Overload protection for electronic devices

Abstract

A mechanism for providing over-current and / or over-voltage protection for a load of an electronic device (200, 300) and over-temperature protection for the electronic device. A thermal fuse (150) of an electronic device is adapted to open when an overheating occurs in a first portion (I1, 311) of the electronic device. The first portion differs from the load and / or is unrelated to a portion on the load side. The thermal conversion component (260) is thermally coupled to a thermal fuse of the electronic device. The thermal conversion component is electrically coupled to the load and is configured to open the thermal fuse in response to a value of an electrical characteristic of a drive signal (through the load) of the load exceeding a predetermined electrical value. Disconnecting the thermal fuse causes an input signal of the electronic device to be electrically disconnected from the load. The thermal fuse has dual functions of thermal protection at a portion different from the load and electrical protection at the load.

Description

Technical Field

[0001] The present invention relates to the field of electronic equipment, and in particular to an electronic equipment with overload protection. Background Art

[0002] Overload protection is an important aspect of electronic equipment that can avoid or reduce damage, degradation, and / or hazardous operating conditions. An overload occurs when an electrical characteristic of the power supplied to the load of the electronic equipment (e.g., current, voltage, or power) exceeds a certain predetermined value.

[0003] One method for implementing overload protection is to use an overload protection circuit. The overload protection circuit generally includes: a sampling portion for sampling the electronic characteristics of the load (e.g., current); a processing portion for comparing the sampled electronic characteristics with a reference value; and an execution portion for disconnecting the load from the power supply (e.g., using one or more switches such as TRIAC, FET, and / or BJT).

[0004] However, due to the wide threshold tolerance of existing switching elements, it is difficult to set the appropriate threshold, especially for low-current applications. Such switching circuits are bulky, affecting the minimum size of electronic devices and consuming additional energy.

[0005] Therefore, there is a need for an improved method for providing overload protection. Summary of the Invention

[0006] The present invention is defined by the claims.

[0007] The inventors discovered that existing overload protection systems require a significant amount of circuitry to successfully isolate the load from the external power supply in the event of an overload. Specifically, it is generally considered necessary to include a sampling section, a processing section, and an execution section. This places a significant burden on the amount of circuitry required and also affects the size of the electronic device.

[0008] WO2016000885A1 discloses a tubular LED lamp having an end cap with a thermal fuse, wherein the thermal fuse is adapted to burn out due to overheating of the end cap, which may be caused by arcing due to a poor connection between a pin in the end cap and a socket in a lighting fixture.

[0009] US20140185175A1 discloses a thermal protection device for an LED lamp, which has a thermal fuse. When the fuse temperature is reached, the thermal fuse will trip.

[0010] CN101728120B discloses a device having two independent thermal sensing and breakdown devices, wherein a thermal sensing trip device and a fusing breakdown device are provided.

[0011] JP2014220184A discloses an LED device including an overcurrent protection device comprising a thermal fuse and a heating element. The heating element is heated by an overcurrent and heats the thermal fuse to cut out the thermal fuse. This device is not used to protect components other than the heating element in the LED device from overheating.

[0012] CN111503989A discloses an appliance having a bimetallic switch for overcurrent conditions and a thermal fuse for overheating protection.

[0013] CN212137973U discloses an LED lighting device that uses an inductor to sense overcurrent and heats a thermal fuse to cut the thermal fuse. The thermal fuse itself is not used to sense overheating in parts other than the inductor in the LED lighting device.

[0014] The present disclosure proposes a method for overcoming the overheating problem and the overload problem at one time, namely, providing overload protection by reusing a thermal fuse (used for high temperature protection). Specifically, it has been proposed to provide a heat conversion circuit that converts the electrical characteristics of the load into heat that is thermally coupled to the thermal fuse and blows the thermal fuse when the electrical characteristics are overloaded. This allows the thermal fuse used for the first function of overheat protection to be used as an isolation mechanism for the second function of overload protection. Most importantly, the overheat protection of the thermal fuse is used for overheating that occurs at different parts of the entire device that are related to the occurrence of overload conditions. Therefore, the thermal fuse can be reused at different locations throughout the device for two different situations: overheating and overload.

