CN211792158U - Household LED lighting circuit - Google Patents

Abstract

The utility model discloses a domestic LED lighting circuit belongs to LED lighting technology field, has solved the power factor among the prior art problem on the low side. A household LED lighting circuit comprises a rectifying circuit, a DC-DC converter, an output filter circuit, a main control circuit and an LED lamp bank circuit, wherein the rectifying circuit is used for converting alternating current into direct current pulse signals, the DC-DC converter is used for converting the direct current pulse signals into direct current, the output filter circuit is used for filtering ripples of the direct current and outputting the direct current of the filtered ripples to the LED lamp bank circuit, and the LED lamp bank circuit is used for lighting; the main control circuit is used for acquiring voltage and current signals at the front end of the DC-DC converter, acquiring current signals at the rear end of the output filter circuit, enabling the output circuit of the output filter circuit to be constant, and adjusting input current of the rectifying circuit through the PWM signal. The power factor of the LED illumination is improved.

Description

Household LED lighting circuit

Technical Field

The utility model belongs to the technical field of the LED lighting technology and specifically relates to a domestic LED lighting circuit is related to.

Background

The LED is a special diode, belongs to a current type nonlinear element, and tiny fluctuation of voltage at two ends of the LED can cause multiplied increase of the current of the LED, so that the LED is damaged by overcurrent.

When a power supply supplies power to a capacitive or inductive load by using a sinusoidal alternating voltage, the input current still has a sinusoidal law, but the input current has a certain lag or lead relative to the sinusoidal input voltage, and the phase difference is represented as phi; in electrotechnical principles, the port voltage U and the effective value I of the current of a single-port network_RMSAs the apparent power; in a sine-wave alternating current circuit, active Power is usually smaller than apparent Power due to the existence of resistive energy dissipation elements in the network, the apparent Power needs to be multiplied by a coefficient smaller than 1 to be equal to the active Power, the coefficient can be expressed by a cosine function cos phi of an included angle between a sine input voltage and the sine input current, the coefficient is called a Power Factor (PF), the active Power is an average value of products of an instantaneous current and an instantaneous voltage in a period, and the apparent Power is a product of effective values of the current and the voltage; the effective value can objectively represent the work capacity and the size of the sine quantity, and the product of the effective values can represent the energy capacity required to be transmitted by an external network under the normal working state of the power grid; after AC input power is rectified and filtered, the nonlinear load makes the current waveform distorted, and the input current is pulseThe waveform contains a large amount of harmonic components, so that the power factor is low, the conventional household LED lamp driving circuit adopts passive power factor correction, the power factor after correction is 0.5-0.8, the power factor is low, household LEDs are electrically connected in parallel, each single LED lamp needs a constant current source matched with the LED lamp to drive, and the wiring cost of the household LED lighting system is increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome above-mentioned technique not enough at least, provide a domestic LED lighting circuit.

The utility model provides a household LED lighting circuit, including rectifier circuit, DC-DC converter, output filter circuit, master control circuit and LED banks circuit, the output of rectifier circuit is connected with the input of DC-DC converter, the output of DC-DC converter is connected with the input of output filter circuit, the output of output filter circuit is connected with LED banks circuit; the main control circuit is respectively connected with the DC-DC converter and the output filter circuit;

the rectifier circuit is used for converting alternating current into direct current pulse signals, the DC-DC converter is used for converting the direct current pulse signals into direct current, the output filter circuit is used for filtering out ripples of the direct current and outputting the direct current of the filtered ripples to the LED lamp bank circuit, and the LED lamp bank circuit is used for lighting;

the main control circuit is used for acquiring voltage and current signals at the front end of the DC-DC converter, acquiring current signals at the rear end of the output filter circuit, enabling the output circuit of the output filter circuit to be constant, and adjusting input current of the rectifying circuit through the PWM signal.

Preferably, the household LED lighting circuit further comprises an EMI filter circuit, an input end of the EMI filter circuit is connected to the alternating current, and an output end of the EMI filter circuit is connected to an input end of the rectifier circuit; the EMI filter circuit is used for eliminating electromagnetic interference in alternating current.

