WO2019165587A1 - Dimming control circuit, controlling method and lighting equipment - Google Patents

Dimming control circuit, controlling method and lighting equipment Download PDF

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Publication number
WO2019165587A1
WO2019165587A1 PCT/CN2018/077490 CN2018077490W WO2019165587A1 WO 2019165587 A1 WO2019165587 A1 WO 2019165587A1 CN 2018077490 W CN2018077490 W CN 2018077490W WO 2019165587 A1 WO2019165587 A1 WO 2019165587A1
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WIPO (PCT)
Prior art keywords
voltage
dimming
reference voltage
control circuit
input port
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PCT/CN2018/077490
Other languages
French (fr)
Inventor
Quentin LIN
Egbert MAO
Original Assignee
Tridonic Gmbh & Co Kg
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Publication date
Application filed by Tridonic Gmbh & Co Kg filed Critical Tridonic Gmbh & Co Kg
Priority to GB2013293.2A priority Critical patent/GB2585300B/en
Priority to PCT/CN2018/077490 priority patent/WO2019165587A1/en
Publication of WO2019165587A1 publication Critical patent/WO2019165587A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light

Definitions

  • Embodiments of the present disclosure generally relate to the field of lighting, and more particularly, to a dimming control circuit, a controlling method and a lighting equipment.
  • the lighting device is LED (Light Emitting Diode) for example.
  • a dimming signal is input to a controller, and the controller control a current generator to generate a driving current according to the dimming signal.
  • the driving current is input to a lighting device to drive the lighting device.
  • Inventor of this disclosure found the following limitation in related art: when the voltage of the dimming signal is below a certain voltage, for example the dimming signal is between 0V and 1V, the driving current is decreasing, thus the output power of the lighting device is decreasing. Therefore, constant driving current could not be obtained when the voltage of the dimming signal is below a certain voltage.
  • embodiments of the present disclosure provide a dimming control circuit, a controlling method and a lighting equipment.
  • a reference voltage providing circuit is used to provide the dimming control circuit with a first reference voltage when the dimming signal is below a predetermined voltage, so that a constant driving current instead of a decreasing driving current could be obtained. Therefore, the output power of the lighting device could be constant when the dimming signal is below the predetermined voltage.
  • a dimming control circuit includes:
  • a dimming signal input port (X2-c) configured to receive a dimming signal
  • a resistor string configured to connect the dimming signal input port and ground
  • a controller configured to compare a first voltage and a second voltage, and output a control signal according to a comparing result, wherein, the first voltage is provided by the resistor string, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current;
  • a reference voltage providing circuit configured to provide the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
  • the first reference voltage is provided according to an internal reference voltage of the controller.
  • the controller comprises a reference input port, configured to be provided with the internal reference voltage, the reference voltage providing circuit connects the reference input port and a first connecting node of the resistor string.
  • the reference voltage providing circuit comprises more than two diodes, which connect in series between the reference input port and the first connecting node.
  • the controller further comprises:
  • a first input port configured to connect to a second connecting node of the resistor string
  • a second input port configured to input the second voltage
  • a first output port configured to output the control signal
  • the first reference voltage is provided according to an external voltage input to the controller.
  • the reference voltage providing circuit comprising at least two resisters and at least one diode, the at least two resisters connect in series between an input port of the external voltage and ground, the at least one diode connects between a first connecting node of the resistor string and a connecting node of the at least two resisters.
  • a dimming control circuit comprising:
  • the first voltage is provided by the resistor string which connects the dimming signal input port and ground
  • the second voltage is generated based on a driving current provided to a lighting device
  • the control signal is used for generating the driving current
  • the first reference voltage is provide according to an internal reference voltage of the controller, or the first reference voltage is provided according to an external voltage input to the controller.
  • a lighting equipment comprises a current generator, a lighting device, and the dimming control circuit according to the second aspect of the disclosure, the dimming control circuit outputs the control signal according to the dimming signal and the driving current, the current generator generates the driving current according to the control signal, the lighting device is provided with the driving current.
