time.

In a preferred embodiment, the leakage current curve rises to a preset current value or falls after the curve rises for a preset time.

In the present embodiment, the dimming circuit 150 includes a bypass module 151 and a dimming module 152. The bypass module 151 is connected to the leakage protection circuit 120, and configured to generate a leakage current according to the leakage detection signal when performing leakage detection and a leakage phenomenon exists; the dimming module 152 is connected to the bypass module, and generates a Pulse Width Modulation (PWM) signal and a bypass control signal according to the dc bus voltage VH, and the bypass module 151 is further configured to generate a bypass current according to the bypass control signal when there is no leakage.

In this embodiment, the dimming module 152 parses the dimming data signal from the dc bus voltage VH and generates a pulse width modulation signal PWM according to the dimming data signal, and the third input terminal of the driving module 130 receives the pulse width modulation signal PWM and supplies power to the external load 140 according to the pulse width modulation signal PWM.

The leakage protection circuit 120 multiplexes the bypass module 151 to perform leakage detection, when leakage detection is performed and a leakage phenomenon exists, a leakage detection signal output by the leakage protection circuit 120 controls the bypass module 151 to be intermittently conducted, and the dimming module 152 stops dimming according to an enable signal; when the leakage phenomenon does not exist, the dimming module 152 starts dimming according to the enable signal, and the bypass control signal output by the dimming module 152 controls the bypass module 151 to be turned on or off, so as to transmit dimming data or power.

Specifically, the leakage protection circuit 120 determines whether there is a leakage phenomenon according to the dc bus voltage VH, and when there is a leakage phenomenon, repeats leakage detection until it is determined that there is no leakage phenomenon; when the leakage phenomenon does not exist, the dimming module 152 provides the driving module 130 with a pulse width modulation signal PWM, where the pulse width modulation signal PWM is used to control the on/off of a main switching tube in the driving module 130, and the duty ratio of the pulse width modulation signal PWM is changed to control the magnitude of the output current, so as to adjust the brightness of the LED lamp 140.

The driving module 130 includes a diode D0 and a driving unit 131, wherein an anode of the diode D0 is connected to the first output terminal of the dc bus voltage VH (i.e., the first output terminal of the rectifier bridge 110), and a cathode thereof is connected to the driving unit 131, mainly for dc blocking and preventing the sine wave voltage from being capacitively filtered. In this embodiment, the leakage protection circuit 120 and the dimming circuit 150 are sequentially connected between the rectifier bridge 110 and the driving module 130.

Fig. 17 shows a circuit schematic of the bypass module of fig. 16. As shown in fig. 17, referring to fig. 17, the bypass module 151 includes a ninth transistor Q9, a third diode D3, a fourth diode D4, an eighth resistor R8, and a ninth resistor R9. The ninth transistor Q9 and the ninth resistor R9 are connected in series between the first output terminal and the second output terminal of the dc bus voltage VH. The gate of the ninth transistor Q9 is connected to the second output terminal of the dc bus voltage VH via an eighth resistor R8. The anode of the third diode D3 is connected to the earth leakage protection circuit 120, and the cathode is connected to the gate of the ninth transistor Q9. The anode of the fourth diode D4 is connected to the dimming module 152, and the cathode is connected to the gate of the ninth transistor Q9. The second output end of the dc bus voltage VH is grounded GND. The ninth transistor Q9 is turned on or off according to the leakage detection signal or the bypass control signal. When leakage detection is performed (for example, when the circuit is just powered on) and a leakage phenomenon exists, the leakage detection signal controls the ninth transistor Q9 to be switched on intermittently, and the ninth transistor Q9 is connected with the seventh resistor R7 in series to form a leakage current path; when there is no leakage, the bypass control signal controls the ninth transistor Q9 to be turned on, and the power supply (i.e., the Ac input power Ac) forms a bypass loop with the ninth transistor Q9 and the ninth resistor R9.

Here, it should be noted that the ninth transistor Q9 and the ninth resistor R9 are equivalent to the first transistor Q1 and the feedback resistor Rcs in the embodiment shown in fig. 3, and are also equivalent to the second transistor Q2 and the feedback resistor Rcs in the embodiment shown in fig. 4, and at this time, the leakage protection circuit 120 multiplexes the ninth transistor Q9 and the ninth resistor R9 in the dimming circuit to realize a leakage protection function.

According to the driving circuit provided by the embodiment of the invention, when the leakage detection is carried out and the leakage phenomenon exists, the bypass module is intermittently conducted to carry out leakage protection, and when the leakage phenomenon does not exist, the bypass module is conducted or turned off to carry out the transmission of dimming data and power so as to realize dimming.

