Electronic safety switches for LED tubes

Abstract

This application relates to an electronic safety switch for an LED lamp tube. The LED lamp assembly includes a safety switch; a plurality of connector pins arranged at first and second ends of the LED lamp assembly, the connector pins being adapted for electrical connection to a luminaire; a plurality of filament simulation circuits, wherein at least one of the connector pins at each of the first and second ends is electrically coupled to a corresponding one of the filament simulation circuits; a plurality of rectifier circuits; one or more LEDs electrically coupled to the outputs of the rectifier circuits; and a safety switch control circuit operatively coupled to the safety switch. At least one of the connector pins at the first end is electrically coupled to an input of a first rectifier circuit via the safety switch, and at least one of the connector pins at the second end is electrically coupled to an input of a second rectifier circuit. The safety switch control circuit is arranged to close the safety switch when a power with a frequency higher than a predetermined threshold is detected at a connector pin at the first or second end of the LED lamp assembly.

Description

Technical Field

[0001] The present invention relates to a safety end cap assembly for a light-emitting diode (LED) lamp device used to replace fluorescent lamps in lighting equipment. Background Technology

[0002] Fluorescent lamps are widely used in various places, such as schools and office buildings. While traditional fluorescent lamps have certain advantages, they also have disadvantages, including disposal problems due to the presence of toxic substances inside the tubes. In recent years, LED-based lamps or LED tubes have emerged as a one-to-one replacement for fluorescent tubes. These LED-based alternatives typically consist of an elongated housing in which multiple LEDs are mounted. End caps are located at each longitudinal end of the housing for connecting the LED circuit board to the lighting device.

[0003] One problem when installing LED tubes into luminaires designed for fluorescent or LED tubes is the potential for dangerous contact with the exposed connector pins of the LED tube during installation. Unlike fluorescent tubes, LED tubes typically have a current path formed by their internal circuitry between the connector pins at opposite ends of the LED tube. Therefore, if the luminaire is powered on while one end of the LED tube is inserted into it, and a person installing the LED tube touches the connector at the other end, that person could suffer an electric shock.

[0004] Various types of mechanical safety switches have been proposed, typically implemented in the end caps of LED tubes. However, these mechanical safety switches often rely on spring elements and moving parts, which can fail, and are difficult to use for certain luminaires where the safety switch on the end cap is hard to access or reach once the LED tube is installed. Summary of the Invention

[0005] The object of the present invention is to solve one or more of the aforementioned problems. In a first aspect, the present invention relates to an LED lamp assembly including a safety switch. The LED lamp assembly includes a plurality of connector pins arranged at a first end and a second end of the LED lamp assembly, the connector pins being adapted for electrical connection to a luminaire, a plurality of filament simulation circuits, wherein at least one of the connector pins at each of the first and second ends of the LED lamp assembly is electrically coupled to a corresponding one of the filament simulation circuits, a plurality of rectifier circuits, one or more LEDs electrically coupled to the outputs of the rectifier circuits, and a safety switch control circuit operatively coupled to the safety switch. At least one of the connector pins arranged at the first end of the LED lamp assembly is electrically coupled to an input of a first rectifier circuit via the safety switch, and at least one of the connector pins arranged at the second end of the LED lamp assembly is electrically coupled to an input of a second rectifier circuit. The safety switch control circuit is arranged to close the safety switch when the safety switch control circuit detects power with a frequency higher than a predetermined threshold at a connector pin arranged at the first end of the LED lamp assembly or at a connector pin arranged at the second end of the LED lamp assembly.

[0006] The LED lamp assembly has a safety switch at only one end, such that at least one of the connector pins located at the second end of the LED lamp assembly is electrically coupled to the input of a second rectifier circuit in the rectifier circuit, rather than via the safety switch. This avoids the more complex configuration with two or more safety switches, which would have higher production costs.

[0007] When the safety switch is closed, current can flow from one end of the LED assembly to the other, specifically between the connector pins at opposite ends of the LED assembly. When the safety switch is open, current cannot flow from one end of the LED assembly to the other via the circuitry used to power the LED (i.e., via the rectifier circuit). The safety switch is preferably a normally open switch, meaning it is in the open position when no power is supplied.

[0008] The safety switch may include two switching elements connected in series, both of which are closed to electrically couple at least one of the connector pins disposed at a first end of the LED lamp assembly to the input of a first rectifier circuit. In this arrangement, a failure of one of the switching elements to the closed position will not cause the safety switch to close, and it provides increased insulation. The safety switch preferably includes an electromechanical relay, wherein two switch contacts serve as two switching elements connected in series. Alternatively, the safety switch may include one or more semiconductor switching elements, such as one or more transistors or MOSFETs. Implementing the safety switch using semiconductor switching elements can extend the lifespan of the LED lamp assembly and reduce audible noise during operation.

[0009] The safety switch control circuit is preferably arranged to close the safety switch when it detects power at a frequency higher than a predetermined threshold at the connector pin. The predetermined threshold can be set to a certain level (e.g., 10 kHz) to distinguish between power received from a magnetic ballast or directly from mains power (i.e., without a ballast) (typically at a frequency of 50 or 60 Hz) and power received from an electronic ballast (typically at a frequency of 20 kHz or higher). In this way, the safety switch control circuit can distinguish the type of luminaire with LED light components installed.

[0010] When installed in luminaires with or without magnetic ballasts, the safety switch control circuit is arranged to keep the safety switch off, remaining in the open position. This prevents current from flowing from one end of the LED assembly to the other via the circuitry used to power the LED, thereby reducing the risk of electric shock from exposed connector pins when installing the LED assembly in luminaires with or without magnetic ballasts.

