CN217302549U - Light emitting device and light emitting system - Google Patents

Abstract

The application relates to a lighting device, and provides a light-emitting device and a light-emitting system, wherein the light-emitting device is connected in series with other light-emitting devices into a string by arranging a buffer element for buffering input power to stabilize the light-emitting device, and the light-emitting device is arranged at a position where the distance between the string and a driver is not less than one half of the total length, so that the phenomenon of flicker can not occur on the whole string of light-emitting devices even if a light source far away from the driver. Meanwhile, the process of controlling the buffer element to be charged by the input power is also set, so that the input power can not fluctuate violently when the light-emitting device is started, and the impact on a driver is avoided.

Description

Light emitting device and light emitting system

Technical Field

The application belongs to the technical field of lighting equipment, and particularly relates to a light-emitting device and a light-emitting system.

Background

In a typical smart light strip, the three basic components that make up the entire product are a power module, a radio frequency control board, and a light strip or light bar, where multiple light bars are connected in series to form a string that is connected to the power/radio frequency control board to obtain input power, some light bars being closer to the power source and some being farther away. In the pixel strip, a pixel chip is placed on the strip, so that the LED (light emitting diode) string of each pixel can be conveniently controlled. For pixel light strips, there are some common features: 1. the pixel chip is internally provided with a switch for controlling the on and off of the LED, but due to the consideration of better electromagnetic compatibility or other reasons, the switch switching among different pixels is not synchronous. 2. Since the flexible circuit board used in the light strip is very thin and has limited space, a bus capacitor cannot be installed per pixel or per several pixels, and on the other hand, the bus capacitor has a relatively high height and can shield light output, the bus capacitor is not installed in the light strip, but is installed in the driver/radio frequency control board. 3. The intelligent lamp strip can usually be prolonged by a relatively long length, and the length of a lamp strip popular in the market is 2 m-10 m. The intelligent lamp area is because above-mentioned three characteristics, the switch switching between the pixel chip is asynchronous to because flexible circuit board buffering filtering is not enough, some random voltage ripples will appear in the busbar voltage, therefore anomalous ripple electric current also can appear in the LED electric current, based on only having a bus capacitor on the radio frequency control panel, so far away from the radio frequency control panel, the scintillation phenomenon just more obvious, this leads to little, the terminal scintillation phenomenon in lamp area.

SUMMERY OF THE UTILITY MODEL

An object of the present application is to provide a light emitting apparatus and a light emitting system, aiming at solving the problem that the dim light phenomenon is more obvious for a light source farther from the input side on a lamp strip. Further, in solving this problem, the present application also avoids interfering with the normal output of the power module/rf control board.

The basic idea of the utility model is that, buffering the stable buffering component of input power in keeping away from the setting of lamp area power input side for input voltage is stable, and then the ripple can not appear in the electric current, consequently, the scintillation can not appear even keeping away from the light source of input side on the lamp area yet. And simultaneously, the utility model discloses still provide the process that the controlling means charges in order to control this buffer element and receive input power, can be so that this buffer element can not be to making input power acutely undulant to avoid causing the impact to power module radio frequency control panel.

A first aspect of embodiments of the present application provides a lighting device, including a power supply bus and at least two lighting units powered by the power supply bus, the lighting device having an extended length along which the at least two lighting units are arranged, wherein the lighting device is configured to be connected end-to-end in sequence with other lighting devices having the power supply bus into a string, a first of the string of lighting devices is connected to a driver, and each power supply bus is electrically connected in series to the driver to access input power for the respective lighting device and transfer the input power to the next lighting device as if;

the light emitting apparatus further comprises:

a buffer element connected to the power supply bus for buffering the input power at the connection position to stabilize the input power; and

a control device coupled to the buffer element for controlling the process of charging the buffer element with the input power when the light emitting device is started;

and the light emitting device is adapted to be placed in the string at a distance from the driver of not less than half of the total length of the string.

