LED driving power supply

Abstract

The present invention discloses an LED driving power supply, comprising a filter circuit, a first non-isolated DC / DC power supply circuit, and a second non-isolated DC / DC power supply circuit connected in sequence, wherein the main power switch tubes in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit are both on a bus, and one is at a high voltage end, and the other is at a low voltage end. In the present invention, without increasing the cost, the main power switch tube in the non-isolated DC / DC power supply circuit not only satisfies the normal operation of the LED driving power supply, but also blocks the leakage of the LED driving power supply, thereby solving the problem that the dimmable LED driving power supply in the prior art cannot truly realize the dimming shutdown function. Furthermore, the present invention can also effectively solve the stroboscopic problem of the LED driving power supply, improve the PF value, reduce the loss, and the input and output range of the LED driving power supply is wide.

Description

Technical Field

[0001] The present application relates to the field of lighting control technology, and more specifically, to an LED driving power supply with a dimming and shutoff function. Background Art

[0002] With the development of technology, the field of LED light sources has put forward higher requirements for energy saving. It is necessary to reduce the loss of LED driver power as much as possible under the premise of meeting the lighting requirements. In this context, a dimmable LED driver power supply has appeared on the market. This type of power supply can adjust the brightness of LED lights according to needs and reduce unnecessary losses. Such as 0-10V dimming, timed dimming and other dimmable LED driver power supplies, as well as LED driver power supplies with dimming shutdown function.

[0003] The existing dimmable LED driver power supply has the following shortcomings:

[0004] 1. If the AC power is rectified and then connected to an LED load, no current will flow through the LED load during the period from when the input voltage is low to when the input voltage crosses zero, causing the LED to light up intermittently, thus causing a flicker problem that is harmful to the eyes;

[0005] 2. If the AC power is rectified and filtered by a filter capacitor before connecting to the LED load, the above-mentioned flicker problem can be solved, but the power factor of this solution is very low;

[0006] 3. As the power of LED lamps continues to increase, high-power LED driver power supplies use aluminum substrates as circuit boards, which can dissipate heat well. However, this solution will produce a large parasitic capacitance between the circuit board and the metal layer. In this case, the LED lamp will also be lit when the power circuit is not working. This situation is particularly prominent in non-isolated LED driver power supplies;

[0007] 4. Based on the problem that the LED lamp will be lit when the power circuit is not working, there are some solutions in the industry. For example, the patent with application number CN201811331396.2 proposes an LED driver power supply with dimming shutdown function. By adding a switch at the high-voltage end and the low-voltage end of the bus, the route from the high-voltage end of the bus to the ground and the route from the low-voltage end of the bus to the ground is blocked. The LED lamp has almost no leakage current to the ground, and the dimming shutdown function is realized. However, this solution requires additional switch tubes and drive circuits, which is complex to control and requires additional costs. Summary of the invention

[0008] In view of this, the technical problem to be solved by the present invention is to propose an LED driving power supply, which can solve the flicker problem while adding PFC function, 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 can truly realize the dimming shutdown function.

[0009] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0010] An LED driving power supply, characterized in that it includes a filter circuit, a first non-isolated DC / DC power supply circuit and a second non-isolated DC / DC power supply circuit; the positive input end of the filter circuit is used to connect to the L line of the power grid, the negative input end of the filter circuit is used to connect to the N line of the power grid, the positive output end of the filter circuit is connected to the positive input end of the first non-isolated DC / DC power supply circuit, the negative output end of the filter circuit is connected to the negative input end of the first non-isolated DC / DC power supply circuit, the positive output end of the first non-isolated DC / DC power supply circuit is connected to the positive input end of the second non-isolated DC / DC power supply circuit, and the first non-isolated DC / DC power supply circuit is connected to the positive input end of the second non-isolated DC / DC power supply circuit. The negative output end of the source circuit is connected to 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 to connect the anode of the driven LED lamp, and the negative output end of the second non-isolated DC / DC power supply circuit is used to connect 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 on the bus, and one of the main power switch tubes on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit is at the high voltage end, and the other is at the low voltage end.

[0011] Furthermore, when the LED driving power supply is operating normally, the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit are controlled separately by two signals, and the first non-isolated DC / DC power supply circuit has a PFC function.

[0012] Furthermore, when the LED driving power supply needs to be dimmed and shut down, the dimming shutdown signal simultaneously shuts down the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit.

[0013] As a specific implementation of the filter circuit, it is characterized by being a rectifier bridge.