Preferably, the EMI filter circuit includes common mode inductance L1, L2, electric capacity CX3, CX4, piezo-resistor RZ, fuse F and thermistor NTC, and the alternating current zero line passes through the thermistor NTC and is connected with the first primary of common mode inductance L1, and the alternating current live wire passes through fuse F and is connected with the second primary of common mode inductance L1, electric capacity CX3 and piezo-resistor RZ parallel connection are between the first primary and the second primary of common mode inductance L1, electric capacity CX4 is connected between the first secondary and the second secondary of common mode inductance L1, the first secondary and the second secondary of common mode inductance L1 are connected with the first primary and the second primary of common mode inductance L2 respectively.

Preferably, the rectifying circuit comprises capacitors C10, C20 and diodes D10-D40, and the capacitors C10 and C20 are connected in series between the first secondary end and the second secondary end of the common-mode inductor L2; the diodes D10 and D20 are connected in series, the diodes D30 and D40 are connected in series, the cathode of the diode D10 is connected with the cathode of the diode D30, the anode of the diode D20 is connected with the anode of the diode D40, and the first secondary end and the second secondary end of the common-mode inductor L2 are respectively connected between the diodes D30 and D40 and between the diodes D10 and D20.

Preferably, the DC-DC converter includes a field effect transistor Q4, a diode D1, a diode D2, a diode D5, and a three-winding transformer T, the three-winding transformer T includes a first primary winding, a second primary winding, and a secondary winding, a cathode of the diode D1 is connected to the rectifier circuit, an anode of the diode D1 is connected to a source of the field effect transistor Q4, a drain of the field effect transistor Q4 is grounded, a gate of the field effect transistor Q4 is connected to the main control circuit, two ends of the first primary winding of the three-winding transformer T are respectively connected to a source of the field effect transistor Q4 and the rectifier circuit, one end of the second primary winding of the three-winding transformer T is grounded, the other end is connected to the DC power supply through the diode D5, and the secondary winding of the three-winding transformer T is connected to the output filter circuit.

Preferably, the DC-DC converter further includes resistors R1-R3 and a capacitor C1, a cathode of the diode D1 is connected to the rectifying circuit through the capacitor C1, the resistor R1 is connected in parallel to the capacitor C1, a gate of the field effect transistor Q4 is connected to the main control circuit through the resistor R2, and a drain of the field effect transistor Q4 is connected to the ground through the resistor R3.

Preferably, the output filter circuit comprises an inductor L4, capacitors E3, E4 and a resistor RS2, two ends of the capacitor E3 are connected to two ends of a secondary winding of the three-winding transformer T, one end of the inductor L4 is connected to one end of the capacitor E3, the other end of the capacitor E3 is connected to one end of the resistor RS2, two ends of the capacitor E4 are respectively connected to the other end of the inductor L4 and the other end of the resistor RS2, and two ends of the capacitor E4 are further connected to the LED lamp bank circuit.

Preferably, the main control circuit comprises an ARM chip, an optical coupler U3, capacitors C3-C5, C7, resistors R8, R9 and R11, the VEB pin of the ARM chip is grounded through a capacitor C3, the capacitors C3, C4 and the resistor R9 are connected in parallel, the X pin of the ARM chip is connected with the cathode of a diode D1 through R8, the ISN pin of the ARM chip is connected with the drain of the field effect transistor Q4 through a resistor R3, the trqcl pin of the ARM chip is connected with an LED lamp set circuit, the ZCD pin of the ARM chip is connected with the second primary winding of the three-winding transformer T, the GND, OUT and VCC pins of the ARM chip are grounded respectively, the gate of the field effect transistor Q4 and a direct current power supply, the ictl of the ARM chip is connected with an output filter circuit, the 4 pin of the optical coupler U3 is grounded through a capacitor C3, the optocoupler pin of the U363 of the U3 is grounded, and the optocoupler pin 3 and the capacitor C5 is connected between the 3 pin, and a pin 1 of the optical coupler U3 is connected with an output filter circuit through a resistor R11, and a pin 1 of the optical coupler U3 is grounded through a capacitor C7.

Preferably, the LED lamp group circuit comprises a plurality of LED lamp groups, each LED lamp group comprises a plurality of LED lamps, one LED lamp group corresponds to one field effect transistor, a grid electrode of the field effect transistor is connected with a QCTRL pin of the ARM chip, and a drain electrode and a source electrode of the field effect transistor are respectively connected with an anode and a cathode of each LED lamp.