Fig. 18 shows a schematic circuit diagram of a driving device of a fifth embodiment of the present invention. Compared with the fourth embodiment of the present invention, the dimming module 152 further includes a high voltage starting module 153, and the high voltage starting module 153 is connected to the leakage protection circuit 120 and the bypass module 151, and is configured to generate a power supply voltage Vcc according to the dc bus voltage VH and control whether to supply power to the dimming module 152 according to the enable signal.

The leakage protection circuit 120 multiplexes the bypass module 151 to perform leakage detection, when leakage detection is performed and a leakage phenomenon exists, a leakage detection signal output by the leakage protection circuit 120 controls the bypass module 151 to be intermittently turned on, an enable signal controls a power supply path between the high-voltage starting module 153 and the dimming module 152 to be turned off, and the dimming module 152 and the driving module 130 do not work; when it is determined that there is no leakage, the bypass control signal output by the dimming module 152 controls the bypass module 151 to be turned on or off, so as to transmit dimming data or power, the enable signal controls the power supply path between the high voltage start module 153 and the dimming module 152 to be turned on, and the dimming module 152 and the driving module 130 operate normally.

The bypass module 151 and the high voltage starting module 153 are connected between the first output terminal and the second output terminal of the dc bus voltage VH (i.e., between the first output terminal and the second output terminal of the rectifier bridge 110), and the bypass module 151 is connected to the leakage protection circuit 120 and the dimming module 152, receives a leakage detection signal generated by the leakage protection circuit 120 and a bypass control signal generated by the dimming module 152, and controls the bypass module 151 to be turned on or off according to the leakage detection signal or the bypass control signal.

Specifically, when leakage detection is performed (immediately after power-on) and there is a leakage phenomenon, the leakage detection signal output by the leakage protection circuit 120 controls the bypass module 151 to be intermittently turned on; when there is no leakage, the bypass control signal outputted by the dimming module 152 controls the bypass module 151 to turn on or off.

The high voltage starting module 153 is connected between the first output terminal and the second output terminal of the dc bus voltage VH (i.e., between the first output terminal and the second output terminal of the rectifier bridge 110), and is configured to generate a power supply voltage Vcc according to the dc bus voltage VH, and is connected to the leakage protection circuit 120, and is configured to control whether to supply power to the dimming module 152 according to an enable signal generated by the leakage protection circuit 120.

Fig. 19 shows a circuit schematic of the dimming module of fig. 18. As shown in fig. 19, the dimming module 152 includes a voltage detection unit 154, a data acquisition unit 155, and a control unit 156. The voltage detection unit 154, the data acquisition unit 155 and the control unit 156 are all powered by the high voltage starting module 153.

The voltage detection unit 154 receives the dc bus voltage VH, and generates a bypass control signal for controlling the on/off of the bypass module 151 according to the dc bus voltage VH.

The data acquisition unit 155 acquires the dc bus voltage VH, and samples the dc bus voltage VH to obtain a data signal. The data signal is transmitted to the control unit 156 for processing, so as to implement the functions of dimming, color temperature adjustment, grouping management, etc. of the lamp.

The control unit 156 is connected to the data acquisition unit 155 and receives data signals. The control unit 156 obtains the dimming data generated by the dimmer 160 according to the data signal, so as to generate different pulse width modulation signals PWM, control the magnitude of the output current or voltage generated by the driving module 130, and implement the dimming function of the LED lamp.

The control unit 156 may provide multiple PWM signals to control dimming of multiple LED lamps according to the dimming requirement.

Fig. 20 shows a schematic circuit diagram of the leakage protection circuit in fig. 18 and a schematic structure diagram of the dimming circuit. As shown in fig. 20, the leakage protection circuit 120 includes a voltage sampling module 121, a leakage current control module 122, and a leakage determining module 123.

The voltage sampling module 121 is configured to sample the dc bus voltage VH to obtain a sampling voltage Vs.

In this embodiment, the voltage sampling module 121 includes a first end to a third end, where the first end and the second end of the voltage sampling module 121 are respectively connected to a first output end and a second output end of the dc bus voltage VH; the third terminal of the voltage sampling module 121 is connected to the leakage current control module 122 and the leakage judging module 123, respectively, and is configured to provide the sampling voltage Vs representing the dc bus voltage VH to the leakage current control module 122 and the leakage judging module 123.

The leakage current control module 122 is connected to the voltage sampling module 121, and configured to generate a sampling control signal and a leakage detection signal according to the sampling voltage Vs and the first reference voltage, so as to control generation of leakage current. Specifically, the leakage current control module 122 is electrically connected to the third terminal of the voltage sampling module 121, and receives the sampled voltage Vs.

