CN212588555U

CN212588555U - LED driving power supply

Info

Publication number: CN212588555U
Application number: CN202021537062.3U
Authority: CN
Inventors: 尹向阳; 符恩亮; 周灿荣
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2020-07-29
Filing date: 2020-07-29
Publication date: 2021-02-23
Anticipated expiration: 2030-07-29

Abstract

The utility model discloses a LED drive power supply, including the filter circuit that connects gradually, DC power supply circuit is kept apart to first non-isolation, DC power supply circuit is kept apart to the second non-, and the main power switch tube in DC power supply circuit is kept apart to first non-isolation and the second non-isolation is all on the generating line, and one is in the high-pressure side, and another is in the low-pressure side. The utility model discloses under the condition that does not increase the cost, the main power switch tube among the non-isolation DC/DC power supply circuit had both satisfied LED drive power supply's normal work, had blocked LED drive power supply's electric leakage simultaneously again, had solved the problem that the LED drive power supply of can adjusting luminance among the prior art can't really realize adjusting luminance and turn off the function, furtherly, the utility model discloses can also effectively solve LED drive power supply's stroboscopic problem, improve the PF value, reduce the loss to LED drive power supply's input-output scope is wide.

Description

LED driving power supply

Technical Field

The application relates to the technical field of lighting control, in particular to an LED driving power supply with a dimming turn-off function.

Background

With the development of the technology, the field of the LED light source has higher requirements on energy saving, and the loss of an LED driving power supply is reduced as much as possible on the premise of meeting the requirement of illumination. Under the background, a dimmable LED driving power supply appears on the market, and the power supply can adjust the brightness of an LED lamp according to requirements and reduce unnecessary loss. Dimmable LED driving power supplies such as 0-10V dimming, timing dimming, etc., and LED driving power supplies having a dimming turn-off function.

The existing dimmable LED driving power supply has the following defects:

1. if the alternating current is rectified and then connected with the LED load, no current flows through the LED load in the period from the lower input voltage to the zero crossing of the input voltage, so that the LED emits light intermittently, and the stroboscopic problem harmful to eyes is caused;

2. if alternating current rectification is filtered by a filter capacitor and then connected with an LED load, the stroboscopic problem can be solved, but the power factor of the scheme is low;

3. with the continuous improvement of the power of the LED lamp, the high-power LED driving power supply uses the aluminum substrate as the circuit board, so that heat can be well dissipated, but the scheme can generate larger parasitic capacitance between the circuit board and the metal layer. In this case, the LED lamp will be lit when the power loop is not operating. Such a situation is particularly prominent in non-isolated LED driving power supplies;

4. based on the problem that the LED lamp is turned on even when the power loop does not work, some solutions are also provided in the industry at present, for example, a patent with application number CN201811331396.2 proposes an LED driving power supply with dimming turn-off function, a switch is added to each of the high-voltage end and the low-voltage end of the bus to block the path from the high-voltage end of the bus to the ground and from the low-voltage end of the bus to the ground, so that the LED lamp hardly has leakage current to the ground, and the dimming turn-off function is realized. However, this solution requires additional switching transistors and driving circuits, is complicated to control, and requires additional cost.

SUMMERY OF THE UTILITY MODEL

In view of this, the to-be-solved technical problem of the present invention is to provide a LED driving power supply, which can increase the PFC function when solving the stroboscopic problem, and more importantly, can also reduce the leakage current of the LED driving power supply, so that the dimmable LED driving power supply in the prior art really realizes the dimming turn-off function.

In order to solve the technical problem, the utility model provides a technical scheme as follows:

an LED drive power supply characterized in that: the filter circuit comprises a filter circuit, a first non-isolated DC/DC power supply circuit and a second non-isolated DC/DC power supply circuit; the positive output end of the first non-isolated DC/DC power supply circuit is connected with the positive input end of the second non-isolated DC/DC power supply circuit, the negative output end of the first non-isolated DC/DC power supply circuit is connected with the negative input end of the second non-isolated DC/DC power supply circuit, the positive output end of the second non-isolated DC/DC power supply circuit is used for connecting the anode of a driven LED lamp, and the negative output end of the second non-isolated DC/DC power supply circuit is used for connecting the cathode of the driven LED lamp; at least one main power switch tube in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is arranged on a bus, and one main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is arranged at a high-voltage end, and the other main power switch tube is arranged at a low-voltage end.

