CN112020169B - Light modulation controller capable of receiving pulse width modulation signal and direct current signal and light modulation method - Google Patents
Light modulation controller capable of receiving pulse width modulation signal and direct current signal and light modulation method Download PDFInfo
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- CN112020169B CN112020169B CN201910392590.XA CN201910392590A CN112020169B CN 112020169 B CN112020169 B CN 112020169B CN 201910392590 A CN201910392590 A CN 201910392590A CN 112020169 B CN112020169 B CN 112020169B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- 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
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The invention provides a dimming controller which is suitable for dimming a light emitting component and comprises a dimming input end, a signal identifier, a selector and a direct current-to-PWM converter. The dimming input receives a dimming signal, which is either DC or PWM. The signal identifier is connected to the dimming input end and used for identifying that the dimming signal positioned on the dimming input end is direct current or PWM. The selector is connected to the dimming input terminal through different direct current signal paths and PWM signal paths and is controlled by the signal identifier. The DC-to-PWM converter is coupled to the selector for converting the DC signal into a PWM signal for dimming the light emitting component. When the signal identifier considers the dimming signal to be direct current, the signal identifier enables the selector to select a direct current signal path to connect the dimming input end to the direct current-to-PWM converter. When the signal identifier considers the dimming signal to be PWM, the signal identifier enables the selector to select a PWM signal path to connect the dimming input terminal to the DC-to-PWM converter.
Description
Technical Field
The present invention relates to a dimming controller and a related dimming method, and more particularly, to a dimming controller capable of receiving dimming signals of different types and a related dimming method.
Background
Good luminous efficiency, reduced component volume, and long component lifetime have LED to the widespread adoption of Light Emitting Diodes (LEDs) in the lighting or backlighting industries. For example, backlight modules in computer or television screens have mostly been converted from conventional cold cathode tube (Cold Cathode Fluorescent Lamp, CCFL) modules to LED modules.
LED modules often require a function of adjusting the brightness of the screen, and thus, the LED modules are likely to have dimming controllers. There are two general dimming modes in the industry: pulse-width-modulation (PWM) dimming (PWM dimming), and analog dimming (analog dimming). PWM dimming is also known as digital dimming. PWM dimming uses a PWM signal that jumps between logic values 0 and 1 to determine the ratio of the LED module in light-emitting time to the entire cycle time, i.e., duty cycle; and when the LED module emits light, the light-emitting brightness of the LED module is a fixed value; the LED module emits substantially no light at a non-light emission time other than the light emission time. In contrast, an LED module employing analog dimming (also referred to as resistive dimming) emits light continuously, but the brightness is controlled by a direct-current (DC) signal. The direct current signal is also called analog (analog) signal.
The dimming controller can preferably receive a direct current signal or a PWM signal, so that the dimming controller can be widely applied.
Disclosure of Invention
The embodiment of the invention provides a dimming controller which is suitable for dimming a light-emitting component. The dimming controller comprises a dimming input end, a signal identifier, a selector and a direct current-to-PWM converter. The dimming input may receive a dimming signal, which may be DC or PWM. The signal identifier is connected to the dimming input end and used for identifying that the dimming signal positioned on the dimming input end is direct current or PWM. The selector can be connected to the dimming input terminal through different direct current signal paths and a PWM signal path, and is controlled by the signal identifier. The DC-to-PWM converter is coupled to the selector for converting a DC signal into a PWM signal for dimming the light emitting component. When the signal identifier considers the dimming signal to be direct current, the signal identifier enables the selector to select the direct current signal path to connect the dimming input end to the direct current-to-PWM converter. When the signal identifier considers the dimming signal to be PWM, the signal identifier enables the selector to select the PWM signal path to connect the dimming input end to the direct current-to-PWM converter.
The embodiment of the invention provides a dimming method which is suitable for dimming a light-emitting component. The dimming method comprises the following steps: receiving a dimming signal, which can be direct current or PWM; identifying the dimming signal as direct current or PWM; providing a direct current signal path and a PWM signal path; when the dimming signal is direct current, selecting the direct current signal path to generate a direct current signal; when the dimming signal is PWM, selecting the PWM signal path for generating the DC signal; and converting the direct current signal to generate a PWM signal for dimming the light emitting component.
Drawings
Fig. 1 shows a dimming controller implemented according to the present invention.
Fig. 2 shows a dimming controller, which can be applied to fig. 1.
Fig. 3 shows a control conversion unit for converting a direct current into a digital PWM, for example, a dimming signal S is shown DIM Saw tooth wave S SAW And PWM signal S PWM Is a waveform of (a).