In this embodiment, the leakage current control module 122 generates a leakage detection signal when or after the sampling voltage Vs is greater than the first reference voltage.

The bypass module 151 generates a leakage current according to the leakage detection signal. The change rate of the leakage current is controllable, and the expected value is achieved by controlling the slope of the leakage current. The bypass module 151 may generate any leakage current according to the leakage detection signal, that is, may control a slope of the leakage current. The leakage current may vary linearly or may be a gentle parabola. When the leakage current linearly changes, the leakage current linearly rises to a preset current value or linearly falls after rising and maintaining for a preset time; when the leakage current is a gentle parabola, the leakage current curve rises to a preset current value or the curve rises and maintains the curve to fall after a preset time.

As shown in fig. 5, the leakage determining module 123 is configured to obtain a first sampled voltage Vs1 at a first sampling time and obtain a second sampled voltage Vs2 at a second sampling time according to the sampling control signal; and judging whether the leakage phenomenon exists according to the first sampling voltage Vs1 and the second sampling voltage Vs2, wherein the first sampling time is earlier than the second sampling time, and the first sampling time and the second sampling time are before the end of the leakage current Ileak.

In this embodiment, the first sampling time is before the generation of the leakage current Ileak or when the generation of the leakage current Ileak is started, and the second sampling time is before the linear decrease of the leakage current Ileak.

Specifically, when the leakage phenomenon does not exist, the leakage human body resistance is 0 ohm, and Vs2 is more than Vs 1; when the leakage phenomenon exists, the leakage human body resistance is larger than 500 ohms, and Vs2 is smaller than or equal to Vs 1. Therefore, whether the leakage phenomenon exists can be judged by comparing the magnitudes of the first sampling voltage Vs1 and the second sampling voltage Vs2, namely when Vs2 > Vs1, the leakage phenomenon does not exist; when Vs2 is less than or equal to Vs1, a leakage phenomenon exists.

The electric leakage determining module 123 is further configured to generate an enable signal EN according to the sampling control signal and the sampling voltage Vs; the enable signal EN is used for controlling the power supply path between the high voltage enabling module 153 and the dimming module 152 to be turned on and off. When the electric leakage detection is performed and the electric leakage phenomenon is judged to exist, the enable signal EN controls the power supply path between the high-voltage starting module 153 and the dimming module 152 to be turned off; and when the leakage phenomenon is not present, controlling the power supply path between the high-voltage starting module 153 and the dimming module 152 to be conducted.

Referring to fig. 20, the bypass module 151 includes a ninth transistor Q9, a third diode D3, a fourth diode D4, an eighth resistor R8, and a ninth resistor R9. The eighth transistor Q8, the ninth transistor Q9 and the ninth resistor R9 are connected in series between the first output terminal and the second output terminal of the dc bus voltage VH. A first node between the ninth transistor Q9 and the ninth resistor R9 outputs a leakage current sampling signal or a sampling signal of a bypass current, and a gate of the ninth transistor Q9 is connected to the second output terminal of the dc bus voltage VH through the eighth resistor R8. The anode of the third diode D3 is connected to the leakage current control module 122, and the cathode is connected to the gate of the ninth transistor Q9. The fourth diode D4 has an anode connected to the voltage detection unit 154 and a cathode connected to the gate of the ninth transistor Q9. The second output end of the dc bus voltage VH is grounded. The ninth transistor Q9 is turned on or off according to the leakage detection signal or the bypass control signal. When the circuit is just powered on and a leakage phenomenon exists, the leakage detection signal controls the ninth transistor Q9 to be switched on intermittently, and the power supply (i.e. the alternating current input power supply Ac) and the eighth transistor Q8, the ninth transistor Q9 and the ninth resistor R9 form a leakage current loop; when there is no leakage, the bypass control signal controls the ninth transistor Q9 to be turned on, and the power supply (i.e., the Ac input power Ac) forms a bypass loop with the eighth transistor Q8, the ninth transistor Q9 and the ninth resistor R9.

