阅读说明：本技术 用于替换荧光灯的led灯装置 (LED lamp device for replacing fluorescent lamp ) 是由 S·罗伊 G·N·纳哈 于 2018-03-13 设计创作，主要内容包括：一种适于由磁性镇流器或电子镇流器供电的用于替换荧光灯的LED灯装置(1)。LED灯装置具有整流电路(4、5)和LED电路(8),LED电路(8)具有可在至少第一电路配置和第二电路配置之间切换的多个LED组(9、10、11、12、13)。LED灯装置还具有辅助电路(31),该辅助电路限定了在第二电路配置中与多个LED组并联连接的导电路径。LED灯装置(1)被配置成当LED灯装置1接收到一系列脉冲串时旁通所述LED组并在导电路径中对电容器(39)充电,并且在一系列脉冲串间的时间间隔期间使电容器(39)进行放电。(An LED lamp arrangement (1) for replacing a fluorescent lamp, adapted to be powered by a magnetic ballast or an electronic ballast. The LED lamp arrangement has a rectifier circuit (4, 5) and an LED circuit (8), the LED circuit (8) having a plurality of LED groups (9, 10, 11, 12, 13) which are switchable between at least a first circuit configuration and a second circuit configuration. The LED lamp arrangement further has an auxiliary circuit (31) defining an electrically conductive path connected in parallel with the plurality of LED groups in the second circuit configuration. The LED lamp device (1) is configured to bypass the LED group and charge a capacitor (39) in the conductive path when the LED lamp device 1 receives a series of bursts, and to discharge the capacitor (39) during a time interval between the series of bursts.)

1. An LED lamp arrangement (1) for replacing a fluorescent lamp adapted to be powered by a ballast, the ballast being a magnetic ballast operating at a first frequency or an electronic ballast operating at a second frequency higher than the first frequency, the electronic ballast having an operating mode in which the electronic ballast generates and outputs a series of pulse trains to the LED lamp arrangement (1), the LED lamp arrangement comprising:

-a rectifying circuit (4, 5) rectifying current drawn from the ballast to produce a rectified current,

-an LED circuit (8) connected to receive the rectified current, the LED circuit (3) comprising a plurality of LED groups (9, 10, 11, 12, 13) switchable between at least a first circuit configuration and a second circuit configuration, wherein the first circuit configuration comprises a larger number of series-connected LED groups than the second circuit configuration;

-an auxiliary circuit (31) defining, in the second circuit configuration, a conductive path connected in parallel with the plurality of LED groups,

Wherein the auxiliary circuit (31) comprises a capacitor (39) in the conductive path, wherein the LED lamp device (1) is configured to: bypassing the LED group and charging the capacitor (39) when the LED lamp device (1) receives a series of bursts from the electronic ballast, and discharging the capacitor (39) during a time interval between the series of bursts.

2. The LED lamp device (1) according to claim 1, wherein the capacitor (39) has a capacitance in the range of 10-50 μ F.

3. The LED lamp device (1) according to claim 1 or 2, wherein the time interval between the series of pulse trains is in the range of 1 to 300 milliseconds.

4. The LED lamp device (1) according to any of the preceding claims, wherein the time interval between the series of pulse trains is substantially constant.

5. The LED lamp device (1) according to any of the preceding claims, wherein the conductive path does not comprise an inductor connected in series with the capacitor.

6. The LED lamp device (1) according to any of the preceding claims, wherein the auxiliary circuit (31) further comprises a control circuit (36) for controlling the operation of the LED lamp device (1).

7. the LED lamp device (1) according to claim 6, wherein a first end of the capacitor (39) is electrically connected to a voltage supply terminal of the control circuit (36) and a second end of the capacitor (39) is connected to a common terminal.

Technical Field

The present invention relates to an LED lamp arrangement (e.g., a retrofit LED lamp) for replacing a fluorescent lamp, adapted to be powered by a ballast, which may be a magnetic ballast or may be an electronic ballast.

background

Fluorescent lamps have existed for many years. This form of illumination was originally a highly efficient alternative to incandescent light bulbs, but fluorescent lamps have recently been replaced by LED illumination in terms of efficiency and power consumption, as well as other aspects listed below.

Fluorescent lamps typically comprise a tube filled with an inert gas and a small amount of mercury, the tube being closed at both ends by double-pin end caps. The end cap contains a glow wire for preheating the gas within the tube and vaporizing the mercury to assist in the ignition of the fluorescent lamp. After a user turns on a main switch (e.g., a wall switch or a cord switch on a ceiling), the fluorescent lamp is ignited, and the heat generated by the conduction current keeps the fluorescent lamp in operation. To facilitate these starting conditions and to limit the current through the fluorescent lamp during operation, and thus the power consumed, a ballast is connected between the mains supply and the fluorescent lamp and supplies power to the lamp via the ballast.