  • a reference voltage providing circuit is used to provide the dimming control circuit with a first reference voltage when the dimming signal is below a predetermined voltage, therefore, a constant driving current could be obtained.
  • Fig. 1 is a diagram of a dimming control circuit in accordance with an embodiment of the present disclosure
  • Fig. 2 is a diagram of a dimming control circuit in accordance with another embodiment of the present disclosure.
  • Fig. 3 shows a flowchart of a controlling method 300 of the dimming control circuit.
  • 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 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.
  • a dimming control circuit is provided in a first embodiment.
  • Fig. 1 is a diagram of a dimming control circuit in accordance with an embodiment of the present disclosure.
  • a dimming control circuit 10 includes a dimming signal input port X2-c, a resistor string 11, a controller 12, and a reference voltage providing circuit 13.
  • the dimming signal input port X2-c is configured to receive a dimming signal.
  • the voltage of the dimming signal may be between a predetermined range, for example, the predetermined range is 0V ⁇ 10V.
  • the resistor string 11 is configured to connect the dimming signal input port X2-c and ground.
  • the resistor string 11 may include at least 2 resisters that connect in series between the dimming signal input port X2-c and ground.
  • the resistor string 11 may include 4 resistors R126, R125, R124 and R133. There is a first connecting node A in the resistor string 11 between R124 and R125, a second connecting node B in the resistor string 11 between R126 and R113.
  • the controller 12 is configured to compare a first voltage and a second voltage, and output a control signal according to a comparing result.
  • the first voltage is provided by the resistor string 11.
  • the second voltage is generated based on a driving current provided to a lighting device. For example, when the driving current is provided to the lighting device, current flows through the lighting device maybe detected, the detected current Isense may be provided to a resister R122 to generate the second voltage.
  • the lighting device is LED (Light Emitting Diode) for example.
  • the control signal is used for generating the driving current, for example, the control signal may be inputted to a current generator, the current generator generate the driving current according to the control signal, and the lighting device is provided with the driving current.
  • the reference voltage providing circuit 13 is configured to provide the resistor string 11 with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
  • the predetermined voltage may be 1V, when the voltage of the dimming signal is below the predetermined voltage, the voltage of the dimming signal is in a range of 0V ⁇ 1V.
  • the reference voltage providing circuit is used to provide the dimming control circuit with the first reference voltage when the dimming signal is below the predetermined voltage, so that a constant driving current could be obtained according to the first reference voltage. Therefore, the output power of the lighting device could be constant when the dimming signal is below the predetermined voltage.
  • the reference voltage providing circuit 13 may not provide the resistor string 11 with the first reference voltage. Therefore, the driving current may be obtained in accordance with the dimming signal.
  • the controller 12 may be a constant voltage /constant current secondary side controller, for example, the controller 12 is NCS1002.
  • the embodiment is not limited there to, the controller 12 may be of other kind.
  • the controller 12 may include a first input port 5, a second input port 6 and a first output port 7.
  • the first input port 5 connects to the second connecting node B of the resistor string, thus the first input port 5 receives the first voltage.
  • the second input port 6 may be inputted the second voltage.
  • the first output port 7 may output the control signal.
  • the controller 12 may further include a reference input port 3, which is provided with an internal reference voltage of the controller 12.
  • inner circuit of the controller 12 has a Zener diode, which is between the reference input port 3 and ground, therefore, voltage of the reference input port 3 is clamped by the Zener diode to the internal reference voltage.
  • the internal reference voltage may be 2.5V as an example.
  • the controller 12 may further include a third input port 2, a second output port 1, a ground port 4 and a power supply port 8.
  • the connection of these port may be referred to related art.
  • the first voltage (in accordance with the dimming signal) at the first input port 5 is compared with the second voltage at the second input port 6, when the first voltage is lower than the second voltage, the first output port 7 will output a first control signal as the control signal.