The high voltage starting module 153 includes an eighth transistor Q8, a voltage regulator tube Z1, a seventh resistor R7, a third diode D3, a fourth diode D4, a second capacitor C2, and a sixth switch S6. A seventh resistor R7 and a zener Z1 are connected in series between the first output terminal and the second output terminal of the dc bus voltage VH. The gate of the eighth transistor Q8 is connected to a second node between the seventh resistor R7 and the regulator tube Z1. The anode of the third diode D3 is connected to ground through the second capacitor C2, and the cathode is connected to the gate of the eighth transistor Q8. An anode of the fourth diode D4 is connected to a node between the eighth transistor Q8 and the ninth transistor Q9, and a cathode is connected to an anode of the third diode D3. The power supply source (i.e., the Ac input power Ac) forms a power supply loop with the eighth transistor Q8, the fourth diode D4 and the second capacitor C2, a third node between the anode of the third diode D3 and the cathode of the fourth diode D4 outputs a power supply voltage Vcc for supplying power to the dimming module 152, and the third node is connected to the dimming module 152 through the sixth switch S6. The control end of the sixth switch S6 is connected to the leakage determining module 123, receives the enable signal EN output by the leakage determining module 123, and controls the power supply path between the high-voltage starting module 153 and the dimming module 152 to be turned on or off according to the enable signal EN.

The gate voltage of the eighth transistor Q8 is stabilized at Vz1 by the seventh resistor R7 and the regulator tube Z1, the eighth transistor Q8 operates in a linear region, the fourth diode D4 is turned on, and the cathode of the fourth diode D4 outputs the power supply voltage Vcc, so that when the circuit is started, the start voltage can be quickly established, and at the moment, Vcc is Vz1-V_Q1gsVd4, where Vz1 is the voltage across the zener diode Z1, V_Q1gsVd4 is a voltage across the fourth diode D4, which is a gate-source voltage of the eighth transistor Q8. When the dc bus voltage VH reaches the valley, that is, when the voltage value of the dc bus voltage VH is low, the power supply voltage Vcc is maintained by the second capacitor C2, and the power supply voltage Vcc is fed back to the gate of the eighth transistor Q8 through the third diode D3, so that the eighth transistor Q8 is ensured to have a sufficient gate voltage to operate in a linear region to maintain the normal operation of the Q1.

The leakage current control module 122 is connected to the gate of the ninth transistor Q9 through the third diode D3, and generates a leakage detection signal to control the on-state of the ninth transistor Q9. The dimming module 152 is connected to the gate of the ninth transistor Q9 through the fourth diode D4, and generates a bypass control signal to control the on-state of the ninth transistor Q9. When both the leakage detection signal and the bypass control signal are low, the ninth transistor Q9 is turned off. When the anode voltage of the third diode D3 is higher than the anode voltage of the fourth diode D4, the leakage detection signal controls the on state of the ninth transistor Q9 to perform leakage detection; when the anode voltage of the fourth diode D4 is higher than the anode voltage of the third diode D3, the bypass control signal controls the on state of the ninth transistor Q9. When the ninth transistor Q9 is turned on, the bypass module 151 is turned on, and the ac input power, the dimmer 160 and the bypass module 151 form a conductive loop. When the ninth transistor Q9 is turned off, the bypass module 151 is turned off, and the conductive loop is opened, so that the dimming data and power are transmitted, thereby realizing dimming.

The voltage detection module 305 includes a third comparator U4, a fourth comparator U5, a fifth operational amplifier U6, a tenth resistor R10, an eleventh resistor R13, a twelfth resistor R12, a thirteenth resistor R13, a seventh switch S7, and an eighth switch S8. The eleventh resistor R13 and the twelfth resistor R12 are connected in series between the first output terminal and the second output terminal of the dc bus voltage VH, and a fourth node between the eleventh resistor R13 and the twelfth resistor R12 outputs a voltage-divided signal corresponding to the dc bus voltage VH. The third comparator U4 has a first input terminal receiving the divided voltage signal, a second input terminal receiving the third reference voltage Vref3, and an output terminal outputting a third control signal Ctrl3, wherein the third control signal Ctrl3 controls the seventh switch S7 to be turned on or off. A first input terminal of the fourth comparator U5 is connected to the fourth node between the eleventh resistor R13 and the twelfth resistor R12, a second input terminal thereof receives the fourth reference voltage Vref4, and an output terminal thereof outputs a fourth control signal Ctrl4, wherein the fourth control signal Ctrl4 controls the eighth switch S8 to be turned on or off. A first input terminal of the fifth operational amplifier U6 is connected to a first node between the ninth transistor Q9 and the thirteenth resistor R13 and receives a sampling signal of a leakage current or a bypass current, a second input terminal receives the fifth reference voltage Vref5 through the thirteenth resistor R13 and the seventh switch S7, and is connected to the ground (a second terminal of the dc bus voltage VH) through the tenth resistor R10, and receives the sixth reference voltage Vref6 through the eighth switch S8, and an output terminal outputs a bypass control signal which controls the operation state of the ninth transistor Q9 through the second diode D2 and is connected to an anode of the second diode D2. The first input terminal of the third comparator U4 is an inverting input terminal, and the second input terminal is a non-inverting input terminal, but the present invention is not limited thereto. The first input terminal of the fourth comparator U5 is an inverting input terminal, and the second input terminal is a non-inverting input terminal, but the present invention is not limited thereto. The first input terminal of the fifth operational amplifier U6 is an inverting input terminal, and the second input terminal is a non-inverting input terminal, but the present invention is not limited thereto.