[0015] According to an example of one aspect of the present invention, an electronic device is provided, comprising: a power supply configured to provide a load driving signal from an input signal; a load powered by the load driving signal; a first part that is different from the load and / or unassociated with a part on the load side; and a thermal fuse electrically coupled between the power supply and the input signal and thermally coupled to the first part, the thermal fuse being configured to disconnect in response to a temperature at the first part exceeding a first temperature threshold, thereby electrically disconnecting the input signal from the power supply.

[0016] The electronic device is characterized in that it also includes a heat conversion component, which is electrically coupled to the load and thermally coupled to the thermal fuse, and is configured to generate a temperature at the thermal fuse that trips the thermal fuse in response to the value of the electrical characteristic of the load driving signal exceeding a predetermined electrical value, thereby electrically disconnecting the input signal from the power supply.

[0017] Thus, embodiments provide a method for using a thermal fuse to disconnect an input signal to an electronic device when the electronic device overheats, and also to decouple or disconnect the input signal from the electronic device (or the rest of the device) when an overload condition occurs on the load of the electronic device, wherein overheating does not occur under the load / overload condition. A basic technique employed by the present invention is that a single fuse performs the dual functions of thermal protection at a first portion that is decoupled from the load / load-driven signal, and overcurrent / overvoltage protection at the load / load-driven signal. In short, the first portion is not where the load is located or where the load-driven signal flows.

[0018] Preferably, the first portion is physically located within or on the electronic device and does not include or is associated with the load-side portion. Therefore, the first portion is distinct from the heat conversion component and the load. The terms "disassociated" and "unassociated" here effectively mean that the first portion is decoupled, preferably thermally decoupled, from the load-side portion. In other words, the temperature of the load does not substantially affect the first portion or the thermal fuse. It is the load's electrical characteristics that affect the first portion or the thermal fuse.

[0019] Even more preferably, the first portion is adapted to couple to an external power source. Thus, the thermal fuse protects against overheating at the coupling between the electronic device and the external power source. Simultaneously, the electrical characteristics of the load may cause overload at the load within the electronic device. Therefore, the thermal fuse can be used repeatedly to protect against both abnormal conditions between the electronic device and the external power source and abnormal conditions within the external power source and the electronic device, providing a wide range of applications.

[0020] Please note that this is just one example, and the first portion may also be a portion not intended to be coupled to an external power supply. For example, the first portion may be a critical component of the power supply, such as a power MOSFET, which requires thermal protection. Furthermore, the thermal conversion component is associated with the load side, which is different from the power supply side that requires overload protection.

[0021] In some examples, the electrical characteristic is the current through the load. Overcurrent protection is an important consideration in the design of many electronic devices to prevent potentially dangerous effects (e.g., breakage or damage to the load, or potential fire). Therefore, the present application facilitates protection against overcurrent at the load.

[0022] To mitigate overcurrent issues, the heat conversion component may include a resistive element electrically connected in series with the load. The resistive element is configured to generate heat in response to current flowing through the resistor and the load, and is thermally coupled to the thermal fuse to provide heat to the thermal fuse, thereby generating a temperature at the thermal fuse that opens the thermal fuse.

[0023] Resistive elements (i.e., resistors) provide a simple and effective mechanism for both sensing the current flowing through a load and converting that current into heat. Specifically, the power dissipated by a resistive element (and therefore the heat output) is proportional to the current flowing through the load, making it a highly sensitive method for implementing overcurrent protection.

[0024] The resistance value of the resistor element can also be easily selected or adjusted to achieve a specific overcurrent condition (e.g., a specific predetermined current value). Therefore, the resistor element provides flexibility in manufacturing or creating the characteristics required for overcurrent protection.

[0025] The resistive element also provides a low cost (materially and economically) technique for providing heat conversion means.This embodiment alleviates the complexity of the known overcurrent protection involving a dedicated comparator described above.

[0026] In some examples, the electrical characteristic is the voltage across the load. Overvoltage is another important consideration when implementing overload protection, for example, to prevent high voltages from appearing across the load to improve the safety of individuals / people in the vicinity of the load.

[0027] Suitable heat conversion components include thermocouples, Peltier devices, or resistive elements connected in parallel with the load.

[0028] In some examples, the electrical characteristic is the power consumed by the load. This method can be used to prevent the load from consuming too much power.

[0029] The electronic device may further include an input interface at the first portion configured to receive an input signal from an external power source.

