EP3777487A1

EP3777487A1 - Method and device of detecting status of lamp, lamp driver

Info

Publication number: EP3777487A1
Application number: EP18918921.0A
Authority: EP
Inventors: Xinhai Li; Yaofeng LIN; Shuanghong Wang
Original assignee: Tridonic GmbH and Co KG
Current assignee: Tridonic GmbH and Co KG
Priority date: 2018-05-15
Filing date: 2018-05-15
Publication date: 2021-02-17
Also published as: WO2019218129A1; EP3777487A4; CN112189380A; CN112189380B

Abstract

A method and device of detecting the status of a lamp, and a lamp driver are provided. The status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp (101). Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.

Description

METHOD AND DEVICE OF DETECTING STATUS OF LAMP, LAMP DRIVER

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of electrical apparatus, and more particularly, to a method and device of detecting a status of a lamp, and a lamp driver.

BACKGROUND

This section introduces aspects that may facilitate better understanding of the present disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
Nowadays, lamp drivers are widely used. When a lamp driver drives a lamp, a status of the lamp should be detected in some cases. For example, according to DALI (Digital Addressable Lighting Interface) standard, an answer to the query actual level command is needed.
Normally, film capacitors or electrolytic capacitors may be used at an output side of the lamp driver. The charge time of the film capacitors is short, and the charge time of the electrolytic capacitors is long. However, low ripple current may be achieved when the electrolytic capacitors are used.
SUMMARY
Inventors of this disclosure found that when the electrolytic capacitors are used at the output side of the lamp driver, the charge time of the electrolytic capacitors is long. Then the status of the lamp may be uncertain. For example, the answer to the query actual level command may be incorrect.
In general, embodiments of the present disclosure provide a method and device of detecting a status of a lamp, and a lamp driver. In the embodiments, the status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp. Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.
In a first aspect, there is provided a method of detecting a status of a lamp, including: determining the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
In an embodiment, determining the status of the lamp according to comparative results between the degrees of output voltages of the driver and thresholds corresponding to output currents of the driver.
In an embodiment, determining the status of the lamp as outputting light when the degree of the output voltages is less than the threshold corresponding to the output current of the driver.
In an embodiment, determining the status of the lamp as outputting light when the degree of the output voltages is less than a first threshold and the output current of the driver is greater than or equal to a predetermined current, and/or determining the status of the lamp as outputting light when the degree of the output voltages is less than a second threshold and the output current of the driver is less than the predetermined current.
In an embodiment, the first threshold is greater than the second threshold.
In an embodiment, the method further includes: determining the status of the lamp as starting up in a first period after the driver is started up.
In an embodiment, the method further includes: calculating slopes of a curve of the output voltages as the degrees of variations of the output voltage.
In an embodiment, the output voltages are averaged in each second period.
In a second aspect, there is provided a device of detecting a status of a lamp, including: a first determining unit configured to determine the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
In an embodiment, the first determining unit determines the status of the lamp according to comparative results between the degrees of output voltages of the driver and thresholds corresponding to output currents of the driver.
In an embodiment, the first determining unit determines the status of the lamp as outputting light when the degree of the output voltages is less than the threshold corresponding to the output current of the driver.
In an embodiment, the first determining unit determines the status of the lamp as outputting light when the degree of the output voltages is less than a first threshold and the output current of the driver is greater than or equal to a predetermined current, and/or determines the status of the lamp as outputting light when the degree of the output voltages is less than a second threshold and the output current of the driver is less than the predetermined current.
In an embodiment, the first threshold is greater than the second threshold.
In an embodiment, the device further includes: a second determining unit configured to determine the status of the lamp as starting up in a first period after the driver is started up.
In an embodiment, the device further includes: a calculating unit configured to calculate slopes of a curve of the output voltages as the degrees of variations of the output voltages.
In an embodiment, the output voltages are averaged in each second period.
In a third aspect, there is provided a lamp driver, including: the device according to the second aspect.
According to various embodiments of the present disclosure, the status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp. Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and benefits of various embodiments of the disclosure will become more fully apparent, by way of example, from the following detailed description with reference to the accompanying drawings, in which like reference numerals or letters are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and not necessarily drawn to scale, in which:
Fig. 1 is a flowchart of a method of detecting a status of a lamp with an embodiment of the present disclosure;
Fig. 2 is another flowchart of a method of detecting a status of a lamp with an embodiment of the present disclosure;
Fig. 3 is a diagram of a device of detecting a status of a lamp with an embodiment of the present disclosure;
Fig. 4 is a schematic diagram of a lamp driver with an embodiment of the present disclosure;
