Patent Description:
Fluorescent lamps in people's daily life are gradually replaced with much cleaner and much more efficient LED lamps.

The conventional fluorescent lamp is powered by a ballast. The ballast is generally disposed on a lamp base. During replacement with LED lamps, the LED lamps are required to be compatible with the original ballast, especially an inductance ballast, to minimize circuit changes.

<CIT> describes a safety circuit for LED lamps. The safety circuit is disposed on one end of the LED lamp for fusing when a current of a power supply loop is excessively large, to prevent the inductance ballast from overheating and causing danger. The safety circuit is configured to limit the current of the power supply loop and is set to a resistance of <NUM> ohm or more. According to Ohm's law, heat is generated when a current passes through a resistor. The heat is an unnecessary loss in non-heating electrical appliances, which reduces system efficiency and increase power consumption, especially in LED lighting appliances. The heat accelerates the attenuation of LED lamp beads and reduces the service life. Therefore, the heat loss is minimized during circuit designing. For example, the current of the power supply loop is <NUM> milliamperes (mA). If the resistance of the safety circuit is set to <NUM> ohms, a heat loss of the safety circuit is <NUM> W.

<CIT> discloses an LED lamp, the LED lamp includes a safety module. The safety module is composed of a first module (F1) and a second module (F2) to prevent overcurrent. When the LED lamp is powered by an electromagnetic ballast and at least one diode in an input rectifier fails, the second module (F2) is disconnected before the first module (F1). After the second module (F2) is disconnected, the LED lamp can still be used as a single-ended lamp tube, and is directly connected to the power supply for use. When the circuit failure in the system is not eliminated, the lamp tube may be burnt, or even other electrical appliances in the circuit system may be ruined in such a usage manner.

<CIT> discloses a self-adaptive LED fluorescent lamp in which the number of the LED lamps in serial connection is automatically changed by automatically detecting the output voltage of the rectifier, to reach the optimal driving efficiency, so as to ensure normal operating under any voltage. This invention provides a protection module comprises a short circuit protection module, an over-voltage protection module and an overheat protection module. The short circuit protection module and the over-voltage protection module are in order connected between the input signal module and the rectifier module, and the overheat protection module is implemented by the IC liner driving chips. However, as the IC-implemented overheat protection module is regulated after monitoring the current of the rectifier module, it may not be able to interrupt the overheating in time to avoid damage to the lamp.

This application is intended to provide a straight tube LED lamp to resolve the above problems.

The invention is defined by a straight tube light emitting diode lamp, as defined in claim <NUM>. This application provides a straight tube LED lamp. The straight tube LED lamp includes: a lamp tube, having a first lamp holder and a second lamp holder respectively located on two ends of the lamp tube, where a first pin and a second pin are disposed on the first lamp holder, and a third pin and a fourth pin are disposed on the second lamp holder; a power module, electrically connected to the first pin and the second pin to receive an external power signal by using the first pin and the second pin and perform power conversion to generate a driving signal; and an LED module, including at least one LED, disposed in the lamp tube, and electrically connected to the power module to receive the driving signal for lightening; and a first safety circuit, disposed between the third pin and the fourth pin to limit a current, where the first safety circuit is configured to be cut off to disconnect the power supply when a voltage across the safety circuit is greater than or equal to <NUM> V. The safety circuit is configured to be connected in series with the power module.

In an embodiment of this application, a resistance value of the first safety circuit is c less than <NUM> ohms.

In an embodiment of this application, the first safety circuit includes: a first current limiting assembly, electrically connected to the third pin and the fourth pin.

In an embodiment of this application, the first current limiting assembly includes a first current fuse. A first contact of the first current fuse is electrically connected to the first pin, and a second contact of the first current fuse is electrically connected to the fourth pin.

In an embodiment of this application, a fusing current of the first current fuse is <NUM> mA or more.

In an embodiment of this application, a fusing current of the first current fuse is <NUM> A or more.