  • the first control signal has low voltage, which will conduct the diode D110A, and the current flows through a photocoupler U111 is getting larger, so that a feedback signal FB changes.
  • the feedback signal FB may be inputted to a first side controller of the current generator 20.
  • the first side controller may perform controlling according to the feedback signal FB, so that the current generator 20 generates the driving current, which will be proved to the lighting device.
  • the first side controller 20 may be NCP1200, and the current generator 20 may work as a switching mode power supplier (SMPS) .
  • SMPS switching mode power supplier
  • the embodiment is not limited there to, the first side controller and the current generator 20 may be of other kind.
  • the driving current is determined by the first voltage at the first input port 5.
  • the first voltage at the first input port 5 is obtained in accordance with the dimming signal; when the voltage of the dimming signal is lower than the predetermined voltage, the first voltage at the first input port 5 is obtained in accordance with the first reference voltage.
  • a third voltage at the third input port 2 is compared with the internal reference voltage at the reference input port 3, when the third voltage is higher than the internal reference voltage, the second output port 1 will output a second control signal.
  • the second control signal has low voltage, which will conduct the diode D110B, and the current flows through the photocoupler U111 is getting larger, so that the feedback signal FB changes.
  • the first side controller may perform controlling according to the feedback signal FB as above mentioned.
  • the third voltage is generated according to a current outputted to the driving current, for example, the driving current may be provided to a resister R114 to generate the third voltage.
  • the first reference voltage may be provided according to the internal reference voltage of the controller 12, therefore, extra power supplier will not be needed for providing the first reference voltage.
  • the reference voltage providing circuit 13 may connect the reference input port 3 of the controller 12 and the first connecting node A of the resistor string.
  • the reference voltage providing circuit 13 may include more than two diodes, such as D113, D114 and D115. The more than two diodes connect in series between the reference input port 3 and the first connecting node A.
  • other electronic element such as resistor or capacitor may be included in the reference voltage providing circuit 13.
  • the reference voltage providing circuit 13 may provide the first reference voltage which is constant voltage to the first connecting node A of the resistor string 11. Therefore, the driving current may be obtained in accordance with the first reference voltage.
  • the driving current may be obtained in accordance with the dimming signal.
  • Fig. 2 is a diagram of a dimming control circuit in accordance with another embodiment of the present disclosure.
  • a dimming control circuit 10a includes a dimming signal input port X2-c, a resistor string 11, a controller 12, and a reference voltage providing circuit 13a.
  • the first reference voltage 13a in Fig. 2 is different from the first reference voltage 13 in Fig. 1. Descriptions for the same element with the same labels in Fig. 1 and Fig. 2 are omitted.
  • the first reference voltage may be provided according to an external voltage input to the controller 12.
  • the external voltage may be provided by a low voltage power supplier (LVPS) .
  • LVPS low voltage power supplier
  • the external voltage provided by the LVPS may be denoted as SVCC.
  • the external voltage may also be provided to the photocoupler U111, the power supply port 8 of the controller 12, and a resister R160.
  • the reference voltage providing circuit 13a includes at least two resisters and at least one diode.
  • the resistors are R131 and R132, the diode may be D113.
  • the at least two resisters R131 and R132 connect in series between an input port E of the external voltage and ground; the at least one diode D113a connects between the first connecting node A of the resistor string 11 and a connecting node C of the at least two resisters.
  • the connecting node C maybe between resisters R131 and R132.
  • first connecting node A and the second connecting node B are different. In other embodiment, the first connecting node A and the second connecting node B may be the same.
  • Fig. 1 and Fig. 2 other components, such as resisters, capacitors and inductors, may be included in the dimming control circuit 10 or 10a, descriptions for these components may be referred to the related art.
  • Fig. 1 and Fig. 2 values for parameters of components, such as resistance, capacitance, and inductance, are shown in Fig. 1 and Fig. 2.