FIG. 5 is a block diagram of a systematic structure of a lamp driver with an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure will now be discussed with reference to several example embodiments. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the present disclosure.
As used herein, the terms “first” and “second” refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises, ” “comprising, ” “has, ” “having, ” “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” Other definitions, explicit and implicit, may be included below.
First embodiment
A method of detecting a status of a lamp is provided in a first embodiment.
Fig. 1 is a flowchart of a method of detecting a status of a lamp with an embodiment of the present disclosure. As shown in Fig. 1, the method includes:
Step 101: determining the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
In an embodiment, the lamp may be any type of lamps. Such as a LED lamp.
In an embodiment, the driver may be any type of lamp drivers. And the driver may include a converter configured to provide constant current.
For example, the converter may be a switched converter clocked at high frequency, such as a resonant half-bridge converter. Alternatively, the converter may be an isolated converter, such as a flyback converter. Furthermore, the converter may be a non-isolated converter, such as a boost converter, buck converter or buck-boost converter.
In the step 101, the status of the lamp is determined according to degrees of variations of output voltages of a driver of the lamp.
In an embodiment, the status of the lamp may include various states, such as, “starting up” , “outputting light” . Furthermore, when the status of the lamp is “outputting light” , the brightness level may be reported directly.
For example, when a query actual level command is received, an answer to the query actual level command may be a value between 0～255, which represents an actual level of brightness.
In an embodiment, the degrees of variations of output voltages may be measured by various parameters.
For example, the degrees of variations of output voltages may be measured by slopes of a curve of the output voltages.
In an embodiment, the status of the lamp may be determined according to comparative results between the degrees of output voltages of the driver and thresholds corresponding to output currents of the driver.
For example, the status of the lamp may be determined as outputting light when the degree of the output voltages is less than the threshold corresponding to the output current of the driver.
In an embodiment, the thresholds may be set corresponding to output currents of the driver. In other words, when the output currents are different, the thresholds used to be compared with output voltages may be different.
For example, when the driver is started up and electrolytic capacitors are used at output side of the driver, the output currents may be large and the output voltages may rise quickly due to charging of the electrolytic capacitors. Thus the threshold used in this period may be a relative large threshold. When the charging is finished and the lamp is on, the output currents may be small and the output voltages may rise according to the output currents slowly. Thus the threshold used in this period may be a relative small threshold.
For example, the status of the lamp may be determined as outputting light when the degree of the output voltages is less than a first threshold and the output current of the driver is greater than or equal to a predetermined current, and/or the status of the lamp may be determined as outputting light when the degree of the output voltages is less than a second threshold and the output current of the driver is less than the predetermined current. Wherein, the first threshold is greater than the second threshold.
In an embodiment, the predetermined current, the first threshold and the second threshold may be set according to actual requirements. Such as types of drivers or lamps.
For example, the predetermined current may be 20%of a maximal output current, the first threshold may be 4%or 5%, and the second threshold may be 0.8%.
In an embodiment, before the step 101, the method may further include:
Step 102: determining the status of the lamp as starting up in a first period after the driver is started up.
In an embodiment, the first period may be set according to actual requirements. Such as types of drivers or lamps.
In an embodiment, the output voltages may be almost unchanged for dozens of milliseconds after the driver is started up. For example, the first period may be 64ms.
Therefore, the detection result of the status of the lamp can be correct in this first period after the driver is started up. Otherwise, the status of the lamp may be determined as outputting light incorrectly due to the almost unchanged output voltages.
In an embodiment, before the steps 101 and 102, the method may further include:
Step 103: calculating slopes of a curve of the output voltages as the degrees of variations of the output voltages.
In an embodiment, the output voltages may be averaged in each second period. That is to say the averaged output voltages are used to be compared with the thresholds and calculate the slopes.
In an embodiment, the second period may be set according to actual requirements. For example, the second period may be 8ms.
In an embodiment, the output voltages may be averaged in each second period, and a third averaged output voltage V3 may be compared with a first averaged output voltage V1 and a second averaged output voltage V2 respectively.
For example, the first averaged output voltage V1 is the averaged output voltage in period 64～72ms after the driver is started up, the second averaged output voltage V2 is the averaged output voltage in period 73～80ms after the driver is started up, and the third averaged output voltage V3 is the averaged output voltage in period 81～88ms after the driver is started up.
When V3<V1* (1+Slope) and V3<V2* (1+Slope) , the determination of the status of the lamp may be carried out. Therefore, influences of shocks of output voltages may be suppressed.
In an embodiment, the output voltages and output currents of the driver may be detected with existing circuits and methods.