[0030] In such an example, a thermal fuse may be electrically coupled between the power source and the input interface; and the input interface and / or the first portion and the thermal fuse may be thermally coupled such that the thermal fuse opens when the temperature at the input interface exceeds a first temperature threshold. Optionally, the first portion is susceptible to heating due to the external power source, thereby protecting the electronic device. Alternatively, the heat source may be internal to the electronic device, and the first portion may be intended to heat the external power source, thereby protecting the external power source.

[0031] In this way, the input interface is located at the first portion. The input interface portion of an electronic device is a location that is particularly susceptible to high temperatures (e.g., due to arcing from an external power source to a node / pin of an improperly connected input interface). For example, the plastic body of an appliance plug or socket often melts. Therefore, providing temperature protection at the input interface location is extremely necessary.

[0032] In some examples, an electronic device (configured as) a tubular LED lamp includes an end cap as a first portion, the end cap being thermally connected to an input interface; a load including one or more LEDs; the input interface extending through the end cap and adapted to contact an external power source at a location external to the end cap; and a thermal fuse located within the end cap such that when a temperature of the input interface exceeds a first temperature threshold, the end cap is heated, which in turn heats the thermal fuse, thereby opening the thermal fuse.

[0033] This presents a particularly advantageous use case scenario for using the proposed technology for overheating and overload protection. In particular, due to the compact nature of the device, the available size of overload protection components in tubular LED lamps is reduced while still delivering high electrical power. Therefore, repurposing thermal fuses using the proposed technology is particularly beneficial.

[0034] The input interface may include at least one pin that is easily heated by an arc between the pin and the external power source due to poor contact with the external power source.

[0035] The electronic device may be configured for use with an electronic ballast.

[0036] The lamp holders of fluorescent lighting fixtures can be unreliable and can become worn and lose firm contact with the pins, causing arcing. Therefore, the present invention is advantageously applicable to tubular LED lamps designed for electronic ballasts.

[0037] In one embodiment, the power supply connects at least one pin of the input interface to the load without performing active power conversion. This approach provides an electronic device (particularly a tubular LED lamp) suitable for use with an electronic ballast, thereby providing a particularly useful use case scenario. The electronic ballast is inherently a current regulator, so a power supply without active power conversion is able to drive LED(s) using the electronic ballast.

[0038] The power supply may include a rectifying device for rectifying an input signal to generate a load driving signal.

[0039] The output of the electronic ballast is AC, while the LEDs are unidirectional components. Therefore, a rectifier helps to make full use of the output of the electronic ballast.

[0040] The power supply may include a bypass / shunt capacitor to bypass a portion of the input signal away from the load and provide the remaining portion of the input signal to the load as a load driving signal.

[0041] Sometimes the current from the electronic ballast is greater than the current required by the LEDs, so a bypass / shunt capacitor can be used to regulate the current going to the LEDs.

[0042] The rectifier and bypass / shunt capacitors are passive components and do not perform any active conversion of the power from the electronic ballast.

[0043] The input interface may include: a first interface node for connecting to a first node of a power source; and a second interface node for connecting to a second node of the power source. A thermal fuse may be coupled between the first interface node and the power source.

[0044] The electronic device may further include a second thermal fuse, different from the thermal fuse, coupled between the second interface node and the power supply. This provides an electronic device capable of being powered using differential signals. This may be useful in many environments. This embodiment provides thermal protection for the other interface, so that both interfaces have corresponding thermal protection.

[0045] Preferably, the electronic device includes an additional heat conversion component, which is electrically coupled to the load and thermally coupled to the second thermal fuse, and is configured to generate a temperature at the second thermal fuse that disconnects the second thermal fuse in response to the value of the electrical characteristic of the load driving signal exceeding a predetermined electrical value, thereby electrically disconnecting the input signal from the power supply.

[0046] This embodiment reuses the thermal protection on the second interface also for overload protection, and either or both thermal fuses can disconnect the electronic device from the power supply and provide higher safety or a larger safety margin.

[0047] The heat conversion component may be thermally coupled to the thermal fuse using thermal glue or thermal adhesive. This provides an effective and low-cost technique for ensuring good and / or effective thermal coupling between the thermal fuse and the heat conversion component.