In an embodiment of this application, the power module includes a second safety circuit and a rectifier circuit. The second safety circuit is coupled between the first pin and the second pin and the rectifier circuit to limit a current. A current threshold of the second safety circuit is less than a current threshold of the first safety circuit.

In an embodiment of this application, the second safety circuit includes a second current limiting assembly electrically connected between the first pin and the rectifier circuit.

In an embodiment of this application, the second safety circuit further includes a third current limiting assembly electrically connected between the second pin and the rectifier circuit.

In an embodiment of this application, the second current limiting assembly and the third current limiting assembly have a same current threshold.

In an embodiment of this application, the second current limiting assembly and the third current limiting assembly each have a different current threshold.

In an embodiment of this application, the second current limiting assembly includes a first resistance fuse, and the third current limiting assembly includes a second resistance fuse.

In an embodiment of this application, the power module includes a second safety circuit and a rectifier circuit; The first safety circuit includes a first current limiting assembly, and the second safety circuit includes a second current limiting assembly. The first current limiting assembly and the second current limiting assembly are of different types. The first safety circuit is configured to be connected in series with the second safety circuit when powered by using an inductance ballast.

In an embodiment of this application, the first current limiting assembly is one of a current fuse and a resistance fuse.

In an embodiment of this application, the second current limiting assembly is one of a current fuse and a resistance fuse.

In an embodiment of this application, the first current limiting assembly includes a first current fuse, and the second current limiting assembly includes a first resistance fuse. A current threshold of the first current fuse is greater than a current threshold of the first resistance fuse.

In an embodiment of this application, a resistance of the first current fuse is less than <NUM> ohms.

In an embodiment of this application, the first current fuse is configured to blow when a voltage across the first current fuse is greater than or equal to <NUM> V.

In an embodiment of this application, the current threshold of the first current fuse is <NUM> A.

In an embodiment of this application, the rectifier circuit includes at least two diodes, and the second safety circuit is configured to be cut off when the diodes of the rectifier circuit are short-circuited.

By means of the technical solutions disclosed in the above embodiments, the unnecessary power consumption of the straight tube LED lamp can be greatly reduced, and the efficiency of the LED lamp can be improved.

To make the foregoing objectives, features, and advantages of the technical solutions more comprehensible, specific embodiments of the technical solutions are described in detail below with reference to the accompanying drawings. The following descriptions of various embodiments of the technical solutions of this application are merely for illustration but are not examples, and do not indicate all embodiments of this application or indicate that this application is limited to specific embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the protection scope of the present disclosure, as defined by the appended claims.

It should be noted that, when a component is referred to as "being disposed on" another component, the component may be directly on the another component, or there may be an intermediate component. When a component is considered to be "connected to" another component, the component may be directly connected to the another component, or there may be an intermediate component. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are merely for purposes of illustration but not indicate a unique implementation.

Unless otherwise defined, meanings of all technical and scientific terms used in this specification are the same as those commonly understood by a person skilled in the art to which this application belongs. In this specification, terms used in the specification of this application are merely intended to describe objectives of the specific embodiments, but are not intended to limit this application. The term "and/or" used in this specification includes any or all combinations of one or more related listed items.

A single resistor in the circuit diagram may be equivalently replaced with a plurality of resistors connected in series or in parallel in an actual circuit. This application is not limited thereto. A capacitor may also be equivalently replaced with a plurality of capacitors connected in series or in parallel.

<FIG> is a schematic structural circuit diagram of a straight tube LED lamp according to an embodiment of this application. The straight tube LED lamp <NUM> includes a lamp tube <NUM>, lamp holders 11a and 11b disposed on two ends of the lamp tube <NUM>, a power module <NUM>, an LED module <NUM>, and a safety circuit <NUM>. A first pin <NUM> and a second pin <NUM> are disposed on the lamp holder 11a, and a third pin <NUM> and a fourth pin <NUM> are disposed on the lamp holder 11b. The first pin <NUM>, the second pin <NUM>, the third pin <NUM>, and the fourth pin <NUM> are metallic pins, and are connected to a lamp base to fix the lamp tube, and are electrically connected to electrical pins of the lamp base to receive an external power signal. The first pin <NUM> and the second pin <NUM> are further electrically connected to the power module <NUM>, and the third pin <NUM> and the fourth pin <NUM> are further electrically connected to the safety circuit <NUM>. The LED module <NUM> is electrically connected to the power module <NUM>. It should be noted that the safety circuit <NUM> is not electrically connected to the power module <NUM> or the LED module <NUM>.