Fig. 4 shows a dimming signal S DIM Having two falling edges FA1 and FA2 and a rising edge RA1.
Fig. 5 illustrates a dimming method employed by the dimming controller of fig. 2.
Fig. 6 shows another dimming controller applicable to fig. 1.
Fig. 7 illustrates a dimming method employed by the dimming controller of fig. 6.
Fig. 8 shows another dimming controller applicable to fig. 1.
Fig. 9 illustrates a dimming method employed by the dimming controller of fig. 8.
Fig. 10 shows another dimming controller applicable to fig. 1.
Fig. 11 illustrates a dimming method employed by the dimming controller of fig. 10.
List of reference numerals
10. 10a, 10b, 10c, 10d: light modulation controller
12: signal identifier
14a, 14b: LED driver
15: low pass filter
16. 16a: DC-to-PWM converter
17a, 17b: selector
18: digital buffer
19: PWM-DC converter
20: signal generator
22: comparator with a comparator circuit
24: operational amplifier
26：68c
28: voltage level converter
30: operational amplifier
31: constant current source
60a, 60b, 60c: dimming method
62. 64, 67, 68a, 68b, 68c, 70a, 70b, 70c, 70d, 72a, 72b, 74, 76: step (a)
C1: capacitance device
CS: current detection terminal
DIM: dimming input terminal
DRV: drive end
FA1, FA2: falling edge
GND: grounding wire
I SET : constant current
LT: light emitting assembly
MNDRV: power transistor
PTH DC : DC signal path
PTH PWM : PWM signal path
RA1: rising edge
RCS: current detection resistor
R1: resistor
RDIM: variable resistor
SB PWM : temporary PWM signal
SC PWM : PWM signal
S DC : DC signal
S DIM : dimming signal
S DIM-PWM : PWM signal
S DRV : drive signal
SD DC : DC signal
SD XX : output of
S PWM : PWM signal
S SAW : sawtooth wave
S SEL : selection signal
T DELAY : predetermined delay
V CS : current detection signal
V DC : DC signal
V REF 、V REF-L 、V REF-H : reference voltage
Detailed Description
In this description, there are some common symbols that represent components having the same or similar structure, function, and principle, and are obvious to those skilled in the art from the teachings of this description. For simplicity of the description, components with the same symbols will not be repeated.
Fig. 1 shows a dimming controller 10 according to the present invention, which is adapted to dim a light emitting device LT by controlling a power transistor MNDRV.
The power transistor MNDRV may be an NMOS transistor, and the light emitting element LT may be one or several Light Emitting Diodes (LEDs) connected in series or parallel. The dimming controller 10 provides a driving signal S through the driving end DRV DRV To control the power transistor MNDRV. Drive signal S DRV Either a PWM signal or a DC signal. The current flowing through the light emitting component LT passes through the current detection resistor RCS to generate a current detection signal V CS Received by the dimmer controller 10 through the current sense terminal CS. The dimming controller 10 receives a dimming signal S from a dimming input DIM DIM Thereby generating a driving signal S DRV 。
As shown in fig. 1, the dimming controller 10 may accept three different external signal input modes to perform dimming. The first is to provide DC signal V from outside DC To the dimming input terminal DIM as a dimming signal S DIM And direct current signal V DC Represents the average luminance that the light emitting element LT should produce. The second type is to connect a variable resistor RDIM between the dimming input DIM and a ground GND, and the resistance of the variable resistor RDIM will be converted into a voltage level of a dc signal on the dimming input DIM, which represents the average brightness of the light emitting device LT. Third is to provide PWM signal S from outside DIM-PWM To the dimming input terminal DIM as a dimming signal S DIM While PWM signal S DIM-PWM The duty cycle of the light emitting element LT represents the average luminance of the light emitting element LT.
In other words, the dimming signal S DIM Either a direct current signal or a PWM signal. Dimming signal S DIM One of two forms is possible, and the two forms are dc and PWM.
Fig. 2 shows a dimmer controller 10a, which may be used as the dimmer controller 10 of fig. 1 in one embodiment. The dimming controller 10a includes a signal identifier 12, a dc-to-PWM converter 16, a selector 17a, an LED driver 14a, and a constant current source 31.
