Non-isolated LED power supply driver with leakage protection function and LED lamp

Abstract

The utility model relates to a non-isolated LED power supply driver with a leakage protection function and an LED lamp. The non-isolated LED power supply driver comprises an AC / DC rectifier, two input ends of which are respectively connected with a live wire and a zero wire of commercial power and are used for rectifying the commercial power into high-voltage direct current; the two input ends of the DC / DC voltage reduction module are connected with the two output ends of the AC / DC rectifier respectively, the DC / DC voltage reduction module is used for reducing the high-voltage direct current into direct current VF voltage needed by LED work, and the two output ends of the DC / DC voltage reduction module are used for being externally connected with an anode and a cathode of an LED lamp respectively; and the electric leakage protection module comprises a switch connected in series with the live wire of the commercial power, a control module for controlling the switch, and a detection module for detecting the electric leakage condition. According to the utility model, the defect of high electric shock risk of a non-isolated power supply is avoided by arranging the leakage protection module, and the advantages of low cost, small size and high energy conversion efficiency of the non-isolated power supply are highlighted.

Description

Technical Field

[0001] The utility model relates to the field of LED lamps, in particular to a non-isolated LED power driver and an LED lamp with a leakage protection function. Background Art

[0002] LED lamps are low-voltage semiconductor devices that require high current stability. However, the 220V AC power supply from household electrical grids cannot meet these low voltage and stability requirements. Therefore, existing LED lamps are equipped with an LED power driver. This LED power driver converts the 220V AC power supply into the stable DC voltage required for LED lamp operation.

[0003] Existing LED power drivers include isolated and non-isolated power supplies. The isolated power supply includes an AC / AC transformer and an AC / DC rectifier. The AC / AC transformer steps down the 220V mains voltage to a lower AC voltage. The AC / DC rectifier then converts the AC voltage into DC power, which powers the LED lamp. The non-isolated power supply includes an AC / DC rectifier module and a DC / DC converter module. The AC / DC rectifier directly rectifies the 220V mains voltage into high-voltage DC power. The DC / DC converter then converts the high-voltage DC power into the DC voltage (VF) required for LED operation. This DC voltage (VF) powers the LED lamp.

[0004] In an isolated power supply, the AC / AC transformer consists of two magnetically coupled coils, with no wires electrically connecting the two coils. Therefore, the LED lamp is not directly connected to the 220V AC power supply, reducing the risk of electric shock. In a non-isolated power supply, however, since there is no AC / AC transformer, the LED lamp is directly connected to the 220V AC power supply, which increases the risk of electric shock.

[0005] Due to the high risk of electric shock from non-isolated power supplies, existing LED power drivers are mostly isolated power supplies. However, the AC / AC transformers used in isolated power supplies are expensive and bulky, and there is a certain amount of energy loss during the power conversion process, resulting in low energy conversion efficiency. Utility Model Content

[0006] Based on this, the purpose of the present invention is to provide a non-isolated LED power supply driver and LED lamp with leakage protection function. By setting a leakage protection module, it avoids the disadvantage of high risk of electric shock of non-isolated power supply, and highlights the advantages of non-isolated power supply such as low cost, small size and high energy conversion efficiency.

[0007] The present invention provides a non-isolated LED power driver with a leakage protection function, comprising: an AC / DC rectifier, whose two input ends are respectively connected to the live and neutral wires of a mains supply, for rectifying the mains supply into high-voltage direct current; a DC / DC step-down module, whose two input ends are respectively connected to the two output ends of the AC / DC rectifier, for stepping down the high-voltage direct current into the DC VF voltage required for LED operation, and whose two output ends are respectively connected to the anode and cathode of an external LED lamp; and a leakage protection module, comprising: a switch connected in series to the live wire of the mains supply, a control module for controlling the switch, and a detection module for detecting leakage. By providing a leakage protection module, the present invention avoids the disadvantage of the high risk of electric shock of non-isolated power supplies, and has the advantages of low cost, small size, and high energy conversion efficiency.

[0008] Furthermore, the detection module is a current detection circuit; the two input ends of the current detection circuit are respectively connected to the live wire and the neutral wire of the AC power, for detecting the first current on the live wire and the second current on the neutral wire, and outputting the detected first current signal and the second current signal to the control module.

[0009] Furthermore, the control module is a microprocessor; the microprocessor controls the switch according to the first current signal and the second current signal.