[0048] Preferably, the thermal coupling of the heat conversion component is such that not less than 10% of the heat generated by the heat conversion component is lost through the thermal coupling to the thermal fuse, for example, not less than 5%, for example, not less than 1%. This ensures that the occurrence of an overload in the load (i.e., the value of the electrical characteristic exceeds a predetermined threshold) is accurately and reliably detected and used to trigger the opening of the thermal fuse.

[0049] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] For a better understanding of the invention, and to show more clearly how it may be put into practice, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0051] Figure 1 An existing electronic device is shown;

[0052] Figure 2 The proposed electronic device is shown;

[0053] Figure 3 A tubular LED lamp is shown; and

[0054] Figure 4 Shown Figure 3 Insert the tubular LED lamp into the lamp holder. DETAILED DESCRIPTION

[0055] The present invention will be described with reference to the accompanying drawings.

[0056] It should be understood that although the detailed description and specific examples illustrate exemplary embodiments of the devices, systems, and methods, these descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of the present invention. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention will be better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that the figures are merely schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar components.

[0057] The present invention provides a mechanism for providing overcurrent and / or overvoltage protection for a load of an electronic device. A heat conversion component is thermally coupled to a thermal fuse of the electronic device, wherein the thermal fuse is adapted to open when a first portion of the electronic device overheats. The heat conversion component is also electrically coupled to the load and configured to open the thermal fuse in response to an electrical characteristic value of a load drive signal (through the load) exceeding a predetermined electrical value. Opening the thermal fuse electrically disconnects the input signal of the electronic device from the load.

[0058] The present invention is based on the recognition that a heat conversion component can be used both as an electrical property sensor and as a trigger / controller for a thermal fuse. This means that the thermal fuse can be used to perform the dual purpose of thermal protection in a first location and overload protection in a load that is itself different from the first location.

[0059] The embodiments can be applied to any suitable electronic device that needs to perform temperature / thermal protection and overload protection on the electronic device load.For example, the electronic device can be an LED lamp, such as a tubular LED lamp.

[0060] In the context of the present invention, the verb "to fuse" or "to open" is used to mean "to electrically fuse" - that is, to trip or break a circuit to prevent current from flowing through a thermal fuse.

[0061] Figure 1 The electronic device 100 includes a thermal fuse 150 according to an existing configuration. The electronic device 100 includes a power supply 110, a load 120, and a thermal fuse 150. The electronic device 100 also includes input interfaces I1 and I2 and a second thermal fuse 155.

[0062] The power supply 110 is configured to receive an input signal S I+ Provide load driving signal S L The power supply 110 can also (as shown) be powered by a second input signal S I- Provide load driving signal S L The input signal and the second input signal may act together as a differential signal. It will be appreciated that, according to well-known principles, a power supply may receive more than two input signals and convert them into load driving signals.

[0063] The input signal (and optional second input signal) is provided at the input interfaces I1, I2 by an external power source (not shown), such as a mains power supply, a driver, or an electronic ballast, such as a ballast for lighting applications. Specifically, the input signal can be provided to the first interface node I1, and (if present) the second input signal can be provided to the second interface node I2. Although not shown, one or more additional input signals can be provided to corresponding one or more additional interface nodes.

[0064] The power supply 110 is configured to convert the input signal(s) S I+ 、S I- Converted into load driving signal S L Therefore, an alternative definition of the power supply 110 is a conversion circuit. The power supply 110 shown includes rectifying devices D1, D2, D3, D4 for rectifying (multiple) input signals (at the input interfaces I1, I2) to generate load driving signals.

[0065] The load 120 is configured to receive a load driving signal S L Suitable examples of the load include a light emitting diode (LED) device comprising one or more LEDs. Other suitable examples will be apparent to those skilled in the art.

[0066] The thermal fuse is electrically coupled between the power supply 110 and the input signal S I+ That is, between the input interfaces I1 and I2 and the power supply 110. Specifically, the thermal fuse 150 is electrically coupled between the first interface node I1 of the input interface and the first node 110A of the power supply.

[0067] Thermal fuse 150 is thermally coupled to a first portion of the electronic device. In response to the temperature at the first portion exceeding a first predetermined temperature threshold, thermal fuse 150 opens (i.e., trips or opens). Opening of the thermal fuse electrically disconnects the input signal from the power supply, i.e., electrically disconnects a portion of the input interface from the power supply.