[0014] As a first specific implementation of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit, it is characterized by:

[0015] The first non-isolated DC / DC power supply circuit is a BUCK circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit;

[0016] The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. One end of the inductor L2 is connected to the cathode of the diode D2 to form the positive input end of the second non-isolated DC / DC power supply circuit, the other end of the inductor L2 is the positive output end of the second non-isolated DC / DC power supply circuit, the source of the switch tube Q2 is the negative input end of the second non-isolated DC / DC power supply circuit, and the drain of the switch tube Q2 is connected to the anode of the diode D2 to form the negative output end of the second non-isolated DC / DC power supply circuit.

[0017] As a second specific implementation of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit, it is characterized by:

[0018] The first non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit;

[0019] The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. One end of the inductor L2 is connected to the cathode of the diode D2 to form the positive input end of the second non-isolated DC / DC power supply circuit, the other end of the inductor L2 is the positive output end of the second non-isolated DC / DC power supply circuit, the source of the switch tube Q2 is the negative input end of the second non-isolated DC / DC power supply circuit, and the drain of the switch tube Q2 is connected to the anode of the diode D2 to form the negative output end of the second non-isolated DC / DC power supply circuit.

[0020] As a third specific implementation of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit, it is characterized by:

[0021] The first non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit;

[0022] The second non-isolated DC / DC power supply circuit is a BUCK circuit, including a switch tube 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 to simultaneously serve as the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The cathode of the diode D2 is connected to the source of the switch tube Q2 and one end of the inductor L2 at the same time. The drain of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

[0023] As a fourth specific implementation of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit, it is characterized by:

[0024] The first non-isolated DC / DC power supply circuit is a BUCK circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit;

[0025] The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. The cathode of the diode D2 is both the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The anode of the diode D2 is simultaneously connected to the drain of the switch tube Q2 and one end of the inductor L2. The source of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

[0026] A fifth specific implementation of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit is characterized in that:

[0027] The non-isolated DC / DC power supply circuit 101 is a four-tube buck-boost topology, including a switch tube Q1, a switch tube Q3, a diode D1, a diode D2, an inductor L1 and a capacitor C1. The drain of the switch tube Q1 is the positive input terminal of the non-isolated DC / DC power supply circuit 101, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 is connected to the drain of the switch tube Q3 and the anode of the diode D2 at the same time, the anode of the diode D2 and one end of the capacitor C1 are connected to form the positive output terminal of the non-isolated DC / DC power supply circuit 101, and the anode of the diode D1, the source of the switch tube Q3 and the other end of the capacitor C1 are connected to form the negative input terminal and the negative output terminal of the non-isolated DC / DC power supply circuit 101;

[0028] The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. The cathode of the diode D2 is both the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The anode of the diode D2 is simultaneously connected to the drain of the switch tube Q2 and one end of the inductor L2. The source of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

[0029] The non-isolated DC / DC power supply circuit of the present invention can be N connected in series, and the technical solution in this case is as follows:

[0030] An LED driving power supply, characterized in that it includes a filter circuit, a first non-isolated DC / DC power supply circuit, a second non-isolated DC / DC power supply circuit, ..., an Nth non-isolated DC / DC power supply circuit, N being a natural number greater than or equal to 3; the positive input end of the filter circuit is used to connect to the L line of the power grid, the negative input end of the filter circuit is used to connect to the N line of the power grid, the positive output end of the filter circuit is connected to the positive input end of the first non-isolated DC / DC power supply circuit, the negative output end of the filter circuit is connected to the negative input end of the first non-isolated DC / DC power supply circuit, the positive output end of the first non-isolated DC / DC power supply circuit is connected to the positive input end of the second non-isolated DC / DC power supply circuit The positive output terminal of the first non-isolated DC / DC power supply circuit is connected to the negative input terminal of the second non-isolated DC / DC power supply circuit, ..., the positive output terminal of the Nth non-isolated DC / DC power supply circuit is used to connect the anode of the driven LED lamp, and the negative output terminal of the Nth non-isolated DC / DC power supply circuit is used to connect the cathode of the driven LED lamp; at least one main power switch tube is 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 of the main power switch tubes on the bus in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit is at the high voltage end and the other is at the low voltage end.

[0031] Furthermore, when the LED driving power supply is operating normally, the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit are controlled separately by N signals, and the first non-isolated DC / DC power supply circuit has a PFC function.

[0032] Furthermore, when the LED driving power supply needs to be dimmed and shut down, the dimming shutdown signal simultaneously shuts down the main power switch tube located on the bus in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit.