The light-emitting device is provided with the buffer element for buffering the input power to enable the light-emitting device to be stable, so that the light-emitting device and other light-emitting devices are connected in series to form a string, the light-emitting device is arranged at the position where the distance between the string and the driver is not less than half of the total length, and the phenomenon of flicker can not occur even if a light source far away from the driver is arranged on the whole string of light-emitting devices. Meanwhile, the process of controlling the buffer element to be charged by the input power is also set, so that the buffer element can not cause severe fluctuation of the input power, and the impact on a driver is avoided.

In an alternative embodiment, the light emitting device is adapted to be placed in said string at a distance from said driver of not less than two thirds of the total length of said string. This solution provides a more reliable implementation, allowing the light source to be located far from the driver without flickering.

In an alternative embodiment, the light emitting device is adapted to be placed at the position of the last in the string.

In an alternative embodiment, the control device is configured to:

increasing the equivalent reactance of the buffer element to the driver to reduce its charging by the input power to reduce the current output by the driver when the light emitting device is activated; and

after the light emitting device is started, restoring the equivalent reactance of the buffer element to the driver to normally buffer the input power.

The control device can enable the buffer element to limit surge current on the power supply bus when the light-emitting equipment is started, so that the light-emitting equipment can be normally started; and the control device can also enable the buffer element to be connected into the circuit after the light-emitting device is started, and the buffer element is used for buffering power ripples generated at the tail end of the light-emitting device during normal operation, so that the flickering phenomenon during normal operation is overcome.

In an alternative embodiment, the control means comprise a controllable switch connected to the supply bus in series with the damping element.

The embodiment of the implementation control device is provided, the controllable switch is used for controlling the buffer element to be disconnected with the power supply bus to increase the equivalent reactance of the buffer element to the driver so as to buffer surge current during starting, and the controllable switch is used for controlling the buffer element to be connected to the power supply bus to restore the equivalent reactance of the buffer element to the driver so as to overcome the flicker phenomenon during normal operation.

In an alternative embodiment, the controllable switch is biased open when the light emitting device is not powered by the input power, the control device further comprising a delay circuit connected to a control terminal of the controllable switch for starting timing when the light emitting device is activated by the input power and keeping the bias of the controllable switch (M1) open, and closing the controllable switch in a linear mode or a saturated conduction mode after a delay.

The delay circuit is set to properly and adjustably delay and control the conduction of the buffer element so as to prevent surge current during startup and trigger the overcurrent protection of the driver.

In an optional embodiment, the delay circuit includes a first resistor and a first capacitor sequentially connected in series between the power supply bus and a common potential, the control end of the controllable switch is connected to a connection node of the first resistor and the first capacitor, and the first resistor and the first capacitor are configured to charge the first capacitor to a voltage that closes the controllable switch after the certain delay of power supply to the power supply bus.

In this embodiment, the delay circuit is formed by combining the resistor and the capacitor, so that the time length of a certain delay can be adjusted by adjusting the parameters of the resistor and the capacitor.

In an alternative embodiment, the delay circuit further comprises a zener diode having its cathode connected to the first resistor and its anode connected to the first capacitor and to the control terminal of the controllable switch, the zener diode being adapted to conduct to charge the first capacitor to a voltage that closes the controllable switch when the voltage of the supply bus exceeds its breakdown voltage.

In this embodiment, the delay circuit further includes a zener diode configured to trigger the operation of the delay circuit, so that the buffering element is not started when the voltage of the power supply bus does not reach the operating voltage, thereby avoiding the situation of bus voltage under-voltage that the buffering element is triggered by mistake and the power supply bus is accessed in advance, and avoiding the problem that surge current occurs after the voltage of the power supply bus rises again.

In an optional embodiment, the control device further includes a discharge element, the discharge element is connected between the power supply bus and the first capacitor to form a discharge loop, and the discharge element is configured to discharge the first capacitor through the discharge loop after the power supply bus is powered down, so that the controllable switch is biased to be opened. Thus, the problem that surge current is caused because the control device keeps being switched on when the light-emitting equipment is restarted is avoided.

In an alternative embodiment, the buffer element comprises a second capacitor connected in series with the control device to the supply bus, the second capacitor having a capacitance above 47 μ F. Specifically, the second capacitor is connected in series between the power supply bus and the control device, and the other end of the control device is grounded. And the capacitance value is only used as an example, and does not represent that the capacitance value of the second capacitor must be set above the value in the implementation process of the scheme.