[0010] Furthermore, the current detection circuit includes: a first sampling resistor, a first current detection chip, a second sampling resistor and a second current detection chip; the first sampling resistor is connected in series to the live wire of the mains; the first input end and the second input end of the first current detection chip are respectively connected to the two ends of the first sampling resistor, and the output end is connected to the first current signal input end of the microprocessor; the second sampling resistor is connected in series to the neutral wire of the mains; the first input end and the second input end of the second current detection chip are respectively connected to the two ends of the second sampling resistor, and the output end is connected to the second current signal input end of the microprocessor.

[0011] Furthermore, the detection module is a current transformer, whose first input end and second input end are respectively connected to the live wire and the neutral wire, and the output end outputs a detection signal; the control module is a first leakage detection circuit, which determines whether leakage occurs based on the detection signal output by the current transformer.

[0012] Furthermore, the input end of the first leakage detection circuit is connected to the output end of the current transformer, which includes a signal conditioning circuit, a signal amplification circuit and a voltage comparison circuit; the input end of the signal conditioning circuit is electrically connected to the output end of the current transformer, and is used to pre-process the detection signal to obtain a conditioned signal; the input end of the signal amplification circuit is electrically connected to the output end of the signal conditioning circuit, and is used to amplify the conditioned signal to obtain an amplified signal; the input end of the voltage comparison circuit is electrically connected to the output end of the signal amplification circuit, and is used to compare the size relationship between the amplified signal and a preset threshold voltage, so as to determine whether leakage occurs and output a leakage judgment result; the leakage judgment result is used to control the on and off of the switch.

[0013] Furthermore, the control module is a second leakage detection circuit; the second leakage detection circuit includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a second operational amplifier and a fifth resistor; the inverting input terminal of the first operational amplifier is connected to the first current signal output by the current detection circuit through the first resistor, the non-inverting input terminal is connected to the second current signal output by the current detection circuit through the second resistor, and the non-inverting input terminal is grounded at the same time through the third resistor; the non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through the fifth resistor, the inverting input terminal is connected to the preset threshold voltage, and the output terminal controls the switch.

[0014] Furthermore, the second leakage detection circuit also includes a voltage stabilizing source, a first voltage dividing resistor and a second voltage dividing resistor; the first voltage dividing resistor and the second voltage dividing resistor are connected in series between the voltage stabilizing source and the ground; the connection node between the first voltage dividing resistor and the second voltage dividing resistor is the output end of the threshold voltage.

[0015] Based on the same inventive concept, the present invention also provides an LED lamp, comprising an LED lamp body, and a power driver for supplying power to the LED lamp body, wherein the power driver is any of the above-mentioned non-isolated LED power drivers with leakage protection function.

[0016] In order to better understand and implement the present invention, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a module schematic diagram of a non-isolated LED power driver with leakage protection function according to Example 1 of the present utility model;

[0018] Figure 2 This is a schematic structural diagram of the leakage protection module of Example 1 of the present utility model;

[0019] Figure 3This is a schematic structural diagram of a leakage protection module according to Example 2 of the present utility model;

[0020] Figure 4 This is a structural diagram of the second leakage detection circuit of Example 3 of the present utility model. DETAILED DESCRIPTION

[0021] It should be clear that the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the embodiments of the present application.

[0022] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of the present application. The singular forms "a," "the," and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0023] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0024] It should be understood that the embodiments of the present application are not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the embodiments of the present application is limited only by the appended claims.

[0025] As described in the background technology, non-isolated power supplies have the advantages of lower cost, smaller size, and higher energy conversion efficiency, but they also have the disadvantage of a higher risk of electric shock. The present invention reduces the risk of electric shock by adding a leakage protection module to the non-isolated power supply, thereby avoiding the disadvantages of non-isolated power supplies and better leveraging their advantages of lower cost, smaller size, and higher energy conversion efficiency compared to existing isolated power supplies.

[0026] Example 1

[0027] See also Figure 1 , Figure 1 The module diagram of the non-isolated LED power driver with leakage protection function according to the first embodiment of the present invention is shown in FIG. The non-isolated LED power driver with leakage protection function according to the first embodiment of the present invention comprises: an AC / DC rectifier, a DC / DC step-down module and a leakage protection module M.

[0028] The two input terminals of the AC / DC rectifier are connected to the live wire L and the neutral wire N of the mains respectively, for rectifying the mains into high-voltage direct current. In this embodiment, the mains refers to 220V alternating current.

[0029] The two input terminals of the DC / DC step-down module are connected to the two output terminals of the AC / DC rectifier, respectively, to step down the high-voltage DC power to the DC VF voltage required for LED operation. The two output terminals of the DC / DC step-down module are connected to the anode and cathode of an external LED lamp, respectively, to power the LED lamp. In this embodiment, the DC / DC step-down module is specifically a DC / DC BUCK circuit.