Compared with the prior art, the beneficial effects of the utility model include: the DC-DC converter converts the direct current pulse signal into direct current, the output filter circuit filters out ripples of the direct current and outputs the direct current of the filtered ripples to the LED lamp bank circuit, and the LED lamp bank circuit is used for lighting; the main control circuit collects voltage and current signals at the front end of the DC-DC converter and collects current signals at the rear end of the output filter circuit, so that the output circuit of the output filter circuit is constant, and the main control circuit is also used for adjusting the input current of the rectifying circuit through a PWM signal; the power factor of the LED illumination is improved.

Drawings

Fig. 1 is a schematic structural diagram of a household LED lighting circuit according to embodiment 1 of the present invention;

fig. 2 is an EMI filter circuit according to embodiment 1 of the present invention;

fig. 3 is a rectifier circuit according to embodiment 1 of the present invention;

fig. 4 is a DC-DC converter according to embodiment 1 of the present invention;

fig. 5 is a household LED lighting circuit according to embodiment 1 of the present invention;

fig. 6 is a topology diagram of a household LED lighting circuit according to embodiment 2 of the present invention;

fig. 7 is a schematic diagram of a series connection mode of the household LED lighting circuit according to embodiment 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

The embodiment of the utility model provides a domestic LED lighting circuit, its schematic structure diagram, as shown in fig. 1, domestic LED lighting circuit includes rectifier circuit, DC-DC converter, output filter circuit, master control circuit and LED banks circuit, the output of rectifier circuit is connected with the input of DC-DC converter, the output of DC-DC converter is connected with the input of output filter circuit, the output of output filter circuit is connected with LED banks circuit; the main control circuit is respectively connected with the DC-DC converter and the output filter circuit;

the rectifier circuit is used for converting alternating current into direct current pulse signals, the DC-DC converter is used for converting the direct current pulse signals into direct current, the output filter circuit is used for filtering out ripples of the direct current and outputting the direct current of the filtered ripples to the LED lamp bank circuit, and the LED lamp bank circuit is used for lighting;

the main control circuit is used for acquiring voltage and current signals at the front end of the DC-DC converter, acquiring current signals at the rear end of the output filter circuit, enabling the output circuit of the output filter circuit to be constant, and adjusting input current of the rectifying circuit through the PWM signal.

In a specific embodiment, a main control circuit is bridged at two ends of a DC-DC converter and an output filter circuit to form an output voltage control loop and a primary side current control loop, and a main control power supply can acquire voltage and current signals at the front end of the DC-DC converter and current signals at the rear end of the output filter circuit; the voltage and current signals at the front end, the master control power supply and the output filter circuit form a primary current control loop, and the current signals at the rear end of the output filter circuit, the master control power supply and the output filter circuit form an output voltage control loop;

the output voltage control loop enables the output voltage of the output filter circuit to follow the reference voltage set in the main control circuit, so that the constancy of the output current is ensured; the primary side current control loop enables the waveform of the input current of the DC-DC converter to track the change of the instantaneous value of the input voltage of the DC-DC converter so as to change, and thus the input current of the driving power supply changes according to a sine wave; the output of the primary current control loop is used as a PWM (pulse-width modulation) modulation signal, and the PWM output by the main control circuit adjusts the on-off of an MOS (metal oxide semiconductor) tube in the DC-DC converter, so that the waveform of input current is approximately the same as that of alternating voltage, and the power factor of an input end is improved;

preferably, the household LED lighting circuit further comprises an EMI filter circuit, an input end of the EMI filter circuit is connected to the alternating current, and an output end of the EMI filter circuit is connected to an input end of the rectifier circuit; the EMI filter circuit is used for eliminating electromagnetic interference in alternating current;

in specific implementation, as shown in fig. 2, the EMI filter circuit generates EMI accompanied by voltage and current, and may conduct electromagnetic interference along a circuit or a medium such as air, and the EMI filter circuit mainly functions to block EMI from a power grid to a power supply, and also functions to suppress a surge and protect the power supply;

preferably, the EMI filter circuit includes common-mode inductors L1, L2, capacitors CX3, CX4, a varistor RZ, a fuse F and a thermistor NTC, the ac neutral line is connected to the first primary end of the common-mode inductor L1 through the thermistor NTC, the ac live line is connected to the second primary end of the common-mode inductor L1 through the fuse F, the capacitors CX3 and the varistor RZ are connected in parallel between the first primary end and the second primary end of the common-mode inductor L1, the capacitor CX4 is connected between the first secondary end and the second secondary end of the common-mode inductor L1, and the first secondary end and the second secondary end of the common-mode inductor L1 are connected to the first primary end and the second primary end of the common-mode inductor L2, respectively;