[0033] The meanings of the terms in the present invention are as follows:

[0034] Busbar: a line connected to the positive output terminal of the rectifier circuit or the negative output terminal of the rectifier circuit, a line connected to the positive output terminal of the first non-isolated DC / DC power supply circuit or the negative output terminal of the rectifier circuit, a line connected to the positive output terminal of the second non-isolated DC / DC power supply circuit or the negative output terminal of the rectifier circuit, ..., a line connected to the positive output terminal of the Nth non-isolated DC / DC power supply circuit or the negative output terminal of the rectifier circuit;

[0035] High voltage end: a line connected to the positive output end of the rectifier circuit, a line connected to the positive output end of the first non-isolated DC / DC power supply circuit, a line connected to the positive output end of the second non-isolated DC / DC power supply circuit, ..., a line connected to the positive output end of the Nth non-isolated DC / DC power supply circuit;

[0036] Low voltage end: a line connected to the negative output terminal of the rectifier circuit, a line connected to the negative output terminal of the first non-isolated DC / DC power supply circuit, a line connected to the negative output terminal of the second non-isolated DC / DC power supply circuit, ..., a line connected to the negative output terminal of the Nth non-isolated DC / DC power supply circuit.

[0037] The working principle of the present invention will be analyzed in conjunction with specific embodiments, which will not be described in detail here. Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. Without increasing the cost, the main power switch tube in the non-isolated DC / DC power supply circuit not only meets the normal operation of the LED driver power supply, but also blocks the leakage of the LED driver power supply, solving the problem that the dimmable LED driver power supply in the prior art cannot truly realize the dimming shutdown function;

[0039] 2. When the first non-isolated DC / DC power supply circuit has a PFC function, the input current phase of the LED driving power supply follows the input voltage phase, thereby realizing a power factor correction function, improving the PF value of the LED driving power supply, and effectively reducing losses;

[0040] 3. In a specific embodiment, the output end of the first non-isolated DC / DC power supply circuit has a capacitor with a large capacitance, thereby reducing the low-frequency current ripple and effectively solving the stroboscopic problem;

[0041] 4. In a specific embodiment, a plurality of non-isolated DC / DC power supply circuits with buck-boost function are used to realize the function of wide input and output voltage range. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The present invention is a principle block diagram of two non-isolated DC / DC power supply circuits;

[0043] Figure 2 The present invention is a principle block diagram of N non-isolated DC / DC power supply circuits;

[0044] Figure 3 is a circuit diagram of a first embodiment of the present invention;

[0045] Figure 4 is a circuit diagram of a second embodiment of the present invention;

[0046] Figure 5 is a circuit diagram of a third embodiment of the present invention;

[0047] Figure 6 is a circuit diagram of a fourth embodiment of the present invention;

[0048] Figure 7 FIG. 5 is a circuit diagram of a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0049] The circuit of the present invention is described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the circuit of the present invention.

[0050] Figure 1 The present invention includes a principle block diagram of two non-isolated DC / DC power supply circuits. The LED driving power supply of the present invention includes a filter circuit, a non-isolated DC / DC power supply circuit 101 and a non-isolated DC / DC power supply circuit 102 connected in sequence. The non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 each have at least one main power switch tube on the bus, and the main power switch tubes on the bus in the non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 are located at one at the high voltage end and the other at the low voltage end. Figure 1 The LED1 connected to the LED driving power supply is an LED light board made of aluminum substrate.

[0051] Need to be explained Figure 1 The main power switch tubes located on the bus in the non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 can be at the high voltage end or the low voltage end, but only one can be at the high voltage end and the other can be at the low voltage end.

[0052] More preferably, in normal operation, the non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 are controlled separately by two signals. When the non-isolated DC / DC power supply circuit 101 has a PFC function, the input current phase of the LED driver power supply follows the input voltage phase, realizing the power factor correction function, improving the PF value of the LED driver power supply, and effectively reducing the loss; when dimming and shutting down are required, the main power switch tubes located on the bus in the non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 will be shut down at the same time under the action of the control circuit shutdown signal, and at the same time block the current flow path from the high-voltage end and the low-voltage end of the bus to the ground, so that the route from the high-voltage end of the bus to the ground and the low-voltage single ground line of the bus is cut off, and the LED lamp has almost no leakage current to the earth, realizing a true dimming and shutting down function. When the non-isolated DC / DC power supply circuit 101 and the non-isolated DC / DC power supply circuit 102 have either or both buck-boost functions, the function of wide input and output voltage range of the LED driver power supply can be realized.

[0053] Figure 2 The present invention includes a principle block diagram of N non-isolated DC / DC power supply circuits, which can achieve a wider input and output voltage range, but the control is complex, including a filter circuit, a non-isolated DC / DC power supply circuit 101, a non-isolated DC / DC power supply circuit 102, ..., a non-isolated DC / DC power supply circuit 10n connected in sequence, n is a natural number greater than or equal to 3, and each of the non-isolated DC / DC power supply circuits 101 to 10n has at least one main power switch tube on the bus, and the main power switch tubes on the bus in the non-isolated DC / DC power supply circuits 101 to 10n are at least one at the high voltage end and one at the low voltage end.