[0030] The leakage protection module M includes a switch K connected in series to the live line L of the mains power supply, a control module M1 for controlling the switch K, and a detection module M2 for detecting leakage. The control module M1 determines whether leakage has occurred based on the leakage detected by the detection module M2. If leakage has occurred, the control module M1 controls the switch K to open, thereby disconnecting the LED lamp from the 220V AC power supply and preventing electric shock to the user.

[0031] Specifically, the switch K switches on and off according to the control signal sent by the control module, and includes but is not limited to a relay, a thyristor switch, and a MOS tube switch.

[0032] Specifically, see Figure 2 , Figure 2 Schematic diagram of the structure of the leakage protection module of the utility model embodiment 1. In this embodiment, the control module M1 is a microprocessor M11 (Micro Processor Unit, MCU); the detection module M2 is a current detection circuit M21.

[0033] The two input terminals A and B of the current detection circuit M21 are respectively connected to the live wire L and the neutral wire N of the mains power supply, and are used to detect the first current on the live wire and the second current on the neutral wire, and output the detected first current signal I1 and the second current signal I2 to the microprocessor M11. The two signal input terminals of the microprocessor M11 are respectively connected to the first current signal I1 and the second current signal I2. A program is provided inside the microprocessor; when the program is executed, the microprocessor M11 calculates the difference between the first current on the live wire and the second current on the neutral wire based on the first current signal I1 and the second current signal I2; when the difference is greater than the set safety current (30mA), the microprocessor M11 determines that a leakage has occurred and sends a control signal to the switch K, causing the switch K to disconnect and the LED lamp to be powered off.

[0034] According to Kirchhoff's current law, the current flowing out of the grid should be equal to the current flowing into the grid. Therefore, when the circuit is operating normally, the first current on the live wire should be equal to the second current on the neutral wire. When the first current on the live wire is not equal to the second current on the neutral wire, the control module M1 can determine that a leakage has occurred.

[0035] Furthermore, if Figure 2 As shown, the current detection circuit M21 of this embodiment specifically includes: a first sampling resistor RS1, a first current detection chip U1, a second sampling resistor RS2, and a second current detection chip U2. The first sampling resistor RS1 is connected in series to the live wire L of the mains power supply. Its resistance is very small, and its influence on the first current can be ignored. The first input terminal IN+ and the second input terminal IN- of the first current detection chip U1 are respectively connected to the two ends of the first sampling resistor RS1, and the output terminal OUT is connected to the first current signal input terminal I1 of the microprocessor M11. The second sampling resistor RS2 is connected in series to the neutral wire L of the mains power supply. Its resistance is very small, and its influence on the second current can be ignored. The first input terminal IN+ and the second input terminal IN- of the second current detection chip U2 are respectively connected to the two ends of the second sampling resistor Rs2, and the output terminal OUT is connected to the second current signal input terminal I2 of the microprocessor M11.

[0036] In this embodiment, the first current detection chip U1 and the second current detection chip U2 are of the model INA240. In other embodiments, the first current detection chip U1 and the second current detection chip U2 can be other models of current detection chips.

[0037] Example 2

[0038] The non-isolated LED power driver with leakage protection function of Example 2 of the present invention differs from Example 1 in that the detection module M2 is a current transformer M22, which is used to collect the first current and the second current on the live wire and the neutral wire and output a detection signal reflecting the difference between the first current and the second current. The control module M1 is a first leakage detection circuit M12, which is used to determine whether leakage has occurred based on the detection signal output by the current transformer M22.

[0039] See also Figure 3 , Figure 3 This is a structural diagram of the leakage protection module in Example 2 of the present utility model.

[0040] Specifically, the first input terminal A and the second input terminal B of the current transformer M22 are connected to the live wire L and the neutral wire N of the mains, respectively, and the output terminal outputs a detection signal. When no leakage occurs, the first current on the live wire should be equal to the second current on the neutral wire. Therefore, the effects of the first current and the second current on the internal magnetic field of the current transformer cancel each other out, and the detection signal output by the current transformer should be close to 0. When leakage occurs, the first current is not equal to the second current, resulting in the detection signal output by the current transformer being different from 0. Moreover, the more severe the leakage, the greater the difference between the first and second currents, and the larger the detection signal output by the current transformer. Therefore, the size of the detection signal output by the current transformer M22 can directly reflect the size of the difference between the first and second currents.