in specific implementation, the rectifying circuit is a single-phase bridge type uncontrollable rectifying circuit, as shown in fig. 3, the rectifying circuit can convert alternating current into direct current, the input of the rectifying circuit is in a sine waveform, and the output of the rectifying circuit is in a half sine wave;

preferably, the rectifying circuit comprises capacitors C10, C20 and diodes D10-D40, and the capacitors C10 and C20 are connected in series between the first secondary end and the second secondary end of the common-mode inductor L2; the diodes D10 and D20 are connected in series, the diodes D30 and D40 are connected in series, the cathode of the diode D10 is connected with the cathode of the diode D30, the anode of the diode D20 is connected with the anode of the diode D40, and the first secondary end and the second secondary end of the common-mode inductor L2 are respectively connected between the diodes D30 and D40 and between the diodes D10 and D20;

preferably, the DC-DC converter includes a field effect transistor Q4, a diode D1, a diode D2, a diode D5, and a three-winding transformer T, the three-winding transformer T includes a first primary winding, a second primary winding, and a secondary winding, a cathode of the diode D1 is connected to the rectifier circuit, an anode of the diode D1 is connected to a source of a field effect transistor Q4, a drain of the field effect transistor Q4 is grounded, a gate of the field effect transistor Q4 is connected to the main control circuit, two ends of the first primary winding of the three-winding transformer T are respectively connected to a source of a field effect transistor Q4 and the rectifier circuit, one end of the second primary winding of the three-winding transformer T is grounded, the other end is connected to the DC power supply through a diode D5, and the secondary winding of the three-winding transformer T is connected to the output filter circuit;

in a specific embodiment, the DC-DC converter is a single-ended flyback DC-DC converter, as shown in fig. 4, the DC-DC converter is a DC-DC alternating current circuit with isolation, an input stage and an output stage of the DC-DC converter are isolated from each other, noise of the input stage is not conducted to the output stage, the output stage has no dangerous voltage to the ground, and the DC-DC converter converts direct current into direct current with another fixed voltage or adjustable voltage by controlling the on/off of an MOS transistor in a circuit;

preferably, the DC-DC converter further includes resistors R1-R3 and a capacitor C1, the cathode of the diode D1 is connected to the rectifying circuit through the capacitor C1, the resistor R1 is connected in parallel to the capacitor C1, the gate of the field effect transistor Q4 is connected to the main control circuit through the resistor R2, and the drain of the field effect transistor Q4 is connected to the ground through the resistor R3;

preferably, the output filter circuit comprises an inductor L4, capacitors E3, E4 and a resistor RS2, two ends of the capacitor E3 are connected to two ends of a secondary winding of the three-winding transformer T, one end of the inductor L4 is connected to one end of the capacitor E3, the other end of the capacitor E3 is connected to one end of the resistor RS2, two ends of the capacitor E4 are respectively connected to the other end of the inductor L4 and the other end of the resistor RS2, and two ends of the capacitor E4 are further connected to the LED lamp bank circuit.

In a specific embodiment, the output filter circuit comprises four elements, namely capacitors E3 and E4, an inductor L4 and a resistor RS2, and has the functions of reducing alternating current components in pulsating direct current voltage as much as possible, keeping direct current components of the pulsating direct current voltage, reducing output voltage ripple coefficients, and smoothing waveforms so as to stabilize current flowing through the LED;

preferably, the main control circuit comprises an ARM chip, an optical coupler U3, capacitors C3-C5, C7, resistors R8, R9 and R11, the VEB pin of the ARM chip is grounded through a capacitor C3, the capacitors C3, C4 and the resistor R9 are connected in parallel, the X pin of the ARM chip is connected with the cathode of a diode D1 through R8, the ISN pin of the ARM chip is connected with the drain of the field effect transistor Q4 through a resistor R3, the trqcl pin of the ARM chip is connected with an LED lamp set circuit, the ZCD pin of the ARM chip is connected with the second primary winding of the three-winding transformer T, the GND, OUT and VCC pins of the ARM chip are grounded respectively, the gate of the field effect transistor Q4 and a direct current power supply, the ictl of the ARM chip is connected with an output filter circuit, the 4 pin of the optical coupler U3 is grounded through a capacitor C3, the optocoupler pin of the U363 of the U3 is grounded, and the optocoupler pin 3 and the capacitor C5 is connected between the 3 pin, a pin 1 of the optocoupler U3 is connected with an output filter circuit through a resistor R11, and a pin 1 of the optocoupler U3 is grounded through a capacitor C7;