[0068] Those skilled in the art will recognize that any of a plurality of parts of the electronic device can be used as the first part. For example, the first part can be a heated part (e.g., a part closest to an external power source or a part exposed to external thermal conditions). Other examples will be apparent to those skilled in the art.

[0069] Suitable examples of the first predetermined temperature threshold are 150°C or 125°C, although other temperatures will be apparent to those skilled in the art.For example, the first predetermined temperature threshold may be any temperature greater than 100°C.

[0070] If the input interface includes more than one interface node (e.g., a second interface node I2), a corresponding thermal fuse 150, 155 can connect each interface node to a power source, e.g., a node of the power source. For example, if the input interface includes a second interface node I2 as shown, the second thermal fuse 155 can connect the second interface node I2 to the second node 110B of the power source 110.

[0071] Each thermal fuse is thermally coupled to a specific portion of the electronic device. Each thermal fuse 150 will open (i.e., trip or trip) in response to the temperature of its specific portion exceeding a specific predetermined temperature threshold. The opening of the thermal fuse will electrically disconnect the corresponding input signal from the power supply, that is, electrically disconnect a portion of the input interface from the power supply.

[0072] Figure 2 An electronic device 200 comprising a thermal fuse 150 according to the proposed method is shown.

[0073] This electronic device differs from the aforementioned electronic devices in that it further includes a heat conversion component 260. The heat conversion component 260 is electrically coupled to a load and is also thermally coupled to a thermal fuse.

[0074] The heat conversion component 260 is configured to generate heat in response to changes in electrical characteristics of a load driving signal (across / through the load 120 ).

[0075] Specifically, the heat conversion component is configured to generate a temperature at the thermal fuse that opens the thermal fuse in response to the value of the electrical characteristic exceeding a predetermined electrical value. The opening of the thermal fuse 150 will input the signal S I+ Electrically disconnected from power source 110.

[0076] Various electrical characteristic options may be used in different embodiments, including current flowing through the load, voltage across the load, and / or power dissipated by the load.

[0077] A suitable example of a heat conversion component for detecting current flowing through a load is a resistive element electrically connected in series with the load. The power dissipated by the current flowing through the resistive element generates heat, the magnitude of which varies with / in response to changes in the current flowing through the load.

[0078] A suitable example of a heat conversion component for sensing the voltage across a load is a resistor across a resistive element electrically connected in parallel with the load. Due to the voltage across the load, the power dissipated by such a resistive element will generate heat, the magnitude of which will vary with / in response to changes in the voltage across the load.

[0079] Another suitable example of a heat conversion component for detecting a voltage across a load is a thermocouple. The thermocouple can be configured to generate voltage-dependent heat (eg, on a particular side or plate of the thermocouple) according to the Seebeck effect.

[0080] Another example of a heat conversion component for detecting voltage across a load is a Peltier device, which is capable of generating heat in response to voltage. A voltage applied across the Peltier device will generate a temperature difference between the two sides of the Peltier device, which can be used as a heat conversion component.

[0081] One suitable example of a heat conversion component for detecting the power dissipated by a load comprises a combination of a first resistive element connected in series with the load and a second resistive element connected in parallel with the load. This combines the two methods described above.

[0082] Other suitable examples will be apparent to those skilled in the art.

[0083] If used, the resistive element(s) may be formed of any suitable material that generates heat in response to current flowing through the resistive element and may be labeled as a heating element. Examples of suitable materials include metallic materials (such as nickel-chrome alloys; kanthal; or white copper) and ceramic / semiconductor materials (such as silicon carbide; silicon nitride). Those skilled in the art will appreciate that common, off-the-shelf resistors are also suitable for use in embodiments because the temperature of such resistors varies in response to the power dissipated by the resistor. Other examples will be apparent to those skilled in the art.

[0084] In one working example, as shown, the heat conversion component includes a resistive element connected in series with the load. The heat dissipated by the resistive element will respond to the current passing through the load (ie, the current amplitude of the load driving signal).

[0085] To explain, it is important to note that when a load is overloaded, the current through the load will increase. Therefore, this current can be converted to temperature using one or more resistive elements (e.g., resistors). It is important to note that the power P (in watts W) dissipated by the resistive element is I2R, which is:

[0086] P=I 2 R (1)

[0087] Where I is the current through the resistive element (measured in amps), and R is the resistance (measured in ohms). Therefore, if the current is twice as high as normal, the resistor will draw four times as much power as normal.