Further, when the LED driving power supply works normally, the main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is separately controlled by two signals, and the first non-isolated DC/DC power supply circuit has a PFC function.

Further, when the LED driving power supply needs dimming and turning off, the dimming and turning off signal simultaneously turns off the main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit.

As a specific embodiment of the filter circuit, the following features: is a rectifier bridge.

As a first specific implementation manner of the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit, the following features are provided:

the first non-isolated DC/DC power supply circuit is a BUCK circuit and comprises a switching tube Q1, a diode D1, an inductor L1 and a capacitor C1, the drain of the switching tube Q1 is the positive input end of the first non-isolated DC/DC power supply circuit, the source of the switching tube Q1 is simultaneously connected with one end of an inductor L1 and the cathode of a diode D1, the other end of the inductor L1 and one end of a capacitor C1 are connected to form the positive output end of the first non-isolated DC/DC power supply circuit, and the anode of the diode D1 and the other end of the capacitor C1 are connected to form the negative input end of the first non-isolated DC/DC power supply circuit and the negative output end of the first non-isolated DC/DC power supply circuit;

the second non-isolated DC/DC power supply circuit is a BUCK-BOOST circuit and comprises a switch tube Q2, a diode D2 and an inductor L2, one end of the inductor L2 is connected with the cathode of the diode D2 and then is a positive input end of the second non-isolated DC/DC power supply circuit, the other end of the inductor L2 is a positive output end of the second non-isolated DC/DC power supply circuit, the source of the switch tube Q2 is a negative input end of the second non-isolated DC/DC power supply circuit, and the drain of the switch tube Q2 is connected with the anode of the diode D2 and then is a negative output end of the second non-isolated DC/DC power supply circuit.

As a second specific embodiment of the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit, the following features are provided:

the first non-isolated DC/DC power supply circuit is a BUCK-BOOST circuit and comprises a switch tube Q1, a diode D1, an inductor L1 and a capacitor C1, the drain electrode of the switch tube Q1 is the positive input end of the first non-isolated DC/DC power supply circuit, the source electrode of the switch tube Q1 is simultaneously connected with one end of an inductor L1 and the cathode of a diode D1, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output end of the first non-isolated DC/DC power supply circuit, and the other end of the inductor L1 and the other end of the capacitor C1 are connected to form the negative input end of the first non-isolated DC/DC power supply circuit and the negative output end of the first non-isolated DC/DC power supply circuit;

As a third specific implementation manner of the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit, the following features are provided:

the second non-isolated DC/DC power supply circuit is a BUCK circuit and comprises a switch tube Q2, a diode D2, an inductor L2 and a capacitor C2, wherein the anode of the diode D2 and one end of the capacitor C2 are connected and then are the positive input end of the second non-isolated DC/DC power supply circuit and the positive output end of the second non-isolated DC/DC power supply circuit, the cathode of the diode D2 is connected with the source of the switch tube Q2 and one end of the inductor L2, the drain of the switch tube Q2 is the negative input end of the second non-isolated DC/DC power supply circuit, and the other end of the inductor L2 is the negative output end of the second non-isolated DC/DC power supply circuit.

As a fourth specific embodiment of the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit, the following features are provided:

the second non-isolated DC/DC power supply circuit is a BUCK-BOOST circuit and comprises a switch tube Q2, a diode D2 and an inductor L2, the cathode of the diode D2 is a positive input end and a positive output end of the second non-isolated DC/DC power supply circuit at the same time, the anode of the diode D2 is connected with the drain of the switch tube Q2 and one end of the inductor L2 at the same time, the source of the switch tube Q2 is a negative input end of the second non-isolated DC/DC power supply circuit, and the other end of the inductor L2 is a negative output end of the second non-isolated DC/DC power supply circuit.