[0011] When installed in a luminaire equipped with an electronic ballast, the safety switch control circuit is configured to close the safety switch only when power is detected between the two ends of the LED assembly (i.e., only when the two ends of the LED assembly are installed in the luminaire), thereby reducing the risk of electric shock from exposed connector pins when the LED assembly is installed in a luminaire equipped with an electronic ballast.

[0012] The safety switch control circuit can be configured to provide a predetermined delay between detecting power at a frequency higher than a predetermined threshold at a connector pin located at the first or second end of the LED lamp assembly and closing the safety switch. This delay (e.g., in the range of 1 to 100 ms) simulates the operation of a fluorescent tube, providing better compatibility with electronic ballasts, which can trigger the safety shut-off function without delay. This delay also stabilizes the operation of the safety switch control circuit and helps prevent unstable switching of the safety switch due to output waveform variations of certain types of electronic ballasts.

[0013] The safety switch control circuit can be arranged to have a first input connected to a connector pin electrically coupled to a first end of the LED lamp assembly and a second input connected to a connector pin electrically coupled to a second end of the LED lamp assembly to receive power as an input signal from both the first and second ends of the LED lamp assembly. This arrangement enables the safety switch control circuit to operate when power and / or input signals are received from either or both ends of the LED lamp assembly.

[0014] The impedance of the safety switch control circuit between the first and second inputs is preferably 10 kΩ or more, more preferably 100 kΩ or more. When the safety switch is off, this reduces the amount of current that may flow between the connector pins at the opposite ends of the LED lamp assembly, further reducing the risk of dangerous electric shock from exposed connector pins when the LED lamp assembly is installed in the luminaire, and reducing the energy consumption of the LED lamp assembly.

[0015] In one embodiment, the safety switch control circuit includes a first high-pass filter electrically coupled to one of the connector pins disposed at a first end of the LED lamp assembly 1, a second high-pass filter electrically coupled to one of the connector pins disposed at a second end of the LED lamp assembly, and logic circuitry having a first input electrically coupled to the first high-pass filter and a second input electrically coupled to the second high-pass filter, and adapted to determine an output for controlling the safety switch based on the first input and / or the second input. The first input of the logic circuitry may be electrically coupled to the first high-pass filter via a third rectifier circuit, and the second input of the logic circuitry may be electrically coupled to the second high-pass filter via a fourth rectifier circuit.

[0016] When the safety switch is off, the LED lamp assembly is adapted to withstand at least 1500V between the connector pins located at the first end of the LED lamp assembly and the connector pins located at the second end of the LED lamp assembly. When the safety switch is off, the LED lamp assembly is also adapted to conduct a current equal to or less than 0.7mA between the connector pins located at the first end of the LED lamp assembly and the connector pins located at the second end of the LED lamp assembly.

[0017] LED lighting assemblies are suitable for operation in luminaires equipped with magnetic ballasts, electronic ballasts, or without ballasts, thus providing greater flexibility when using LED lighting assemblies.

[0018] When the LED lighting assembly is operated in a luminaire with or without a magnetic ballast, the LED lighting assembly can be adapted to supply power to the LED via a connector pin disposed at a second end of the LED lighting assembly, rather than from a connector pin disposed at a first end of the LED lighting assembly.

[0019] The LED lamp assembly may further include a switching power supply, wherein the LED lamp assembly is adapted to supply power to the LED via the switching power supply when a safety switch control circuit detects power at a frequency equal to or lower than a predetermined threshold at a connector pin disposed at a first end of the LED lamp assembly or at a connector pin disposed at a second end of the LED lamp assembly.

[0020] When the safety switch control circuit detects a power frequency higher than a predetermined threshold at a connector pin located at the first end of the LED lamp assembly or at a connector pin located at the second end of the LED lamp assembly, the LED lamp assembly can be adapted to turn off or disconnect the power supply from the switching power supply to the LED.

[0021] When power with a frequency below 1 kHz is applied to the connector pins, the first filament simulation circuit in the filament simulation circuit electrically coupled to at least one of the connector pins at the first end of the LED lamp assembly has a first impedance, and the second filament simulation circuit in the filament simulation circuit electrically coupled to at least one of the connector pins at the second end of the LED lamp assembly has a second impedance higher than the first impedance. The first rectifier circuit can be a half-wave rectifier, and the second rectifier circuit can be a full-wave rectifier. Attached Figure Description

[0022] The advantages of the invention will become apparent after considering the following detailed disclosure of exemplary, non-limiting embodiments thereof, particularly when taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 An example of an LED light assembly is shown;

[0024] Figure 2 An example of mounting an LED light assembly into a luminaire is shown;

[0025] Figure 3 This is a simplified block diagram of an embodiment of an LED lamp assembly including a safety switch;

[0026] Figure 4 It is shown Figure 3 A simplified block diagram showing more details of the LED light assembly;

[0027] Figure 5 This is a simplified circuit diagram of one embodiment of a safety switch control circuit for an LED lamp assembly with a safety switch;

[0028] Figure 6 This is a simplified block diagram of an embodiment of an LED lamp assembly suitable for operation in a luminaire equipped with a magnetic ballast, an electronic ballast, or without a ballast;

[0029] Figure 7 It is a simplified circuit diagram of an LED lamp assembly installed in a lamp with a magnetic ballast;

[0030] Figure 8 It is a simplified circuit diagram of an LED lamp assembly installed in a luminaire equipped with an electronic ballast; and

[0031] Figure 9This is a simplified circuit diagram of an LED lamp assembly installed in a luminaire without any ballast installed. Detailed Implementation

[0032] Figure 1 An embodiment of an LED lamp assembly 1 is shown. The LED lamp assembly 1 includes a translucent or transparent elongated housing 2 and has one or more LEDs arranged within the housing 2. Typically, an end cap assembly 3 is provided at each end of the housing 2, from which connector pins 4a, 4b extend. Although the LED lamp assembly 1 in this embodiment is in the form of an elongated tube, other shapes are also possible.