In this embodiment, the straight tube LED lamp <NUM> has a lamp tube powered at a single end. When directly powered by a mains supply, the straight tube LED lamp can be normally lightened by receiving an external power signal merely by using the first pin <NUM> and the second pin <NUM>. The third pin <NUM> and the fourth pin <NUM> may be idle. The power module <NUM> receives the external power signal by using the first pin <NUM> and the second pin <NUM> and performs power conversion. The power module converts the external power signal to a driving signal for the LED module <NUM>, so as to lighten the LED module. The external power signal is a mains supply signal or power supply signals of other types. This application is not limited thereto. The external power supply is configured to provide the external power signal.

In some embodiments, when the straight tube LED lamp <NUM> is misused, for example, the lamp holder 11b of the straight tube LED lamp <NUM> receives the external power signal, the safety circuit <NUM> is cut off to disconnect the power supply, so as to prevent the system from overheating and causing danger. In this embodiment, the safety circuit <NUM> is configured to be cut off when voltages on the third pin <NUM> and the fourth pin <NUM> are equal to or greater than <NUM> V.

In order to ensure the circuit safety of conventional fluorescent lamps, a filament is tested by using a voltage of <NUM> V in accordance with the standard of the International Electrotechnical Commission (IEC), to ensure that a current of the filament is less than <NUM> A. According to Ohm's law, setting a resistance value of safety circuit <NUM> to be greater than or equal to <NUM>Ω can satisfy the safety standard of the IEC. However, a higher resistance of the safety circuit <NUM> leads to more unnecessary power consumption, resulting in a waste of energy.

In this embodiment, when a test voltage of <NUM> V is applied to the third pin <NUM> and the fourth pin <NUM>, that is, when the voltage applied to the safety circuit <NUM> is <NUM> V, the safety circuit <NUM> is cut off. In this case, a current between the third pin <NUM> and the fourth pin <NUM> is zero, that is, less than <NUM> A. Therefore, the safety requirements of the IEC can be satisfied.

In this embodiment, the safety circuit <NUM> includes a current fuse. The current fuse includes two contacts. A first contact is electrically connected to the third pin <NUM>, and a second contact is electrically connected to the fourth pin <NUM>.

A current of a common LED lamp is about <NUM> mA. In some embodiments, in order to protect the LED lamp more effectively, a threshold of the safety circuit <NUM> is set to <NUM> mA. When a current flowing through the safety circuit <NUM> is greater than or equal to <NUM> mA, the safety circuit <NUM> is cut off.

In some embodiments, in order to satisfy the safety standard of the IEC, the safety circuit <NUM> is configured to be cut off when the current flowing through the safety circuit is equal to or greater than <NUM> mA. In some embodiments, the resistance of the safety circuit <NUM> is configured to be less than <NUM> ohms.

<FIG> is a schematic structural circuit diagram of a straight tube LED lamp according to another embodiment of this application. In this embodiment, the configuration of the straight tube LED lamp <NUM> is the same as that described in the embodiment of <FIG>. Further, the power module <NUM> includes a safety circuit <NUM> and a rectifier circuit <NUM>. The safety circuit <NUM> is a current limiting assembly, and is coupled between the power supply pins (the first pin <NUM> and the second pin <NUM>) and the rectifier circuit, to limit a supply current from the external power signal to the rectifier circuit <NUM>. When the current flowing through the safety circuit <NUM> is greater than the set threshold, the safety circuit <NUM> is cut off, so that LED lamp <NUM> stops receiving the external power signal to ensure the circuit safety.