  • parameters of components may have other values.
  • the reference voltage providing circuit is used to provide the dimming control circuit with the first reference voltage (constant voltage) when the dimming signal is below the predetermined voltage, so that a constant driving current could be obtained according to the first reference voltage. Therefore, the output power of the lighting device could be constant when the voltage of the dimming signal is below the predetermined voltage.
  • a controlling method of a dimming control circuit The dimming control 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. 3 shows a flowchart of a controlling method 300 of the dimming control circuit.
  • the method 300 includes:
  • Block 301 receiving a dimming signal, via a dimming signal input port (X2-c) ;
  • Block 302 comparing a first voltage and a second voltage, and outputting a control signal according to a comparing result, the first voltage is provided by the resistor string which connects the dimming signal input port and ground, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current;
  • Block 303 providing the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
  • the first reference voltage is provide according to an internal reference voltage of the controller, or the first reference voltage is provided according to an external voltage input to the controller.
  • the first reference voltage constant voltage
  • the output power of the lighting device could be constant when the voltage of the dimming signal is below the predetermined voltage.
  • the lighting equipment includes a current generator, a lighting device, and the dimming control circuit according to the first aspect of embodiments.
  • the dimming control circuit 10 (or 10a) outputs the control signal according to the dimming signal and the driving current
  • the current generator 20 generates the driving current according to the control signal
  • the lighting device 30 is provided with the driving current.

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  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)

Abstract

A dimming control circuit, a controlling method and a lighting equipment.. The dimming control circuit includes: a dimming signal input port (X2-c), configured to receive a dimming signal; a resistor string, configured to connect the dimming signal input port and ground; a controller, configured to compare a first voltage and a second voltage, and output a control signal according to a comparing result, the first voltage is provided by the resistor string, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current; a reference voltage providing circuit, configured to provide the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage. Therefore, the output power of the lighting device could be constant when the dimming signal is below the predetermined voltage.

Description

DIMMING CONTROL CIRCUIT, CONTROLLING METHOD AND LIGHTING EQUIPMENT TECHNICAL FIELD
Embodiments of the present disclosure generally relate to the field of lighting, and more particularly, to a dimming control circuit, a controlling method and a lighting 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.
In related art, a dimming signal is input to a controller, and the controller control a current generator to generate a driving current according to the dimming signal. The driving current is input to a lighting device to drive the lighting device.
When the voltage of the dimming signal is between 1V and 10V, the driving current rises from minimum to maximum value, thus an output power of the lighting device rises from minimum to maximum value.
SUMMARY
Inventor of this disclosure found the following limitation in related art: when the voltage of the dimming signal is below a certain voltage, for example the dimming signal is between 0V and 1V, the driving current is decreasing, thus the output power of the lighting device is decreasing. Therefore, constant driving current could not be obtained  when the voltage of the dimming signal is below a certain voltage.
In general, embodiments of the present disclosure provide a dimming control circuit, a controlling method and a lighting equipment. In the embodiments, a reference voltage providing circuit is used to provide the dimming control circuit with a first reference voltage when the dimming signal is below a predetermined voltage, so that a constant driving current instead of a decreasing driving current could be obtained. Therefore, the output power of the lighting device could be constant when the dimming signal is below the predetermined voltage.
In a first aspect, there is provided a dimming control circuit, includes:
a dimming signal input port (X2-c) , configured to receive a dimming signal;
a resistor string, configured to connect the dimming signal input port and ground;
a controller, configured to compare a first voltage and a second voltage, and output a control signal according to a comparing result, wherein, the first voltage is provided by the resistor string, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current;
a reference voltage providing circuit, configured to provide the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
In an embodiment, the first reference voltage is provided according to an internal reference voltage of the controller.
In an embodiment, the controller comprises a reference input port, configured to be provided with the internal reference voltage, the reference voltage providing circuit connects the reference input port and a first connecting node of the resistor string.