As shown in fig. 20, when power-up starts, the leakage protection circuit 120 controls the ninth transistor Q9 to be turned on intermittently through the first diode D1, at this time, the sixth switch S6 is turned off, the dimming module 152 and the driving module 130 do not operate, the anode of the second diode D2 is at a low level, and the leakage current control module 122 controls the ninth transistor Q9 to be turned on according to the leakage detection signal, so as to generate the leakage current Ileak. Before the leakage current control module 122 generates the leakage current Ileak or when the leakage current Ileak starts to be generated, the leakage determination module 123 controls the leakage determination module 123 to obtain a first sampling voltage Vs1 from the voltage sampling module 121; before the leakage current Ileak linearly decreases, the sampling control signal controls the leakage judging module 123 to obtain a second sampling voltage Vs2 from the voltage sampling module 121. When Vs2 > Vs1, there is no leakage, and then the leakage detection signal is low, i.e. the anode of the first diode D1 is always low, the enable signal EN generated by the leakage determining module 123 controls the sixth switch S6 to close, so as to supply power to the dimming module 152. When the voltage Vs2 is less than or equal to the voltage Vs1, a leakage phenomenon exists, the enable signal EN controls the sixth switch S6 to be switched off, the leakage detection signal is a pulse square wave, and the ninth transistor Q9 is controlled to be switched on intermittently until the leakage phenomenon is detected to be absent.

In normal operation, that is, when there is no leakage, the enable signal EN controls the sixth switch S6 to be closed, the anode voltage of the first diode D1 is at a low level, the ninth transistor Q9 is controlled by the bypass control signal output by the fifth operational amplifier U6, the high level maintaining time of the bypass control signal is the same as the high level maintaining time of the third control signal Ctrl3, the bypass control signal controls the current of the ninth transistor Q9 and the on and off of the ninth transistor Q9, the transmission of dimming data, the transmission of power, and the power supply path of the dimmer are performed, and the dimming module 152 operates normally.

Referring to fig. 21, when the third control signal Ctrl3 generated at the output terminal of the third comparator U4 is at a high level, the seventh switch S7 is closed, the voltage at the positive input terminal of the fifth operational amplifier U6 is Vref5 × R10/(R10+ R13), the eighth transistor Q8 and the ninth transistor Q9 are controlled to operate in a linear region, and the current flowing through the eighth transistor Q8 and the ninth transistor Q9 is Vref5 × R10/((R10+ R13) ((R9)). At this time, the dimmer 160 generates dimming data, and the bypass module 151 is turned on for transmission of the dimming data.

Similarly, when the fourth control signal Ctrl4 output by the fourth comparator U5 controls the bypass module 151 to turn on during the chopping of the dimmer 160 (i.e., when the dimmer 160 is off), and supplies power to the dimmer 160, the ac input power, the dimmer, and the bypass module form a power supply loop. That is, when the fourth control signal Ctrl4 is at a high level, the eighth switch S8 is closed, the eighth transistor Q8 and the ninth transistor Q9 are controlled to operate in a linear region, and the current flowing through the eighth transistor Q8 and the ninth transistor Q9 is Vref 4/R9.

The current flowing through the eighth transistor Q8 and the ninth transistor Q9 are set to different values at different stages to achieve different impedances of the bypass module 151, which can be used for supplying power to the dimmer and transmitting dimming data, respectively.

When the third control signal Ctrl3 and the fourth control signal Ctrl4 are both low, the ninth transistor Q9 is turned off, and the eighth transistor Q8 operates in a linear region to continue outputting the supply voltage Vcc. At this time, the bypass module 151 is turned off to perform power transmission.

According to the driving circuit provided by the embodiment of the invention, when electric leakage detection is carried out and electric leakage phenomenon exists, the bypass module is intermittently conducted to carry out electric leakage judgment, and meanwhile, a power supply path between the high-voltage starting module and the dimming module is turned off to carry out electric leakage protection; when no electric leakage exists, the bypass module is turned off to realize power transmission, so that the dimming of the LED lamp is realized.

Furthermore, the leakage protection circuit performs leakage detection by detecting leakage current generated by the bypass module, and the leakage protection circuit multiplexes the bypass module to realize leakage protection.