[0041] Specifically, the input end of the first leakage detection circuit M12 is connected to the output end of the current transformer M22, and the first leakage detection circuit M12 includes a signal conditioning circuit M121, a signal amplification circuit M122, and a voltage comparison circuit M123. The input end of the signal conditioning circuit M121 is electrically connected to the output end of the current transformer M22, and is used to pre-process the detection signal to obtain a conditioned signal. The input end of the signal amplification circuit M122 is electrically connected to the output end of the signal conditioning circuit M121, and is used to amplify the conditioned signal to obtain an amplified signal. The input end of the voltage comparison circuit M123 is electrically connected to the output end of the signal amplification circuit M122, and is used to compare the magnitude relationship between the amplified signal and a preset threshold voltage, thereby determining whether leakage has occurred and outputting a leakage determination result. The leakage determination result is used to control the on / off of the switch K.

[0042] Example 3

[0043] The non-isolated LED power driver with leakage protection function of Example 3 of the present invention differs from Example 1 in that the control module M1 is a second leakage detection circuit M13. The second leakage detection circuit outputs a control signal to the switch K based on the first current signal and the second current signal, causing the switch K to automatically open when leakage occurs.

[0044] Specifically, see Figure 4 , Figure 4 This is a schematic diagram of the structure of the second leakage detection power supply of Example 3 of the present utility model. The second leakage detection circuit M13 includes: a first operational amplifier A1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a second operational amplifier A2, a fifth resistor R5 and a driving module.

[0045] The inverting input of the first operational amplifier A1 is connected to the first current signal I1 output by the current detection circuit M21 via a first resistor R1, and the non-inverting input is connected to the second current signal I2 output by the current detection circuit M21 via a second resistor R2. The non-inverting input is also connected to ground via a third resistor R3. A fourth resistor R4 is connected across the output and inverting input of the first operational amplifier A1. Based on the virtual short circuit principle of the operational amplifier, it can be deduced that when the resistance of the first resistor R1 is equal to the resistance of the second resistor R2, the voltage at the output of the first operational amplifier A1 is proportional to the difference between the first current signal OUT1 and the second current signal OUT2, and can directly reflect the difference between the first current on the live wire L and the second current on the neutral wire N.

[0046] The non-inverting input terminal of the second operational amplifier A2 is connected to the output terminal of the first operational amplifier A1 through the fifth resistor R5, the inverting input terminal is connected to the preset threshold voltage TH1, and the output terminal controls the switch K through the driving module.

[0047] Furthermore, the preset threshold voltage TH1 can be obtained by dividing the voltage of a voltage-stabilizing source. The second leakage detection circuit M13 also includes a voltage-stabilizing source, a first voltage-dividing resistor, and a second voltage-dividing resistor; the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series between the voltage-stabilizing source and ground; and the connection node between the first voltage-dividing resistor and the second voltage-dividing resistor serves as the output terminal of the threshold voltage TH1.

[0048] When the preset threshold voltage TH1 is appropriately adjusted, the following can be achieved: when the voltage at the output of the first operational amplifier A1 is greater than the threshold voltage TH1, it indicates that the difference between the first current on the live wire and the second current on the neutral wire is greater than the safe current, and the output of the second operational amplifier A2 outputs a high level. When the voltage at the output of the first operational amplifier A1 is less than the threshold voltage, it indicates that the difference between the first current on the live wire and the second current on the neutral wire is less than the safe current, and the output of the second operational amplifier A2 outputs a low level. Therefore, the level of the output of the second operational amplifier A2 can directly reflect whether leakage has occurred. When leakage occurs, the second operational amplifier A2 outputs a high-level control signal to the driver module, which then controls the switch K to open. When leakage does not occur, the second operational amplifier A2 outputs a low-level control signal to the driver module, which controls the switch K to close normally.

[0049] In this embodiment, the driver module controls the switch K to be disconnected when the control signal is at a high level. In other embodiments in which the driver module controls the switch K to be disconnected when the control signal is at a low level, the second leakage detection circuit M13 may further include an inverter having an input connected to the output of the second operational amplifier A2; the output of the inverter controls the switch K through the driver module.

[0050] The present invention has the following technical effects: By adding a leakage protection module to a non-isolated power supply, the present invention reduces the risk of electric shock, thereby avoiding the disadvantages of non-isolated power supplies and better leveraging their advantages over existing isolated power supplies, such as lower cost, smaller size, and higher energy conversion efficiency. Furthermore, the present invention automatically detects leakage through a detection circuit, which is lower cost, faster response, and more cost-effective than solutions that use an MCU for leakage detection, further improving circuit safety.