In an alternative embodiment, the damping element and the control device are not detachable in the light emitting apparatus; or said buffer element and said control means may be assembled in said light emitting device. Thus, the design for addressing the flicker phenomenon may be fixed in the lighting device to be produced and sold together, or may be produced and sold separately as a detachable accessory.

In an alternative embodiment, the lighting device is a LED strip or light bar.

A second aspect of embodiments of the present application provides a light emitting system, including:

a driver for outputting the input power and having an overcurrent protection function of an output current;

the above-described light-emitting device; and

other light emitting devices having a power bus;

the light emitting device is used for being connected with the other light emitting devices in a string, a first light emitting device in the string is connected to a driver, each power supply bus is connected to the driver in series, so that input power is connected to the light emitting device and is transmitted to the power supply bus of the next light emitting device, and the control device of the light emitting device controls the process that the buffer element is charged by the input power so as to prevent the driver from triggering the overcurrent protection function when the buffer element is charged.

The light-emitting system comprises a plurality of light-emitting devices, the light-emitting devices are sequentially connected with other light-emitting devices through power supply buses to form a lamp strip or a lamp strip, and the light-emitting devices are arranged at positions, close to the rear half part, of the lamp strip or the lamp strip, so that the rear half part of the whole lamp strip or the lamp strip is provided with a buffer element and a control device, the buffer element can buffer input power to enable the input power to be stable, and the phenomenon of flickering can not occur even if a light source far away from a driver is arranged on the whole string of light-emitting devices; and the charging process of the buffer element is controlled by the control device, so that the output of the driver is prevented from forming surge current on the power supply bus, and the overcurrent protection function of the driver is triggered.

In an alternative embodiment, the driver comprises:

a switching power supply; and

and the radio frequency control circuit is used for receiving a radio frequency control signal, is connected with the at least two light-emitting units of each light-emitting device, and is used for controlling the at least two light-emitting units to emit light according to the radio frequency control signal.

In this embodiment, the driver includes a switching power supply and a radio frequency control, and a user can control each light-emitting unit to emit light according to a preset rule by providing a radio frequency control signal to the radio frequency control circuit.

The above-mentioned and non-mentioned advantages of the present application will be described in the detailed description section or will be understood by those of ordinary skill in the art with reference to the following drawings.

Drawings

Fig. 1 is a schematic structural diagram of a light emitting system having a light emitting device according to an embodiment of the present disclosure.

Fig. 2 is a circuit diagram of a lighting system with a lighting device according to an embodiment of the present disclosure.

Fig. 3 is a circuit diagram of a lighting system with a lighting device according to a second embodiment of the present application.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more, and "several" means one or more unless specifically limited otherwise. The terms "portion" and "another portion" are used merely to describe that two features are different and not meant to be limiting in other respects.

Referring to fig. 1 to 3, an embodiment of the present application provides a light emitting device 20, where the light emitting device 20 is an LED strip or an LED light bar. The lighting device 20 comprises a power bus Vbus and at least two lighting units 22 powered by the power bus Vbus, the lighting units 22 for example comprising LED lamp beads, the lighting device 20 (power bus Vbus) having an extended length, the at least two lighting units 22 being arranged along the extended length, the at least two lighting units 22 generally being separate and coupled to the power bus Vbus. The light emitting unit 22 is also referred to as a pixel. The light emitting unit 22 includes light emitting diodes of three colors of red, green and blue as indicated by reference numeral x 3R/G/B, and three MOSFETs as indicated by reference numeral R/G/Bx3 for respectively controlling the brightness of the three light emitting diodes in a PWM manner, wherein one light emitting diode is connected in series with the corresponding MOSFET. The lighting unit 22 further comprises a warm white led indicated by reference FW and a MOSFET connected in series therewith for PWM control of the warm white led, and a cold white led indicated by reference CW and a MOSFET connected in series therewith for PWM control of the cold white led. All the series-connected light-emitting diodes and the MOSFETs are connected in parallel on the supply bus Vbus. A driving circuit 221 is connected to each MOSFET of the light emitting cell 22, and can control each MOSFET independently. In addition, a resistor is connected in series with each light emitting diode and determines how much current is supplied to the light emitting diode from the bus voltage when the MOSFET is turned on. In fig. 2, only one light emitting unit 22 is shown in the light emitting device 20 for simplicity.