[0088] The temperature of a resistor is closely related to the power dissipated by the resistor. Therefore, when the current is twice the "normal" current, the temperature of the resistor is four times higher than normal. In this way, the heat conversion component can amplify the current.

[0089] By thermally coupling a heat conversion component to a thermal fuse, only one additional component (the heat conversion component) is required to electrically disconnect the electronic device from the external power source—because the thermal fuse can be reused as an electrical disconnect element in addition to its original purpose as a thermal disconnect element. By using the heat conversion component to enable the thermal fuse to perform dual duties, this approach can reduce or minimize the number of components required to electrically disconnect the electronic device from the external power source. Consequently, fewer components are required, and the space occupied by the electronic device can be reduced.

[0090] The thermal coupling of heat conversion component 260 to thermal fuse 150 has been previously explained. A person skilled in the art will appreciate various methods for thermally coupling heat conversion component 260 to the thermal fuse. For example, thermal glue or a thermal adhesive may be used to thermally couple the heat conversion component to the thermal fuse. As another example, the heat conversion component may be directly coupled to the thermal fuse via a thermally conductive element (e.g., metal).

[0091] Preferably, the thermal coupling of the heat conversion component is such that no more than 10%, for example, no more than 5%, or for example, no more than 1%, of the heat generated by the heat conversion component is lost through the thermal coupling to the thermal fuse. This can be achieved by using an appropriate amount of thermal glue / adhesive and / or the size of the thermally conductive element and by appropriately positioning the heat conversion component relative to the thermal fuse.

[0092] It has been previously explained how thermal fuse 150 opens (ie, trips or trips) in response to the temperature of the first portion exceeding a first predetermined temperature threshold.

[0093] The first portion may be, for example, a first interface node or a region containing the first interface node.Thus, the input interface and the thermal fuse may be thermally coupled such that a temperature at the input interface exceeding a first predetermined temperature threshold trips the thermal fuse.

[0094] Similarly, as previously explained, if the input interface includes more than one interface node (e.g., the second interface node I2), a corresponding thermal fuse 150, 155 can connect each interface node to a power source, e.g., a node of the power source. In this case, each thermal fuse is thermally coupled to a specific portion of the electronic device and will melt (i.e., trip or open) in response to the temperature of the specific portion exceeding a specific predetermined temperature threshold.

[0095] The specific portion of each thermal fuse may be an interface node associated with the thermal fuse, i.e., an interface node to which the thermal fuse is connected to a power source. Thus, each pair of input interface nodes and thermal fuses may be thermally coupled together such that a temperature exceeding a specific predetermined temperature threshold at each input interface node will cause the corresponding thermal fuse (i.e., the thermal fuse to which it is electrically connected) to be opened.

[0096] Figure 2 Also shown is an optional feature of the power supply, a bypass / shunt capacitor C1. The bypass / shunt capacitor bypasses a portion of the input signal from the load and provides the remaining portion of the input signal to the load as the load drive signal.

[0097] Figure 2 Another optional feature of the power supply is also shown, namely a smoothing capacitor C2 . The smoothing capacitor is configured to smooth the signal produced by the rectifying means D1 , D2 , D3 , D4 , thereby producing a DC-like voltage for the load 120 .

[0098] Preferably, the power supply 110 is configured to connect / convert an input signal (eg, an input interface) to / for a load without performing active power conversion. This provides an electronic device configured for use with an electronic ballast.

[0099] It should be understood that the first portion does not include a load and / or only includes components or parts whose temperature is not affected or is negligibly affected by the electrical characteristics of the load driving signal. In other words, changes in the electrical characteristics of the load driving signal may not be sufficient to cause a temperature rise or change in the first portion.

[0100] Figure 3 One embodiment of the electronic device 300 is shown, which is configured as a tubular LED lamp. For a tubular LED lamp, the load 120 includes one or more light emitting diodes (LEDs). Figure 4 A tubular LED lamp is shown inserted into a lamp holder 40 .