[0033] Connector pins 4a and 4b are exposed to mechanically and electrically connect the LED lamp assembly 1 to the luminaire. The luminaire may be designed to accommodate, for example, standard-sized fluorescent tubes, such as T5, T8, T10, or T12 tubes. The LED lamp assembly 1 typically includes two connector pins 4a and 4b at both ends of the housing 2, but other numbers of connector pins may be used in various arrangements to accommodate different designs of the LED lamp and the luminaire.

[0034] Figure 2 An example of mounting an LED lamp assembly 1 into a luminaire 5 is shown. The mounting process typically involves inserting one end of the LED lamp assembly 1 into the body 6 of the luminaire 5, such that connector pins 4a, 4b at one end of the LED lamp assembly are mechanically and electrically connected to corresponding fixed connectors 7a, 7b of the luminaire. In the illustrated case, connector pin 4b at the insertion end will connect to fixed connector 7b. However, it is possible to power the luminaire using electricity during installation, resulting in voltage across luminaire connector 7b.

[0035] LED lamp assembly 1 typically includes internal circuitry for powering the LEDs in the lamp, and this internal circuitry typically provides a path for current to flow from one end of LED lamp assembly 1 to the other. In this case, there is a danger that voltage may exist on the exposed connector pin 4a at the uninstalled end of LED lamp assembly 1, posing a risk of electric shock if someone installing the lamp accidentally touches the exposed connector pin 4a. Note that this can occur regardless of which end of LED lamp assembly 1 is installed into the lamp fixture first; therefore, the uninstalled end may pose an electrical hazard.

[0036] In view of this problem, the LED lamp assembly 1 includes a safety switch 30 to provide a degree of electrical insulation between connector pins 4a, 4b at each end of the LED lamp assembly 1.

[0037] Figure 3A simplified block diagram of an embodiment of an LED lamp assembly 1 including a safety switch 30 is shown. For clarity, many components that may be necessary for the operation of the lamp but are irrelevant to the present description are omitted from the figure.

[0038] In this example, the LED lamp assembly 1 includes two connector pins 4a, 4b at both ends, adapted for electrical connection to the luminaire 5. The connector pins may also provide a mechanical connection to the luminaire, and / or other connector pins or connecting members may provide additional or alternative electrical and / or mechanical connections. The connector pins 4a, 4b at each end of the LED lamp assembly are electrically coupled to corresponding rectifier circuits 11a, 11b, which in various embodiments may include half-wave or full-wave rectifiers. The output of the rectifier circuits 11a, 11b is a rectified voltage that can supply power to the LED circuit 12 to generate light. The LED circuit 12 may consist of one or more LEDs 12a connected across the outputs of the rectifier circuits 11a, 11b, or may include additional circuitry connected to the outputs of the rectifier circuits 11a, 11b and supplying power to one or more LEDs 12a (e.g., as shown in the image). Figure 6 (As shown).

[0039] Circuits 13a and 13b are provided, which are connected to two connector pins 4a and 4b at each end of the LED lamp assembly. Circuits 13a and 13b can be used to simulate the heating filament present in a conventional fluorescent tube, as further described below.

[0040] Safety switch control circuit 32 is operatively coupled to safety switch 30. At least one 4a of the connector pins located at one end of the LED lamp assembly 1 (referred to herein as the first end) is electrically coupled via safety switch 30 to the input of a corresponding 11a in the rectifier circuit, and at least one 4b of the connector pins located at the other end of the LED lamp assembly 1 (referred to herein as the second end) is not electrically coupled via safety switch to the input of the second 11b in the rectifier circuit. The LED lamp assembly 1 includes only one safety switch, although the switch may have multiple switching elements, such as multiple poles of an electromechanical relay.

[0041] like Figure 3 As shown, safety switch 30 is connected between connector pin 4a at the first end of LED lamp assembly 1 and rectifier 11a, which is arranged to supply power to LED 12a from connector pin 4a. LED lamp assembly 1 has only one safety switch at one end, such that connector pin 4b at the second end of LED lamp assembly 1 is electrically coupled to the input of the second rectifier circuit 11b without an intermediate switch. This avoids the more complex configuration with two or more safety switches, which would have higher production costs.

[0042] When safety switch 30 is closed, current can flow from connector pin 4a at the first end of LED lamp assembly 1 to connector pin 4b at the second end of LED lamp assembly 1 via rectifiers 11a and 11b, supplying power to LED 12a. This allows current to flow from one end of LED lamp assembly 1 to the other, i.e., between connector pins 4a and 4b at both ends of LED lamp assembly 1. Note that this is necessarily the case if LED lamp assembly 1 is operated in luminaire 5, which supplies power between the connector pins at both ends of LED lamp assembly.

[0043] When safety switch 30 is open, the electrical connection between connector pin 4a and rectifier 11a is broken. This prevents current from flowing from one end of LED lamp assembly 1 to the other via the circuitry used to power LED 12a, i.e., through rectifiers 11a and 11b. Note that when installed in a luminaire 5 that supplies power to connector pin 4b at the second end of LED lamp assembly 1, LED lamp assembly 1 can still operate with safety switch 30 open.

