CN116250376A - Control circuit, LED driver and control method - Google Patents

Control circuit, LED driver and control method Download PDF

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Publication number
CN116250376A
CN116250376A CN202080103900.2A CN202080103900A CN116250376A CN 116250376 A CN116250376 A CN 116250376A CN 202080103900 A CN202080103900 A CN 202080103900A CN 116250376 A CN116250376 A CN 116250376A
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China
Prior art keywords
signal
modulation signal
chip
dimmable
input
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CN202080103900.2A
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Chinese (zh)
Inventor
毛秋翔
王双红
林胜叠
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Tridonic GmbH and Co KG
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Tridonic GmbH and Co KG
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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]
    • H05B45/30—Driver circuits
    • H05B45/36—Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/305—Frequency-control circuits
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/39—Circuits containing inverter bridges
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dc-Dc Converters (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

The invention provides a control circuit, an LED driver and a control method. The controller is configured to output a modulation signal to the dimmable chip upon detection of the DC input, and the dimmable chip drives a switch of the transformer or the converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.

Description

Control circuit, LED driver and control method
Technical Field
Embodiments of the present disclosure relate generally to the field of electrical devices, and more particularly to control circuits, LED drivers, and control methods.
Background
This section presents a simplified summary that may facilitate a better understanding of aspects of the disclosure. Accordingly, the statements of this section are to be read in this light, and not as admissions of prior art.
In the lighting field, more and more products need to pass EMI (electromagnetic interference) tests with DC (direct current) emergency inputs, but the switching frequency is too constant to pass EMI tests.
To address this problem, for example, for products using dimmable chips, an EMI filter comprising a plurality of inductors may be added to the input of the product.
Disclosure of Invention
The inventors of the present disclosure have found that EMI filters comprising multiple inductors are large in size and costly.
In general, embodiments of the present disclosure provide a control circuit, an LED driver, and a control method. In an embodiment, the controller is configured to output a modulation signal to the dimmable chip upon detection of the DC input, and the dimmable chip drives a switch of the transformer or the converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.
In a first aspect, there is provided a control circuit comprising: a dimmable chip configured to drive a switch of a transformer or a converter; and a controller configured to output a modulation signal to the dimmable chip upon detection of the DC input, the dimmable chip driving the switch according to the modulation signal.
In one embodiment, when a DC input is detected, a modulation signal is output to the DIM pin of the dimmable chip.
In one embodiment, the modulated signal is a periodic modulated signal.
In one embodiment, the modulated signal is a PWM signal.
In one embodiment, the switch is a high frequency switch and the switch includes two transistors.
In one embodiment, the controller is configured to not output a modulation signal to the dimmable chip when an AC input is detected.
In one embodiment, the dimmable chip is further configured to regulate the output current of the transformer or converter.
In one embodiment, the controller is a microcontroller unit (MCU).
In a second embodiment, there is provided an LED driver including: the control circuit according to the first embodiment.
In one embodiment, the LED driver further comprises: a transformer or converter configured to transfer energy to an output controlled by the switch.
In one embodiment, the LED driver further comprises: a detection circuit configured to detect whether an input of the LED driver is a DC input or an AC input.
In a third embodiment, there is provided a control method of an LED driver, the control method including: when detecting the DC input, the controller outputs a modulation signal to the dimmable chip; and the dimmable chip drives the switch of the transformer or the converter according to the modulation signal.
In one embodiment, the modulated signal is a periodic modulated signal.
In one embodiment, the modulated signal is a PWM signal.
According to various embodiments of the present disclosure, the controller is configured to output a modulation signal to the dimmable chip upon detection of the DC input, and the dimmable chip drives a switch of the transformer or the converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.
Drawings
The above and other aspects, features and advantages of various embodiments of the present disclosure will become more 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 figures are illustrated for the sake of a better understanding of the embodiments of the disclosure and are not necessarily drawn to scale, wherein:
FIG. 1 is a diagram of a control circuit having an embodiment of the present disclosure;
FIG. 2 is a diagram of an LED driver having an embodiment of the present disclosure;
FIG. 3 is a circuit diagram of an LED driver having an embodiment of the present disclosure;
