EP3741190A1

EP3741190A1 - Ripple suppression circuit, controlling method and driving equipment

Info

Publication number: EP3741190A1
Application number: EP18907985.8A
Authority: EP
Inventors: Zhiwen Chen; Juyuan CHEN; Qiuxiang MAO
Original assignee: Tridonic GmbH and Co KG
Current assignee: Tridonic GmbH and Co KG
Priority date: 2018-02-28
Filing date: 2018-02-28
Publication date: 2020-11-25
Also published as: CN111742618A; WO2019165589A1; EP3741190A4

Abstract

A ripple suppression circuit, a controlling method and a driving equipment. The ripple suppression circuit includes: a first input port and a second input port, configured to receive an input signal; a first output port and a second output port, configured to output an output signal, the second input port connects with the second output port; at least one capacitor, configured to connect between the first input port and the second input port; a main transistor, configured to connect between the first input port and the first output port, and suppress ripples in the input signal; and a protection circuit, configured to connect between the first input port and the first output port, the protection circuit connects the first input port with the first output port when there is a short circuit between the first output port and the second output port. Therefore, the main transistor can be protected.

Description

RIPPLE SUPPRESSION CIRCUIT, CONTROLLING METHOD AND DRIVING EQUIPMENT

Technical Field

Embodiments of the present disclosure generally relate to the field of lighting, and more particularly, to a ripple suppression circuit, a controlling method and a driving equipment.

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.
In the field of lighting technology, it is often needed to configure a driving current, which is used to drive a lighting device. The lighting device is LED (Light Emitting Diode) for example.
The lighting device is driven by a driver, which outputs direct current to the lighting device. For most of low cost drivers, output current has high ripple coefficient, e.g. ±30%or even higher. High ripple coefficient may make the lighting device to flicker.
A ripple suppression circuit may connect with output port of the driver, to suppress ripples in the output current. Therefore, flicker can be eliminated by using the ripple suppression circuit.
Summary
Inventor of this disclosure found the following limitation in related art: when output port of the ripple suppression circuit is shorted, energy stored in secondary side of the driver will rush through transistor of the ripple suppression circuit, and the transistor will be destroyed as a result. Therefore, transistor with higher voltage rating and higher avalanche energy is used to survive.
In general, embodiments of the present disclosure provide a ripple suppression circuit, a controlling method and a driving equipment. In the embodiments, a protection circuit is used to form path for discharging, when output port of the ripple suppression circuit is shorted. Therefore, the transistor in the ripple suppression circuit will be protected, and the transistor with lower voltage rating and lower avalanche energy can be used.
In a first aspect, there is provided a ripple suppression circuit, includes:
a first input port and a second input port, configured to receive an input signal;
a first output port and a second output port, configured to output an output signal, the second input port connects with the second output port;
at least one capacitor, configured to connect between the first input port and the second input port;
a main transistor, configured to connect between the first input port and the first output port, and suppress ripples in the input signal; and
a protection circuit, configured to connect between the first input port and the first output port, the protection circuit connects the first input port with the first output port when there is a short circuit between the first output port and the second output port.
In an embodiment, the protection circuit includes a transient voltage suppressor (TVS) , which reversely connects between the first input port and the first output port.
In an embodiment, the protection circuit includes at least two diodes, which forwardly connects in series between the first input port and the first output port.
In an embodiment, the ripple suppression circuit is integrated in a driving circuit, which provides the input signal to the ripple suppression circuit; or the ripple suppression circuit is placed in a separated device from the driving circuit.
In an embodiment, the device has a first housing in which the ripple suppression circuit is placed.
In an embodiment, the first housing includes: a base part, on which the ripple suppression circuit mounted; a first cover part, configured to cover the at least one capacitor, the main transistor and the protection circuit; and a second cover part, configured to cover the first input port, the second input port, the first output port and the second output port.
In an embodiment, the device is placed within or externally a second housing in which the driving circuit is placed.
In a second aspect, there is provided a controlling method of a ripple suppression circuit, includes:
receiving an input signal via a first input port and a second input port;
outputting an output signal via a first output port and a second output port, wherein, the second input port connects with the second output port, and at least one capacitor connects between the first input port and the second input port;
suppressing ripples of the input signal by a main transistor, the main transistor connects between the first input port and the first output port; and
connecting the first input port with the first output port by a protection circuit, when there is a short circuit between the first output port and the second output port.
In a third aspect, there is provided a driving equipment, includes a driving circuit and the ripple suppression circuit according to the first aspect of the disclosure, the input signal is provided by the driving circuit.
The disclosure also relates to a driving equipment, includes a driving circuit, and the ripple suppression circuit according to the first aspect of the disclosure, the ripple suppression circuit is placed in a first housing, the first housing includes a base part, on which the ripple suppression circuit mounted; a first cover part, configured to cover the at least one capacitor, the main transistor and the protection circuit; and a second cover part, configured to cover the first input port, the second input port, the first output port and the second output port.
According to various embodiments of the present disclosure, a protection circuit is used to provide the ripple suppression circuit with a path for discharging when output port of the ripple suppression circuit is shorted, so that the transistor in the ripple suppression circuit will be protected.