In this embodiment, the safety circuit <NUM> includes a resistance fuse. When a current flowing through the resistance fuse is greater than a set threshold, the resistance fuse blows. Different types of current limiting assemblies are used for the safety circuit <NUM> and the safety circuit <NUM>.

The rectifier circuit <NUM> is a half-bridge or full-bridge rectifier circuit. The rectifier circuit <NUM> includes at least two diodes. When the power module <NUM> fails, for example, when the diodes in the rectifier circuit <NUM> are short-circuited or disconnected, causing the current flowing through the safety circuit <NUM> to be greater than the set threshold, the safety circuit <NUM> is cut off to ensure the circuit safety.

<FIG> is a schematic structural circuit diagram of a power module <NUM> according to an embodiment of this application. In this embodiment, the power module <NUM> includes a safety circuit <NUM> and a rectifier circuit <NUM>. The safety circuit <NUM> includes a resistance fuse F1. The resistance fuse F1 is coupled between the first pin <NUM> and the rectifier circuit. The second pin <NUM> is electrically connected to the rectifier circuit. The external power signal is transmitted to the LED lamp through the first pin <NUM> and the second pin <NUM>. A current flowing through the resistance fuse F1 is the current of the external power signal. When the current is greater than a threshold set for the resistance fuse F1, the resistance fuse F1 blows, so that the LED lamp <NUM> stops receiving the external power signal (supply of the external power signal to the LED lamp <NUM> is stopped).

In other embodiments, the resistance fuse F1 may be replaced with a current fuse or other current limiting assemblies. This application is not limited thereto.

<FIG> is a schematic structural circuit diagram of a power module <NUM> according to another embodiment of this application. In this embodiment, the power module <NUM> includes a safety circuit <NUM> and a rectifier circuit <NUM>. The safety circuit <NUM> includes resistance fuses F1 and F2. The resistance fuse F1 is coupled between the first pin <NUM> and the rectifier circuit, and the resistance fuse F2 is coupled between the second pin <NUM> and the rectifier circuit. The external power signal is supplied to the LED lamp <NUM> through the first pin <NUM> and the second pin <NUM>. A current flowing through the resistance fuse F1 is equal to a current flowing through the resistance fuse F2. When the current flowing through the resistance fuse F1 is greater than a set threshold, the resistance fuse F1 blows. When the current flowing through the resistance fuse F2 is greater than the set threshold, the resistance fuse F2 blows. In this embodiment, the threshold of the resistance fuse F1 is the same as the threshold of the resistance fuse F2. By disposing two resistance fuses in a power supply loop of the LED lamp <NUM>, the circuit can be more reliable. When one of the resistance fuses fail to blow, the other resistance fuse can still protect the circuit.

The threshold of the resistance fuse F1 is the same as the threshold of the resistance fuse F2. Alternatively, the resistance fuses F1 and F2 may be replaced with current fuses or other current limiting assemblies. This application is not limited thereto.

<FIG> is a schematic structural circuit diagram of an LED lamp lighting system according to an embodiment of this application. In this embodiment, an LED lamp lighting system <NUM> further includes an inductance ballast <NUM> and a safety circuit <NUM>, in addition to the straight tube LED lamp <NUM>. The inductance ballast <NUM> is electrically connected to an external power signal input terminal L and the fourth pin <NUM>, and the second pin <NUM> is electrically connected to the third pin <NUM> by using the safety circuit <NUM>. The first pin <NUM> is electrically connected to an external power signal input terminal N.

During replacement of the conventional fluorescent lamp, power is directly supplied to the straight tube LED lamp <NUM> according to the connection method described in <FIG>, so as to minimize circuit changes. In this way, not only circuit changes are reduced, but also the straight tube LED lamp <NUM> can be normally powered either when the straight tube LED lamp is either positively or negatively connected to the lamp base.