As a fifth specific implementation manner of the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit, the method is characterized in that:

the non-isolated DC/DC power circuit 101 is a four-tube buck-boost topology and comprises a switching tube Q1, a switching tube Q3, a diode D1, a diode D2, an inductor L1 and a capacitor C1, wherein the drain of the switching tube Q1 is the positive input end of the non-isolated DC/DC power circuit 101, the source of the switching tube Q1 is simultaneously connected with one end of the inductor L1 and the cathode of the diode D1, the other end of the inductor L1 is simultaneously connected with the drain of the switching tube Q3 and the anode of the diode D2, the anode of the diode D2 and one end of the capacitor C1 are connected and then are the positive output end of the non-isolated DC/DC power circuit 101, and the anode of the diode D1, the source of the switching tube Q3 and the other end of the capacitor C1 are connected and then are simultaneously the negative input end of the non-isolated DC/DC power circuit 101 and the negative output end;

The utility model discloses a non-isolation DC/DC power supply circuit can be for a N series connection, and technical scheme at this moment is as follows:

an LED drive power supply characterized in that: the DC/DC power supply circuit comprises a filter circuit, a first non-isolation DC/DC power supply circuit, a second non-isolation DC/DC power supply circuit, an Nth non-isolation DC/DC power supply circuit, wherein N is a natural number which is greater than or equal to 3; the positive output end of the first non-isolated DC/DC power supply circuit is connected with the negative input end of the second non-isolated DC/DC power supply circuit, the positive output end of the Nth non-isolated DC/DC power supply circuit is used for connecting the anode of a driven LED lamp, and the negative output end of the Nth non-isolated DC/DC power supply circuit is used for connecting the cathode of the driven LED lamp; at least one main power switch tube is arranged on the bus in each of the first non-isolated DC/DC power supply circuit to the Nth non-isolated DC/DC power supply circuit, and at least one main power switch tube is arranged on the bus in each of the first non-isolated DC/DC power supply circuit to the Nth non-isolated DC/DC power supply circuit and is arranged at a high-voltage end and a low-voltage end.

Further, when the LED driving power supply works normally, the main power switch tubes on the bus in the first to Nth non-isolated DC/DC power supply circuits are separately controlled by N signals, and the first non-isolated DC/DC power supply circuit has a PFC function.

Further, when the LED driving power supply needs dimming and turning off, the dimming and turning-off signal simultaneously turns off the main power switch tubes on the bus in the first to Nth non-isolated DC/DC power supply circuits.

The meaning of the terms of the present invention is explained as follows:

bus bar: a line connected to a positive output terminal of the rectifier circuit or a negative output terminal of the rectifier circuit, a line connected to a positive output terminal of the first non-isolated DC/DC power supply circuit or a negative output terminal of the rectifier circuit, a line connected to a positive output terminal of the second non-isolated DC/DC power supply circuit or a negative output terminal of the rectifier circuit, a line connected to a positive output terminal of the nth non-isolated DC/DC power supply circuit or a negative output terminal of the rectifier circuit;

high-voltage end: a line connected to a positive output terminal of the rectifier circuit, a line connected to a positive output terminal of the first non-isolated DC/DC power supply circuit, a line connected to a positive output terminal of the second non-isolated DC/DC power supply circuit, a line connected to a positive output terminal of the nth non-isolated DC/DC power supply circuit;

low-voltage end: a line connected to a negative output of the rectifier circuit, a line connected to a negative output of the first non-isolated DC/DC power supply circuit, a line connected to a negative output of the second non-isolated DC/DC power supply circuit, a line connected to a negative output of the nth non-isolated DC/DC power supply circuit.

The utility model discloses a theory of operation will combine specific embodiment to carry out the analysis, and it is not repeated here, compares with prior art, the utility model discloses following beneficial effect has:

1. under the condition of not increasing the cost, a main power switch tube in the non-isolated DC/DC power circuit not only meets the normal work of the LED driving power supply, but also can block the electric leakage of the LED driving power supply, and the problem that the dimmable LED driving power supply in the prior art cannot really realize the dimming turn-off function is solved;

2. when the first non-isolated DC/DC power supply circuit has the PFC function, the input current phase of the LED driving power supply is made to follow the input voltage phase, so that the power factor correction function is realized, the PF value of the LED driving power supply is improved, and the loss is effectively reduced;

3. in a specific embodiment, the output end of the first non-isolated DC/DC power supply circuit is provided with a capacitor with a larger capacitance value, so that the current ripple of low frequency is reduced, and the stroboscopic problem is effectively solved;

4. in a specific embodiment, a plurality of non-isolated DC/DC power supply circuits with the voltage boosting and reducing functions are used, and the function of wide input and output voltage range is realized.