When the leakage-protected driving circuit is connected in parallel to both ends of the normal driving circuit (the leakage-protected driving circuit is not connected), the dimmer 160 can operate normally, the waveform of the dc bus voltage VH carries dimming information, as shown in fig. 22, the second sampling voltage Vs2 obtained at the time t2 is smaller than the first sampling voltage Vs1 obtained at the time t1, and the leakage-protected driving circuit performs leakage protection until Vs2 is greater than Vs 1.

When a single driving circuit is connected in series with the dimmer 160, only the leakage protection circuit 120 is operated, and the dimming module 152 and the driving module 130 are not operated when leakage protection is performed, as shown in fig. 23, the waveform of the dc bus voltage VH does not have dimming information, and only a leakage loop can be generated through the internal capacitance of the dimmer 160. When leakage protection is performed, if the second sampling voltage Vs2 obtained at the time t2 is smaller than the first sampling voltage Vs1 obtained at the time t1, leakage protection is performed until Vs2 > Vs 1.

Fig. 24 shows a schematic circuit diagram of a driving apparatus provided in a sixth embodiment of the present invention. Compared with the seventh embodiment of the present invention, the dimmer 160 further comprises a second input end, the second input end of the dimmer 160 is connected to the second end of the ac input, and the second output end of the dimmer is connected to the second input end of the rectifier bridge.

According to the driving circuit provided by the embodiment of the invention, when the leakage detection is carried out and the leakage phenomenon exists, the bypass module is intermittently conducted to carry out leakage protection, and when the leakage phenomenon does not exist, the bypass module is conducted, the alternating current input power supply, the light modulator and the bypass module form a conductive loop, so that the power supply of the light modulator and the transmission of light modulation data are realized; when no electric leakage exists, the bypass module is turned off to realize power transmission, so that the dimming of the LED lamp is realized.

Fig. 25 shows a schematic circuit diagram of a driving apparatus provided in a seventh embodiment of the present invention. Compared with the fifth embodiment of the present invention, the dimmer 160 further comprises a second input terminal, the second input terminal of the dimmer 160 is connected to the second terminal of the ac input, and the second output terminal of the dimmer is connected to the second input terminal of the rectifier bridge.

According to the driving circuit provided by the embodiment of the invention, when the electric leakage phenomenon exists, the bypass module is intermittently conducted to judge the electric leakage, and meanwhile, the power supply path between the high-voltage starting module and the dimming module is turned off to perform electric leakage protection; when no electric leakage exists, the bypass module is turned off to realize power transmission, so that the dimming of the LED lamp is realized.

Embodiments of the invention are described above, and these embodiments do not set forth any exhaustive details or limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The scope of the invention should be determined from the following claims.

Claims

1. An earth leakage protection circuit, comprising:

the voltage sampling module is used for acquiring direct-current bus voltage and sampling the direct-current bus voltage to obtain sampling voltage;

the leakage current control module is connected with the voltage sampling module and used for generating a sampling control signal and a leakage control signal according to the sampling voltage and the first reference voltage and generating leakage current according to the leakage control signal;

and the electric leakage judging module is connected with the voltage sampling module and the electric leakage current control module and used for acquiring a first sampling voltage at a first sampling moment and a second sampling voltage at a second sampling moment according to the sampling control signal and judging whether an electric leakage phenomenon exists and generating an enabling signal according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment.

2. The leakage protection circuit of claim 1, wherein the leakage current control module generates a leakage current when or after the sampled voltage is greater than the first reference voltage.

3. The leakage protection circuit of claim 2, wherein the leakage current linearly rises to a predetermined current value or linearly falls after rising for a predetermined time.

4. The leakage protection circuit of claim 2, wherein the leakage current curve rises to a predetermined current value or falls after the curve rises for a predetermined time.

5. The leakage protection circuit of claim 1, wherein the first sampling time is before the leakage current is generated or when the leakage current starts to be generated, and the second sampling time is before the leakage current linearly decreases.

6. The leakage protection circuit of claim 1, wherein the first sampling time and the second sampling time are during a linear rise of the leakage current.

7. The earth leakage protection circuit of claim 1, wherein when an earth leakage phenomenon exists, power is not supplied to the load according to the enable signal;

and when the electric leakage phenomenon does not exist, supplying power to the load according to the enabling signal.

8. The leakage protection circuit of claim 1, wherein a leakage phenomenon exists when the second sampling voltage is less than or equal to the first sampling voltage;

when the second sampling voltage is greater than the first sampling voltage, no leakage phenomenon exists.