fig. 4 is a flowchart of a control method of an LED driver having an embodiment of the present disclosure.
Detailed Description
The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only in order to enable those skilled in the art to better understand the present disclosure and thus practice the present disclosure, and are not intended to limit the scope of the present disclosure in any way.
The terms "first" and "second" as used herein refer to different elements. The singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "containing" specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Other explicit and implicit definitions may be included below.
First embodiment
In a first embodiment, a control circuit is provided.
Fig. 1 is a diagram of a control circuit having an embodiment of the present disclosure. As shown in fig. 1, the control circuit 100 includes:
a dimmable chip 110 configured to drive a switch of a transformer or a converter; and
a controller 120 configured to output a modulation signal to the dimmable chip upon detection of a DC input.
In one embodiment, the dimmable chip 110 drives the switch by a drive signal. For example, the driving signals are output from TX1 and TX2 pins of the dimmable chip 110.
In one embodiment, the control circuit 100 may be applied in any product that includes a dimmable chip, such as an LED driver.
The LED driver may comprise a transformer or a converter.
In one embodiment, a transformer or converter delivers energy to an output controlled by a switch.
In one embodiment, the switch is a high frequency switch. For example, the switch includes two transistors, such as Field Effect Transistors (FETs).
In one embodiment, the LED driver may be dimmable via the dimmable chip 110 with a PWM (pulse width modulation) signal or an analog signal. That is, the dimmable chip 110 is further configured to adjust the output current of the transformer or the converter according to the PWM signal or the analog signal.
In one embodiment, the dimmable chip 110 may be any type of dimmable chip, such as RED2821.
In one embodiment, the controller 120 outputs a modulation signal to the dimmable chip 110 according to the detection signal.
For example, when a DC input is detected, the controller 120 outputs a modulation signal to the dimmable chip 110. And when an AC input is detected, the controller 120 does not output a modulation signal to the dimmable chip 110. The DC input or AC input is a power supply input or a mains supply input.
For example, when a DC input is detected, the modulated signal is output to the DIM pin of the dimmable chip.
For example, when a DC input of the LED driver is detected, the pin of the controller 120 is not pulled down and the controller 120 outputs a modulation signal. Alternatively, when a DC input of the LED driver is detected, a pin of the controller 120 is pulled down and the controller 120 outputs a modulation signal.
In one embodiment, any detection method may be used to detect whether the input to the LED driver is a DC input or an AC input.
For example, AC current may pass through a capacitor, while DC current may be isolated by a capacitor, and this characteristic of the capacitor may be applied to detect whether the input of the LED driver is a DC input or an AC input.
When AC is input, a path including a capacitor is turned on and an optocoupler connected to the path is turned on, and a low level is provided to a pin of the controller 120. In other words, the pin of the controller 120 is pulled down, and the controller 120 does not output the modulation signal to the dimmable chip 110.
When DC is input, the path including the capacitor is opened and the optocoupler is opened, and a low level is not provided to the pin of the controller 120. In other words, the pin of the controller 120 is not pulled down, and the controller 120 outputs a modulation signal to the dimmable chip 110.
In one embodiment, the controller 120 is configured to receive a signal from the dimming interface and to modulate the signal depending on the signal from the dimming interface and whether a DC input is detected. That is, the controller 120 combines the signal from the dimming interface and the detection signal, and outputs the modulated signal to the dimmable chip 110.
In one embodiment, the dimmable chip 110 drives the switch according to the modulation signal.
In one embodiment, the modulated signal is a pulse modulated signal or an amplitude modulated signal. For example, the modulation signal is a PWM (pulse width modulation) signal or a pulse duration modulation signal or an analog signal, such as an analog signal voltage level.
The parameters of the PWM signal or the analog signal may be set according to actual requirements.
For example, the frequency of the PWM signal may be set to 100Hz to 100kHz.
For example, the duty cycle of the PWM signal or analog signal may be adjusted according to the requirements of the output current.
When a PWM signal or an analog signal is input to the DIM pin of the dimmable chip 110, the TX1 and TX2 pins of the dimmable chip 110 may output a driving signal to the switch at a high level of the PWM signal, and the TX1 and TX2 pins may not output a driving signal to the switch at a low level of the PWM signal. Thus, the switch is driven according to the PWM signal. Thus, due to the change in the switching frequency of the converter or transformer, EMI testing is possible.
In one embodiment, the controller is a microcontroller unit (MCU).
In one embodiment, other configurations and functions of the control circuit may be similar to those in the relevant art, and further details of these components should not be described further herein.