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 diagram of a ripple suppression circuit in accordance with an embodiment of the present disclosure;
Fig. 2 is a diagram of a ripple suppression circuit in accordance with another embodiment of the present disclosure;
Fig. 3 shows the first housing in accordance with the embodiment of the present disclosure;
Fig. 4 (A) and (B) show photographs of the tube in accordance with the embodiment of the present disclosure;
Fig. 5 shows a flowchart of a controlling method 500 of the ripple suppression circuit in accordance with the 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 aspect of embodiments
A ripple suppression circuit is provided in a first embodiment.
Fig. 1 is a diagram of a ripple suppression circuit in accordance with an embodiment of the present disclosure. As shown in Fig. 1, a ripple suppression circuit 10 includes a first input port X1-a, a second input port X1-b, a first output port X2-a, a second output port X2-b, at least one capacitor C01, C02, a main transistor Q01, and a protection circuit 11.
In the embodiment, the first input port X1-a and the second input port X1-b are configured to receive an input signal. The input signal may be direct current/voltage which has ripples. The input signal may be provided by a driving circuit. The ripple suppression circuit may connect to the secondary side of the driving circuit.
The first output port X2-a and the second output port X2-b are configured to output an output signal. The second input port X1-b connects with the second output port X2-b, thus the second input port X1-b and the second output port X2-b may have the same voltage, for example, voltage of ground.
In the embodiment, the at least one capacitor C01 and C02 are configured to connect between the first input port X1-a and the second input port X1-b. In FIG. 1, two capacitors C01 and C02 are taken as an example, the embodiment will not be limited thereto, number of capacitor will be one, or more than two.
In the embodiment, the main transistor Q01 is configured to connect between the first input port X1-a and the first output port X2-a. The main transistor Q01 is used to suppress ripples in the input signal.
As shown in FIG. 1, the main transistor Q01 is a bipolar transistor, for example an NPN bipolar transistor. Emitter of the bipolar transistor connects to the first output port X2-a, collector of the bipolar transistor connects to the first input port X1-a, base of the bipolar transistor connects to a connecting node TP2 via a resistor R01. The connecting node TP2 is between a first diode D01 and a capacitor C03 that connects in series between the first input port X1-a and the second input port X1-b. The embodiment will not be limited thereto; the main transistor Q01 can be of other type, for example a MOS FET (Metal-Oxide-Semiconductor Field-Effect Transistor) .
In the embodiment, the protection circuit 11 is configured to connect between the first input port X1-a and the first output port X2-a. The protection circuit connects the first input port X1-a with the first output port X2-a when there is a short circuit between the first output port X1-a and the second output port X2-a.
According to the embodiments, a protection circuit connects the first input port X1-a with the first output port X2-a when output port of the ripple suppression circuit is shorted, therefore, the protection circuit can form path for discharging, the main transistor in the ripple suppression circuit will be protected, and the main transistor with lower voltage rating and lower avalanche energy can be used.
In the embodiment, the protection circuit 11 may include a transient voltage suppressor (TVS) D61, which reversely connects between the first input port X1-a and the first output port X2-a. When output port of the ripple suppression circuit is shorted, for example the first input port X1-a and the second input port X1-b are shorted, charges stored in the at least one capacitor C01 and C02 will discharge. Once voltage built on the TVS D61 reaches a threshold, TVS D61 will conduct to form path for discharging. Therefore, discharging will not be performed through the main transistor Q01, the main transistor Q01 is protected and safe.
In an embodiment, the TVS D61 may be SMC (surface mounting) packaging or axial, radial type. The threshold of the TVS D61 may be 5V, the transient pulse power of the TVS D61 is 1500W. However, the values for threshold and the transient pulse power are not limited thereto, they may depend on design.
Fig. 2 is a diagram of a ripple suppression circuit in accordance with another embodiment of the present disclosure. As shown in Fig. 2, a ripple suppression circuit 10a includes a first input port X1-a, a second input port X1-b, a first output port X2-a, a second output port X2-b, at least one capacitor C01, C02, a main transistor Q01, and a protection circuit 11a.
The protection circuit 11a in Fig. 2 is different from the protection circuit 11 in Fig. 1. Descriptions for the same element with the same labels in Fig. 1 and Fig. 2 are omitted.
In the embodiment, as shown in Fig. 2, the protection circuit 11a includes at least two diodes, which forwardly connects in series between the first input port X1-a and the first output port X2-a.
As shown in Fig. 2, the at least two diodes may be diodes D03, D04 and D05. When output port of the ripple suppression circuit is shorted, for example the first input port X1-a and the second input port X1-b are shorted, charges stored in the at least one capacitor C01 and C02 will discharge. Once voltage built on the at least two diodes reaches a threshold, the at least two diodes D03, D04 and D05 will conduct to form path for discharging. Therefore, discharging will not be performed through the main transistor Q01, the main transistor Q01 is protected and safe.
According to embodiment shown in Fig. 2, diodes D03, D04 and D05 are cheap ones. Therefore, cost of the protection circuit 11a is getting lower.
In the embodiment, as shown in Fig. 1 and Fig. 2, other components, such as resisters R02 and R03, capacitors C03, may be included in the ripple suppression circuit 10 (or 10a) . Descriptions for these components may be referred to the related art.
The driving circuit may be formed by a flyback converter or resonant halfbridge converter or LLC converter including a transformer. Instead of the transformer there might from an inductor a part of a switched converter e.g. a buck converter or boost converter which forms the driving circuit. The clocking of the driving circuit and especially the transformer by at least one controllable switch which is clocked at high frequency may depend on a controlling signal inputted to a control input of the driving circuit. For instance the frequency and /or the duty cycle of the controllable switch of the driving circuit may be adjusted in dependency on the controlling signal inputted to an input of the driving circuit.