9. The leakage protection circuit of claim 1, wherein a leakage phenomenon exists when the second sampling voltage is less than or equal to a sum of the first sampling voltage and a preset bias voltage;

when the second sampling voltage is larger than the sum of the first sampling voltage and a preset bias voltage, no electric leakage phenomenon exists.

10. The earth leakage protection circuit of claim 1, wherein power is supplied to the load when it is determined that there is no earth leakage one or more times in succession.

11. The earth leakage protection circuit of claim 1, wherein the earth leakage phenomenon is determined again before the determination is not completed for a plurality of consecutive times.

12. The earth leakage protection circuit of claim 1, wherein the rate of change of the sampled voltage in the event of earth leakage is greater than, equal to, or less than the rate of change in the event of no electrical leakage.

13. The leakage protection circuit of claim 1, wherein the voltage sampling module comprises a first end and a third end, wherein the first end and the second end of the voltage sampling module are respectively connected to a first output end and a second output end of the dc bus voltage, and the third end is respectively connected to the leakage current control module and the leakage current determination module.

14. The leakage protection circuit of claim 13 wherein the first and second outputs of the dc bus voltage are each across a dc voltage source.

15. The leakage protection circuit of claim 13 wherein the first and second outputs of the dc bus voltage are first and second outputs of a rectifier bridge, respectively.

16. The leakage protection circuit of claim 15 wherein the first output of the dc bus voltage is coupled to the input of the rectifier bridge through a first diode and a second diode.

17. The leakage protection circuit of claim 16 wherein the first diode is connected between a first input terminal of a rectifier bridge and a first output terminal of the dc bus voltage;

the second diode is connected between the second input terminal of the rectifier bridge and the first output terminal of the dc bus voltage.

18. The earth leakage protection circuit of claim 13, wherein the earth leakage control module comprises:

the judging unit is used for generating a sampling control signal and a leakage control signal according to the sampling voltage and the first reference voltage;

the leakage current control unit is used for generating a reference signal according to the leakage current control signal; wherein the reference signal is a reference voltage or a reference current;

and the leakage current generating unit is used for generating leakage current according to the reference signal.

19. The earth leakage protection circuit of claim 18, wherein the determining unit comprises a first comparator, a delay unit and a first switch;

the first input end of the first comparator receives a sampling voltage, the second input end of the first comparator receives a first reference voltage, and the output end of the first comparator outputs a sampling control signal and a leakage control signal and is connected with the ground end through a first switch;

the delay unit is connected between the output end of the first comparator and the control end of the first switch, and controls the on and off of the first switch.

20. The leakage protection circuit of claim 18, wherein the leakage current generating unit comprises a second operational amplifier, a feedback resistor, and a first transistor;

the first input end of the second operational amplifier is connected with the leakage current control unit and receives the reference voltage, the second input end of the second operational amplifier is connected with the grounding end through the feedback resistor, and the output end of the second operational amplifier is connected with the control end of the first transistor;

the first transistor and the feedback resistor are connected in series between a first output end of the direct current bus voltage and a ground end.

21. The leakage protection circuit of claim 20, wherein the reference voltage is a voltage signal having a preset rising slope, a preset falling slope, and a preset maximum voltage.

22. The leakage protection circuit of claim 20, wherein the reference voltage is a voltage signal having a preset rising slope, a preset falling slope, and a preset rising time.

23. The leakage protection circuit of claim 18, wherein the leakage current generating unit comprises a third operational amplifier, a second transistor, a third resistor, and a feedback resistor;

the first input end of the third operational amplifier receives a second reference voltage, the second input end of the third operational amplifier is connected with the output end of the leakage current control unit, receives the reference current, and is connected with the ground end through a third resistor and a feedback resistor, and the output end of the third operational amplifier is connected with the control end of the second transistor;

the second transistor and the feedback resistor are connected in series between a first output end of the direct current bus voltage and a ground end.

24. The leakage protection circuit of claim 23, wherein the reference current is a current signal having a predetermined falling slope, a predetermined rising slope, and a predetermined maximum current.

25. The leakage protection circuit of claim 23, wherein the reference current is a current signal having a preset falling slope, a preset rising slope, and a preset falling time.

26. The earth leakage protection circuit of claim 13, wherein the earth leakage determining module comprises:

the first sampling and holding unit is used for acquiring a first sampling voltage at a first sampling moment according to the sampling control signal;

the second sampling and holding unit is used for acquiring a second sampling voltage at a second sampling moment according to the sampling control signal;

the comparison unit is used for comparing the first sampling voltage with the second sampling voltage to obtain a comparison result so as to judge whether the electric leakage phenomenon exists or not;

the counting unit is used for generating an enabling signal according to the comparison result;

when the comparison result of one or more times of continuous comparison judges that the electric leakage phenomenon does not exist, the enabling signal controls the power supply to the load;

when the comparison result of one or more times judges that the electric leakage phenomenon exists, the enabling signal controls not to supply power to the load, and the judgment whether the electric leakage phenomenon exists or not is restarted, and the counting unit restarts counting.