Drawings

FIG. 1 is a schematic block diagram of the present invention including two non-isolated DC/DC power circuits;

FIG. 2 is a schematic block diagram of the present invention including N non-isolated DC/DC power circuits;

fig. 3 is a schematic circuit diagram of a first embodiment of the present invention;

fig. 4 is a schematic circuit diagram of a second embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a third embodiment of the present invention;

fig. 6 is a schematic circuit diagram of a fourth embodiment of the present invention;

fig. 7 is a schematic circuit diagram of a fifth embodiment of the present invention.

Detailed Description

The circuit of the present invention will be described with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

Fig. 1 is the utility model discloses a schematic block diagram that contains two non-isolation DC/DC power supply circuit, the utility model discloses a LED drive power supply respectively has at least one main power switch tube on the generating line in filter circuit, non-isolation DC/DC power supply circuit 101 and the non-isolation DC/DC power supply circuit 102 that connect gradually, and non-isolation DC/DC power supply circuit 101 and non-isolation DC/DC power supply circuit 102 lie in main power switch tube one on the generating line in the high-pressure side, another is at the low-pressure side. The LED1 connected to the LED driving power supply in fig. 1 is an LED lamp panel made of an aluminum substrate.

It should be noted that the main power switch tubes on the bus in the non-isolated DC/DC power circuit 101 and the non-isolated DC/DC power circuit 102 in fig. 1 may be at the high-voltage end or the low-voltage end, but only one is at the high-voltage end and one is at the low-voltage end.

Preferably, when the non-isolated DC/DC power circuit 101 and the non-isolated DC/DC power circuit 102 work normally, the two signals are separately controlled, and when the non-isolated DC/DC power circuit 101 has a PFC function, the input current phase of the LED driving power supply follows the input voltage phase, so that the power factor correction function is realized, the PF value of the LED driving power supply is improved, and the loss is effectively reduced; when dimming is required to be turned off, the main power switch tubes on the bus in the non-isolated DC/DC power circuit 101 and the non-isolated DC/DC power circuit 102 are turned off simultaneously under the action of a control circuit turn-off signal, and current flow paths of the high-voltage end and the low-voltage end of the bus to the ground are blocked, so that the paths of the high-voltage end of the bus to the ground and the low-voltage end of the bus to the ground are cut off, the LED lamp almost has no leakage current to the ground, and the real dimming turn-off function is realized. When the non-isolated DC/DC power supply circuit 101 and the non-isolated DC/DC power supply circuit 102 are selected or both have the voltage boosting and reducing functions, the function of wide input and output voltage range of the LED driving power supply can be realized.

Fig. 2 is the utility model discloses the functional block diagram who contains a plurality of non-isolation DC/DC power supply circuit of N, can realize that input/output voltage range is wider, but control is complicated, including the filter circuit who connects gradually, non-isolation DC/DC power supply circuit 101, non-isolation DC/DC power supply circuit 102, say.

Similarly, when the LED driving power supply works normally, the non-isolated DC/DC power supply circuit 101 to the non-isolated DC/DC power supply circuit 10N are separately controlled by N signals, and when the non-isolated DC/DC power supply circuit 101 has a PFC function, the input current phase of the LED driving power supply follows the input voltage phase, so that the power factor correction function is realized, the PF value of the LED driving power supply is improved, and the loss is effectively reduced; when dimming is required to be turned off, the main power switch tube on the bus from the non-isolated DC/DC power circuit 101 to the non-isolated DC/DC power circuit 10n can be turned off at the same time under the action of a control circuit turn-off signal, the routes of the bus high-voltage end to the ground and the bus low-voltage end to the ground are also cut off, the LED lamp hardly has leakage current to the ground, and the real dimming turn-off function is realized. When one, part or all of the non-isolated DC/DC power supply circuit 101 to the non-isolated DC/DC power supply circuit 10n has the voltage boosting and reducing function, the function of wide input and output voltage range of the LED driving power supply can be realized.

First embodiment

Fig. 3 shows a circuit principle of a first embodiment of the present invention, which is a specific circuit of fig. 1.