In an embodiment, the reference voltage providing circuit comprises more than two diodes, which connect in series between the reference input port and the first connecting node.
In an embodiment, the controller further comprises:
a first input port, configured to connect to a second connecting node of the resistor string;
a second input port, configured to input the second voltage; and
a first output port, configured to output the control signal.
In an embodiment, the first reference voltage is provided according to an external voltage input to the controller.
In an embodiment, the reference voltage providing circuit comprising at least two resisters and at least one diode, the at least two resisters connect in series between an input port of the external voltage and ground, the at least one diode connects between a first connecting node of the resistor string and a connecting node of the at least two resisters.
In a second aspect, there is provided a controlling method of a dimming control circuit, comprising:
receiving a dimming signal, via a dimming signal input port (X2-c) ;
comparing a first voltage and a second voltage, and outputting a control signal according to a comparing result, wherein, the first voltage is provided by the resistor string which connects the dimming signal input port and ground, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current; and
providing the resistor string a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
In an embodiment, the first reference voltage is provide according to an internal reference voltage of the controller, or the first reference voltage is provided according to an external voltage input to the controller.
In a third aspect, there is provided a lighting equipment, comprises a current generator, a lighting device, and the dimming control circuit according to the second  aspect of the disclosure, the dimming control circuit outputs the control signal according to the dimming signal and the driving current, the current generator generates the driving current according to the control signal, the lighting device is provided with the driving current.
According to various embodiments of the present disclosure, a reference voltage providing circuit is used to provide the dimming control circuit with a first reference voltage when the dimming signal is below a predetermined voltage, therefore, a constant driving current could be obtained.
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 dimming control circuit in accordance with an embodiment of the present disclosure;
Fig. 2 is a diagram of a dimming control circuit in accordance with another embodiment of the present disclosure;
Fig. 3 shows a flowchart of a controlling method 300 of the dimming control circuit.
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 dimming control circuit is provided in a first embodiment.
Fig. 1 is a diagram of a dimming control circuit in accordance with an embodiment of the present disclosure. As shown in Fig. 1, a dimming control circuit 10 includes a dimming signal input port X2-c, a resistor string 11, a controller 12, and a reference voltage providing circuit 13.
In the embodiment, the dimming signal input port X2-c is configured to receive a dimming signal. The voltage of the dimming signal may be between a predetermined range, for example, the predetermined range is 0V～10V.
In the embodiment, the resistor string 11 is configured to connect the dimming signal input port X2-c and ground. The resistor string 11 may include at least 2 resisters that connect in series between the dimming signal input port X2-c and ground. For example, as shown in Fig. 1, the resistor string 11 may include 4 resistors R126, R125, R124 and R133. There is a first connecting node A in the resistor string 11 between R124 and R125, a second connecting node B in the resistor string 11 between R126 and R113.
In the embodiment, the controller 12 is configured to compare a first voltage  and a second voltage, and output a control signal according to a comparing result.
In the embodiment, the first voltage is provided by the resistor string 11. The second voltage is generated based on a driving current provided to a lighting device. For example, when the driving current is provided to the lighting device, current flows through the lighting device maybe detected, the detected current Isense may be provided to a resister R122 to generate the second voltage. In the embodiment, the lighting device is LED (Light Emitting Diode) for example.
The control signal is used for generating the driving current, for example, the control signal may be inputted to a current generator, the current generator generate the driving current according to the control signal, and the lighting device is provided with the driving current.
In the embodiment, the reference voltage providing circuit 13 is configured to provide the resistor string 11 with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage. For example, the predetermined voltage may be 1V, when the voltage of the dimming signal is below the predetermined voltage, the voltage of the dimming signal is in a range of 0V～1V.
According to the embodiments, the reference voltage providing circuit is used to provide the dimming control circuit with the first reference voltage when the dimming signal is below the predetermined voltage, so that a constant driving current could be obtained according to the first reference voltage. Therefore, the output power of the lighting device could be constant when the dimming signal is below the predetermined voltage.