27. The earth leakage protection circuit of claim 18, wherein the determining unit comprises a second comparator, a delay unit, a square wave generator, a fourth switch, a fifth switch, and fifth and sixth resistors,

the first input end of the second comparator receives the sampling voltage, the second input end of the second comparator receives the first reference voltage, and the output end of the second comparator is connected with the grounding end through a fifth resistor and a fourth switch and is respectively connected with the delay unit and the square wave generator;

a node between the fifth resistor and the fourth switch outputs a leakage control signal and a sampling control signal;

the delay unit is connected with the grounding end through a sixth resistor and a fifth switch, and the voltage on a node between the sixth resistor and the fifth switch controls the on and off of the fourth switch;

the square wave generator outputs a square wave signal to control the on and off of the fifth switch;

the square wave period output by the square wave generator is at least greater than half of the power frequency period.

28. A method for controlling a leakage protection circuit, comprising:

acquiring direct current bus voltage, and sampling the direct current bus voltage to obtain sampling voltage;

generating a sampling control signal and a leakage current control signal according to the sampling voltage and a first reference voltage, and generating leakage current according to the leakage current control signal;

and acquiring a first sampling voltage at a first sampling moment and a second sampling voltage at a second sampling moment according to the sampling control signal, and judging whether a leakage phenomenon exists and generating an enable signal according to the first sampling voltage and the second sampling voltage, wherein the first sampling moment is earlier than the second sampling moment.

29. The control method of claim 28, wherein a leakage current is generated when or after the sampled voltage is greater than the first reference voltage.

30. The control method of claim 29, wherein the leakage current linearly increases to a predetermined current value or linearly decreases after the leakage current increases for a predetermined time.

31. The control method of claim 29, wherein the leakage current curve rises to a predetermined current value or falls after the curve rises for a predetermined time.

32. The control method of claim 28, wherein the first sampling time is before the generation of the leakage current or when the generation of the leakage current starts, and the second sampling time is before the leakage current linearly decreases.

33. The control method of claim 28, wherein the first sampling time and the second sampling time are during a linear rise of the leakage current.

34. The control method according to claim 28, wherein when there is a leakage phenomenon, power is not supplied to the load according to the enable signal;

35. The control method according to claim 28, wherein when the second sampling voltage is less than or equal to the first sampling voltage, a leakage phenomenon exists;

36. The control method according to claim 28, wherein when the second sampling voltage is less than or equal to the sum of the first sampling voltage and a preset bias voltage, a leakage phenomenon exists;

37. The control method according to claim 28, wherein power is supplied to the load when it is determined that there is no leakage phenomenon one or more times in succession.

38. The control method according to claim 28, wherein the electric leakage phenomenon is present before the determination is not completed for a plurality of consecutive times, and the determination as to whether the electric leakage phenomenon is present is performed again.

39. The method of claim 28, wherein generating a sampling control signal and a leakage current control signal based on the sampling voltage and a first reference voltage comprises:

judging whether the sampling voltage is greater than a first reference voltage or not;

when the sampling voltage is greater than a first reference voltage, generating a sampling control signal and a leakage current control signal;

generating a reference signal according to the leakage control signal, wherein the reference signal is a reference voltage or a reference current;

generating a leakage current according to the reference signal.

40. The control method according to claim 39, wherein the reference voltage is a voltage signal having a preset rising slope, a preset falling slope, and a preset maximum voltage.

41. The control method of claim 39, wherein the reference voltage is a voltage signal having a preset rising slope, a preset falling slope, and a preset rising time.

42. The control method of claim 39, wherein the reference current is a current signal having a preset falling slope, a preset rising slope, and a preset maximum current.

43. The control method of claim 39, wherein the reference current is a current signal having a preset falling slope, a preset rising slope, and a preset falling time.

44. The control method according to claim 28, wherein a rate of change of the sampling voltage at the time of electric leakage is greater than, equal to, or less than a rate of change at the time of electric leakage.

45. A driver circuit, comprising:

the earth leakage protection circuit of any one of claims 1-27;

the driving module is connected with the electric leakage protection circuit and used for receiving an enabling signal, and when an electric leakage phenomenon exists, the driving module does not supply power to a load according to the enabling signal; and when the electric leakage phenomenon does not exist, the driving module supplies power to the load according to the enabling signal.