[0044] Safety switch 30 is preferably a normally open switch, that is, it is in the open position when safety switch 30 is not energized. This prevents current from flowing from one end of LED lamp assembly 1 to the other end when no power is applied to the LED lamp assembly, thus ensuring a safe position.

[0045] Safety switch 30 may include two switching elements connected in series, both closing to electrically couple at least one 4a of the connector pins disposed at the first end of the LED lamp assembly 1 to the input of the first rectifier circuit 11a. This provides redundancy such that a failure of one of the switching elements to the closed position will not cause safety switch 30 to close, and also provides increased insulation. Safety switch 30 preferably includes an electromechanical relay, wherein two switch contacts serve as two switching elements connected in series. Alternatively, safety switch 30 may include one or more semiconductor switching elements, such as one or more transistors or MOSFETs.

[0046] When the safety switch control circuit 32 detects power at connector pins 4a and 4b with a frequency higher than a predetermined threshold, the safety switch control circuit 32 is arranged to close the safety switch 30. The predetermined threshold can be set to a certain level (e.g., 10 kHz) to distinguish between power received from a magnetic ballast or directly from mains power (i.e., without a ballast) (typically 50 or 60 Hz) and power received from an electronic ballast (typically 20 kHz or higher).

[0047] In this way, the safety switch control circuit 32 can distinguish the type of luminaire 5 in which the LED lamp assembly 1 is installed. When installed in a luminaire 5 with or without a magnetic ballast (where connector pins 4a, 4b receive low-frequency power, such as 50 or 60 Hz), the safety switch control circuit 32 is arranged to not close the safety switch 30, which remains in the open position. This prevents current from flowing from one end of the LED lamp assembly 1 to the other via the circuitry used to power the LED 12a, thus solving the problem of potential electric shock caused by exposed connector pins when the LED lamp assembly 1 is installed in a luminaire 5 with or without a magnetic ballast.

[0048] When the LED lamp assembly 1 is operated in a luminaire 5 equipped with a magnetic ballast 21 or without a ballast, the LED lamp assembly 1 can be adapted to supply power to the LED 12a via connector pin 4b disposed at the second end of the LED lamp assembly 1, instead of from connector pin 4a disposed at the first end of the LED lamp assembly 1. In this embodiment, the second rectifier circuit 11b is preferably implemented as a full-wave rectifier so that power can be efficiently supplied to the LED 12a from connector 4b disposed at the second end of the LED lamp assembly 1. In this way, when installed in this type of luminaire 5, the LED lamp assembly 1 can operate as follows: Figure 7 and Figure 9 As further explained in the description. Note that the first rectifier circuit 11a can be implemented as a full-wave or half-wave rectifier because the first rectifier circuit 11a supplies power to the LED 12a when the LED lamp assembly 1 receives power from the connector pins 4a, 4b arranged at both ends of the LED lamp assembly 1.

[0049] When installed in a luminaire 5 equipped with an electronic ballast (where connector pins 4a, 4b receive high-frequency power, e.g., 20kHz), the safety switch control circuit 32 is arranged to close the safety switch 30 when it detects power at both ends of the LED lamp assembly 1. In this type of luminaire 5, power is applied between the two ends of the lamp, i.e., between connector pin 4a at the first end and connector pin 4b at the second end. During the installation of the LED lamp assembly 1 into this type of luminaire, if only one end of the lamp is installed in the luminaire and the other end is not installed, the safety switch control circuit 32 will not detect power and will not close the safety switch 30. This prevents current from flowing from one end of the LED lamp assembly 1 to the other end via the circuitry used to power LED 12a, thus solving the problem of potential electric shock caused by exposed connector pins when the LED lamp assembly 1 is installed into the luminaire 5 equipped with an electronic ballast. Once the two ends of the LED lamp assembly 1 are installed in this type of lamp fixture 5, the safety switch control circuit 32 will detect the power applied to the connector pins 4a and 4b at both ends of the LED lamp assembly 1, and will close the safety switch 30 to enable the lamp to operate. Figure 8 As described in the description.

[0050] The safety switch control circuit 32 can be configured to provide a predetermined delay between detecting power at a frequency higher than a predetermined threshold at connector pins 4a, 4b located at the first or second end of the LED lamp assembly 1 and closing the safety switch 30. This delay offers several advantages. It simulates the operation of a fluorescent tube, which typically requires a short delay after receiving power and illuminating. Some electronic ballasts are designed to detect this delay and, if used with a lamp that immediately draws operating current, perform a safety shutdown. The short delay period implemented in the safety switch control circuit 32 (e.g., a delay in the range of 1 to 100 ms) simulates a fluorescent tube and avoids this type of safety shutdown. Furthermore, this delay stabilizes the operation of the safety switch control circuit 32 and helps prevent unstable switching of the safety switch 30 due to variations in the output waveform of certain types of electronic ballasts.

[0051] The LED lamp assembly 1 with safety switch 30 is preferably designed to meet one or more requirements specified in applicable safety regulations, such as IEC standard 62776:2014, entitled "double-capped LED lamps designed to retrofit linear fluorescent lamps – safety specifications". When safety switch 30 is off, the LED lamp assembly 1 is preferably able to withstand a voltage of at least 1500V applied between the two ends of the LED lamp assembly (e.g., at least 2500V if one or more semiconductor switching elements are used to implement safety switch 30), that is, 1500V between connector pin 4a at the first end of the LED lamp assembly 1 and connector pin 4b at the second end of the LED lamp assembly 1, without arcing or breakdown. When a voltage of 500V is applied between the two ends of the LED lamp assembly and the safety switch 30 is open, the LED lamp assembly 1 preferably conducts a current equal to or less than 0.7mA peak value, that is, between the connector pin 4a arranged at the first end of the LED lamp assembly 1 and the connector pin 4b arranged at the second end of the LED lamp assembly 1.