At first introduction, the only ballast available is a simple inductive or reactive element placed in series with the fluorescent lamp power supply, which limits power consumption by limiting alternating current due to the frequency dependent impedance of the inductor. The undesirable result is a relatively low power factor and a relatively high reactive power. These types of ballasts are commonly referred to as magnetic ballasts.

More recently, other types of ballasts, such as electronic ballasts, have been introduced. These ballasts typically first convert ac mains power to dc power and then convert the dc power to high frequency ac power to drive the fluorescent lamps.

LED lamps are more efficient than fluorescent lamps. In addition, they have many other advantages. For example, LED lamps do not require mercury, LED lamps are more directional, LEDs require less effort to control or regulate power consumption, and have a longer life than fluorescent lamps. Therefore, it is generally desirable to replace fluorescent lamps with LED lamps in existing lighting devices.

U.S. patent No.9,441,795, incorporated herein by reference, discloses a retrofit LED lamp that uses an LED circuit connected between the outputs of a rectifying circuit. The LED circuit includes a LED string. When the ballast is a magnetic ballast, the LED circuits are switched in a configuration where the LED strings are connected in series. When the ballast is an electronic ballast, the LED circuits are switched in a configuration where the LED strings are connected in parallel. The type of ballast is detected by sensing the frequency of the alternating current supplied to the ballast. A lower frequency indicates that the ballast is a magnetic ballast and a higher frequency indicates that the ballast is an electronic ballast.

On some commercially available electronic ballasts, the output voltage of the retrofit lamp ballast peaks in a pulse pattern within a few seconds after the lamp is turned off, causing the lamp to produce visible light flicker. These light flashes are annoying to the user.

Disclosure of Invention

It is an object of the invention to avoid light flicker after the LED lamp arrangement is switched off.

A first aspect of the invention relates to a LED lamp device according to claim 1.

The LED lamp arrangement adapted to be powered by a ballast may be adapted to replace a fluorescent lamp, e.g. an LED lamp arrangement with such a ballast may be adapted to replace a fluorescent lamp in a lighting arrangement.

The ballast may be a magnetic ballast operating at a first frequency or an electronic ballast operating at a second frequency higher than the first frequency.

The usual operating frequency (first frequency) of the magnetic ballast may be, for example, 50Hz, while the usual operating frequency (second frequency) of the electronic ballast may be, for example, 40 kHz.

The LED lamp device according to the present invention may also be adapted to replace a fluorescent lamp when the electronic ballast has an operation mode in which the electronic ballast generates a series of pulse trains and outputs the series of pulse trains to the LED lamp device. The mode of operation may relate to operation after the lamp has been switched off. The lighting device may be controlled by a main switch (e.g., a switch on a wall). The mode of operation of the electronic ballast may be a shutdown operation in less than 10 seconds after the main switch is closed (e.g., by a user).

In this way, a user can freely install the LED lamp device to the lighting device to replace the fluorescent lamp without having to worry about whether the ballast is a magnetic ballast or an electronic ballast, and in the latter case whether the electronic ballast has a (shut-down) mode of operation that produces a series of pulse trains.

In one embodiment, an LED lamp apparatus includes: a rectifying circuit rectifying a current drawn from the ballast to generate a rectified current; and an LED circuit connected to receive the rectified current.

The LED circuit may comprise a plurality of LED groups switchable between at least a first circuit configuration and a second circuit configuration. The first circuit configuration may comprise a larger number of groups of LEDs connected in series than the second circuit configuration. Different circuit configurations may have different circuit arrangements of LED groups, wherein at least a part of the LED groups are connected in different ways into the circuit. For example, the plurality of circuit configurations may differ in the number of LED groups connected in series compared to the number of LED groups connected in parallel. This allows the LED circuit to change its circuit configuration to suit the corresponding ballast. For example, the LED lamp arrangement may be configured to switch to a first circuit configuration when the ballast is a magnetic ballast and to switch to a second circuit configuration when the ballast is an electronic ballast.

The LED lamp device may comprise an auxiliary circuit defining an electrically conductive path connected in parallel with the plurality of LED groups in the second circuit configuration. This may be accomplished by connecting a wire (e.g., a wire, a metal layer, etc.) across at least one LED group and other components (e.g., capacitors) along the wire. In this way, when this LED group is connected in parallel with the other LED groups in the second circuit configuration, the conductive path will also be connected in parallel with the other LED groups.