The filter circuit is a rectifier bridge BD1, the positive input end of the rectifier bridge BD1 is used for connecting an L line of a power grid, the negative input end of the rectifier bridge BD1 is used for connecting an N line of the power grid, the positive output end of the rectifier bridge BD1 is connected with the positive input end of the non-isolated DC/DC power circuit 101, and the negative output end of the rectifier bridge BD1 is connected with the negative input end of the non-isolated DC/DC;

the non-isolated DC/DC power supply circuit 101 is a BUCK circuit and comprises a switch tube Q1, a diode D1, an inductor L1 and a capacitor C1, the drain of the switch tube Q1 is the positive input end of the non-isolated DC/DC power supply circuit 101, the source of the switch tube Q1 is simultaneously connected with one end of an inductor L1 and the cathode of a diode D1, the other end of the inductor L1 and one end of a capacitor C1 are connected and then are the positive output end of the non-isolated DC/DC power supply circuit 101, and the anode of the diode D1 and the other end of a capacitor C1 are connected and then are simultaneously the negative input end of the non-isolated DC/DC power supply circuit 101 and the negative output end of the non-isolated DC/DC power supply circuit 101;

the non-isolated DC/DC power circuit 102 is a BUCK-BOOST circuit and comprises a switch tube Q2, a diode D2 and an inductor L2, wherein one end of the inductor L2 is connected with the cathode of the diode D2 and then is a positive input end of the non-isolated DC/DC power circuit 102, the other end of the inductor L2 is a positive output end of the non-isolated DC/DC power circuit 102, the source of the switch tube Q2 is a negative input end of the non-isolated DC/DC power circuit 102, and the drain of the switch tube Q2 is connected with the anode of the diode D2 and then is a negative output end of the non-isolated DC/DC power circuit 102.

The driven LED lamp LED1 in fig. 2 has its anode connected to the positive output of the non-isolated DC/DC power circuit 102 and its cathode connected to the negative output of the non-isolated DC/DC power circuit 102.

The working principle of the embodiment is as follows:

when the LED driving power supply works normally, two signals of the two non-isolated DC/DC power supply circuits are controlled separately, when the non-isolated DC/DC power supply circuit 101 has a PFC function, the input current phase of the LED driving power supply follows the input voltage phase, the power factor correction function is realized, the PF value of the LED driving power supply is improved, and the loss is effectively reduced.

When the switching tube Q1 is conducted and the switching tube Q2 is conducted, the power grid energy stores energy in the inductor L1 and the inductor L2 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1, the inductor L2, the LED lamp and the switching tube Q2, and meanwhile, energy is provided for the LED lamp.

When the switching tube Q1 is turned on and the switching tube Q2 is turned off, the grid energy is stored in the inductor L1 and the capacitor C1 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1 and the capacitor C1. The LED lamp keeps on through inductance L2, LED lamp, diode D2 freewheel circuit, and the energy is provided by inductance L2.

When the switching tube Q1 is turned off and the switching tube Q2 is turned on, the inductor L1 and the capacitor C1 follow current through a loop of the inductor L1, the inductor L2, the LED lamp and the diode D1 to provide energy for the LED lamp.

When the switching tube Q1 is turned off and the switching tube Q2 is turned off, the inductor L1 freewheels through the capacitor C1 and the diode D1. Inductor L2 freewheels through LED lamp and diode D2 to provide power to the LED lamp.

When dimming is required, the dimming turn-off signal turns off the switching tube Q1 and the switching tube Q2 at the same time. When the inductor L2 energy is consumed, the LED lamp is turned off, and meanwhile, because the high-voltage end and the low-voltage end of the bus are blocked by the switching tubes, the LED lamp has no leakage current to the ground, and the real dimming turn-off function is realized.

Second embodiment

Fig. 4 shows a circuit principle of a second embodiment of the present invention, which is different from the first embodiment in that the non-isolated DC/DC power circuit 101 is a BUCK-BOOST circuit, and includes a switch Q1, a diode D1, an inductor L1 and a capacitor C1, a drain of the switch Q1 is a positive input terminal of the non-isolated DC/DC power circuit 101, a source of the switch Q1 is connected to one end of the inductor L1 and a cathode of the diode D1, an anode of the diode D1 and one end of the capacitor C1 are connected to form a positive output terminal of the non-isolated DC/DC power circuit 101, and another end of the inductor L1 and another end of the capacitor C1 are connected to form a negative input terminal of the non-isolated DC/DC power circuit 101 and a negative output terminal of the non-isolated DC/DC power circuit 101.

The working principle of the embodiment is as follows:

when the non-isolated DC/DC power circuit 101 has a PFC function, the input current phase of the LED driving power supply follows the input voltage phase, so that the power factor correction function is realized, the PF value of the LED driving power supply is improved, and the loss is effectively reduced.