The dc-to-PWM converter 16 is a form converter. If dimming signal S DIM Is a DC signal which the DC-to-PWM converter 16 can convert to provide a corresponding PWM signal S PWM . In fig. 2, the dc-to-PWM converter 16 includes a signal generator 20, an operational amplifier 24, and a comparator 22. Please refer to fig. 3. Fig. 3 shows a dimming signal S DIM-- And the control conversion unit is used for converting a direct current signal into digital PWM. For example, a common circuit such as the operational amplifier 24 is configured as a Unity-Gain Buffer (Unity-Gain Buffer) for adjusting the dimming signal S DIM Is reproduced at the non-inverting input of comparator 22. The signal generator 20 generates a sawtooth wave S SAW Is provided to an inverting input of comparator 22. The comparator 22 compares the dimming signal S DIM And saw tooth wave S SAW To generate PWM signal S PWM I.e. as shown in fig. 3.
The signal identifier 12 is connected to the dimming input terminal DIM for identifying the dimming signal S at the dimming input terminal DIM DIM For DC or PWM, to generate a selection signal S SEL Which controls the selector 17a. In the embodiment of fig. 2, the signal S is selected SEL When the logical 1 is detected, the signal identifier 12 recognizes the dimming signal S DIM Is a PWM signal; conversely, when the signal identifier 12 considers the dimming signal S DIM When the signal is a DC signal, the selector 17a makes the selection signal S SEL Is logically 0.
In one embodiment, the signal identifier 12 is based on the dimming signal S DIM To determine the selection signal S SEL . Please refer to fig. 4, wherein a dimming signal S is shown DIM Having two falling edges FA1 and FA2 and a rising edge RA1. The signal identifier 12 may generate the selection signal based on whether there are a sufficient number of falling and rising edges, the absolute value of which is greater than a predetermined value, within a predetermined time. For example, if the signal identifier 12 finds that there are more than 4 falling edges and rising edges in 8ms, the absolute value of the slope is greater than 0.1V/us, the dimming signal S is asserted DIM Is a PWM signal, which makes the selection signal S SEL Is logically 1. Conversely, if no more than 4 falling and rising edges with absolute slopes greater than 0.1V/us are present in 8ms, the dimming signal S is asserted DIM Is a direct current signal, makes the selection signal S SEL Is logically 0.
For example, in fig. 4, the signal identifier 12 will dim the signal S DIM Low to cross reference voltage V REF-H And is considered to be the beginning of the falling edge FA 1. Then compare at a predetermined delay T DELAY Post dimming signal S DIM With reference voltage V REF-L Thereby determining whether the absolute value of the slope of the falling edge FA1 is greater than (V) REF-H –V REF-L )/T DELAY . Similarly, the signal identifier 12 will adjust the dimming signal S DIM Up to and across reference voltage V REF-L At this time, the start of the rising edge RA1 is considered. Then compare at a predetermined delay T DELAY Post dimming signal S DIM With reference voltage V REF-H Thereby determining whether the absolute value of the slope of the rising edge RA1 is greater than (V) REF-H –V REF-L )/T DELAY . In another embodiment, the signal identifier 12 can also be based on the dimming signal S DIM From reference voltage V REF-H To reference voltage V REF-L Whether or not the fall time of (2) is greater than a predetermined delay T DELAY To identify whether the falling edge is steep enough to represent the falling edge of a PWM signal. Similarly, the signal identifier 12 may also be based on dimmingSignal S DIM From reference voltage V REF-L To reference voltage V REF-H Whether or not the rise time of (2) is greater than a predetermined delay T DELAY To identify whether a rising edge is steep enough to represent a rising edge of a PWM signal.
The selector 17a in fig. 2, which is controlled by the signal identifier 12, has two inputs for receiving the PWM signals S, respectively PWM Dimming signal S DIM . The selector 17a includes a digital buffer 18 and a multiplexer (multiplexer) 26. When the signal identifier 12 considers the dimming signal S DIM When the signal is a DC signal, the selector 17a selects the PWM signal S PWM To LED driver 14a. When the signal identifier 12 considers the dimming signal S DIM When the signal is a PWM signal, the dimming signal S DIM Passes through the digital buffer 18 to the multiplexer 26, is selected by it and passes to the LED driver 14a. In other words, the output of multiplexer 26, if not PWM dimming signal S DIM Is representative of a DC dimming signal S DIM PWM signal S of (2) PWM 。
The selection signal S shown in FIG. 2 SEL Only the selector 17a is controlled, but the present invention is not limited thereto. For example, in one embodiment, when the signal identifier 12 asserts the dimming signal S DIM In the case of a PWM signal, the signal identifier 12 is provided by selecting the signal S SEL So that the dc-to-PWM converter 16 is turned off entirely to save power. Similarly, when the signal identifier 12 considers the dimming signal S DIM In the case of a DC signal, the digital buffer 18 may also be selectively turned off to save unnecessary power.