preferably, the LED lamp group circuit comprises a plurality of LED lamp groups, each LED lamp group comprises a plurality of LED lamps, one LED lamp group corresponds to one field effect transistor, a gate of the field effect transistor is connected to a QCTRL pin of the ARM chip, and a drain and a source of the field effect transistor are respectively connected to an anode and a cathode of the LED lamp;

in a specific embodiment, as shown in fig. 5, the household LED lighting circuit is shown with LED lamp group circuits, it can be known that LED lamp groups in different spaces are connected in series, that is, the same constant current source can be used to drive all the LED lamp groups of the household LED lighting circuit, and an MOS switch is connected in parallel at two ends of each LED lamp group; the ARM chip is in a Cotex-M4(32bit) model and is used for collecting an input current signal and an input voltage signal from a single-phase bridge type uncontrollable rectifying and filtering circuit and an output current signal from an output filtering circuit; the LED lamp bank is processed by an ARM chip, a PWM control signal is sent to a single-ended flyback DC-DC converter to achieve constant current control and power factor correction, and the ARM chip is also used for an MOS switch to send a control signal to control the on and off of the LED lamp bank; the MOS switch is a circuit constructed by utilizing the principle that the grid (g) of the MOS transistor controls the on-off of the source(s) and the drain (d) of the MOS transistor, and the ARM chip controls the on-off of the MOS transistor respectively.

Example 2

The embodiment of the utility model provides a still provide a domestic LED lighting circuit, domestic LED lighting circuit topological diagram, as shown in FIG. 6, including EMI filter circuit, single-phase bridge type uncontrollable rectifier circuit, single-ended flyback DC-DC converter, output filter circuit, LED banks circuit and ARM control circuit (master control circuit), EMI filter circuit, single-phase bridge type uncontrollable rectifier circuit, single-ended flyback DC-DC converter, output filter circuit and LED banks order electricity are connected, ARM control circuit includes Cortex-M4 type ARM chip;

the driving power supply is composed of the EMI filter circuit, the single-phase bridge type uncontrollable rectifying circuit, the single-end flyback DC-DC converter and the output filter circuit, the series connection mode schematic diagram of the household LED lighting circuit is shown in figure 7, after the 220V and 50Hz alternating current enters the driving power supply, the alternating current firstly passes through the EMI filter circuit to eliminate electromagnetic interference, then enters the single-phase bridge type uncontrollable rectifying circuit, is converted into a direct current pulse signal under the action of unidirectional conductivity of a diode, is input into the single-end flyback DC-DC converter, and is converted into controllable direct current through the on-off of an MOS (metal oxide semiconductor) tube, enters the output filter circuit, filters ripples and then is output to the LED lamp bank;

the Cortex-M4 type ARM chip is bridged at two ends of the single-ended flyback DC-DC converter to form a feedback circuit, acquires voltage and current signals output by the rectifying circuit and current signals flowing through the LED lamp bank, processes the signals by using the Cortex-M4 type ARM chip, outputs PWM signals, controls the on-off of the single-ended flyback DC-DC converter, and enables the phases of voltage signals and current signals of a secondary side inductance coil of the transformer to be consistent, thereby realizing constant current control and power factor correction;

the LED lamp group circuit is characterized in that a plurality of LED lamp groups are connected in series, so that the current flowing through each LED lamp group is the same, the LED lamp groups can be driven by the same constant current source, MOS switches are connected to two ends of each LED lamp group in parallel, a level signal is sent to a Cortex-M4 type ARM chip through a piezoelectric switch by taking an enhanced NMOS as an example, the Cortex-M4 type ARM chip outputs high level to an MOS tube, the NMOS is switched on, the LED lamp groups are extinguished, otherwise, the Cortex-M4 type ARM chip outputs low level to the NMOS tube, the NMOS is pinched off, and the LED lamp groups are lightened;

