WO2020010621A1

WO2020010621A1 - Method and device of controlling dimmable driver, dimmable driver

Info

Publication number: WO2020010621A1
Application number: PCT/CN2018/095656
Authority: WO
Inventors: Xinhai Li; Yaofeng LIN; Jialiang YAN
Original assignee: Tridonic Gmbh & Co Kg; Yaofeng LIN
Priority date: 2018-07-13
Filing date: 2018-07-13
Publication date: 2020-01-16
Also published as: GB2587285B; GB2587285A; GB202019115D0

Abstract

A method and device of controlling a dimmable driver (201), and a dimmable driver (201). The output voltage of the dimmable driver is increased when the dimmable driver (201)is in a condition of light load or in a low dimming level(101). The output voltage of the dimmable driver(201) can be maintained above the minimum voltage required for good constant current control in the illuminating device(202) when the dimmable driver(201) is in a condition of light load. Therefore, accurate dimming can be realized and flicker of the illuminating device (202) can be eliminated.

Description

METHOD AND DEVICE OF CONTROLLING DIMMABLE DRIVER, DIMMABLE 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 controlling a dimmable driver, and a dimmable 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, dimmable drivers are widely used in illuminating fields. With a dimmable driver, the luminescent intensity of an illuminating device may be adjusted in a wide range.

A PWM (Pulse Width Modulation) dimming is a common way to achieve the dimming. Normally the PWM dimming is applied for constant voltage (CV) drivers. For example, the CV driver is dimmable with PWM or the CV driver includes an external PWM dimmer.

SUMMARY

Inventors of this disclosure found that when the dimmable driver is in a condition of light load, the dimmable driver may be not stable. For example, when the driver is in a burst mode (also called bounce mode) , high ripple may be generated in an output voltage of the driver. Thus the output voltage may fluctuate and fall below the minimum voltage required for good constant current control in the illuminating device when the dimmer is conducting. This may lead to an inaccuracy in dimming, and the illuminating device may flicker.

In general, embodiments of the present disclosure provide a method and device of controlling a dimmable driver, and a dimmable driver. In the embodiments, the output voltage of the dimmable driver is increased when the dimmable driver is in a condition of light load or in a low dimming level. The output voltage of the dimmable driver can be maintained above the minimum voltage required for good constant current control in the illuminating device when the dimmable driver is in a condition of light load. Therefore, accurate dimming can be realized and flicker of the illuminating device can be eliminated.

In a first aspect, there is provided a method of controlling a dimmable driver, including: increasing the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.

In an embodiment, the method further includes: determining a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.

In an embodiment, the load condition is determined as the light load when the output current is less than a first threshold or the input power is less than a second threshold.

In an embodiment, the method further includes: determining a dimming level by detecting a PWM signal for dimming.

In an embodiment, the dimming level is determined as the low dimming level when a duty ratio of the PWM signal is less than a third threshold.

In an embodiment, increasing the output voltage of the dimmable driver by adjusting a feedback loop of the output voltage of the dimmable driver.

In an embodiment, increasing the output voltage of the dimmable driver by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.

In a second aspect, there is provided a device of controlling a dimmable driver, including: an adjusting unit configured to increase the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.

In an embodiment, the device further includes: a first determining unit configured to determine a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.

In an embodiment, the device further includes: a second determining unit configured to determine a dimming level by detecting a PWM signal for dimming.

In an embodiment, the adjusting unit increases the output voltage of the dimmable driver by adjusting a feedback loop of the output voltage of the dimmable driver.

In an embodiment, the adjusting unit increases the output voltage of the dimmable driver by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.

In a third aspect, there is provided a dimmable driver, including: the device according to the second aspect.

According to various embodiments of the present disclosure, the output voltage of the dimmable driver is increased when the dimmable driver is in a condition of light load or in a low dimming level. The output voltage of the dimmable driver can be maintained above the minimum voltage required for good constant current control in the illuminating device when the dimmable driver is in a condition of light load. Therefore, accurate dimming can be realized and flicker of the illuminating device can be eliminated.