[0052] Figure 4 A simplified block diagram is shown, illustrating more details of one embodiment of the LED lamp assembly 1. In this embodiment, a safety switch control circuit 32 is powered by and receives input from both ends of the LED lamp assembly 1. The circuit 32 has a first input electrically coupled to connector pin 4a at a first end of the LED lamp assembly 1 (via filament simulation circuit 13a in this embodiment), which extends to a point on the connector pin side of the safety switch 30, such that the safety switch control circuit 32 receives power from connector pin 4a even when the safety switch 30 is open. The safety switch control circuit 32 has a second input electrically coupled to one of the connector pins 4b at a second end of the LED lamp assembly 1 (via filament simulation circuit 13b in this embodiment). This arrangement allows the safety switch control circuit 32 to receive power from connector pins 4a, 4b at one or both ends of the LED lamp assembly 1, regardless of the state of the safety switch 30. In this way, when the connector pins 4a and 4b at either end of the LED lamp assembly 1 establish a connection with the corresponding connector in the lamp and receive power from the lamp, the safety switch control circuit 32 is energized, and the safety switch 30 can also be controlled when the LED lamp assembly 1 is installed into the lamp 5.

[0053] The safety switch control circuit 32 preferably has a high input impedance, for example, a resistance of 10 kΩ between its two inputs, preferably 100 kΩ or greater (measured at a frequency of 10 kHz), so that the impedance between the two ends of the LED lamp assembly is also high when the safety switch 30 is open. This limits the amount of current flowing through the safety switch control circuit 32 and the amount of power wasted in the control circuit, and also reduces the current flowing through the LED lamp assembly 1 when the safety switch 30 is open to a low value (preferably less than 0.7 mA peak when a voltage of 500 V is applied between the two ends of the LED lamp assembly). This low leakage current allows the LED lamp assembly 1 to comply with applicable safety regulations and provides better compatibility with a range of electronic ballasts. If the leakage current is too high, some electronic ballasts will perform a safety shutdown, and an input impedance of 250 kΩ or greater is preferably selected to achieve broad compatibility with electronic ballasts on the market.

[0054] In this embodiment, the safety switch control circuit 32 includes a first high-pass filter 41 electrically coupled to one of the connector pins 4a at a first end of the LED lamp assembly 1 and a second high-pass filter 42 electrically coupled to one of the connector pins 4b arranged at a second end of the LED lamp assembly 1. The safety switch control circuit 32 also includes logic circuitry 45 having a first input electrically coupled to the first high-pass filter 41 and a second input electrically coupled to the second high-pass filter 42, and is adapted to determine an output for controlling the safety switch 30 based on the first input and / or the second input.

[0055] The safety switch control circuit 32 may also include rectifier circuits 43 and 44, wherein the first input of the logic circuit 45 is electrically coupled to the first high-pass filter 41 via the third rectifier circuit 43, and the second input of the logic circuit 45 is electrically coupled to the second high-pass filter 42 via the fourth rectifier circuit 44.

[0056] High-pass filters 41 and 42 are used to allow high-frequency signals (e.g., in the form of high-frequency voltage or current) from connector pins 4a and 4b to pass through, while substantially blocking or reducing low-frequency signals. For example, high-pass filters 41 and 42 can be configured to allow current from pins 4a and 4b to pass through when the pins receive power at a frequency higher than a predetermined threshold (e.g., higher than 10 kHz), as is expected when the LED lamp assembly 1 is installed in a luminaire 5 equipped with an electronic ballast (which operates at 20 kHz), and high-pass filters 41 and 42 can be configured to substantially block or reduce current from connector pins 4a and 4b when the pins receive power at a frequency lower than a predetermined threshold (e.g., lower than 10 kHz), as is expected when the LED lamp assembly 1 is installed in a luminaire 5 equipped with a magnetic ballast or without a ballast (which operates at 50 or 60 Hz). In this way, the safety switch control circuit 32 can distinguish the type of lamp with LED lamp assembly 1 installed, namely, lamp 5 with magnetic ballast or without ballast (connector pins 4a, 4b receive low frequency (e.g. 50 or 60 Hz) power) or lamp with electronic ballast (connector pins 4a, 4b receive high frequency (e.g. 20 kHz) power).

[0057] When included in the circuit, rectifier circuits 43 and 44 rectify the outputs from high-pass filters 41 and 42 to provide DC current to power logic circuit 45 and input signals.

[0058] The logic circuit 45 receives electrical signals via high-pass filters 41 and 42, and performs a predetermined time delay between detecting power with a frequency higher than a predetermined threshold at connector pins 4a and 4b located at the first or second end of the LED lamp assembly 1 and closing the safety switch 30, as described above. This delay simulates the delayed start-up of the fluorescent tube to improve compatibility with electronic ballasts with a safety shut-off function and stabilizes the operation of the safety switch control circuit 32 to prevent unstable switching of the safety switch 30 due to variations in the output waveform of certain electronic ballasts.

[0059] The logic circuit 45 can be implemented using discrete logic such as operational amplifier comparator circuits, or it can be implemented using programmable microcontrollers, FPGAs or other types of circuits.