As can be seen from the above embodiments, the controller is configured to output a modulation signal to the dimmable chip upon detection of a DC input, and the dimmable chip drives the switch of the transformer or converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.
Second embodiment
In a second embodiment, an LED driver is provided.
Fig. 2 is a diagram of an LED driver with an embodiment of the present disclosure.
As shown in fig. 2, the LED driver 10 includes:
a control circuit 100 configured to drive at least one switch according to a modulation signal, the structure and function of which are the same as those described in the first embodiment, which shall not be described further herein;
a detection circuit 200 configured to detect whether an input of the LED driver is a DC input or an AC input;
a dimming interface 600 configured to receive a dimming signal and control an output current or output power of the LED driver 10;
a converter or transformer 300 configured to transfer energy to an output controlled by the switch.
In one embodiment, the LED driver 10 may further include a filter circuit 400 and a rectifying circuit 500, which may be similar in construction and function to those in the relevant art, and further details of these components should not be described herein.
In one embodiment, the LED driver 10 may be used to drive the LED 20 as an output load. The LED driver 10 may control the current, voltage, or power supplied to the LED 20 according to the dimming signal received by the dimming interface 600. The control circuit 100 may combine two signals received from the detection circuit 200 and the dimming interface 600, and may drive the switch according to the combination of the two signals.
Fig. 3 is a circuit diagram of an LED driver having an embodiment of the present disclosure.
As shown in fig. 3, a dimmable chip RED2821, which is one example of an integrated control chip for an LED driver, and a micro controller unit MCU constitute a control circuit 100.
When AC is input, the path including the capacitor C1 is turned on and the optocoupler connected to the path is turned on, and a low level is provided to the pin of the MCU 120. And the MCU does not output a PWM signal or an analog signal to the DIM pin of the dimmable chip RED2821, the TX1 and TX2 pins of the dimmable chip RED2821 output driving signals to the switch composed of the transistors Q1 and Q2, and the switch operates.
When DC is input, the path including the capacitor C1 is opened and the optocoupler is opened, and a low level is not provided to the pin of the MCU. Then, the MCU outputs PWM signals or analog signals to the DIM pins of the dimmable chip RED2821 according to signals (DIM+ and DIM-) from the dimming interface. The dimming interface 600 is preferably designed to receive a dimming control signal, such as a 1V-10V dimming signal. When a PWM signal or an analog signal is input to the DIM pin of the dimmable chip 110, the TX1 and TX2 pins of the dimmable chip RED2821 output a driving signal to the switch at a high level of the PWM signal or the analog signal, and the TX1 and TX2 pins do not output a driving signal to the switch at a low level of the PWM signal or the analog signal. Thus, the switch is driven and operated according to the PWM signal or the analog signal.
In one embodiment, other configurations and functions of the LED driver may be similar to those in the relevant art, and further details of these components should not be described further herein.
As can be seen from the above embodiments, the controller is configured to output a modulation signal to the dimmable chip upon detection of a DC input, and the dimmable chip drives the switch of the transformer or converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.
Third embodiment
In a third embodiment, a control method of an LED driver is provided, which corresponds to the control circuit described in the first embodiment.
Fig. 4 is a flowchart of a control method of an LED driver having an embodiment of the present disclosure. As shown in fig. 4, the method includes:
step 401: when detecting the DC input, the controller outputs a modulation signal to the dimmable chip; and
step 402: the dimmable chip drives a switch of the transformer or the converter according to the modulation signal.
In one embodiment, the modulated signal is a pulse modulated signal or an amplitude modulated signal. For example, the modulation signal is a PWM signal or an analog signal.
In one embodiment, reference may be made to what has been described in the first embodiment for a specific implementation of the steps described above, which shall not be described further herein.
As can be seen from the above embodiments, the controller is configured to output a modulation signal to the dimmable chip upon detection of a DC input, and the dimmable chip drives the switch of the transformer or converter according to the modulation signal. Accordingly, due to the change in the switching frequency of the converter or transformer, the EMI test can be passed, and an EMI filter including a plurality of inductors is not required, and a compact size and low cost are realized.
Generally, although operations are shown 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 some cases, multitasking and parallel processing may be advantageous. Also, while several specific implementation details are included in the above discussion, these specific implementation details should not be construed as limiting the scope of the present disclosure, but as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.
Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the 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 (15)