[0054] Similarly, in normal operation, the non-isolated DC / DC power supply circuit 101 to the non-isolated DC / DC power supply circuit 10n are controlled separately by N signals. When the non-isolated DC / DC power supply circuit 101 has a PFC function, the input current phase of the LED driver power supply follows the input voltage phase, realizing the power factor correction function, improving the PF value of the LED driver power supply, and effectively reducing the loss; when dimming and shutting down are required, the main power switch tubes located on the bus in the non-isolated DC / DC power supply circuit 101 to the non-isolated DC / DC power supply circuit 10n will be shut down at the same time under the action of the control circuit shutdown signal, and the route from the high-voltage end of the bus to the ground and the low-voltage end of the bus to the ground is also cut off, and the LED lamp has almost no leakage current to the ground, and a true dimming shutdown function is also realized. When one, part or all of the non-isolated DC / DC power supply circuits 101 to the non-isolated DC / DC power supply circuits 10n have a buck-boost function, the function of a wide input and output voltage range of the LED driver power supply can be realized.

[0055] First embodiment

[0056] Figure 3 The circuit principle of the first embodiment of the present invention is: Figure 1 A specific circuit.

[0057] The filter circuit is a rectifier bridge BD1, the positive input end of the rectifier bridge BD1 is used to connect to the L line of the power grid, the negative input end is used to connect to the N line of the power grid, the positive output end is connected to the positive input end of the non-isolated DC / DC power supply circuit 101, and the negative output end is connected to the negative input end of the non-isolated DC / DC power supply circuit 101;

[0058] The non-isolated DC / DC power supply circuit 101 is a BUCK circuit, including 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 terminal of the non-isolated DC / DC power supply circuit 101, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 is connected to one end of the capacitor C1 to form the positive output terminal of the non-isolated DC / DC power supply circuit 101, and the anode of the diode D1 is connected to the other end of the capacitor C1 to form the negative input terminal and the negative output terminal of the non-isolated DC / DC power supply circuit 101;

[0059] The non-isolated DC / DC power supply circuit 102 is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. One end of the inductor L2 is connected to the cathode of the diode D2 to form the positive input end of the non-isolated DC / DC power supply circuit 102, and the other end of the inductor L2 is the positive output end of the non-isolated DC / DC power supply circuit 102. The source of the switch tube Q2 is the negative input end of the non-isolated DC / DC power supply circuit 102, and the drain of the switch tube Q2 is connected to the anode of the diode D2 to form the negative output end of the non-isolated DC / DC power supply circuit 102.

[0060] Figure 2 The anode of the driven LED lamp LED1 is connected to the positive output terminal of the non-isolated DC / DC power supply circuit 102 , and the cathode is connected to the negative output terminal of the non-isolated DC / DC power supply circuit 102 .

[0061] The working principle of this embodiment is as follows:

[0062] During normal operation, the 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, thereby realizing a power factor correction function, improving the PF value of the LED driving power supply, and effectively reducing losses.

[0063] When the switch tube Q1 is turned on and the switch tube Q2 is turned on, the grid energy passes through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1, the inductor L2, the LED lamp and the switch tube Q2, stores energy in the inductor L1 and the inductor L2, and provides energy for the LED lamp at the same time.

[0064] When the switch tube Q1 is turned on and the switch tube Q2 is turned off, the grid energy is stored in the inductor L1 and the capacitor C1 through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1 and the capacitor C1. The LED lamp is kept on through the freewheeling loop of the inductor L2, the LED lamp and the diode D2, and the energy is provided by the inductor L2.

[0065] When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the inductor L1 and the capacitor C1 continue to flow through the circuit of the inductor L1, the inductor L2, the LED lamp and the diode D1 to provide energy to the LED lamp.

[0066] When the switch tube Q1 is turned off and the switch tube Q2 is turned off, the inductor L1 continues to flow through the capacitor C1 and the diode D1. The inductor L2 continues to flow through the LED lamp and the diode D2 to provide energy to the LED lamp.

[0067] When dimming is required, the dimming shutdown signal will turn off the switch tubes Q1 and Q2 at the same time. When the energy of the inductor L2 is consumed, the LED light goes out. At the same time, because the high-voltage and low-voltage ends of the bus are blocked by the switch tubes, the LED light has no leakage current to the ground, realizing the true dimming shutdown function.