The driving circuit may generate a driving current or driving voltage for the lighting device. The driving circuit may output the driving current or driving voltage for the lighting device at the first input port X1-a and the second input port X1-b in order to output the input signal to the ripple suppression circuit 10 (or 10a) .
In one embodiment, the ripple suppression circuit 10 (or 10a) can be integrated with a driving circuit (not shown) , which provides the input signal to the ripple suppression circuit 10 (or 10a) . Therefore, the ripple suppression circuit 10 (or 10a) and the driving circuit may be placed on one printed circuit board.
In another embodiment, the ripple suppression circuit 10 (or 10a) may be placed in a separated device from the driving circuit. When the ripple suppression circuit 10 (or 10a) is used, the separated device can mechanically and electrically connect with the driving circuit, so as to suppress ripples in the output signal of the driving circuit. When the ripple suppression circuit 10 (or 10a) is not used or replacement is needed, the separated device can be disassembled from the driving circuit. Therefore, it is easy to use the ripple suppression circuit with different driving circuits, and replacement can be available.
In the embodiment, the device may include the ripple suppression circuit 10 (or 10a) and a first housing in which the ripple suppression circuit 10 (or 10a) is placed.
Fig. 3 shows the first housing in accordance with the embodiment of the present disclosure. As shown in Fig. 3, the first housing 30 includes a base part 31, a first cover part 32 and a second cover part 33.
In the embodiment, the ripple suppression circuit 10 (or 10a) can be mounted on the base part 31. The first cover part 32 may be configured to cover the at least one capacitor (C01 and C02) , the main transistor Q01 and the protection circuit 10 (or 10a) . The second cover part 33 may be configured to cover the first input port X1-a, the second input port X1-b, the first output port X2-a and the second output port X2-b.
Fig. 3 is an example of the first housing, the embodiment is not limited thereto. The first housing may has other form with different form factors for different application, so that the device can be compatible to work with different driving circuits.
For example, the first housing may has a form of tube, the ripple suppression circuit 10 (or 10a) is placed in the tube. Fig. 4 (A) and (B) shows photographs of the tube in accordance with the embodiment. Circles on Fig. 4 (A) and (B) denote the tubes where the ripple suppression circuit 10 (or 10a) is placed in.
In the embodiment, the driving circuit may be placed in a second housing, thus the second housing and the driving circuit forms a driver. Descriptions about the second housing can be referred to related art, such as CN201444716U.
In an embodiment, the device with the first housing may be placed within the second housing. The first housing may has different form factors for different application, so that the device can be placed in the second housing.
In another embodiment, the device with the first housing may be placed externally the second housing.
As can be seen from the above mentioned embodiments, a protection circuit connects the first input port X1-a with the first output port X2-a when output port of the ripple suppression circuit is shorted, therefore, the protection circuit can form path for discharging, the main transistor in the ripple suppression circuit will be protected, and the main transistor with lower voltage rating and lower avalanche energy can be used.
In addition, the ripple suppression circuit may be placed in a separated device as accessory of the driving circuit. The separated device can mechanically and electrically connect with the driving circuit, so as to suppress ripples in the output signal of the driving circuit. The separated device can be disassembled from the driving circuit, when replacement is needed or the ripple suppression circuit is not used. Therefore, it is easy to use the ripple suppression circuit with different driving circuits, and replacement can be available.
In addition, the first housing may has different form factors for different application, so that the device can be placed in the driver.
The first housing may include a strain relief, e.g. for the wiring of the lighting device, in addition to the ripple suppression circuit.
Second aspect of embodiments
A controlling method of a ripple suppression circuit. The ripple suppression circuit of the first aspect of embodiments is provided in an embodiment. The same contents as those in the first aspect of embodiments are omitted.
Fig. 5 shows a flowchart of a controlling method 500 of the ripple suppression circuit.
As shown in Fig. 5, the method 500 includes:
Block 501: receiving an input signal via a first input port and a second input port;
Block 502: outputting an output signal via a first output port and a second output port, the second input port connects with the second output port, and at least one capacitor connects between the first input port and the second input port;
Block 503: suppressing ripples of the input signal by a main transistor, the main transistor connects between the first input port and the first output port;
Block 504: connecting the first input port with the first output port by a protection circuit, when there is a short circuit between the first output port and the second output port.
In the embodiment, the protection circuit may include a TVS D61 or at least two diodes, which forwardly connects in series between the first input port and the first output port.
As can be seen from the above mentioned embodiments, a protection circuit connects the first input port X1-a with the first output port X2-a when output port of the ripple suppression circuit is shorted, therefore, the protection circuit can form path for discharging, the main transistor in the ripple suppression circuit will be protected, and the main transistor with lower voltage rating and lower avalanche energy can be used.
Third aspect of embodiments
A driving equipment is provided in an embodiment. The driving equipment includes a driving circuit and the ripple suppression circuit according to the first aspect of embodiments.
In the embodiment, the ripple suppression circuit receives the input signal provided by the driving circuit, and outputs signal with low ripple coefficient. The signal with low ripple coefficient may be provided to a lighting device, so that flicker of the lighting device can be reduced.
In the embodiment, the ripple suppression circuit may be integrated in the driving circuit, or, the ripple suppression circuit may be placed in a separated device from the driving circuit.
In the embodiment, the ripple suppression circuit may be placed in a first housing to form the separated device. The driving circuit may be placed in a second housing to form a driver. The first housing may be placed within or externally the second housing.
Further, 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 ripple suppression circuit, comprising:

a first input port and a second input port, configured to receive an input signal;

a first output port and a second output port, configured to output an output signal, the second input port connects with the second output port;

at least one capacitor, configured to connect between the first input port and the second input port;

a main transistor, configured to connect between the first input port and the first output port, and suppress ripples in the input signal; and

a protection circuit, configured to connect between the first input port and the first output port, the protection circuit connects the first input port with the first output port when there is a short circuit between the first output port and the second output port.
The ripple suppression circuit according to claim 1, wherein,

the protection circuit comprises a transient voltage suppressor (TVS) , which reversely connects between the first input port and the first output port.
The ripple suppression circuit according to claim 1, wherein,

the protection circuit comprises at least two diodes, which forwardly connects in series between the first input port and the first output port.
The ripple suppression circuit according to claim 1, wherein,

the ripple suppression circuit is integrated in a driving circuit, which provides the input signal to the ripple suppression circuit; or

the ripple suppression circuit is placed in a separated device from the driving circuit.
The ripple suppression circuit according to claim 4, wherein,

the device has a first housing in which the ripple suppression circuit is placed.
The ripple suppression circuit according to claim 5, wherein,

the first housing comprises:

a base part, on which the ripple suppression circuit mounted;

a first cover part, configured to cover the at least one capacitor, the main transistor and the protection circuit; and

a second cover part, configured to cover the first input port, the second input port, the first output port and the second output port.
The ripple suppression circuit according to claim 5, wherein,

the device is placed within or externally a second housing in which the driving circuit is placed.
A driving equipment, comprises a driving circuit, and the ripple suppression circuit according to one of claims 1-7, wherein:

the input signal is provided by the driving circuit.
A driving equipment, comprises a driving circuit, and the ripple suppression circuit according to one of claims 1-3, the ripple suppression circuit is placed in a first housing,

the first housing comprises:

a base part, on which the ripple suppression circuit mounted;

a first cover part, configured to cover the at least one capacitor, the main transistor and the protection circuit; and

a second cover part, configured to cover the first input port, the second input port, the first output port and the second output port.
A controlling method of a ripple suppression circuit, comprising:

receiving an input signal via a first input port and a second input port;

outputting an output signal via a first output port and a second output port, wherein, the second input port connects with the second output port, and at least one capacitor connects between the first input port and the second input port ;

suppressing ripples of the input signal by a main transistor, the main transistor connects between the first input port and the first output port; and

connecting the first input port with the first output port by a protection circuit, when there is a short circuit between the first output port and the second output port.