In addition, when the voltage of the dimming signal is equal or higher than the predetermined voltage, the reference voltage providing circuit 13 may not provide the resistor string 11 with the first reference voltage. Therefore, the driving current may be obtained in accordance with the dimming signal.
In the embodiment, the controller 12 may be a constant voltage /constant current secondary side controller, for example, the controller 12 is NCS1002. However,  the embodiment is not limited there to, the controller 12 may be of other kind.
In the embodiment, as shown in Fig. 1, the controller 12 may include a first input port 5, a second input port 6 and a first output port 7.
In the embodiment, the first input port 5 connects to the second connecting node B of the resistor string, thus the first input port 5 receives the first voltage.
In the embodiment, the second input port 6 may be inputted the second voltage.
In the embodiment, the first output port 7 may output the control signal.
In the embodiment, as shown in Fig. 1, the controller 12 may further include a reference input port 3, which is provided with an internal reference voltage of the controller 12. For example, inner circuit of the controller 12 has a Zener diode, which is between the reference input port 3 and ground, therefore, voltage of the reference input port 3 is clamped by the Zener diode to the internal reference voltage. The internal reference voltage may be 2.5V as an example.
In the embodiment, as shown in Fig. 1, the controller 12 may further include a third input port 2, a second output port 1, a ground port 4 and a power supply port 8. The connection of these port may be referred to related art.
For example, the first voltage (in accordance with the dimming signal) at the first input port 5 is compared with the second voltage at the second input port 6, when the first voltage is lower than the second voltage, the first output port 7 will output a first control signal as the control signal. The first control signal has low voltage, which will conduct the diode D110A, and the current flows through a photocoupler U111 is getting larger, so that a feedback signal FB changes.
As shown in Fig. 1, the feedback signal FB may be inputted to a first side controller of the current generator 20. The first side controller may perform controlling according to the feedback signal FB, so that the current generator 20 generates the driving current, which will be proved to the lighting device. For example, the first side controller 20 may be NCP1200, and the current generator 20 may work as a switching mode power supplier (SMPS) . However, the embodiment is not limited there to, the first side controller  and the current generator 20 may be of other kind.
As can be seen from the above descriptions, the driving current is determined by the first voltage at the first input port 5. In this embodiment, when the voltage of the dimming signal is equal or higher than the predetermined voltage, the first voltage at the first input port 5 is obtained in accordance with the dimming signal; when the voltage of the dimming signal is lower than the predetermined voltage, the first voltage at the first input port 5 is obtained in accordance with the first reference voltage.
In addition, as shown in Fig. 1, a third voltage at the third input port 2 is compared with the internal reference voltage at the reference input port 3, when the third voltage is higher than the internal reference voltage, the second output port 1 will output a second control signal. The second control signal has low voltage, which will conduct the diode D110B, and the current flows through the photocoupler U111 is getting larger, so that the feedback signal FB changes. The first side controller may perform controlling according to the feedback signal FB as above mentioned. As shown in Fig. 1, the third voltage is generated according to a current outputted to the driving current, for example, the driving current may be provided to a resister R114 to generate the third voltage.
In the embodiment, the first reference voltage may be provided according to the internal reference voltage of the controller 12, therefore, extra power supplier will not be needed for providing the first reference voltage.
For example, the reference voltage providing circuit 13 may connect the reference input port 3 of the controller 12 and the first connecting node A of the resistor string. As shown in Fig. 1, the reference voltage providing circuit 13 may include more than two diodes, such as D113, D114 and D115. The more than two diodes connect in series between the reference input port 3 and the first connecting node A. However, the embodiment is not limited there to, other electronic element such as resistor or capacitor may be included in the reference voltage providing circuit 13.