[0101] Tubular lamp 300 includes at least one end cap 310, 320. An input interface extends through the end cap for connection to an external power source. The end cap holds the input interface and is thermally coupled thereto. Thermal fuse 150 is positioned within the end cap and is thermally coupled thereto. The thermal fuse 150 is positioned such that when the temperature of the input interface exceeds a first temperature threshold, the end cap heats the thermal fuse, which in turn heats the thermal fuse, thereby opening the thermal fuse.

[0102] In this way, the end cap 310 acts as a thermal coupling mechanism for thermally coupling heat or thermal energy from the input interface to the thermal fuse.The end cap and thermal fuse may, for example, be thermally coupled together (eg, using thermal glue / adhesive).

[0103] The tubular lamp 300 may include a lamp body 390 that houses at least the load 120 and optionally the power supply 110. Alternatively, the power supply may be housed in an end cap or caps.

[0104] The input interface may include one or more pins 311, 312, 321, 322, i.e., at least one pin. Each pin may be configured to connect or contact an external power source to obtain (a plurality of) input signals therefrom. Figure 4 As shown, the pins 311 are configured to contact the socket 42 in the lamp holder 40. The socket provides a connection for the tubular lamp 300 to an external power source. It is understood by those skilled in the art that the contact between the pins and the fluorescent lamp holder / socket may be poor / insecure, for example, it may be loose. For example, due to poor contact with the external power source / socket 42, each pin may be easily heated by an arc between the pin and the external power source. The arc is caused by Figure 4 It will be appreciated that each pin may act as an interface node such that heating at the pin results in heating of the thermal fuse.

[0105] In this way, the first part of the electronic device may be the part comprising the one or more pins of the input interface, e.g. the one or more pins of the input interface.

[0106] As previously described, the power supply 110 can be configured to connect an input signal (e.g., an input interface) to a load / convert an input signal for the load without performing active power conversion. Thus, the conversion power circuit can connect at least one pin of the input interface to the load without performing active power conversion.

[0107] Most importantly, Figure 3 and Figure 4 Heat conversion component 260 is shown thermally coupled to thermal fuse 150 . Figure 3 and Figure 4 FIG. 2 shows that the heat conversion component 260 is electrically connected to the load 120 via a schematic wire. The specific connection method can be as follows: Figure 2As shown, the heat conversion component 260 converts the electrical characteristics of the load driving signal into heat. When the electrical characteristics are overloaded, the heat generated on the heat conversion component 260 is sufficient to heat the thermal fuse 150 and disconnect the thermal fuse 150.

[0108] Figure 3 Also conceptually shown are additional input interface nodes, and corresponding additional thermal fuses 350, 355. Each respective thermal fuse 150, 155, 350, 355 connects a respective interface node to the power supply 110. Each thermal fuse may be thermally coupled to a particular portion of the electronic device and will melt (i.e., trip or open) in response to the temperature of the particular portion thereof exceeding a particular predetermined temperature threshold.

[0109] Figure 4 Only one end of the tubular LED lamp is shown, which includes an end cap 310 and a portion of a lamp body 390 .

[0110] Figure 3 Also shown is another thermal conversion component 260' electrically coupled to the load 120 and thermally coupled to the additional thermal fuse 350. The other thermal conversion component 260' can be electrically connected in series with the load in the same manner as the thermal conversion component 260: that is, two resistors are connected in series with the LED 120. The thermal conversion component 260' can open the additional thermal fuse 350 in response to the electrical characteristic value of the LED current exceeding a predetermined electrical value, thereby electrically disconnecting the input signal from the power supply.

[0111] Various modifications to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0112] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0113] If the term "suitable for" is used in the claims or the specification, it should be noted that the term "suitable for" should be equivalent to the term "configured to". If the term "arranged" is used in the claims or the specification, it should be noted that the term "arranged" should be equivalent to the term "system", and vice versa.

[0114] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An electronic device (200, 300), comprising: The power supply (110) is configured to receive an input signal (S I+ ) provides load driving signal (S L ); The load driving signal (S L ) a load (120) powered by the power supply; and a first portion (I1, 311) different from the load and / or unassociated with a portion at the side of the load (120); A thermal fuse (150) is electrically coupled between the power supply (110) and the input signal (S I+ ) and is thermally coupled to the first portion (I1, 311), the thermal fuse (150) being configured to disconnect in response to the temperature at the first portion (I1, 311) exceeding a first temperature threshold, thereby I+ ) is electrically disconnected from the power source (110); The electronic device (200, 300) is characterized in that it also includes: A heat conversion component (260) is electrically coupled to the load (120) and thermally coupled to the thermal fuse (150), and is configured to respond to the load drive signal (S L ) exceeds a predetermined electrical value and generates a temperature at the thermal fuse (150) that disconnects the thermal fuse (150), thereby converting the input signal (S I+ ) is electrically disconnected from the power source (110).