[0060] Figure 5 A simplified circuit diagram of one embodiment of the safety switch control circuit 32 is shown.

[0061] In this embodiment, the first filament simulation circuit 13a includes resistors R1 and R2 connected in series between two connector pins 4a at the first end of the LED lamp assembly 1, and the second filament simulation circuit 13b includes resistor R3 and capacitor C3 connected in series between two connector pins 4b at the second end of the LED lamp assembly 1. The safety switch 30 includes an electromagnetic relay having a coil 30a and two switch contacts 30b and 30c connected in series. The safety switch 30 is connected to resistors R1 and R2 on one side of the switch and to rectifier circuit 11a on the other side of the switch, thereby enabling the safety switch 30 to connect or disconnect the connector pins 4a at the first end of the LED lamp assembly 1 and the rectifier circuit 11a.

[0062] In this embodiment, high-pass filters 41 and 42 include capacitors C1 and C2, respectively, and the third rectifier circuit 43 and the fourth rectifier circuit 44 include diodes D1, D2 and D3, D4, respectively. Capacitor C1 is connected on one side between resistors R1 and R2 and on the other side between diodes D1 and D2, and capacitor C2 is connected on one side to connector pin 4b and on the other side between diodes D3 and D4.

[0063] Zener diode Z1 is connected across the outputs of the third and fourth rectifier circuits 43 and 44 to stabilize the rectified voltage. Logic circuit 45 is connected across the rectified voltage outputs of the third and fourth rectifier circuits 43 and 44. Logic circuit 45 drives transistor T1. When transistor T1 is on, it energizes the coil 30a of safety switch 30; when transistor T1 is off, it de-energizes the coil 30a. The switch contacts 30b and 30c of safety switch 30 are connected in series. When coil 30a is energized, contacts 30b and 30c are closed; when coil 30a is de-energized, contacts 30b and 30c are open.

[0064] In this embodiment, the filament simulation circuits 13a and 13b are different. The first filament simulation circuit 13a (in Figure 5 The example shown includes series-connected resistors R1 and R2 providing low resistance between the two connector pins 4a at the first end of the LED assembly 1, regardless of whether the power applied to the first connector pin 4a is low-frequency or high-frequency. The second filament analog circuit 13b (in...) Figure 5The example shown includes a series-connected resistor R3 and capacitor C3 providing a variable impedance between two connector pins 4b at the second end of the LED lamp assembly 1. The impedance varies depending on the frequency of the power applied between the two connector pins 4b at the second end of the LED lamp assembly 1. When the power applied to the connector pins 4b has a high frequency (e.g., when power is supplied from an electronic ballast operating at 20 kHz), the second filament analog circuit 13b provides a higher impedance, and when the power applied to the connector pins 4b has a low frequency (e.g., when power is supplied from a magnetic ballast operating at 50 or 60 Hz), it provides a lower impedance.

[0065] Figure 6 A simplified block diagram of one embodiment of an LED lamp assembly 1 is shown, which is suitable for operation in various types of lamps 5 equipped with magnetic ballasts and electronic ballasts or without ballasts.

[0066] The LED lamp assembly 1 in this embodiment includes an LED circuit 12 with a first power supply circuit 50, which supplies power to the LED 12a when power is supplied to the LED lamp assembly 1 at a frequency higher than a predetermined threshold (e.g., power supplied by the electronic ballast 25 at a frequency of 20 kHz or higher). The LED circuit 12 in this embodiment also includes a second power supply circuit 51, which supplies power to the LED 12a when power is supplied to the LED lamp assembly 1 at a frequency lower than the predetermined threshold (e.g., power supplied by the magnetic ballast 21 at a frequency of 50 or 60 Hz, or power not supplied via a ballast).

[0067] When the power supplied to the LED lamp assembly 1 has a frequency higher than a predetermined threshold, the LED lamp assembly 1 can be adapted to turn off or disconnect the power supply from the switching power supply 57 to the LED 12a. For example, for this purpose, a separate frequency detector circuit can be included in the LED lamp assembly. Figure 6 (Not shown in the image) The frequency detector circuit controls the first switch 52 to connect / turn on or disconnect / turn off the power supply of the first power circuit 50 to the LED 12a, and controls the second switch 55 to connect / turn on or disconnect / turn off the power supply of the second power circuit 51 (including the switching power supply 57) to the LED 12a.

[0068] The first power supply circuit 50 may include a variable impedance 53 configured to have a relatively high impedance when power is supplied from a constant power electronic ballast to the LED lamp assembly 1, and a relatively low impedance when power is supplied from a constant current electronic ballast. When a current or voltage supplied to the LED lamp assembly 1 is detected to be higher than a predetermined threshold (e.g., for which a current or voltage detector circuit may be included in the LED lamp) (indicating that power is being supplied by the constant power electronic ballast), the variable impedance 53 may be configured to switch to a higher impedance mode. Further details of the LED lamp assembly 1, including the first and second power supply circuits 50, 51, can be found in US 10,342,079, the entire contents of which are incorporated herein by reference.

[0069] The LED lamp assembly 1 is preferably suitable for operation in a luminaire 5 equipped with a magnetic ballast or an electronic ballast, or without any ballast. To better understand the operation of the LED lamp assembly 1, Figure 7-9 The various usage modes of the LED lamp assembly 1 in different types of lamps are shown.