The LED driver 14a controls the power transistor MNDRV according to the output of the multiplexer 26, thereby controlling the current flowing through the light emitting element LT. When the output of the multiplexer 26 is logically 1, the voltage level converter 28 outputs the reference voltage V REF The operational amplifier 30 controls the power transistor MNDRV so that the current of the light emitting element LT is approximately V REF /R CS Wherein R is CS The resistance value of the current detection resistor RCS. When the output of the multiplexer 26 is logically 0, the voltage level converter 28 outputs 0V to make the current of the light emitting device LT largeAbout 0.
Constant current source 31 provides constant current I SET Which flows through the dimming input terminal DIM and can be used for generating a DC dimming signal S DIM . If there is a variable resistor RDIM between the dimming input terminal DIM and the ground GND, a constant current I SET Can flow through a variable resistor RDIM to generate direct current voltage at a dimming input end DIM as a dimming signal S DIM . When the outside directly provides the DC signal V DC Or PWM signal S DIM-PWM As the dimming signal S DIM At the time, constant current I SET Substantially does not affect the DC signal V DC Or PWM signal S DIM-PWM 。
Fig. 5 illustrates a dimming method 60a employed by the dimming controller 10a of fig. 2.
In step 62, the dimming controller 10a receives the dimming signal S through the dimming input DIM DIM It may be a PWM signal or a dc signal.
Dimming controller 10a of fig. 2 and dimming controller 10b of fig. 5The dimming method 60a has the following advantages. When dimming signal S DIM In the case of a DC signal, a corresponding PWM signal S can be generated PWM The LED driver 14a is provided to drive the light emitting element LT. When dimming signal S DIM In the case of a PWM signal, the dimming signal S DIM The dimming signal is directly sent to the LED driver 14a, so that the actually required dimming state can be faithfully and accurately reflected. In other words, no matter what the dimming signal S DIM The dimming controller 10a can properly drive the light emitting element LT either as a direct current signal or as a PWM signal.
Fig. 6 shows a dimmer controller 10b, which in one embodiment may be used as the dimmer controller 10 of fig. 1. The dimming controller 10b includes a signal identifier 12, a PWM-to-dc converter 19, a selector 17b, an LED driver 14b, and a constant current source 31. In fig. 6, some devices have been disclosed in fig. 2, and the operation thereof can be known from the previous explanation about fig. 2, and will not be described again.
The PWM-to-dc converter 19 is a form converter. If dimming signal S DIM Is a PWM signal which is converted by a PWM-to-DC converter 19 to provide a corresponding DC signal S DC . In fig. 6, the PWM-dc converter 19 includes a digital buffer 18, a resistor R1, and a capacitor C1. The digital buffer 18 handles the dimming signal S DIM Is provided to resistor R1. The resistor R1 and the capacitor C1 form a low-pass filter for generating a DC signal S DC Which approximately represents the dimming signal S DIM Is provided).
The selector 17b in fig. 6, which is controlled by the signal identifier 12, has two inputs for receiving the dc signal S respectively DC Dimming signal S DIM . The selector 17b includes an operational amplifier 24 and a multiplexer 26. When the signal identifier 12 considers the dimming signal S DIM In the case of a DC signal, the operational amplifier 24 serves as a unit gain buffer for supplying the dimming signal S DIM To the multiplexer 26, which in turn transmits the dimming signal S DIM To LED driver 14b. When the signal identifier 12 considers the dimming signal S DIM When the signal is a PWM signal, the selector 17b selects the DC signal S DC And deliverTo LED driver 14b. In other words, the output of the multiplexer 26 is not the DC dimming signal S DIM Is representative of PWM dimming signal S DIM Direct current signal S of (2) DC 。
The LED driver 14b controls the power transistor MNDRV according to the output of the multiplexer 26, thereby controlling the current flowing through the light emitting element LT. For example, when the voltage level of the output of the multiplexer 26 is V OUT At this time, the operational amplifier 30 controls the power transistor MNDRV so that the current of the light emitting element LT is about V OUT /R CS 。
Fig. 7 illustrates a dimming method 60b employed by the dimming controller 10b of fig. 6. The dimming method 60b has some steps identical or similar to those of the dimming method 60a, and can be known from the previous description of the dimming method 60a or the dimming controller 10a, and will not be described again.