In one embodiment, the auxiliary circuit includes a capacitor in the conductive path, wherein the LED lamp device is configured to bypass the LED group and charge the capacitor when the LED lamp device receives a series of bursts of pulses from the electronic ballast and discharge the capacitor during a time interval between the series of bursts of pulses.

When the pulse train arrives, current is conducted mainly through the parallel conducting path and not through the LED during this time, since the LED is bypassed and the capacitor is charged. Thus, the LED emits no light or little light, making it barely visible to the user. Since the capacitor has been sufficiently discharged (not necessarily 100% discharged) in the time interval between the bursts, the conductive path will be able to perform the above-mentioned function again when the next burst arrives. In this way, the problem of flashing can be avoided.

The capacitance of the capacitor should be high enough to avoid quickly reaching a maximum state of charge upon receipt of the burst signal and low enough to be sufficiently discharged during the time interval. In a preferred embodiment, the capacitor has a capacitance in the range of 10 μ F-50 μ F.

a series of pulse trains may represent a voltage source. The voltage during the time interval between the series of bursts may be less than 1 VRMS.

The time interval between a series of bursts may be in the range of 1 millisecond to 300 milliseconds.

The time interval between a series of bursts may be substantially constant.

To bypass the LEDs during the LEDs, the conductive path (connected in parallel with the LED group) should have a lower impedance than the LEDs. At the operating frequency of the electronic ballast (e.g., 40kHz), the inductor has a high impedance because its impedance is proportional to the signal frequency. Therefore, the conductive path via the capacitor (with low impedance at the operating frequency of the electronic ballast) should have low inductance, and preferably no inductance. In a preferred embodiment, the conductive path does not include an inductive element (e.g., an inductor) connected in series with the capacitor.

In one embodiment, the auxiliary circuit further comprises a control circuit for controlling the operation of the LED lamp device. A first end of the capacitor may be electrically connected to a voltage supply terminal (e.g., Vcc terminal) of the control circuit, and a second end of the capacitor may be connected to a common terminal (e.g., to a return connection line of the rectifier circuit). In this way, the capacitor can function not only to cope with the pulse train but also to stabilize the voltage supplied to the control circuit of the LED lamp device.

Drawings

These and other aspects of the invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings.

Fig. 1 shows an embodiment of an LED lamp device according to the invention.

Fig. 2 shows the shutdown behavior of the output voltage of some commercially available electronic ballasts.

Detailed Description

Fig. 1 shows an embodiment of an LED lamp device 1 according to the invention. The LED lamp device 1 is configured to replace a fluorescent lamp such as a fluorescent tube.

The LED lamp device 1 may comprise an LED circuit 8, the LED circuit 8 comprising a plurality of LED groups 9, 10, 11, 12, 13 emitting light when current flows through the LEDs. In the embodiment shown, the LED circuit 8 comprises five groups of LEDs 9, 10, 11, 12, 13 via connecting diodes. The number of groups may be a number other than five, for example the LED lamp device 1 may comprise two, three or another number of LED groups, as described in WO 2016/151125 a9, which is incorporated herein by reference. Each LED group may comprise a plurality of LEDs connected in series or parallel or a combination of both, and may also have one or more comprising a single LED group. In one embodiment, the LED string comprises a plurality (e.g., 10-20) of LEDs connected in series.

The LED lamp device 1 may comprise a rectifying circuit 4, 5. The rectifier circuit may comprise a plurality of components. In the illustrated embodiment, the rectifying circuit includes two bridge rectifiers. Other types of rectifiers may also be used. The rectifying circuits 4, 5 may be electrically connected to a first connection line 6 and a second connection line 7 connected to a common terminal. The current drawn from the ballast, received via the pin pairs 2-2 'and 3-3' of the LED lamp device 1, is rectified by the rectifying circuit 4, 5 and the rectified current is supplied to the LED circuit 8 via the first connection line 6 and the second connection line 7.

As described in US 9,441,795, the connections between the LED groups 9, 10, 11, 12, 13 can be switched in a plurality of circuit configurations including a first circuit configuration and a second configuration by controlling the switches 26 and 27. In the illustrated embodiment, the first circuit configuration corresponds to a state in which both switches 26 and 27 are open. In such a circuit configuration, the LED groups 9, 10, 11, 12, 13 may be connected in series between the first connection line 6 and the second connection line 7. In the second circuit configuration, both switches 26 and 27 may be closed. In such a circuit configuration, the LED groups 9, 10, 11, 12, 13 may be connected in parallel between the first connection line 6 and the second connection line 7.