In this embodiment, power is supplied from the external power signal to the straight tube LED lamp <NUM> through a power supply loop formed by the power signal input terminal L, the inductance ballast <NUM>, the safety circuit <NUM>, the safety circuit <NUM>, the power module <NUM>, and the power signal input terminal N. The inductance ballast <NUM>, the safety circuit <NUM>, the safety circuit <NUM>, and the power module <NUM> are connected in series.

In this embodiment, the safety circuit <NUM> includes a fuse for replacing an original starter. The fuse can not only connect the circuits, but also prevent the circuit of the power supply loop from exceeding a threshold current. A threshold current of the fuse is set to <NUM> Ma.

In this embodiment, the safety circuit <NUM> includes a current limiting assembly <NUM>. The current limiting assembly <NUM> may be a fuse or other electronic elements capable of current limitation. A fuse is used as an example for description in this application. The threshold of the fuse is set to <NUM> mA. When a current flowing through the fuse is greater than <NUM> mA, the fuse blows, that is, the safety circuit <NUM> is cut off, and the power supply loop is cut off, so as to prevent the current of the straight tube LED lamp <NUM> from exceeding the safety threshold and causing circuit damage or even fire.

It should be particularly noted that, since the current limiting assembly <NUM> in the safety circuit <NUM> is connected in series with the power supply loop, the current flowing through the straight tube LED lamp <NUM> is the same as the current flowing through the current limiting assembly <NUM>. For example, when the straight tube LED lamp <NUM> is normally lightened, the current in the power supply loop is <NUM> mA. If a resistance of the current limiting assembly <NUM> is relatively large, for example, is <NUM> ohms, according to Ohm's law, a power consumed for the current limiting assembly <NUM> is <NUM> W. The power is completely converted to heat. The current limiting assembly <NUM> consumes energy of <NUM> kW·h over a year. In addition, the heat generated by the current limiting assembly <NUM> increases an operating temperature of the straight tube LED lamp <NUM>, reducing the service life of the straight tube LED lamp <NUM>. If the resistance of the current limiting assembly <NUM> is set to <NUM> ohms or less, the power consumed for the current limiting assembly is greatly reduced. Therefore, the unnecessary power consumption is greatly reduced, and the straight tube LED lamp is more environmentally friendly and energy saving and has a longer service life.

In some embodiments, the current limiting assembly <NUM> is a fuse with a resistance value of <NUM> ohm or less.

<FIG> is a schematic structural circuit diagram of an LED lamp lighting system according to another embodiment of this application A circuit structure of the LED lamp lighting system in this embodiment is the same as the LED lamp lighting system shown in <FIG>. Further, the power module <NUM> in this embodiment includes a safety circuit <NUM> and a rectifier circuit <NUM>. The safety circuit <NUM> is a current limiting assembly, and is coupled between the power supply pins (the first pin <NUM> and the second pin <NUM>) and the rectifier circuit, to limit a supply current of the external power signal. When a current flowing through the safety circuit <NUM> is greater than a set threshold, the safety circuit <NUM> is cut off, so that the external power signal cannot be supplied to the rectifier circuit <NUM>, that is, the supply to the power module is stopped. The current limiting assembly included in the safety circuit <NUM> may be a current fuse or a resistance fuse. This application is not limited thereto.

When the straight tube LED lamp fails, for example, the power module <NUM> fails or the rectifier circuit <NUM> in the power module <NUM> fails, the current in the power supply loop surges. If the power supply loop is not cut off in time, circuit devices may generate heat and be damaged, or even lead to a fire, resulting in an accident.

In some embodiments, in order to prevent the current increase of the power supply loop caused by an LED lamp failure or the like, an operation threshold of the safety circuit <NUM> is set to be less than those of the safety circuit <NUM> and the safety circuit <NUM>. That is, when the circuit fails, the third safety circuit is first cut off. In this way, when the circuit failure originates from the outside of the straight tube LED lamp <NUM>, the operation of the third current limiting assembly can prevent an abnormal current of the loop from damaging the straight tube LED lamp <NUM>. After the circuit failure is eliminated, the third safety circuit is replaced, so that the straight tube LED lamp <NUM> can still be normally used.