Fig. 2 is another flowchart of a method of detecting a status of a lamp with an embodiment of the present disclosure. As shown in Fig. 2, the method includes:
Step 201: determining the status of the lamp as starting up in a first period after the driver is started up;
Step 202: calculating slopes of a curve of the output voltages of the driver;
Step 203: determining whether the slope is less than the threshold corresponding to the output current of the driver. Get back to step 202 when the determining result is “no” , and execute step 204 when the determining result is “yes” ;
Step 204: determining the status of the lamp as outputting light.
As can be seen from the above embodiments, the status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp. Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.
Second embodiment
A device of device of detecting a status of a lamp is provided in a second embodiment. The device is corresponding to the method described in the first embodiment.
Fig. 3 is a diagram of a device of detecting a status of a lamp with an embodiment of the present disclosure.
As shown in Fig. 3, a device 300 of detecting a status of a lamp includes:
a first determining unit 301 configured to determine the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
In an embodiment, the device 300 may further include:
a second determining unit 302 configured to determine the status of the lamp as starting up in a first period after the driver is started up.
In an embodiment, the device 300 may further include:
a calculating unit 303 configured to calculate slopes of a curve of the output voltages as the degrees of variations of the output voltages.
In an embodiment, functions of the first determining unit 301, second determining unit 302 and calculating unit 303 may be corresponding to the steps of the method in the first embodiment, and shall not be described herein any further.
As can be seen from the above embodiments, the status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp. Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.
Third embodiment
A lamp driver is provided in a third embodiment.
In an embodiment, the lamp driver may be any type of lamp drivers. Such as a LED driver, or other drivers.
Fig. 4 is a schematic diagram of a lamp driver with an embodiment of the present disclosure. As shown in Fig. 4, a lamp driver 400 includes:
a device 401 of detecting a status of a lamp; and
a converter 402 configured to provide constant current.
In an embodiment, the device 401 is identical to the device 300 described in the second embodiment, which shall not be described herein any further.
For example, the converter 402 may be a switched converter clocked at high frequency, such as a resonant half-bridge converter. Alternatively, the converter may be an isolated converter, such as a flyback converter. Furthermore, the converter may be a non-isolated converter, such as a boost converter, buck converter or buck-boost converter.
In case that the converter 402 is formed by an isolated converter, such as a flyback converter or an isolated resonant converter like a LLC converter, the central processing unit 501 may be located on the primary side of the isolated converter. The first determining unit 301 may comprise sensing means to sense the output voltage of a driver of the lamp. The first determining unit 301 may comprise sensing means located on the secondary side of the isolated converter to directly determine the output voltage or sensing means located on the primary side of the isolated converter to indirectly determine the output voltage of a driver of the lamp. Such indirect determination of the output voltage of a driver of the lamp may be performed for instance by an additional winding connected to the power transferring transformer which forms a part of the isolated converter.
FIG. 5 is a block diagram of a systematic structure of a lamp driver with an embodiment of the present disclosure. As shown in Fig. 5, a lamp driver 500 may include a central processing unit 501 and a memory 502, the memory 502 being coupled to the central processing unit 501.
In one implementation, the functions of the device of of detecting a status of a lamp may be integrated into the central processing unit 501. The central processing unit 501 may be configured to: determine the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
As shown in Fig. 5, the lamp driver 500 may further include a converter 503.
In this embodiment, the lamp driver 500 does not necessarily include all the parts shown in FIG. 5. Also, this figure is illustrative only, and other types of structures may also be used, so as to supplement or replace this structure and achieve a telecommunications function or other functions.
In an embodiment, the central processing unit 501 is sometimes referred to as a controller or control, and may include a microprocessor or other processor devices and/or logic devices. The central processing unit 501 receives input and controls operations of every components of the electronic apparatus 500.
The memory 502 may be, for example, one or more of a buffer memory, a flash memory, a hard drive, a mobile medium, a volatile memory, a nonvolatile memory, or other suitable devices. And the central processing unit 501 may execute the program stored in the memory 502, to realize information storage or processing, etc. Functions of other parts are similar to those of the prior art, which shall not be described herein any further. The parts of the electronic apparatus 500 may be realized by specific hardware, firmware, software, or any combination thereof, without departing from the scope of the present disclosure.
As can be seen from the above embodiments, the status of the lamp can be determined according to degrees of variations of output voltages of a driver of the lamp. Therefore, the status of the lamp can be detected accurately no matter what types of capacitors are used at the output side of the driver. Furthermore, no additional hardware or electronic element is needed, thus the cost and space may be saved.
Generally, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.
Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A method of detecting a status of a lamp, comprising:

determining the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
The method according to claim 1, wherein,

determining the status of the lamp according to comparative results between the degrees of output voltages of the driver and thresholds corresponding to output currents of the driver.
The method according to claim 2, wherein,

determining the status of the lamp as outputting light when the degree of the output voltages is less than the threshold corresponding to the output current of the driver.
The method according to claim 3, wherein,

determining the status of the lamp as outputting light when the degree of the output voltages is less than a first threshold and the output current of the driver is greater than or equal to a predetermined current, and/or

determining the status of the lamp as outputting light when the degree of the output voltages is less than a second threshold and the output current of the driver is less than the predetermined current.
The method according to claim 4, wherein,

the first threshold is greater than the second threshold.
The method according to any one of claims 1-5, wherein, the method further comprises:

determining the status of the lamp as starting up in a first period after the driver is started up.
The method according to any one of claims 1-6, wherein, the method further comprises:

calculating slopes of a curve of the output voltages as the degrees of variations of the output voltages.
The method according to any one of claims 1-7, wherein,

the output voltages are averaged in each second period.
A device of detecting a status of a lamp, comprising:

a first determining unit configured to determine the status of the lamp according to degrees of variations of output voltages of a driver of the lamp.
The device according to claim 9, wherein,

the first determining unit determines the status of the lamp according to comparative results between the degrees of output voltages of the driver and thresholds corresponding to output currents of the driver.
The device according to claim 10, wherein,

the first determining unit determines the status of the lamp as outputting light when the degree of the output voltages is less than the threshold corresponding to the output current of the driver.
The device according to claim 11, wherein,

the first determining unit determines the status of the lamp as outputting light when the degree of the output voltages is less than a first threshold and the output current of the driver is greater than or equal to a predetermined current, and/or determines the status of the lamp as outputting light when the degree of the output voltages is less than a second threshold and the output current of the driver is less than the predetermined current.
The device according to claim 12, wherein,

the first threshold is greater than the second threshold.
The device according to any one of claims 9-13, wherein, the device further comprises:

a second determining unit configured to determine the status of the lamp as starting up in a first period after the driver is started up.
The device according to any one of claims 9-14, wherein, the device further comprises:

a calculating unit configured to calculate slopes of a curve of the output voltages as the degrees of variations of the output voltages.
The device according to any one of claims 9-15, wherein,

the output voltages are averaged in each second period.
A lamp driver, comprising:

the device according to any one of claims 9-16.