an ARM control circuit is bridged at two ends of the single-ended flyback DC-DC converter and the output filter circuit to form an output voltage control loop and a primary side current control loop; the output voltage control loop enables the output voltage of the output filter circuit to follow the reference voltage set in the ARM control circuit, so that the constancy of the output current is ensured; the primary side current control loop enables the waveform of the input current of the single-ended flyback DC-DC converter to track the change of the instantaneous value of the input voltage of the single-ended flyback DC-DC converter so as to change, and thus the input current of the driving power supply changes according to a sine wave; the output of the primary side current control loop is used as a PWM modulation signal, the PWM output by the ARM control circuit controls the on-off of an MOS tube in the single-ended flyback DC-DC converter, so that the waveform of input current is approximately the same as that of alternating current voltage, and the power factor of the input end of the whole circuit is improved.

It should be noted that the description of example 1 and example 2 is not repeated, and they can be referred to each other.

The utility model discloses a domestic LED lighting circuit, convert alternating current to direct current pulsating signal through rectifier circuit, DC-DC converter converts direct current pulsating signal into direct current, the ripple of output filter circuit filtering direct current to export the direct current of filtering ripple to LED banks circuit, LED banks circuit is used for the illumination; the main control circuit collects voltage and current signals at the front end of the DC-DC converter and collects current signals at the rear end of the output filter circuit, so that the output circuit of the output filter circuit is constant, and the main control circuit is also used for adjusting the input current of the rectifying circuit through a PWM signal; the main control circuit, the DC-DC converter and the output filter circuit form an output voltage control loop and a primary current control loop, the output of the primary current control loop is used as a PWM (pulse-width modulation) modulation signal, and the PWM signal output by the main control circuit adjusts the on-off state of an MOS (metal oxide semiconductor) tube in the DC-DC converter, so that the waveform of the input current of the whole circuit is approximately the same as that of the alternating current voltage, thereby improving the power factor of LED illumination, saving electric energy, simultaneously improving the quality of the electric energy and being beneficial to the safe and stable operation of a power grid; the output voltage control loop enables the output voltage of the output filter circuit to follow the reference voltage set in the main control circuit, so that the constancy of the output current is guaranteed, a plurality of LED lamp groups can be driven by the same constant current source, and compared with the mode that a single LED lamp is provided with a driving power supply, the wiring cost of the household LED lighting system is reduced.

The above description of the present invention does not limit the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the scope of the claims of the present invention.

Claims (9)

1. A household LED lighting circuit is characterized by comprising a rectifying circuit, a DC-DC converter, an output filter circuit, a main control circuit and an LED lamp bank circuit, wherein the output end of the rectifying circuit is connected with the input end of the DC-DC converter, the output end of the DC-DC converter is connected with the input end of the output filter circuit, and the output end of the output filter circuit is connected with the LED lamp bank circuit; the main control circuit is respectively connected with the DC-DC converter and the output filter circuit;

the rectifier circuit is used for converting alternating current into direct current pulse signals, the DC-DC converter is used for converting the direct current pulse signals into direct current, the output filter circuit is used for filtering out ripples of the direct current and outputting the direct current of the filtered ripples to the LED lamp bank circuit, and the LED lamp bank circuit is used for lighting;

the main control circuit is used for acquiring voltage and current signals at the front end of the DC-DC converter, acquiring current signals at the rear end of the output filter circuit, enabling the output circuit of the output filter circuit to be constant, and adjusting input current of the rectifying circuit through the PWM signal.

2. The household LED lighting circuit as claimed in claim 1, further comprising an EMI filter circuit, wherein an input terminal of the EMI filter circuit is connected with the alternating current, and an output terminal of the EMI filter circuit is connected with an input terminal of the rectifying circuit; the EMI filter circuit is used for eliminating electromagnetic interference in alternating current.

3. The household LED lighting circuit as claimed in claim 2, wherein the EMI filter circuit comprises common mode inductors L1, L2, capacitors CX3, CX4, piezoresistors RZ, fuses F and thermistors NTC, wherein the AC neutral line is connected with the first primary end of the common mode inductor L1 through the thermistors NTC, the AC live line is connected with the second primary end of the common mode inductor L1 through the fuses F, the capacitors CX3 and the piezoresistors RZ are connected in parallel between the first primary end and the second primary end of the common mode inductor L1, the capacitor CX4 is connected between the first secondary end and the second secondary end of the common mode inductor L1, and the first secondary end and the second secondary end of the common mode inductor L1 are connected with the first primary end and the second primary end of the common mode inductor L2 respectively.