The lighting device 20 is arranged to be connected end-to-end in turn with other lighting devices 30 having a supply bus Vbus to form a complete string of lighting devices 200. It is to be noted that, in order to facilitate the distinction between the light emitting device 20 and the other light emitting devices 30, the light emitting device 20 is hereinafter referred to as a first light emitting device 20, and the other light emitting devices 30 are hereinafter referred to as second light emitting devices 30. And will be expressed by "light-emitting device 20/30" when the light-emitting device 20 is not distinguished from the other light-emitting devices 30.

The first of the entire string of luminaires 200 (luminaire 20/30) is connected to the driver 10, and each supply bus Vbus is electrically connected in series to the driver 10 to access input power for the respective luminaire 20/30 and pass the input power to the next luminaire 20/30 as is. In fig. 2, a second light emitting device 30 is directly connected to the driver 10, and the supply bus of the second light emitting device 30 taps input power to the second light emitting device 30 and delivers the input power to the first light emitting device 20.

Taking fig. 1 as an example, there are many more second light emitting devices 30 between the second light emitting device 30 and the first light emitting device 20, and then the first light emitting device 20 is further away from the driver 10. Also, although not shown, a second light emitting device 30 may also be present after the first light emitting device 20 (i.e. further away from the driver 10). The input power of the first light emitting device 20 (and subsequently the second light emitting device 30) further from the driver 10 may not be sufficiently buffered, the bus voltage may be low or unstable, and thus the current of the light emitting unit 22 on the light emitting device 20/30 may be unstable (see the above description, the current is determined by the series resistance and is related to the bus voltage, so the voltage instability may cause the current instability), and thus the light emitting unit 22 may flicker. In order to solve the problem, the light emitting device of the present application buffers the input power of the first light emitting device 20 and the light emitting unit 22 thereof, which are far from the driving box, specifically, a buffer element 40 is disposed at the first light emitting device 20, and the buffer element 40 is connected to the power supply bus Vbus and is used for buffering the input power, particularly the voltage, at the connection position to stabilize the input power, and avoid the light emitting unit 22 from flickering. Generally, the first light emitting device 20 of the present application is adapted to be placed in the entire string of light emitting devices 200 at a distance from the driver 10 not less than half of the total length of the entire string of light emitting devices 200. The buffer element 40 of the first light emitting device 20 may also provide a voltage stabilizing function for the bus voltage of the front (i.e. closer to the driver 10) and rear (i.e. further from the driver 10) second light emitting devices 30 in its vicinity, in particular the second light emitting devices 30 behind it, avoiding the light emitting units 22 of these second light emitting devices 30 to flicker. In an alternative embodiment, the first light emitting device 20 is adapted to be placed in the entire string of light emitting devices 200 at a distance from the driver 10 of not less than two thirds of the total length of the entire string of light emitting devices 200. A further embodiment is provided so that the light source remote from the driver 10 is not subject to flicker. Such as the first light emitting device 20, is intended to be placed in a position which may be the last one of the entire string of light emitting devices 200.

It is noted that at start-up (including a first start-up and a second start-up after a period of shut-down), since the buffer element 40 is not charged, additional power needs to be provided to charge it, which may cause severe fluctuations (increases) in the input power of the first light emitting device 20, which may affect the proper operation of the driver 10. Therefore, the present application proposes that a control device 50 is coupled to the buffer element 40 for controlling the charging process of the buffer element 40 by the input power when the first light emitting device 20 is started (i.e. the whole string of light emitting devices 200 is started). In an alternative embodiment, the control device 50 is configured to increase the equivalent reactance of the buffering element 40 to the driver 10 to reduce the charging thereof by the input power when the first light-emitting device 20 is started, so as to control (e.g. reduce) the current output by the driver 10, limit the peak value of the current, and avoid the occurrence of an inrush current which may cause the driver 10 to start up unstably and even enter into an overcurrent protection; the control device 50 is further configured to restore the equivalent reactance of the buffer element 40 to the driver 10 after the start-up of the first light emitting device 20 to make it buffer the input power normally, and to buffer the power ripple generated at the end of the first light emitting device 20 during normal operation, thereby overcoming the flicker phenomenon during normal operation.