[0070] Figure 7 A simplified circuit diagram of an LED lamp assembly 1 installed in a luminaire including a magnetic (i.e., inductive) ballast 21 is shown. An AC power supply 20 supplies power via the magnetic ballast 21 to connector pins 4a, 4b at each end of the LED lamp assembly 1. The AC power supply 20 is typically AC mains power, such as 110 / 120Vac or 230 / 240Vac, at a frequency of 50 or 60Hz. Luminaires with magnetic ballasts and designed to operate fluorescent lamps typically include a starter unit 22 connected to connector pins 4a, 4b at each end of the LED lamp to provide a starting voltage to illuminate the fluorescent tube. When LED lamps are installed in luminaires of this design, a low-impedance starter unit 22 is typically installed in the luminaire between its terminals to replace any existing starter unit. This provides a short circuit across the starter unit 22 and completes the circuitry for supplying AC power to one end of the LED lamp assembly.

[0071] In this example, the first end of LED light assembly 1 (in) Figure 7 The left side includes a safety switch 30. The filament analog circuit 13a at the first end (see...) Figure 3 It has low impedance, for example, including a resistive element providing, for example, a 10-20 ohm resistance between connector pins 4a at the first end. The filament analog circuit 13b at the second end (see...) Figure 3It has low impedance at high frequencies (e.g., 10 kHz and above) and high impedance at low frequencies (e.g., below 1 kHz, such as 50 or 60 Hz). The filament analog circuit 13 at the second end may include, for example, resistive and capacitive elements, providing a resistance between the connector pins 4b at the second end, said resistance being several megaohms (MΩ) at 50 or 60 Hz and 10-20 ohms at 20 kHz.

[0072] In this configuration, power is supplied from AC power supply 20 to connector pin 4b at the second (right) end of LED lamp assembly 1 via magnetic ballast 21, connector pin 4a at the first (left) end of LED lamp assembly 1, filament simulation circuit 13a, and improved starter unit 22. Safety switch control circuit 32 detects the power applied to connector pins 4a and 4b. Because the frequency of the power is low, for example 50 or 60 Hz and below a predetermined threshold, safety switch control circuit 32 does not close safety switch 30; safety switch 30 remains open, thereby disconnecting at least one of the connector pins 4a from the rest of LED lamp assembly 1.

[0073] During the installation of LED lamp assembly 1, one end of LED lamp assembly 1 is installed first, and the connector pin 4a or 4b at the installed end is connected to the corresponding connector in the lamp fixture and receives power. However, the safety switch 30 remains open to prevent current from flowing through LED lamp assembly 1. Therefore, accidental contact with the exposed connector pin 4a or 4b at the uninstalled end of LED lamp assembly 1 will not result in electric shock.

[0074] Once installation is complete, LED assembly 1 receives power via connector pin 4b at the second end of LED assembly 1 and supplies power to LED 12a via connector pin 4b, thereby enabling the LED to function properly.

[0075] Figure 8 A simplified circuit diagram of an LED lamp assembly 1 installed in a luminaire including an electronic ballast 25 is shown. An AC power supply 20 supplies power to the electronic ballast 25, which outputs power at a high frequency typically 20 kHz or higher. The electronic ballast 25 applies power across the LED lamp assembly 1 between connector pin 4a at the first end and connector pin 4b at the second end.

[0076] During the installation of LED lamp assembly 1, one end of LED lamp assembly 1 is installed first, and the connector pin 4a or 4b at the installed end is connected to the corresponding connector in the lamp fixture and receives power. However, the safety switch 30 remains open to prevent current from flowing through LED lamp assembly 1. Therefore, accidental contact with the exposed connector pin 4a or 4b at the uninstalled end of LED lamp assembly 1 will not result in electric shock.

[0077] Once fully installed in the luminaire 5, the safety switch control circuit 32 detects the power applied between connector pins 4a and 4b at each end. Because the power frequency is high, for example 20 kHz and above a predetermined threshold, the safety switch control circuit 32 closes the safety switch 30, which connects connector pin 4a at the first end of the LED assembly 1, rectifiers 11a and 11b, and connector pin 4b at the second end of the LED assembly 1, completing the circuit between the two ends of the LED assembly 1 and allowing current to flow through the circuit supplying power to the LED 12a.

[0078] Figure 9 A simplified circuit diagram is shown for an LED lamp assembly 1 installed in a luminaire designed without a ballast. An AC power supply 20 supplies power only to connector pins 4a and 4b at one end of the LED lamp assembly 1. The AC power supply 20 is typically an AC mains power supply, for example, 110 / 120Vac or 230 / 240Vac, with a frequency of 50 or 60Hz.

[0079] As referenced above Figure 7 and Figure 8 As described above, during the installation of the LED lamp assembly 1, the safety switch 30 remains open to prevent current from flowing through the LED lamp assembly 1, thus preventing electric shock from accidental contact with the exposed connector pins at the uninstalled end of the LED lamp assembly 1. Once fully installed in the luminaire 5, the connector pin 4b at the second end of the LED lamp assembly receives power from the luminaire 5 and supplies power to the LED 12a via the connector pin 4b, enabling the LED lamp to function normally.

[0080] In this disclosure, the terms “disconnect” and “close” cover on / off switching such as that produced by an electromechanical relay, or the off and on states of a transistor or MOSFET, i.e., the change between an on or connected state with relatively low impedance and an off or open state with relatively high impedance.

[0081] Those skilled in the art will understand that the embodiments described herein relate to LED light assemblies with safety switches, and that features described with respect to one embodiment can be used or combined with features of other embodiments. Although the principles of the invention have been illustrated above with reference to specific embodiments, it should be understood that this description is exemplary only and is not intended to limit the scope of protection, which is determined by the appended claims.