When the voltage of the dimming signal is lower than the predetermined voltage, the more than two diodes D113, D114 and D115 conduct, so that the reference voltage providing circuit 13 may provide the first reference voltage which is constant voltage to  the first connecting node A of the resistor string 11. Therefore, the driving current may be obtained in accordance with the first reference voltage.
When the voltage of the dimming signal is equal or higher than the predetermined voltage, the more than two diodes D113, D114 and D115 may not conduct, the reference voltage providing circuit 13 will not provide the resistor string 11 with the first reference voltage. Therefore, the driving current may be obtained in accordance with the dimming signal.
Fig. 2 is a diagram of a dimming control circuit in accordance with another embodiment of the present disclosure. As shown in Fig. 2, a dimming control circuit 10a includes a dimming signal input port X2-c, a resistor string 11, a controller 12, and a reference voltage providing circuit 13a.
The first reference voltage 13a in Fig. 2 is different from the first reference voltage 13 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 first reference voltage may be provided according to an external voltage input to the controller 12. The external voltage may be provided by a low voltage power supplier (LVPS) .
As shown in Fig. 1 and Fig. 2, the external voltage provided by the LVPS may be denoted as SVCC. The external voltage may also be provided to the photocoupler U111, the power supply port 8 of the controller 12, and a resister R160.
As shown in Fig. 2, the reference voltage providing circuit 13a includes at least two resisters and at least one diode. For example, the resistors are R131 and R132, the diode may be D113.
In the embodiment, the at least two resisters R131 and R132 connect in series between an input port E of the external voltage and ground; the at least one diode D113a connects between the first connecting node A of the resistor string 11 and a connecting node C of the at least two resisters. The connecting node C maybe between resisters R131 and R132.
In Fig. 1 and Fig. 2, the first connecting node A and the second connecting node B are different. In other embodiment, the first connecting node A and the second connecting node B may be the same.
In the embodiment, as shown in Fig. 1 and Fig. 2, other components, such as resisters, capacitors and inductors, may be included in the  dimming control circuit  10 or 10a, descriptions for these components may be referred to the related art.
In the embodiment, values for parameters of components, such as resistance, capacitance, and inductance, are shown in Fig. 1 and Fig. 2. However, the embodiment is not limited there to, parameters of components may have other values.
As can be seen from the above mentioned embodiments, the reference voltage providing circuit is used to provide the dimming control circuit with the first reference voltage (constant voltage) when the dimming signal is below the predetermined voltage, so that a constant driving current could be obtained according to the first reference voltage. Therefore, the output power of the lighting device could be constant when the voltage of the dimming signal is below the predetermined voltage.
Second aspect of embodiments
A controlling method of a dimming control circuit. The dimming control 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. 3 shows a flowchart of a controlling method 300 of the dimming control circuit.
As shown in Fig. 3, the method 300 includes:
Block 301: receiving a dimming signal, via a dimming signal input port (X2-c) ;
Block 302: comparing a first voltage and a second voltage, and outputting a control signal according to a comparing result, the first voltage is provided by the resistor string which connects the dimming signal input port and ground, the second voltage is  generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current;
Block 303: providing the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
In the embodiment, the first reference voltage is provide according to an internal reference voltage of the controller, or the first reference voltage is provided according to an external voltage input to the controller.
As can be seen from the above mentioned embodiments, when the dimming signal is below the predetermined voltage, the first reference voltage (constant voltage) is provided for dimming control, so that a constant driving current could be obtained according to the first reference voltage instead of the dimming signal. Therefore, the output power of the lighting device could be constant when the voltage of the dimming signal is below the predetermined voltage.
Third aspect of embodiments
A lighting equipment is provided in an embodiment. The lighting equipment includes a current generator, a lighting device, and the dimming control circuit according to the first aspect of embodiments.
In the embodiment, as shown in Fig. 1 or Fig. 2, the dimming control circuit 10 (or 10a) outputs the control signal according to the dimming signal and the driving current, the current generator 20 generates the driving current according to the control signal, and the lighting device 30 is provided with the driving current.