1. A control circuit, comprising:
a dimmable chip configured to drive a switch of a transformer or a converter; and
a controller configured to output a modulation signal to the dimmable chip upon detection of a DC input,
the adjustable light chip drives the switch according to the modulation signal.
2. The control circuit of claim 1, wherein,
the controller is configured to receive a signal from the dimming interface and the modulation signal is dependent on the signal from the dimming interface and whether a DC input is detected.
3. The control circuit according to claim 1 or 2, wherein,
when a DC input is detected, the modulated signal is output to the DIM pin of the dimmable chip.
4. The control circuit according to claim 1 or 2, wherein,
the modulation signal is a pulse modulation signal or an amplitude modulation signal.
5. The control circuit of claim 4, wherein,
the modulation signal is a PWM signal or an analog signal.
6. The control circuit of claim 1, wherein,
the switch is a high-frequency switch,
and the switch comprises two transistors.
7. The control circuit of claim 1, wherein,
the controller is configured not to output the modulation signal to the dimmable chip when an AC input is detected.
8. The control circuit of claim 1, wherein,
the dimmable chip is further configured to adjust an output current of the transformer or the converter.
9. The control circuit of claim 1, wherein,
the controller is a microcontroller unit (MCU).
10. An LED driver, comprising:
the control circuit according to any one of claims 1 to 9.
11. The LED driver of claim 10, wherein the LED driver further comprises:
a dimming interface configured to receive a dimming signal and control an output current or output power of the LED driver.
12. The LED driver according to claim 10 or 11, wherein the LED driver further comprises:
a transformer or converter configured to transfer energy to an output controlled by the switch; and
a detection circuit configured to detect whether an input of the LED driver is a DC input or an AC input.
13. A control method of an LED driver, the control method comprising:
when detecting the DC input, the controller outputs a modulation signal to the dimmable chip; and is also provided with
The adjustable light chip drives a switch of a transformer or a converter according to the modulation signal.
14. The control method according to claim 13, wherein,
the modulation signal is a pulse modulation signal or an amplitude modulation signal.
15. The control method according to claim 13 or 14, wherein,
the modulation signal is a PWM signal or an analog signal.
CN202080103900.2A 2020-08-14 2020-08-14 Control circuit, LED driver and control method Pending CN116250376A (en)

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Application Number Priority Date Filing Date Title
PCT/CN2020/109141 WO2022032632A1 (en) 2020-08-14 2020-08-14 Control circuit, led driver and control method

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