[0068] Second embodiment

[0069] Figure 4 This is the circuit principle of the second embodiment of the present invention. The difference from the first embodiment is that the non-isolated DC / DC power supply circuit 101 is a BUCK-BOOST circuit, including 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 terminal of the non-isolated DC / DC power supply circuit 101, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output terminal of the non-isolated DC / DC power supply circuit 101, and the other end of the inductor L1 and the other end of the capacitor C1 are connected to form the negative input terminal and the negative output terminal of the non-isolated DC / DC power supply circuit 101.

[0070] The working principle of this example is as follows:

[0071] During normal operation, the two non-isolated DC / DC power supply circuits are controlled separately by two signals. 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, thereby realizing a power factor correction function, improving the PF value of the LED driving power supply, and effectively reducing losses.

[0072] When the switch tube Q1 is turned on and the switch tube Q2 is turned on, the grid energy stores energy in the inductor L1. At the same time, the capacitor C1 provides energy to the LED lamp through the loop formed by the capacitor C1, the LED lamp and the inductor L2, so that the LED lamp emits light.

[0073] When the switch tube Q1 is turned on and the switch tube Q2 is turned off, the grid energy stores energy in the inductor L1. The LED lamp is kept on through the freewheeling circuit of the LED lamp, inductor L2, and diode D2, and the energy is provided by the inductor L2.

[0074] When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the inductor L1 and the capacitor C1 continue to flow through the loop formed by the inductor L1, the LED lamp, the inductor L2 and the diode D1 to provide energy to the LED lamp.

[0075] When the switch tube Q1 is turned off and the switch tube Q2 is turned off, the inductor L1 continues to flow through the capacitor C1 and the diode D1. The inductor L2 continues to flow through the LED lamp and the diode D2 to provide energy to the LED lamp.

[0076] When dimming shutdown is required, the dimming shutdown signal will shut down the switch tubes Q1 and Q2 at the same time. When the energy of the inductor L2 is consumed, the LED light goes out. Similarly, because the high-voltage and low-voltage ends of the bus are blocked by the switch tubes, the LED light has no leakage current to the ground, realizing the true dimming shutdown function.

[0077] Third embodiment

[0078] Figure 5 This is the circuit principle of the third embodiment of the present invention. The difference between this embodiment and the second embodiment is that the non-isolated DC / DC power supply circuit 102 is a BUCK circuit, including a switch tube 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 to simultaneously serve as the positive input terminal and the positive output terminal of the non-isolated DC / DC power supply circuit 102. The cathode of the diode D2 is connected to the source of the switch tube Q2 and one end of the inductor L2 at the same time. The drain of the switch tube Q2 is the negative input terminal of the non-isolated DC / DC power supply circuit 102, and the other end of the inductor L2 is the negative output terminal of the non-isolated DC / DC power supply circuit 102.

[0079] The working principle of this embodiment is as follows:

[0080] During normal operation, the two non-isolated DC / DC power supply circuits are controlled separately by two signals. 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, thereby realizing a power factor correction function, improving the PF value of the LED driving power supply, and effectively reducing losses.

[0081] When the switch tube Q1 is turned on and the switch tube Q2 is turned on, the grid energy stores energy in the inductor L1. At the same time, the capacitor C1 provides energy to the LED lamp through the loop formed by the capacitor C1, the switch tube Q2, the inductor L2 and the LED lamp, making the LED lamp emit light.

[0082] When the switch tube Q1 is turned on and the switch tube Q2 is turned off, the grid energy stores energy in the inductor L1. The LED lamp is kept on through the freewheeling circuit formed by the inductor L2, the LED lamp, and the diode D2, and the energy is provided by the inductor L2.

[0083] When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the inductor L1 and the capacitor C1 continue to flow through the loop formed by L1, the switch tube Q2, the inductor L2, the LED lamp and the diode D1 to provide energy to the LED lamp.

[0084] When the switch tube Q1 is turned off and the switch tube Q2 is turned off, the inductor L1 continues to flow through the capacitor C1 and the diode D1. The inductor L2 continues to flow through the LED lamp and the diode D2 to provide energy to the LED lamp.

[0085] When dimming shutdown is required, the dimming shutdown signal will shut down the switch tubes Q1 and Q2 at the same time. When the energy of the inductor L2 is consumed, the LED light goes out. Similarly, because the high-voltage and low-voltage ends of the bus are blocked by the switch tubes, the LED light has no leakage current to the ground, realizing the true dimming shutdown function.

[0086] Fourth embodiment

[0087] Figure 6 This is the circuit principle of the fourth embodiment of the present invention. The difference between this embodiment and the first embodiment is that the non-isolated DC / DC power supply circuit 102 is different, as follows:

[0088] The non-isolated DC / DC power supply circuit 102 is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. The cathode of the diode D2 is both the positive input terminal and the positive output terminal of the non-isolated DC / DC power supply circuit 102. The anode of the diode D2 is simultaneously connected to the drain of the switch tube Q2 and one end of the inductor L2. The source of the switch tube Q2 is the negative input terminal of the non-isolated DC / DC power supply circuit 102. The other end of the inductor L2 is the negative output terminal of the non-isolated DC / DC power supply circuit 102.