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 controlling a dimmable driver with an embodiment of the present disclosure；

Fig. 2 is a block diagram of an illuminating system with an embodiment of the present disclosure;

Fig. 3 is a diagram of a device of controlling a dimmable driver with an embodiment of the present disclosure;

Fig. 4 is a schematic diagram of a dimmable driver with an embodiment of the present disclosure;

FIG. 5 is a block diagram of a systematic structure of a dimmable 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 controlling a dimmable driver is provided in a first embodiment.

Fig. 1 is a flowchart of a method of controlling a dimmable driver with an embodiment of the present disclosure. As shown in Fig. 1, the method includes:

Step 101: increasing the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.

Fig. 2 is a block diagram of an illuminating system with an embodiment of the present disclosure. As shown in Fig. 2, the illuminating system includes a dimmable driver 201, an illuminating device 202 and a feedback loop 203.

In an embodiment, the driver 201 may be any type of dimmable drivers. For example, the driver 201 is dimmable with PWM or the driver 201 includes an external PWM dimmer. And the driver may be a constant voltage (CV) driver.

For example, as shown in Fig. 2, the driver 201 includes a converter 204 and a PWM dimmer 205.

In an embodiment, the converter 204 may be configured to provide constant current for the illuminating device 202.

For example, the converter 204 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 an embodiment, the PWM dimmer 205 may adjust the output current of the converter 201 with a PWM signal, so as to realize the dimming of the illuminating device 202. A dimming level is related to a duty ratio of the PWM signal.

For example, the dimming level is high when the duty ratio of the PWM signal is high and the dimming level is low when the duty ratio of the PWM signal is low.

In an embodiment, the illuminating device 202 may be any type of illuminating devices. For example, the illuminating device 202 may be a LED strip.

In an embodiment, the feedback loop 203 is configured to supply a feedback of the output voltage of the driver 201. Functions and circuit configuration of the feedback loop 203 may be similar to those of the prior art.

In the step 101, the output voltage may be increased by adjusting a feedback loop of the output voltage of the dimmable driver. In this way, the output voltage can be adjusted simply and with low cost.

For example, the output voltage may be increased by adjusting the feedback loop 203.

In an embodiment, the output voltage may be increased by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.

For example, the feedback loop 203 may include a resistance configured to adjust the output voltage of the driver 201. When the value of the resistance is increased, the output voltage is also increased, or, when the value of the resistance is reduced, the output voltage is increased.

In the step 101, the degree of the increase of the output voltage may be determined according to actual requirements. For example, the output voltage may be increased to a value to make sure a good constant current control in the illuminating device.

For example, for a 24V CV driver, the output voltage may be increased to 26V ～ 28V when the driver is in a condition of light load or in a low dimming level.

In an embodiment, before the step 101, the method may further include:

Step 102: determining a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.

In an embodiment, the load condition may be determined as the light load when the output current is less than a first threshold or the input power is less than a second threshold.

The output current or the input power of the driver may be detected with existing circuits. Furthermore, the first threshold and the second threshold may be predetermined according to actual requirements.

In an embodiment, before the steps 101, similar to the step 102, the method may further include:

Step 103: determining a dimming level by detecting a PWM signal for dimming.

The duty ratio of the PWM signal may be detected with existing circuits. Furthermore, the third threshold may be predetermined according to actual requirements.

As can be seen from the above embodiments, the output voltage of the dimmable driver is increased when the dimmable driver is in a condition of light load or in a low dimming level. The output voltage of the dimmable driver can be maintained above the minimum voltage required for good constant current control in the illuminating device when the dimmable driver is in a condition of light load. Therefore, accurate dimming can be realized and flicker of the illuminating device can be eliminated.

Second embodiment

A device of device of controlling a dimmable driver 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 controlling a dimmable driver with an embodiment of the present disclosure.

As shown in Fig. 3, a device 300 of controlling a dimmable driver includes:

an adjusting unit 301 configured to increase the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.

In an embodiment, the adjusting unit 301 may increase the output voltage of the dimmable driver by adjusting a feedback loop of the output voltage of the dimmable driver.