In some usage scenarios, the safety circuit <NUM> is bypassed. In this case, the first safety circuit or the second safety circuit operates when the circuit fails. When the second safety circuit operates first, if the circuit failure originates from the outside of the straight tube LED lamp, a user may modify the circuit to directly connect the first pin <NUM> and the second pin <NUM> to the mains supply, so that the straight tube LED lamp <NUM> can still be normally used. If the circuit failure originates from the straight tube LED lamp <NUM>, for example, the rectifier circuit in the power module <NUM> fails, if the user still modifies the circuit (directly connecting the first pin <NUM> and the second pin <NUM> to the mains supply) to use the straight tube LED lamp, the circuit failure in the straight tube LED lamp causes the first current limiting assembly to operate or the mains line to be abnormal.

In this embodiment, the threshold of the safety circuit <NUM> is set to be less than that of the safety circuit <NUM>. Therefore, when the current of the power supply loop surges as a result of a circuit failure, the safety circuit <NUM> operates before the safety circuit <NUM> to cut off the power supply loop of the power module. In this case, even if the user modifies the circuit to directly connect the first pin <NUM> and the second pin <NUM> to the mains supply (referring to <FIG>), the LED lamp still cannot be lightened normally. In this case, the safety circuit <NUM> is cut. By means of the configuration, the circuit safety and the user safety can be guaranteed more effectively.

Similar to the above embodiment, in order to satisfy the safety standard of the IEC, the current limiting assembly included in the safety circuit <NUM> is a current fuse, and the current limiting assembly used in the safety circuit <NUM> is a resistance fuse. The costs of the current fuse are higher than that of the resistance fuse. In order to reduce the maintenance costs, the threshold of the safety circuit <NUM> is set to be lower than that of the safety circuit <NUM>. That is, when the power module <NUM> fails and the current of the power supply loop exceeds a rated current, the safety circuit <NUM> is cut off before the safety circuit <NUM>. In this way, only the resistance fuse in the safety circuit <NUM> needs to be replaced during repair. In this embodiment, the current threshold of the safety circuit <NUM> is set to <NUM> A. When a current flowing through the safety circuit <NUM> is greater than or equal to <NUM> A, the safety circuit <NUM> is cut off.

The fuse in the above embodiment may be a current fuse or a resistance fuse. This application is not limited thereto.

Claim 1:
A straight tube light emitting diode, LED, lamp (<NUM>), comprising:
a lamp tube (<NUM>), having a first lamp holder (11a) and a second lamp holder (11b) respectively located on two ends of the lamp tube, wherein a first pin (<NUM>) and a second pin (<NUM>) are disposed on the first lamp holder, and a third pin (<NUM>) and a fourth pin (<NUM>) are disposed on the second lamp holder;
a power module (<NUM>), electrically connected to the first pin (<NUM>) and the second pin (<NUM>), wherein the power module (<NUM>) is configured to receive an external power signal via the first pin (<NUM>) and the second pin (<NUM>) and configured to perform power conversion to generate a driving signal; and
an LED module (<NUM>), comprising at least one LED, disposed in the lamp tube, and electrically connected to the power module (<NUM>) to receive the driving signal for lightening; and
a first safety circuit (<NUM>), disposed between the third pin (<NUM>) and the fourth pin (<NUM>) to limit a current,
characterized in that:
when the first safety circuit (<NUM>) receives the external power signal, the first safety circuit (<NUM>) is configured to be cut off to disconnect the external power signal when a voltage across the first safety circuit (<NUM>) is greater than or equal to <NUM> V, wherein
the first safety circuit (<NUM>) is configured to be connected in series with the power module (<NUM>),
wherein a resistance value of the first safety circuit (<NUM>) is less than <NUM> ohms.