In the embodiment shown, when the LED groups 9, 10, 11, 12, 13 are connected in series (e.g. in a first circuit configuration), the voltage across the LED circuit 8 is represented by the sum of the forward voltages of a larger number of LED groups. When the LED groups are connected in parallel (e.g. in the second circuit configuration), the voltage across the LED circuit 8 is represented by the forward voltage of a smaller number of LED groups, e.g. about 1/5 which is the voltage in the first circuit configuration. A lower voltage is suitable when the LED lamp arrangement 1 is energized by an electronic ballast, whereas a higher voltage is suitable when the LED lamp arrangement is energized by a magnetic ballast.

The switches 26 and 27 may be controlled by a signal indicating whether the ballast is a magnetic ballast or an electronic ballast so that the LED circuit 8 is switched to the appropriate circuit configuration (e.g., the first circuit configuration or the second circuit configuration as described above). The signals controlling the switches 26 and 27 are described in US 9,441,795.

The LED lamp device 1 may further comprise an auxiliary circuit 31. The auxiliary circuit may comprise a conductive path connected in parallel with the at least one LED group 13. In the embodiment shown, the conductive path comprises a capacitor 39.

Fig. 2 shows a typical shutdown behavior of a burst occurring in an electronic ballast. During time interval t0-ti, the LED lamp device 1 is in its normal operation and receives current from the electronic ballast at a frequency of approximately 40 kHz. Within a few seconds after the lamp is turned off at time t1, the ballast generates a series of pulse train voltages and provides these pulse train voltages to the LED lamp assembly. The burst voltage may have a frequency (e.g., substantially 40k) that is the operating frequency of the ballast, and the interval between the burst voltages may be several milliseconds to several hundred milliseconds.

In the embodiment shown in fig. 1, the auxiliary circuit 31 is arranged to discharge the capacitor 39 during the time interval between t1 and the first burst voltage and during the time interval between the burst voltages. When the burst voltage is present, particularly during the peak 41 of each burst, the fully discharged capacitor 39 conducts current and bypasses the LEDs. In this way, since the LEDs do not conduct current or hardly conduct any current, those LEDs do not emit light or emit only a small amount of light that is hardly visible to the user, and therefore flashing caused by the pulse train can be avoided.

In the embodiment shown, the capacitance of capacitor 39 is high enough to sink the burst current and low enough to be discharged sufficiently during the relevant time interval so that it can sink the current from the next burst. Preferably, capacitor 39 has a capacitance in the range of 10 μ F-50 μ F.

Reference is again made to fig. 1. Optionally, the auxiliary circuit 31 may further comprise a control circuit 36 for controlling at least a part of the operation of the LED lamp device 1. In the embodiment shown, the auxiliary circuit 31 comprises a control circuit 36, which may be an integrated circuit, for controlling one or both of the switches 26, 27. In the embodiment shown, the voltage supply terminal of the control circuit 36 is connected to a capacitor 39. In this way, since the capacitor 39 is connected in parallel with the at least one LED group 13, the forward voltage of the LEDs can be used as a voltage source. In this embodiment, the capacitor 39 also functions to stabilize the voltage supplied to the control circuit 36.

Alternatively, the LED lamp device 1 may comprise an elongated cylindrical housing to form a lamp tube. The connector pin pairs 2-2 'and 3-3' may be arranged at both ends of an elongated cylindrical housing to connect the LED lamp device 1 to a ballast.

Optionally, the LED lamp device 1 may further comprise an inductive element 28 and a switch 29 connected across the inductive element 28 for controlling the current when a particular type of electronic ballast is detected. Such electronic ballasts are known as constant power ballasts. The operation of the inductive element 28 and the switch 29 and the detection of a constant power ballast is described in detail in WO 2016/151125. For example, the LED lamp apparatus 1 may be configured to detect whether the current drawn from the ballast exceeds a reference value, and if so, open the switch 29. This results in a current flow through the LED circuit 8 and the inductive element 28, which has a high impedance at the operating frequency of the electronic ballast, thereby limiting the current. The current drawn from the ballast may be estimated using a sensor circuit. The sensor circuit may include a resistor 30 as shown in fig. 1. Since the voltage across the resistor is substantially proportional to the current, the current drawn from the ballast can be estimated by measuring the voltage across the resistor 30.

While the principles of the invention have been set forth above in connection with specific embodiments, it is to be understood that this description is made only by way of example and not as a limitation on the scope of protection which is defined by the appended claims.