[0089] The working principle of this embodiment is as follows:

[0090] During normal operation, the two non-isolated DC / DC power supply circuits are controlled separately by two signals, wherein the non-isolated DC / DC power supply circuit 101 has a PFC control function, so that the input current phase of the LED driving power supply follows the input voltage phase, thereby realizing the function of improving the PF value of the LED driving power supply.

[0091] When the switch tube Q1 is turned on and the switch tube Q2 is turned on, the grid energy passes through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1, the LED lamp, the inductor L2 and the switch tube Q2, stores energy in the inductor L1 and the inductor L2, and provides energy for the LED lamp at the same time.

[0092] When the switch tube Q1 is turned on and the switch tube Q2 is turned off, the grid energy passes through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1, and the capacitor C1 to store energy in the inductor L1 and the capacitor C1. The LED lamp continues to light up through the inductor L2, the diode D2, and the LED lamp loop, and the energy is provided by the inductor L2.

[0093] When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the inductor L1 and the capacitor C1 continue to flow through the loop formed by the inductor L1, the LED lamp, the inductor L2 and the diode D1 to provide energy to the LED lamp.

[0094] When the switch tube Q1 is turned off and the switch tube Q2 is turned off, the inductor L1 continues to flow through the capacitor C1 and the diode D1. The inductor L2 continues to flow through the diode D2 and the LED lamp to provide energy to the LED lamp.

[0095] When dimming is required, the dimming shutdown signal will turn off the switch tubes Q1 and Q2 at the same time. When the energy of the inductor L2 is consumed, the LED light goes out. Similarly, because the high-voltage and low-voltage ends of the bus are blocked by the switch tubes, the LED light has no leakage current to the ground, realizing the true dimming shutdown function.

[0096] Fifth embodiment

[0097] Figure 7 This is the circuit principle of the fifth embodiment of the present invention. The difference between this embodiment and the fourth embodiment is that the non-isolated DC / DC power supply circuit 101 is different, as follows:

[0098] The non-isolated DC / DC power supply circuit 101 is a composite topology, which is called a four-tube buck-boost topology in Part 4 of Chapter 9 of "Mastering Switching Power Supply Design (2nd Edition)". The ISBN number of the book is 978-7-115-36795-2, and it is published by Posts and Telecommunications Press. The four-tube buck-boost topology includes a switch tube Q1, a switch tube Q3, a diode D1, a diode D2, an inductor L1 and a capacitor C1. The drain of the switch tube Q1 is the positive input terminal of the non-isolated DC / DC power supply circuit 101. The source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time. The other end of the inductor L1 is connected to the drain of the switch tube Q3 and the anode of the diode D2 at the same time. The anode of the diode D2 and one end of the capacitor C1 are connected to form the positive output terminal of the non-isolated DC / DC power supply circuit 101. The anode of the diode D1, the source of the switch tube Q3 and the other end of the capacitor C1 are connected to form the negative input terminal and the negative output terminal of the non-isolated DC / DC power supply circuit 101.

[0099] The switch tube Q1 and the switch tube Q3 in the non-isolated DC / DC power supply circuit 101 of this embodiment are both main power switch tubes, wherein the switch tube Q1 is located on the bus, and the switch tube Q3 is no longer on the bus.

[0100] The non-isolated DC / DC power supply circuit 101 is a composite topology. The working principle of this embodiment is as follows:

[0101] During normal operation, the two non-isolated DC / DC power supply circuits are controlled separately by two signals, wherein the non-isolated DC / DC power supply circuit 101 has a PFC control function, so that the input current phase of the LED driving power supply follows the input voltage phase, thereby realizing the function of improving the PF value of the LED driving power supply.

[0102] When the switch tubes Q1, Q2, and Q3 are turned on at the same time, the grid energy is stored in the inductor L1 through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1, and the switch tube Q3. The capacitor C1 stores energy in the inductor L2 through the loop formed by the capacitor C1, the LED lamp, the inductor L2, and the switch tube Q2, and provides energy for the LED lamp. When the switch tubes Q1 and Q2 are turned on and the switch tube Q3 is turned off, the grid energy is stored in the inductor L1 and the inductor L2 through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1, the diode D2, the LED lamp, the inductor L2, and the switch tube Q2, and provides energy for the LED lamp.