The control device 50 comprises a controllable switch M1 connected in series with the damping element 40 to the supply bus Vbus. The controllable switch M1 is, for example, a MOS transistor, and the snubber element 40 comprises a capacitor C0 connected in series with the control device 50 to the supply bus Vbus. In an alternative embodiment, the capacitor C0 is connected in series between the supply bus Vbus and the MOS transistor, the other end of which is connected to the common potential Return. As a preferred example, the capacitance value of the capacitor C0 is above 47 μ F, which does not mean that the capacitance value of the capacitor C0 must be set above this value in the implementation of the present solution. The loop of the capacitor C0 connected to the power supply bus Vbus is disconnected through the MOS transistor, so that the surge current caused by the connection of the capacitor C0 when the whole string of light-emitting equipment 200 is started is avoided, and therefore the equivalent reactance of the driver 10 is increased by disconnecting the loop of the capacitor C0 connected to the power supply bus Vbus, so that the surge current during the starting is buffered, and the overcurrent protection on the driver 10 is triggered; in addition, after the whole string of light emitting devices 200 is started, the capacitor C0 is connected to the power supply bus Vbus through the MOS transistor, and the equivalent reactance of the capacitor C0 to the driver 10 is restored, so that the capacitor C0 can buffer the bus voltage to overcome the flicker phenomenon during normal operation. In addition, the controllable switch M1 may also be other switching devices, such as a transistor, etc.

In an alternative embodiment, the controllable switch M1 is biased open when the first light emitting device 20 is not powered by the input power, and the control device 50 further comprises a delay circuit 52 connected to the control terminal of the controllable switch M1, wherein the delay circuit 52 is configured to start timing when the first light emitting device 20 is powered by the input power, keep the bias of the controllable switch M1 open, and close the controllable switch M1 in the linear mode or the saturated conduction mode after a certain delay. The delay circuit 52 is arranged to control the switching on of the control device 50 with an appropriate and adjustable delay to switch the buffer element 40 to the supply bus Vbus, which corresponds to a start-up procedure of the entire string of light emitting devices 200, during which the switch-on of the capacitor C0 is switched off to prevent inrush currents during start-up of the entire string of light emitting devices 200.

In an alternative embodiment, the delay circuit 52 includes a first resistor R1 and a first capacitor C1 connected in series between the power bus Vbus and the common potential Return, a control terminal (e.g., a gate of a MOS transistor) of the controllable switch M1 is connected to a connection node of the first resistor R1 and the first capacitor C1, and the first resistor R1 and the first capacitor C1 are configured to charge the first capacitor C1 to a voltage that closes the controllable switch M1 after a certain delay of power-up of the power bus Vbus. In this embodiment, the delay circuit 52 is formed by a combination of the resistor R1 and the capacitor C1, and the duration of a certain delay can be adjusted by adjusting parameters of the resistor R1 and the capacitor C1.

In an alternative embodiment, the delay circuit 52 further comprises a zener diode D1, the cathode of the zener diode D1 is connected to the first resistor R1, the anode is connected to the first capacitor C1 and the control terminal of the controllable switch M1, the zener diode D1 is used to conduct to charge the first capacitor C1 when the voltage of the supply bus Vbus exceeds its breakdown voltage, so as to reach the voltage at which the controllable switch M1 is closed. Zener diode D1 is used for triggering delay circuit 52, so can set up when the voltage of power supply bus Vbus does not reach first light emitting device 20 operating voltage, does not start buffer element 40 to avoid under the circumstances of bus voltage under-voltage the mistake trigger buffer element 40 and insert power supply bus Vbus in advance, and then avoid after the voltage of power supply bus Vbus risees again, can meet surge current's problem. As some examples, the breakdown voltage of the zener diode D1 is 18V to 21V or more, and accordingly, the rated voltage of the first capacitor C1 may be 5V to 6V, and the capacitance value may be about 2.2 μ F.