[0051] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the concept of the present invention, and the present invention is intended to encompass such modifications and variations.

Claims

1. A non-isolated LED power driver with leakage protection function, characterized in that: include: An AC / DC rectifier, whose two input terminals are connected to the live wire and the neutral wire of the mains respectively, for rectifying the mains into high-voltage direct current; A DC / DC step-down module, whose two input terminals are respectively connected to the two output terminals of the AC / DC rectifier, is used to step down the high-voltage DC power into the DC VF voltage required for LED operation, and whose two output terminals are respectively used to connect to the anode and cathode of an external LED lamp; The leakage protection module comprises: a switch connected in series to the live wire of the commercial power, a control module for controlling the switch, and a detection module for detecting leakage conditions.

2. The non-isolated LED power driver with leakage protection function according to claim 1, characterized in that: The detection module is a current detection circuit; The two input ends of the current detection circuit are respectively connected to the live wire and the neutral wire of the mains, for detecting a first current on the live wire and a second current on the neutral wire, and outputting the detected first current signal and second current signal to the control module.

3. The non-isolated LED power driver with leakage protection function according to claim 2, characterized in that: The control module is a microprocessor; the microprocessor controls the switch according to the first current signal and the second current signal.

4. The non-isolated LED power driver with leakage protection function according to claim 3, characterized in that: The current detection circuit includes: a first sampling resistor, a first current detection chip, a second sampling resistor and a second current detection chip; The first sampling resistor is connected in series to the live wire of the mains; The first input terminal and the second input terminal of the first current detection chip are respectively connected to the two ends of the first sampling resistor, and the output terminal is connected to the first current signal input terminal of the microprocessor; The second sampling resistor is connected in series to the neutral line of the mains; The first input terminal and the second input terminal of the second current detection chip are respectively connected to the two ends of the second sampling resistor, and the output terminal is connected to the second current signal input terminal of the microprocessor.

5. The non-isolated LED power driver with leakage protection function according to claim 1, characterized in that: The detection module is a current transformer, the first input terminal and the second input terminal of which are connected to the live wire and the neutral wire respectively, and the output terminal outputs a detection signal; The control module is a first leakage detection circuit, which determines whether leakage occurs according to the detection signal output by the current transformer and controls the switch according to the judgment result.

6. The non-isolated LED power driver with leakage protection function according to claim 5, characterized in that: The input end of the first leakage detection circuit is connected to the output end of the current transformer, and the first leakage detection circuit includes a signal conditioning circuit, a signal amplification circuit and a voltage comparison circuit; The input end of the signal conditioning circuit is electrically connected to the output end of the current transformer, and is used to pre-process the detection signal to obtain a conditioned signal; The input end of the signal amplifying circuit is electrically connected to the output end of the signal conditioning circuit, and is used to amplify the conditioned signal to obtain an amplified signal; The input end of the voltage comparison circuit is electrically connected to the output end of the signal amplification circuit, and is used to compare the magnitude relationship between the amplified signal and a preset threshold voltage, thereby determining whether leakage occurs and outputting a leakage judgment result; the leakage judgment result is used to control the on and off of the switch.

7. The non-isolated LED power driver with leakage protection function according to claim 2, characterized in that: The control module is a second leakage detection circuit; The second leakage detection circuit includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a second operational amplifier and a fifth resistor; The inverting input terminal of the first operational amplifier is connected to the first current signal output by the current detection circuit through a first resistor, the non-inverting input terminal is connected to the second current signal output by the current detection circuit through a second resistor, and the non-inverting input terminal is grounded through a third resistor; The non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through a fifth resistor, the inverting input terminal is connected to a preset threshold voltage, and the output terminal controls the switch.

8. The non-isolated LED power driver with leakage protection function according to claim 7, characterized in that: The second leakage detection circuit further includes a voltage stabilizing source, a first voltage dividing resistor and a second voltage dividing resistor; The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series between the voltage-stabilizing source and the ground; The connection node between the first voltage-dividing resistor and the second voltage-dividing resistor is the output end of the threshold voltage.

9. The non-isolated LED power driver with leakage protection function according to any one of claims 1 to 8, characterized in that: The switch is a relay.

10. An LED lamp comprising an LED lamp body and a power driver for supplying power to the LED lamp body, characterized in that: The power driver is a non-isolated LED power driver with leakage protection function as described in any one of claims 1 to 9.

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