4. The household LED lighting circuit as claimed in claim 3, wherein the rectification circuit comprises capacitors C10, C20 and diodes D10-D40, wherein the capacitors C10 and C20 are connected in series between the first secondary end and the second secondary end of the common-mode inductor L2; the diodes D10 and D20 are connected in series, the diodes D30 and D40 are connected in series, the cathode of the diode D10 is connected with the cathode of the diode D30, the anode of the diode D20 is connected with the anode of the diode D40, and the first secondary end and the second secondary end of the common-mode inductor L2 are respectively connected between the diodes D30 and D40 and between the diodes D10 and D20.

5. The household LED lighting circuit according to claim 1, wherein the DC-DC converter comprises a field effect transistor Q4, diodes D1, D2, D5 and a three-winding transformer T, the three-winding transformer T comprises a first primary winding, a second primary winding and a secondary winding, the cathode of the diode D1 is connected with the rectifying circuit, the anode of the diode D1 is connected with the source of a field effect transistor Q4, the drain electrode of the field effect transistor Q4 is grounded, the grid electrode of the field effect transistor Q4 is connected with the main control circuit, two ends of the first primary winding of the three-winding transformer T are respectively connected with the source electrode of the field effect transistor Q4 and the rectifying circuit, one end of a second primary winding of the three-winding transformer T is grounded, the other end of the second primary winding of the three-winding transformer T is connected with a direct-current power supply through a diode D5, and a secondary winding of the three-winding transformer T is connected with an output filter circuit.

6. The household LED lighting circuit as claimed in claim 5, wherein the DC-DC converter further comprises resistors R1-R3 and a capacitor C1, the cathode of the diode D1 is connected to the rectifying circuit through the capacitor C1, the resistor R1 is connected in parallel with the capacitor C1, the gate of the field effect transistor Q4 is connected to the main control circuit through a resistor R2, and the drain of the field effect transistor Q4 is connected to the ground through the resistor R3.

7. The household LED lighting circuit as claimed in claim 5, wherein the output filter circuit comprises an inductor L4, capacitors E3, E4 and a resistor RS2, two ends of the capacitor E3 are connected with two ends of a secondary winding of a three-winding transformer T, one end of the inductor L4 is connected with one end of a capacitor E3, the other end of the capacitor E3 is connected with one end of a resistor RS2, two ends of a capacitor E4 are respectively connected with the other end of the inductor L4 and the other end of the resistor RS2, and two ends of the capacitor E4 are further connected with the LED lamp bank circuit.

8. The household LED lighting circuit as claimed in claim 7, wherein the main control circuit comprises an ARM chip, an optical coupler U3, capacitors C3-C5, C7, resistors R8, R9, R11, a VEB pin of the ARM chip is grounded through a capacitor C3, capacitors C3, C4 and a resistor R9 are connected in parallel, an X pin of the ARM chip is connected with a cathode of a diode D1 through a R8, an ISN pin of the ARM chip is connected with a drain of the field effect transistor Q4 through a resistor R3, a QCTRL pin of the ARM chip is connected with an LED lamp set circuit, a ZCD pin of the ARM chip is connected with a second primary winding of the three-winding transformer T, GND, OUT and VCC pins of the ARM chip are grounded, a gate of the field effect transistor Q4 and a DC power supply respectively, an ICTRL of the ARM chip is connected with an output filter circuit, a 4 pin of the ARM U3 is grounded through a capacitor C3, and a pin 3 of the optical coupler U3 is grounded, the capacitor C5 is connected between pins 1 and 2 of the optocoupler U3, pin 1 of the optocoupler U3 is connected with an output filter circuit through a resistor R11, and pin 1 of the optocoupler U3 is grounded through a capacitor C7.

9. The household LED lighting circuit as claimed in claim 8, wherein the LED lamp set circuit comprises a plurality of LED lamp sets, each LED lamp set comprises a plurality of LED lamps, one LED lamp set corresponds to one field effect transistor, a grid electrode of the field effect transistor is connected with a QCTRL pin of an ARM chip, and a drain electrode and a source electrode of the field effect transistor are respectively connected with an anode and a cathode of the LED lamp.

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