In an alternative embodiment, the control device 50 further includes a discharging element D2, the discharging element D2 is connected between the power bus Vbus and the first capacitor C1 to form a discharging loop, and the discharging element D2 is configured to discharge the first capacitor C1 through the discharging loop after the power failure of the power bus Vbus, so that the controllable switch M1 is biased to be opened. In this way, the problem of inrush current caused by the control device 50 remaining on when the first light emitting device 20 is restarted is avoided. The discharge element D2 is, for example, a schottky diode having an anode connected to the first capacitor C1 and to the control terminal of the controllable switch M1 and a cathode connected to the supply bus Vbus. The discharge can be performed via the supply bus (Vbus) which has been powered down and the common potential Return by the discharge element D2.

Specifically, for the discharging process, it is generally considered that, when the power supply is turned off, the charge on the first capacitor C1 is transmitted to the power supply bus Vbus through the discharging element D2, and can be consumed by the light emitting unit 22 (see the discharging path 11 shown in fig. 3) and the driver 10 (see the discharging path 12 shown in fig. 3) which are turned on to the power supply bus Vbus;

in addition, the application also specifically arranges a discharge circuit on the power supply bus Vbus to rapidly discharge (see a discharge path 13 shown in fig. 3), the discharge circuit is a main discharge path, and can perform a discharge process according to the bus voltage, for example, when the power supply bus Vbus is lower than a certain voltage (for example, 10V, 12V), the discharge process is conducted to discharge, wherein the bus voltage discharges in a constant current manner between the certain voltage and 5V, and the bus voltage lower than 5V will not need constant current discharge.

In an alternative embodiment, the control device 50 further includes a current limiting resistor R2, the current limiting resistor R2 is connected in series to the control terminal of the controllable switch M1, and is used for limiting the driving current to protect the controllable switch M1.

Alternatively, the buffer member 40 and the control device 50 are not detachable in the first light emitting apparatus 20, and thus, a design capable of solving the flicker phenomenon may be fixed in the first light emitting apparatus 20 to be produced and sold together to reduce the production cost. In another way, the buffer element 40 and the control device 50 in the first light emitting device 20 may be separate from the rest of the first light emitting device 20 and assembled together by the end user, e.g. the buffer element 40 and the control device 50 may be produced, sold separately from the rest of the first light emitting device 20, or sold in the form of one or more second light emitting devices 30 provided with a set of buffer elements 40 and control devices 50, for improved convenience, compatibility. The cushioning element 40 and the control device 50 are assembled by the user onto one second light emitting device 30 to form the complete first light emitting device 20, which first light emitting device 20 is attached by the user in the middle, rear section or final position of the string of light strips.

A second aspect of embodiments of the present application provides a lighting system comprising a driver 10, a first lighting device 20 as disclosed herein above, and a second lighting device 30 having a supply bus Vbus.

The driver 10 is used for outputting input power, and has an overcurrent protection function of output current, and when the output current exceeds a threshold value, the driver 10 will close the output; the first light emitting device 20 is adapted to be connected with the second light emitting device 30 in a string of light emitting devices 200, a first light emitting device 20/30 in the string of light emitting devices 200 is connected to the driver 10, and each supply bus Vbus is connected in series to the driver 10 for receiving input power for the light emitting device and transferring the input power to the supply bus Vbus of the next like light emitting device. It will be appreciated that the supply bus Vbus of the last light emitting device 20/30 in the entire string of light emitting devices 200 does not pass power to the (non-existent) next light emitting device 20/30. Wherein the control device 50 below the light emitting device 20 controls the process of the buffer element 40 being charged by the input power to avoid that the driver 10 triggers the overcurrent protection function when charging the buffer element 40.

The first light emitting device 20 and the second light emitting device 30 included in the light emitting system provided by the application are sequentially connected through the power supply bus Vbus to form a lamp strip or a lamp bar.

The first light-emitting device 20 is arranged at a position close to the rear half part of the lamp strip or the lamp strip, so that the whole rear half part of the lamp strip or the lamp strip is provided with the buffer element 40 and the control device 50, the buffer element 40 can buffer the input power to stabilize the input power, and the flicker phenomenon can not occur on the whole string of light-emitting devices 200 even if the light-emitting units 22 far away from the driver 10; and the charging process of the buffer element 40 is controlled by the control device 50 so as to avoid the output of the driver 10 forming an inrush current on the supply bus Vbus and triggering the overcurrent protection function of the driver 10.