[0103] When the switch tubes Q1 and Q3 are turned on and the switch tube Q2 is turned off, the grid energy is stored in the inductor L1 through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1 and the switch tube Q3. The LED lamp is kept lit through the loop formed by the inductor L2, the diode D3 and the LED lamp, and the energy is provided by the inductor L2.

[0104] When the switch tube Q1 is turned on and the switch tubes Q2 and Q3 are turned off, the grid energy is stored in the inductor L1 through the loop formed by the rectifier bridge BD1, the switch tube Q1, the inductor L1 and the switch tube Q3. The LED lamp is kept lit through the loop formed by the inductor L2, the diode D3 and the LED lamp, and the energy is provided by the inductor L2.

[0105] When the switch tube Q1 is turned off and the switch tubes Q2 and Q3 are turned on, the inductor L1 continues to flow through the loop formed by the switch tube Q3, the diode D1 and the inductor L1, and the capacitor C1 stores energy in the inductor L2 through the loop formed by the capacitor C1, the LED lamp, the inductor L2 and the switch tube Q2, and provides energy for the LED lamp at the same time.

[0106] When the switch tubes Q1 and Q2 are turned off and the switch tube Q3 is turned on, the inductor L1 continues to flow through the loop formed by the switch tube Q3, the diode D1 and the inductor L1. The LED lamp maintains the light through the loop formed by the inductor L2, the diode D3 and the LED lamp, and the energy is provided by the inductor L2.

[0107] When the switch tubes Q1 and Q3 are turned off and the switch tube Q2 is turned on, the inductor L1 continues to flow through the loop formed by the diode D2, the capacitor C1, the diode D1 and the inductor L1. The capacitor C1 stores energy in the inductor L2 through the loop formed by the capacitor C1, the LED lamp, the inductor L2 and the switch tube Q2, and provides energy for the LED lamp at the same time.

[0108] When the switch tubes Q1, Q2 and Q3 are turned off at the same time, the inductor L1 continues to flow through the loop formed by the diode D2, the capacitor C1, the diode D1 and the inductor L1. The LED lamp is kept on through the loop formed by the inductor L2, the diode D3 and the LED lamp, and the energy is provided by the inductor L2.

[0109] When dimming is required, the dimming shutdown signal will turn off the switch tubes Q1 and Q2 at the same time. When the energy of the inductor L2 is consumed, the LED light goes out. Similarly, because the high-voltage and low-voltage ends of the bus are blocked by the switch tubes, the LED light has no leakage current to the ground, realizing the true dimming shutdown function.

[0110] The above are only preferred embodiments of the present invention. It should be pointed out that the above preferred embodiments should not be regarded as limitations of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention. All circuits that use the ideas of the present invention are within the scope of the rights of the present invention.

Claims

1. An LED driving power supply, characterized in that: The invention 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 input terminal of the filter circuit is used to connect to the L line of the power grid, the negative input terminal of the filter circuit is used to connect to the N line of the power grid, the positive output terminal of the filter circuit is connected to the positive input terminal of the first non-isolated DC / DC power supply circuit, the negative output terminal of the filter circuit is connected to the negative input terminal of the first non-isolated DC / DC power supply circuit, the positive output terminal of the first non-isolated DC / DC power supply circuit is connected to the positive input terminal of the second non-isolated DC / DC power supply circuit, and the negative output terminal of the first non-isolated DC / DC power supply circuit is connected to the positive input terminal of the second non-isolated DC / DC power supply circuit. The negative input terminal of the second non-isolated DC / DC power supply circuit is connected, the positive output terminal of the second non-isolated DC / DC power supply circuit is used to connect the anode of the driven LED lamp, and the negative output terminal of the second non-isolated DC / DC power supply circuit is used to connect the cathode of the driven LED lamp; each of the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit has at least one main power switch tube on the bus, and one of the main power switch tubes on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit is at the high voltage end, and the other is at the low voltage end; In normal operation, the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit are controlled separately by two signals, and the first non-isolated DC / DC power supply circuit has a PFC function; When dimming shutdown is required, the dimming shutdown signal simultaneously shuts down the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit and the second non-isolated DC / DC power supply circuit.

2. The LED driving power supply according to claim 1, characterized in that: The filter circuit is a rectifier bridge.

3. The LED driving power supply according to claim 1, characterized in that: The first non-isolated DC / DC power supply circuit is a BUCK circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit; The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. One end of the inductor L2 is connected to the cathode of the diode D2 to form the positive input end of the second non-isolated DC / DC power supply circuit, the other end of the inductor L2 is the positive output end of the second non-isolated DC / DC power supply circuit, the source of the switch tube Q2 is the negative input end of the second non-isolated DC / DC power supply circuit, and the drain of the switch tube Q2 is connected to the anode of the diode D2 to form the negative output end of the second non-isolated DC / DC power supply circuit.