Claims

1. An LED lamp assembly including a safety switch, suitable for operation in a luminaire equipped with a magnetic ballast, an electronic ballast, or without a ballast, the LED lamp assembly comprising: Multiple connector pins are arranged at a first end and a second end of the LED lamp assembly, the multiple connector pins being adapted for electrical connection to the lamp; Multiple filament simulation circuits, wherein at least one of the multiple connector pins at each of the first and second ends of the LED lamp assembly is electrically coupled to a corresponding filament simulation circuit in the multiple filament simulation circuits. Multiple rectifier circuits; One or more LEDs are electrically coupled to the output of the rectifier circuit; The safety switch control circuit is operationally grounded to the safety switch. Wherein, at least one of the plurality of connector pins arranged at the first end of the LED lamp assembly is electrically coupled to the input of the first rectifier circuit in the plurality of rectifier circuits via the safety switch, and at least one of the plurality of connector pins arranged at the second end of the LED lamp assembly is electrically coupled to the input of the second rectifier circuit in the plurality of rectifier circuits; The safety switch control circuit is configured to detect whether the frequency power at the connector pins exceeds a predetermined threshold, in order to distinguish between power received from a magnetic ballast or power directly received from the mains power supply and power received from an electronic ballast. The safety switch control circuit is configured to close the safety switch when it detects power with a frequency higher than the predetermined threshold at a connector pin located at the first end of the LED lamp assembly and at a connector pin located at the second end of the LED lamp assembly. When the LED lamp assembly is operated in a luminaire equipped with an electronic ballast, the safety switch control circuit is configured to close the safety switch when it detects power applied between the two ends of the LED lamp assembly. When the LED lamp assembly is operated in a luminaire equipped with or without a magnetic ballast, the safety switch control circuit is configured not to close the safety switch, and the LED lamp assembly is adapted to supply power to the LED via a connector pin disposed at a second end of the LED lamp assembly, rather than from a connector pin disposed at a first end of the LED lamp assembly.

2. The LED lamp assembly according to claim 1, wherein, The safety switch control circuit is configured to provide a predetermined delay between detecting power at a frequency higher than a predetermined threshold at a connector pin located at the first or second end of the LED assembly and closing the safety switch.

3. The LED lamp assembly according to claim 1, wherein, The safety switch control circuit has a first input to a connector pin electrically coupled to a first end of the LED lamp assembly and a second input to a connector pin electrically coupled to a second end of the LED lamp assembly, so as to receive power from both the first and second ends of the LED lamp assembly as input signals.

4. The LED lamp assembly according to claim 3, wherein, The safety switch control circuit has an impedance of 10 kiloohms or greater between the first input and the second input.

5. The LED lamp assembly according to claim 1, wherein, The safety switch control circuit includes: A first high-pass filter and a second high-pass filter, wherein the first high-pass filter is electrically coupled to one of the plurality of connector pins disposed at a first end of the LED lamp assembly, and the second high-pass filter is electrically coupled to one of the plurality of connector pins disposed at a second end of the LED lamp assembly; and A logic circuit having a first input electrically coupled to a first high-pass filter and a second input electrically coupled to a second high-pass filter, and the logic circuit being adapted to determine an output for controlling the safety switch based on the first input and / or the second input.

6. The LED lamp assembly according to claim 5, wherein, The first input of the logic circuit is electrically coupled to the first high-pass filter via a third rectifier circuit, and the second input of the logic circuit is electrically coupled to the second high-pass filter via a fourth rectifier circuit.

7. The LED lamp assembly according to claim 1, wherein, The safety switch includes two switching elements connected in series, both of which are closed to electrically couple at least one of the plurality of connector pins disposed at the first end of the LED lamp assembly to the input of the first rectifier circuit.

8. The LED lamp assembly according to claim 1, wherein, When the safety switch is off, the LED lamp assembly is able to withstand at least 1500V between the connector pins located at the first end of the LED lamp assembly and the connector pins located at the second end of the LED lamp assembly.

9. The LED lamp assembly according to claim 1, wherein, When the safety switch is off, the LED lamp assembly conducts a current equal to or less than 0.7mA between the connector pins located at the first end of the LED lamp assembly and the connector pins located at the second end of the LED lamp assembly.

10. The LED lamp assembly according to claim 1, further comprising a switching power supply, wherein, When the safety switch control circuit detects power at a frequency equal to or lower than the predetermined threshold at a connector pin located at the first end of the LED assembly or at a connector pin located at the second end of the LED assembly, the LED assembly is adapted to supply power to the LED via the switching power supply.

11. The LED lamp assembly according to claim 10, wherein, When the safety switch control circuit detects a power frequency higher than the predetermined threshold at a connector pin located at the first end of the LED lamp assembly or at a connector pin located at the second end of the LED lamp assembly, the LED lamp assembly is adapted to turn off or disconnect the power supply from the switching power supply to the LED.

12. The LED lamp assembly according to claim 1, wherein, When power with a frequency below 1 kHz is applied to the connector pin, the first filament simulation circuit of the plurality of connector pins electrically coupled to at least one of the connector pins at the first end of the LED lamp assembly has a first impedance, and the second filament simulation circuit of the plurality of connector pins electrically coupled to at least one of the connector pins at the second end of the LED lamp assembly has a second impedance higher than the first impedance.

13. The LED lamp assembly according to claim 1, wherein, The first rectifier circuit is a half-wave rectifier, and the second rectifier circuit is a full-wave rectifier.

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