The driver 10 comprises a switching power supply 101 and a radio frequency control circuit 102, the switching power supply 101 for example being used to supply input power to the supply bus Vbus; the rf control circuit 102 receives an externally input rf control signal, and is connected to the light-emitting units 22 of the light-emitting devices 20/30 through data lines DIN for controlling the light-emitting units 22 to emit light according to the rf control signal.

Each light-emitting unit 22 includes a driving circuit 221 and a plurality of light-emitting lamp beads, where the plurality of light-emitting lamp beads include red R, green G, and blue B LED lamp beads, and a warm white lamp bead FW and a cool white lamp bead CW, each light-emitting lamp bead is connected in series between the power supply bus Vbus and the common potential Return through a switch (e.g., an MOS transistor), and the driving circuit 221 receives a radio frequency control signal to control on/off of each switch to control on/off of each light-emitting lamp bead in a PWM mode. Illustratively, the driving circuit 221 is a data logic PWM driver.

Further, the driver 10 further includes a current detection module 103 and an output current detection component Rsen, wherein the output current detection component Rsen (e.g. a sampling resistor) is connected between the common potential Return and the ground GND, the current detection module 103 is connected to the common potential Return and the rf control circuit 102, the current detection module 103 is configured to detect a current (corresponding to an output current of the detection driver 10) on the common potential Return of the light emitting device 20/30, and the rf control circuit 102 controls whether the light emitting unit 22 operates according to the magnitude of the current, for example, when the current exceeds an overcurrent, the light emitting unit 22 is turned off to avoid the light emitting device 20/30 from being damaged. The current detection module 103 may include an analog-to-digital converter, and the radio frequency control circuit 102 may be implemented by a single chip.

Further, the driver 10 further includes a voltage detection section connected between the power supply bus Vbus and the radio frequency control circuit 102 for detecting a bus voltage; and

a voltage converter part and a low dropout regulator LDO which are connected in series between the power supply bus Vbus and the radio frequency control circuit 102 and are used for supplying power to the radio frequency control circuit 102; and

a PMOS transistor for driving the power supply bus Vbus to turn off/output the input power, which can be used as a master switch of the entire string of light emitting devices 200, and is turned off when the entire string of light emitting devices 200 is in standby, and can also emergency-cut off the power supply to the light emitting device 20/30 in case of overcurrent (described below);

a gate driving section connected in series between the power supply bus Vbus and the radio frequency control circuit 102, for driving a PMOS transistor that turns off/outputs input power to the power supply bus Vbus; and

an overcurrent detecting part connected between the gate driving part and the output current detecting part Rsen for controlling the gate driving part to drive the PMOS tube to be disconnected when the output current is overcurrent; and

a crystal oscillator connected with the radio frequency control circuit 102 for providing a clock, a Flash for storing data and a radio frequency matching circuit of a coupling antenna.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (14)

1. A light emitting device (20) comprising a supply bus (Vbus) and at least two light emitting units (22) powered by said supply bus (Vbus), said light emitting device (20) having an extended length along which said at least two light emitting units (22) are arranged, wherein said light emitting device (20) is adapted to be connected end-to-end in series with other light emitting devices (30) having a supply bus (Vbus) in sequence, a first one of the light emitting devices of the series being connected to a driver (10), and each supply bus (Vbus) being electrically connected in series to said driver (10) for receiving input power for the respective light emitting device and transferring this input power to the next light emitting device as present;

characterized in that the light emitting device (20) further comprises:

a buffer element (40) connected to the supply bus (Vbus) for buffering the input power at the connection position to stabilize the input power; and

-control means (50) coupled to said buffer element (40) for controlling the charging of said buffer element (40) by said input power upon activation of said light emitting device (20);

and the light emitting device (20) is adapted to be placed in the string at a distance from the driver (10) of not less than half of the total length of the string.