For example, the adjusting unit 301 may increase the output voltage of the dimmable driver by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.

In an embodiment, the device 300 may further include:

a first determining unit 302 configured to determine a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.

For example, the load condition is determined as the light load when the output current is less than a first threshold or the input power is less than a second threshold.

In an embodiment, the device 300 may further include:

a second determining unit 303 configured to determine a dimming level by detecting a PWM signal for dimming.

For example, the dimming level is determined as the low dimming level when a duty ratio of the PWM signal is less than a third threshold.

In an embodiment, functions of the adjusting unit 301, first determining unit 302 and second determining unit 303 may be corresponding to the steps of the method in the first embodiment, and shall not be described herein any further.

Third embodiment

A dimmable driver is provided in a third embodiment.

In an embodiment, the driver may be any type of dimmable drivers. For example, the driver is dimmable with PWM or the driver includes an external PWM dimmer. And the driver may be a constant voltage (CV) driver.

Furthermore, the dimmable driver may be used for driving any illuminating device, such as a LED light or a LED strip.

Fig. 4 is a schematic diagram of a dimmable driver with an embodiment of the present disclosure. As shown in Fig. 4, a dimmable driver 400 includes:

a device 401 of controlling a dimmable driver;

a converter 402 configured to provide constant current and

a dimmer 403 configured to adjust the output current of the converter 402 with a PWM signal.

In an embodiment, the device 401 may be identical to the device 300 described in the second embodiment, which shall not be described herein any further.

Furthermore, the converter 402 and the dimmer 403 may be identical to the converter 204 and the dimmer 205 described in the first embodiment, which shall not be described herein any further.

FIG. 5 is a block diagram of a systematic structure of a dimmable driver with an embodiment of the present disclosure. As shown in Fig. 5, a dimmable 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 401 of controlling a dimmable driver may be integrated into the central processing unit 501. The central processing unit 501 may be configured to: increase the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.

As shown in Fig. 5, the dimmable driver 500 may further include a converter 503 and a dimmer 504, which may be identical to the converter 204 and the dimmer 205 described in the first embodiment, which shall not be described herein any further.

In this embodiment, the dimmable driver 500 does not necessarily include all 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.

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 controlling a dimmable driver, comprising:

increasing the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.
The method according to claim 1, wherein, the method further comprises:

determining a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.
The method according to claim 2, wherein,

the load condition is determined as the light load when the output current is less than a first threshold or the input power is less than a second threshold.
The method according to claim 1, wherein, the method further comprises:

determining a dimming level by detecting a PWM signal for dimming.
The method according to claim 4, wherein,

the dimming level is determined as the low dimming level when a duty ratio of the PWM signal is less than a third threshold.
The method according to claim 1, wherein,

increasing the output voltage of the dimmable driver by adjusting a feedback loop of the output voltage of the dimmable driver.
The method according to claim 6, wherein,

increasing the output voltage of the dimmable driver by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.
A device of controlling a dimmable driver, comprising:

an adjusting unit configured to increase the output voltage of the dimmable driver when the dimmable driver is in a condition of light load or in a low dimming level.
The device according to claim 8, wherein, the device further comprises:

a first determining unit configured to determine a load condition by detecting an output current of the dimmable driver or an input power of the dimmable driver.
The device according to claim 9, wherein,

the load condition is determined as the light load when the output current is less than a first threshold or the input power is less than a second threshold.
The device according to claim 8, wherein, the device further comprises:

a second determining unit configured to determine a dimming level by detecting a PWM signal for dimming.
The device according to claim 11, wherein,

the dimming level is determined as the low dimming level when a duty ratio of the PWM signal is less than a third threshold.
The device according to claim 8, wherein,

the adjusting unit increases the output voltage of the dimmable driver by adjusting a feedback loop of the output voltage of the dimmable driver.
The device according to claim 13, wherein,

the adjusting unit increases the output voltage of the dimmable driver by adjusting a value of a resistance of the feedback loop of the output voltage of the dimmable driver.
A dimmable driver, comprising:

the device according to any one of claims 8-14.