When the switching tube Q1 is turned on and the switching tube Q2 is turned on, the inductor L1 is stored with energy from the power grid, and the capacitor C1 supplies energy to the LED lamp through a loop formed by the capacitor C1, the LED lamp and the inductor L2, so that the LED lamp emits light.

When the switching tube Q1 is turned on and the switching tube Q2 is turned off, the inductor L1 is stored with the energy of the power grid. The LED lamp keeps on through LED lamp, inductance L2, diode D2 freewheel return circuit, and the energy is provided by inductance L2.

When the switching tube Q1 is turned off and the switching tube Q2 is turned on, the inductor L1 and the capacitor C1 follow current through a loop formed by the inductor L1, the LED lamp, the inductor L2 and the diode D1 to provide energy for the LED lamp.

When dimming is required, the dimming turn-off signal turns off the switching tube Q1 and the switching tube Q2 at the same time. When the inductor L2 is exhausted, the LED lamp is turned off, and similarly, the high-voltage end and the low-voltage end of the bus are blocked by the switch tubes. The LED lamp has no leakage current to the ground, and the real dimming turn-off function is realized.

Third embodiment

Fig. 5 shows the circuit principle of the third embodiment of the present invention, the non-isolated DC/DC power circuit 102 of the present embodiment is a BUCK circuit, which includes a switch Q2, a diode D2, an inductor L2 and a capacitor C2, the anode of the diode D2 and one end of the capacitor C2 are connected and then are the positive input terminal of the non-isolated DC/DC power circuit 102 and the positive output terminal of the non-isolated DC/DC power circuit 102, the cathode of the diode D2 is connected to the source of the switch Q2 and one end of the inductor L2, the drain of the switch Q2 is the negative input terminal of the non-isolated DC/DC power circuit 102, and the other end of the inductor L2 is the negative output terminal of the non-isolated DC/DC power circuit 102.

The working principle of the embodiment is as follows:

When the switching tube Q1 is turned on and the switching tube Q2 is turned on, the inductor L1 is stored with energy from the power grid, and the capacitor C1 supplies energy to the LED lamp through a loop formed by the capacitor C1, the switching tube Q2, the inductor L2 and the LED lamp, so that the LED lamp emits light.

When the switching tube Q1 is turned on and the switching tube Q2 is turned off, the inductor L1 is stored with the energy of the power grid. The LED lamp keeps on through a freewheeling circuit formed by an inductor L2, the LED lamp and a diode D2, and energy is provided by an inductor L2.

When the switching tube Q1 is turned off and the switching tube Q2 is turned on, the inductor L1 and the capacitor C1 follow current through a loop formed by the inductor L1, the switching tube Q2, the inductor L2, the LED lamp and the diode D1 to provide energy for the LED lamp.

Fourth embodiment

Fig. 6 shows a circuit principle of a fourth embodiment of the present invention, which is different from the first embodiment in that the non-isolated DC/DC power circuit 102 is different, specifically as follows:

the non-isolated DC/DC power supply circuit 102 is a BUCK-BOOST circuit and comprises a switch tube Q2, a diode D2 and an inductor L2, wherein the cathode of the diode D2 is the positive input end and the positive output end of the non-isolated DC/DC power supply circuit 102 at the same time, the anode of the diode D2 is connected with the drain of the switch tube Q2 and one end of the inductor L2 at the same time, the source of the switch tube Q2 is the negative input end of the non-isolated DC/DC power supply circuit 102, and the other end of the inductor L2 is the negative output end of the non-isolated DC/DC power supply circuit 102.

The working principle of the embodiment is as follows:

when the LED driving power supply works normally, the two non-isolated DC/DC power supply circuits are controlled by two signals separately, wherein the non-isolated DC/DC power supply circuit 101 has a PFC control function, so that the phase of input current of the LED driving power supply follows the phase of input voltage, and the function of improving the PF value of the LED driving power supply is realized.

When the switching tube Q1 is turned on and the switching tube Q2 is turned on, the power grid energy stores energy in the inductor L1 and the inductor L2 and provides energy for the LED lamp through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1, the LED lamp, the inductor L2 and the switching tube Q2.