2. A light emitting device according to claim 1, characterized in that the light emitting device (20) is adapted to be placed in the string at a distance from the driver (10) of not less than two thirds of the total length of the string.

3. A light emitting device according to claim 2, characterized in that the light emitting device (20) is adapted to be placed at the position of the last in the string.

4. A light emitting device according to claim 3, characterized in that the control means (50) are adapted to:

-increasing the equivalent reactance of the buffer element (40) to the driver (10) to reduce its charging by the input power to reduce the current output by the driver (10) upon start-up of the light emitting device; and

after the light emitting device is started, restoring the equivalent reactance of the buffering element (40) to the driver (10) so that it normally buffers the input power.

5. Light emitting device according to any one of claims 1 to 4, characterized in that the control means (50) comprise a controllable switch (M1) connected to the supply bus (Vbus) in series with the buffer element (40).

6. A light emitting device according to claim 5, characterized in that the controllable switch (M1) is biased open when the light emitting device is not powered by the input power,

the control device (50) further comprises a delay circuit (52) connected to a control terminal of the controllable switch (M1) for starting timing and keeping the bias of the controllable switch (M1) open when the lighting device is activated by the input power, and for closing the controllable switch (M1) in a linear mode or a saturated conduction mode after a certain delay.

7. Light emitting device according to claim 6, characterized in that the delay circuit (52) comprises a first resistor (R1) and a first capacitor (C1) connected in series in sequence between the supply bus (Vbus) and a common potential, the control terminal of the controllable switch (M1) being connected to the connection node of the first resistor (R1) and the first capacitor (C1), the first resistor (R1) and the first capacitor (C1) being configured to charge the first capacitor (C1) up to a voltage that closes the controllable switch (M1) after the certain delay of powering up the supply bus (Vbus).

8. A light device as claimed in claim 7, characterized in that the delay circuit (52) further comprises a Zener diode (D1), the cathode of the Zener diode (D1) being connected to the first resistor (R1), the anode being connected to the first capacitor (C1) and to the control terminal of the controllable switch (M1), the Zener diode (D1) being adapted to conduct to charge the first capacitor (C1) to a voltage at which the controllable switch (M1) closes, when the voltage of the supply bus (Vbus) exceeds its breakdown voltage.

9. Light emitting device according to claim 7, characterized in that the control means (50) further comprises a discharge element (D2), the discharge element (D2) being connected between the supply bus (Vbus) and a first capacitance (C1) to form a discharge loop, the discharge element (D2) being configured to discharge the first capacitance (C1) through the discharge loop after a power failure of the supply bus such that the controllable switch (M1) is biased open.

10. A light emitting device according to any one of claims 1 to 4, characterized in that the buffer element (40) comprises a second capacitance (C0) connected to the supply bus (Vbus) in series with the control means (50), the second capacitance (C0) having a capacitance value above 47 μ F.

11. A light emitting device according to any one of claims 1 to 4, characterized in that the damping element (40) and the control means (50) are not detachable in the light emitting device (20); or

The buffer element (40) and the control device (50) are assemblable in the light emitting apparatus (20).

12. The lighting device according to any one of claims 1 to 4, wherein the lighting device is a LED strip or a light bar.

13. A lighting system, comprising:

a driver (10) for outputting the input power and having an overcurrent protection function of an output current;

a light emitting device (20) according to any one of claims 1 to 12; and

other light emitting devices (30) having a supply bus;

the lighting device (20) is configured to be connected in series with the other lighting devices (30), a first one of the lighting devices in the series is connected to a driver (10), and each supply bus (Vbus) is connected in series to the driver (10) to receive input power for the lighting device and to transfer the input power to the supply bus (Vbus) of the next lighting device as such, the control device (50) of the lighting device (20) controls the process of charging the buffer element (40) with the input power to prevent the driver (10) from triggering the overcurrent protection function when charging the buffer element (40).

14. A lighting system according to claim 13, characterized in that the driver (10) comprises:

a switching power supply (101); and

and the radio frequency control circuit (102) is used for receiving a radio frequency control signal, is connected with the at least two light-emitting units (22) of each light-emitting device, and is used for controlling each at least two light-emitting units (22) to emit light according to the radio frequency control signal.

Images