4. The LED driving power supply according to claim 1, characterized in that: The first non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit; The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. One end of the inductor L2 is connected to the cathode of the diode D2 to form the positive input end of the second non-isolated DC / DC power supply circuit, the other end of the inductor L2 is the positive output end of the second non-isolated DC / DC power supply circuit, the source of the switch tube Q2 is the negative input end of the second non-isolated DC / DC power supply circuit, and the drain of the switch tube Q2 is connected to the anode of the diode D2 to form the negative output end of the second non-isolated DC / DC power supply circuit.

5. The LED driving power supply according to claim 1, characterized in that: The first non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the anode of the diode D1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit; The second non-isolated DC / DC power supply circuit is a BUCK circuit, including a switch tube 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 to simultaneously serve as the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The cathode of the diode D2 is connected to the source of the switch tube Q2 and one end of the inductor L2 at the same time. The drain of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

6. The LED driving power supply according to claim 1, characterized in that: The first non-isolated DC / DC power supply circuit is a BUCK circuit, including 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 terminal of the first non-isolated DC / DC power supply circuit, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 and one end of the capacitor C1 are connected to form the positive output terminal 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 terminal of the first non-isolated DC / DC power supply circuit and the negative output terminal of the first non-isolated DC / DC power supply circuit; The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. The cathode of the diode D2 is both the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The anode of the diode D2 is simultaneously connected to the drain of the switch tube Q2 and one end of the inductor L2. The source of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

7. The LED driving power supply according to claim 1, characterized in that: The non-isolated DC / DC power supply circuit 101 is a four-tube buck-boost topology, including a switch tube Q1, a switch tube Q3, a diode D1, a diode D2, an inductor L1 and a capacitor C1. The drain of the switch tube Q1 is the positive input terminal of the non-isolated DC / DC power supply circuit 101, the source of the switch tube Q1 is connected to one end of the inductor L1 and the cathode of the diode D1 at the same time, the other end of the inductor L1 is connected to the drain of the switch tube Q3 and the anode of the diode D2 at the same time, the anode of the diode D2 and one end of the capacitor C1 are connected to form the positive output terminal of the non-isolated DC / DC power supply circuit 101, and the anode of the diode D1, the source of the switch tube Q3 and the other end of the capacitor C1 are connected to form the negative input terminal and the negative output terminal of the non-isolated DC / DC power supply circuit 101; The second non-isolated DC / DC power supply circuit is a BUCK-BOOST circuit, including a switch tube Q2, a diode D2 and an inductor L2. The cathode of the diode D2 is both the positive input terminal and the positive output terminal of the second non-isolated DC / DC power supply circuit. The anode of the diode D2 is simultaneously connected to the drain of the switch tube Q2 and one end of the inductor L2. The source of the switch tube Q2 is the negative input terminal of the second non-isolated DC / DC power supply circuit. The other end of the inductor L2 is the negative output terminal of the second non-isolated DC / DC power supply circuit.

8. An LED driving power supply, characterized in that: The invention comprises a filter circuit, a first non-isolated DC / DC power supply circuit, a second non-isolated DC / DC power supply circuit, ..., an Nth non-isolated DC / DC power supply circuit, wherein N is a natural number greater than or equal to 3; the positive input end of the filter circuit is used to connect to the L line of the power grid, the negative input end of the filter circuit is used to connect to the N line of the power grid, the positive output end of the filter circuit is connected to the positive input end of the first non-isolated DC / DC power supply circuit, the negative output end of the filter circuit is connected to the negative input end of the first non-isolated DC / DC power supply circuit, the positive output end of the first non-isolated DC / DC power supply circuit is connected to the positive input end of the second non-isolated DC / DC power supply circuit, the first non-isolated The negative output terminal of the DC / DC power supply circuit is connected to the negative input terminal of the second non-isolated DC / DC power supply circuit, ..., the positive output terminal of the Nth non-isolated DC / DC power supply circuit is used to connect the anode of the driven LED lamp, and the negative output terminal of the Nth non-isolated DC / DC power supply circuit is used to connect the cathode of the driven LED lamp; at least one main power switch tube in each of the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit is on the bus, and at least one main power switch tube on the bus in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit is at the high voltage end and the other is at the low voltage end; In normal operation, the main power switch tubes located on the busbars in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit are controlled separately by N signals, and the first non-isolated DC / DC power supply circuit has a PFC function; When dimming shutdown is required, the dimming shutdown signal simultaneously shuts off the main power switch tubes located on the bus in the first non-isolated DC / DC power supply circuit to the Nth non-isolated DC / DC power supply circuit.

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