When the switching tube Q1 is turned on and the switching tube Q2 is turned off, the grid energy is stored in the inductor L1 and the capacitor C1 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1 and the capacitor C1. The LED lamp keeps on lighting through the inductor L2, the diode D2 and the LED lamp loop, and energy is provided by the inductor L2.

When the switching tube Q1 is turned off and the switching tube Q2 is turned off, the inductor L1 freewheels through the capacitor C1 and the diode D1. The inductor L2 freewheels through the diode D2 and the LED lamp to supply power to the LED lamp.

When dimming is required, the dimming turn-off signal turns off the switching tube Q1 and the switching tube Q2 at the same time. When the inductor L2 energy is consumed, the LED lamp is turned off, and similarly, because the high-voltage end and the low-voltage end of the bus are blocked by the switching tubes, the LED lamp has no leakage current to the ground, and the real dimming turn-off function is realized.

Fifth embodiment

Fig. 7 shows a circuit principle of a fifth embodiment of the present invention, which is different from the fourth embodiment in a non-isolated DC/DC power circuit 101, and specifically includes the following steps:

the non-isolated DC/DC power circuit 101 is a composite topology, which is called a four-transistor buck-boost topology in chapter 9, chapter 4 of Smart switching Power supply design (2 nd edition), ISBN number 978-7-115-36795-2, published by people's post and telecommunications Press. The four-transistor buck-boost topology comprises a switch transistor Q1, a switch transistor Q3, a diode D1, a diode D2, an inductor L1 and a capacitor C1, wherein the drain of the switch transistor Q1 is the positive input end of a non-isolated DC/DC power circuit 101, the source of the switch transistor Q1 is simultaneously connected with one end of the inductor L1 and the cathode of the diode D1, the other end of the inductor L1 is simultaneously connected with the drain of the switch transistor Q3 and the anode of the diode D2, the anode of the diode D2 and one end of the capacitor C1 are connected and then become the positive output end of the non-isolated DC/DC power circuit 101, and the anode of the diode D1, the source of the switch transistor Q3 and the other end of the capacitor C1 are connected and then become the negative input end of the non-isolated DC/DC power circuit 101 and the negative output end of the non-.

The switch Q1 and the switch Q3 in the non-isolated DC/DC power circuit 101 of this embodiment are both main power switches, wherein the switch Q1 is located on the bus, and the switch Q3 is no longer on the bus.

The non-isolated DC/DC power circuit 101 is a composite topology and the working principle of this embodiment is as follows:

When the switching tube Q1, the switching tube Q2 and the switching tube Q3 are simultaneously conducted, the grid energy stores the energy in the inductor L1 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1 and the switching tube Q3. The capacitor C1 stores energy in the inductor L2 through a loop formed by the capacitor C1, the LED lamp, the inductor L2 and the switching tube Q2, and provides energy for the LED lamp. When the switching tube Q1 and the switching tube Q2 are turned on and the switching tube Q3 is turned off, the energy of the power grid is stored in the inductor L1 and the inductor L2 and is provided for the LED lamp at the same time through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1, the diode D2, the LED lamp, the inductor L2 and the switching tube Q2.

When the switching tube Q1 and the switching tube Q3 are turned on and the switching tube Q2 is turned off, the grid energy is used for storing energy in the inductor L1 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1 and the switching tube Q3. The LED lamp keeps on through a loop formed by the inductor L2, the diode D3 and the LDE lamp, and energy is provided by the inductor L2.

When the switching tube Q1 is turned on and the switching tube Q2 and the switching tube Q3 are turned off, the grid energy stores the energy in the inductor L1 through a loop formed by the rectifier bridge BD1, the switching tube Q1, the inductor L1 and the switching tube Q3. The LED lamp keeps on through a loop formed by the inductor L2, the diode D3 and the LDE lamp, and energy is provided by the inductor L2.

When the switching tube Q1 is turned off and the switching tube Q2 and the switching tube Q3 are turned on, the inductor L1 continues current through a loop formed by the switching tube Q3, the diode D1 and the inductor L1, and the capacitor C1 stores energy in the inductor L2 through a loop formed by the capacitor C1, the LED lamp, the inductor L2 and the switching tube Q2, and provides energy for the LED lamp.