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 (10)

  1. A dimming control circuit, comprising:
    a dimming signal input port (X2-c) , configured to receive a dimming signal;
    a resistor string, configured to connect the dimming signal input port and ground;
    a controller, configured to compare a first voltage and a second voltage, and output a control signal according to a comparing result, wherein, the first voltage is provided by the resistor string, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current;
    a reference voltage providing circuit, configured to provide the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
  2. The dimming control circuit according to claim 1, wherein,
    the first reference voltage is provided according to an internal reference voltage of the controller.
  3. The dimming control circuit according to claim 2, wherein,
    the controller comprises a reference input port, configured to be provided with the internal reference voltage,
    the reference voltage providing circuit connects the reference input port and a first connecting node of the resistor string.
  4. The dimming control circuit according to claim 3, wherein,
    the reference voltage providing circuit comprises more than two diodes, which connect in series between the reference input port and the first connecting node.
  5. The dimming control circuit according to claim 3, wherein,
    the controller further comprises:
    a first input port, configured to connect to a second connecting node of the resistor string;
    a second input port, configured to input the second voltage; and
    a first output port, configured to output the control signal.
  6. The dimming control circuit according to claim 1, wherein,
    the first reference voltage is provided according to an external voltage input to the controller.
  7. The dimming control circuit according to claim 6, wherein,
    the reference voltage providing circuit comprising at least two resisters and at least one diode,
    wherein,
    the at least two resisters connect in series between an input port of the external voltage and ground,
    the at least one diode connects between a first connecting node of the resistor string and a connecting node of the at least two resisters.
  8. A lighting equipment, comprises a current generator, a lighting device, and the dimming control circuit according to one of claims 1-7, wherein:
    the dimming control circuit outputs the control signal according to the dimming signal and the driving current,
    the current generator generates the driving current according to the control signal,
    the lighting device is provided with the driving current.
  9. A controlling method of a dimming control circuit, comprising:
    receiving a dimming signal, via a dimming signal input port (X2-c) ;
    comparing a first voltage and a second voltage, and outputting a control signal according to a comparing result, wherein, the first voltage is provided by the resistor string which connects the dimming signal input port and ground, the second voltage is generated based on a driving current provided to a lighting device, the control signal is used for generating the driving current; and
    providing the resistor string with a first reference voltage when the voltage of the dimming signal is below a predetermined voltage.
  10. The controlling method of a dimming control circuit according to claim 9, wherein,
    the first reference voltage is provide according to an internal reference voltage of the controller, or
    the first reference voltage is provided according to an external voltage input to the controller.
PCT/CN2018/077490 2018-02-28 2018-02-28 Dimming control circuit, controlling method and lighting equipment WO2019165587A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201307950Y (en) * 2008-05-21 2009-09-09 深圳市阳光富源科技有限公司 Multi-stage dimming control circuit for LED streetlight
CN201639821U (en) * 2010-02-01 2010-11-17 佛山市伊戈尔电业制造股份有限公司 Dimming control circuit of LED lamp
TWI390299B (en) * 2008-09-25 2013-03-21 Chimei Innolux Corp Backlight module and display including dimming control circuit
TWI467548B (en) * 2012-08-10 2015-01-01 Innocom Tech Shenzhen Co Ltd Backlight module and driving method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201307950Y (en) * 2008-05-21 2009-09-09 深圳市阳光富源科技有限公司 Multi-stage dimming control circuit for LED streetlight
TWI390299B (en) * 2008-09-25 2013-03-21 Chimei Innolux Corp Backlight module and display including dimming control circuit
CN201639821U (en) * 2010-02-01 2010-11-17 佛山市伊戈尔电业制造股份有限公司 Dimming control circuit of LED lamp
TWI467548B (en) * 2012-08-10 2015-01-01 Innocom Tech Shenzhen Co Ltd Backlight module and driving method thereof

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