2. The electronic device according to claim 1, wherein the first part (I1, 311) is adapted to be coupled to a device providing the input signal (S I+ ) is an external power source, the power source (110) is adapted to be connected to the first part (I1, 311) at the input end and to provide the load driving signal (S) at the output end L ),and The electrical characteristic is the current through the load (120).

3. The electronic device according to claim 2, wherein the heat conversion component (260) comprises a resistance element electrically connected in series with the load (120), the resistance element: configured to generate heat in response to the current flowing through the resistor and the load (120); and Thermally coupled to the thermal fuse (150) to provide the heat to the thermal fuse (150) so as to generate the temperature at the thermal fuse (150) that opens the thermal fuse (150).

4. The electronic device of claim 1, wherein the electrical characteristic is a voltage across the load (120).

5. The electronic device of claim 1, wherein the electrical characteristic is power consumed by the load (120).

6. The electronic device according to any one of claims 2 to 3, wherein the first part (I1, 311) comprises an input interface (I1, I2), the input interface being configured to receive the input signal from the external power source, wherein: The thermal fuse is electrically coupled between the power supply and the input interface; and The input interface and / or the first portion are thermally coupled to a thermal fuse such that a temperature at the input interface exceeding the first temperature threshold opens the thermal fuse, wherein the first portion is susceptible to being heated by or capable of heating the external power source.

7. The electronic device according to claim 6, wherein: The electronic device is a tubular LED lamp comprising an end cap (310, 320), the end cap retaining the first part (I1, 311) and being thermally connected to the input interface (I1, I2); The load (120) includes one or more LEDs; The input interface (I1, I2) extends through the end cover (310, 320) and is adapted to contact the external power source at a position outside the end cover (310, 320); and The thermal fuse (150) is placed inside the end cover (310, 320), so that the temperature of the input interface (I1, I2) exceeding the first temperature threshold heats the end cover (310, 320), and the end cover (310, 320) in turn heats the thermal fuse (150), thereby disconnecting the thermal fuse (150).

8. An electronic device according to claim 6 or 7, wherein the input interface (I1) comprises at least one pin, which is easily heated by an arc between the pin and the external power supply due to poor contact with the external power supply.

9. The electronic device according to claim 8, configured for use with an electronic ballast, wherein the power supply (110) connects the at least one pin of the input interface (I1) to the load (120) without performing active power conversion.

10. The electronic device according to claim 9, wherein the power supply (110) comprises a rectifying device (D1, D2, D3, D4) for rectifying the input signal (S I+ ) to generate the load driving signal (S L ).

11. The electronic device according to claim 10, wherein the power supply (110) further comprises a bypass / shunt capacitor (C1) to I+ ) is bypassed from the load (120) and the input signal (S I+ ) is provided to the load (120) as the load drive signal (S L ).

12. The electronic device according to any one of claims 6 to 11, wherein the input interface (I1, I2) comprises: A first interface node (I1) for connecting to a first node (110A) of the power source (110); as well as The second interface node (I2) is used to connect to a second node (110B) of the power source (110).

13. The electronic device of claim 12, wherein the thermal fuse (150) is coupled between the first interface node and the power source (110).

14. The electronic device according to claim 13, further comprising: a second thermal fuse (350) different from the thermal fuse (150), the second thermal fuse (350) being coupled between the second interface node (I2) and the power source (110), and Another heat conversion component (260') is electrically coupled to the load (120) and thermally coupled to the second thermal fuse (350), and is configured to respond to the load drive signal (S L ) exceeds the predetermined electrical value and generates a temperature at the second thermal fuse (350) that disconnects the second thermal fuse (350), thereby converting the input signal (S I+ ) is electrically disconnected from the power source (110).

15. The electronic device according to any one of claims 1 to 14, wherein the heat conversion component (260) is thermally coupled to the thermal fuse (150) using thermal glue or thermal adhesive.

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