When the switching tube Q1 and the switching tube Q2 are turned off and the switching tube Q3 is turned on, the inductor L1 continues current through a loop formed by the switching tube Q3, the diode D1 and the inductor L1, the LED lamp keeps on through a loop formed by the inductor L2, the diode D3 and the LDE lamp, and energy is provided by the inductor L2.

When the switching tube Q1 and the switching tube Q3 are turned off and the switching tube Q2 is turned on, the inductor L1 performs follow current through a loop formed by the diode D2, the capacitor C1, the diode D1 and the inductor L1, and the capacitor C1 performs energy storage on the inductor L2 through a loop formed by the capacitor C1, the LED lamp, the inductor L2 and the switching tube Q2 and provides energy for the LED lamp at the same time.

When the switching tube Q1, the switching tube Q2 and the switching tube Q3 are turned off at the same time, the inductor L1 performs follow current through a loop formed by the diode D2, the capacitor C1, the diode D1 and the inductor L1, the LED lamp maintains the lamp on through the loop formed by the inductor L2, the diode D3 and the LDE lamp, and energy is provided by the inductor L2.

The above is only the preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as a limitation of the present invention, and for those skilled in the art, a plurality of improvements and decorations can be made without departing from the spirit and scope of the present invention, and all circuits using the idea of the present invention are within the scope of the present invention.

Claims

1. An LED drive power supply characterized in that: the filter circuit comprises a filter circuit, a first non-isolated DC/DC power supply circuit and a second non-isolated DC/DC power supply circuit; the positive output end of the first non-isolated DC/DC power supply circuit is connected with the positive input end of the second non-isolated DC/DC power supply circuit, the negative output end of the first non-isolated DC/DC power supply circuit is connected with the negative input end of the second non-isolated DC/DC power supply circuit, the positive output end of the second non-isolated DC/DC power supply circuit is used for connecting the anode of a driven LED lamp, and the negative output end of the second non-isolated DC/DC power supply circuit is used for connecting the cathode of the driven LED lamp; at least one main power switch tube in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is arranged on a bus, and one main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is arranged at a high-voltage end, and the other main power switch tube is arranged at a low-voltage end.

2. The LED driving power supply according to claim 1, wherein: during normal operation, the main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit is separately controlled by two signals, and the first non-isolated DC/DC power supply circuit has a PFC function.

3. The LED driving power supply according to claim 1, wherein: when dimming is needed to be turned off, the dimming turn-off signal turns off the main power switch tube on the bus in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit at the same time.

4. The LED driving power supply according to any one of claims 1 or 3, wherein: the filter circuit is a rectifier bridge.

5. The LED driving power supply according to any one of claims 1 to 3, wherein:

6. The LED driving power supply according to any one of claims 1 to 3, wherein:

7. The LED driving power supply according to any one of claims 1 to 3, wherein:

8. The LED driving power supply according to any one of claims 1 to 3, wherein:

9. The LED driving power supply according to any one of claims 1 to 3, wherein:

10. An LED drive power supply characterized in that: the DC/DC power supply circuit comprises a filter circuit, a first non-isolation DC/DC power supply circuit, a second non-isolation DC/DC power supply circuit, an Nth non-isolation DC/DC power supply circuit, wherein N is a natural number which is greater than or equal to 3; the positive output end of the first non-isolated DC/DC power supply circuit is connected with the negative input end of the second non-isolated DC/DC power supply circuit, the positive output end of the Nth non-isolated DC/DC power supply circuit is used for connecting the anode of a driven LED lamp, and the negative output end of the Nth non-isolated DC/DC power supply circuit is used for connecting the cathode of the driven LED lamp; at least one main power switch tube is arranged on the bus in each of the first non-isolated DC/DC power supply circuit to the Nth non-isolated DC/DC power supply circuit, and at least one main power switch tube is arranged on the bus in each of the first non-isolated DC/DC power supply circuit to the Nth non-isolated DC/DC power supply circuit and is arranged at a high-voltage end and a low-voltage end.

11. The LED driving power supply according to claim 10, wherein: during normal operation, the main power switch tubes on the bus in the first to Nth non-isolated DC/DC power supply circuits are separately controlled by N signals, and the first non-isolated DC/DC power supply circuit has a PFC function.

12. The LED driving power supply according to claim 10, wherein: when dimming is needed to be turned off, the dimming turn-off signal simultaneously turns off the main power switch tubes on the bus in the first to Nth non-isolated DC/DC power supply circuits.