The selection signal S shown in FIG. 6 SEL Only the selector 17b is controlled, but the present invention is not limited thereto. For example, in one embodiment, when the signal identifier 12 asserts the dimming signal S DIM In the case of a PWM signal, the signal identifier 12 is provided by selecting the signal S SEL The operational amplifier 24 is disabled or turned off to save power. Similarly, when the signal identifier 12 considers the dimming signal S DIM In the case of a DC signal, the digital buffer 18 may also be selectively turned off to save unnecessary powerAnd energy consumption.
The dimming controller 10b of fig. 6 and the dimming method 60b of fig. 7 have the following advantages. When dimming signal S DIM In the case of a direct current signal, the direct current signal can be transmitted to the LED driver 14b to drive the light emitting element LT with approximately faithful. When dimming signal S DIM In the case of a PWM signal, the PWM-DC converter 19 generates a corresponding DC signal S DC The LED driver 14b is provided to drive the light emitting element LT. Thus, no matter what the dimming signal S DIM The dimming controller 10b may provide the appropriate dc signal to the LED driver 14b for either dc or PWM.
The invention is not limited to driving only LEDs, but in other embodiments other light emitting devices may be driven.
Fig. 8 shows a dimmer controller 10c, which in one embodiment may be used as the dimmer controller 10 of fig. 1. The dimming controller 10c includes a signal identifier 12, a PWM-to-dc converter 19, a selector 17b, a dc-to-PWM converter 16a, an LED driver 14a, and a constant current source 31. In fig. 8, some devices have been disclosed in fig. 2 and 6, and the operation thereof may be known from the previous descriptions related to fig. 2 and 6, which will not be described again.
The PWM-to-dc converter 19 is a form converter. If dimming signal S DIM Is a PWM signal which is converted by a PWM-to-DC converter 19 to provide a corresponding DC signal S DC . In fig. 8, the PWM to dc converter 19 includes a digital buffer 18 and a low pass filter 15. The digital buffer 18 handles the dimming signal S DIM Generates a temporary PWM signal SB PWM And is provided to resistor R1. The low-pass filter 15 has a resistor R1 and a capacitor C1 for low-pass filtering the temporary PWM signal SB PWM To generate a DC signal S DC Which approximately represents the dimming signal S DIM Is provided).
Temporary PWM signal SB PWM The duty cycle of (d) will be related to the dimming signal S DIM The duty cycle of the same, but temporary PWM signal SB PWM The logic level of the logic "1" of (2) is not necessarily equal to the dimming signal S DIM Logic level one of logic "1" of (2)And (5) sampling. For example, when the dimming signal S DIM When the logic is 0, the logic level is 0V; when dimming signal S DIM With a logic "1", its logic level may be 1V, 3V or 5V. While the temporary PWM signal SB PWM The logic level of logic "0" is 0V, while the logic level of logic "1" must be a default 5V. Therefore, the digital buffer 18 can also be regarded as a level shifter (level shifter), regardless of the dimming signal S DIM The logic level of the logic "1" of (2) may enable the temporary PWM signal SB PWM With a default logic level.
The selector 17b in fig. 8, which is controlled by the signal identifier 12, has two inputs for receiving the dc signals S, respectively DC Dimming signal S DIM . The selector 17b includes an operational amplifier 24 and a multiplexer 26. When the signal identifier 12 considers the dimming signal S DIM In the case of a DC signal, the operational amplifier 24 serves as a unit gain buffer for supplying the dimming signal S DIM To multiplexer 26 as DC signal SD DC To the dc-to-PWM converter 16a. When the signal identifier 12 considers the dimming signal S DIM When the signal is a PWM signal, the selector 17b selects the DC signal S DC As a direct current signal SD DC To the dc-to-PWM converter 16a. In other words, the output of the multiplexer 26 (DC signal SD DC ) If not DC, the dimming signal S DIM Is representative of PWM dimming signal S DIM Direct current signal S of (2) DC 。
The selector 17b equally passes through different direct current signal paths PTH DC PWM signal path PTH PWM Is connected to the dimming input DIM. The digital buffer 18 and the low-pass filter 15 in the PWM-to-DC converter 19 are both located in the PWM signal path PTH PWM And (3) upper part. When the signal identifier 12 considers the dimming signal S DIM When the signal is direct current, the signal identifier 12 causes the selector 17b to select the direct current signal path PTH DC To connect the dimming input DIM to the dc-to-PWM converter 16a. When the signal identifier 12 considers the dimming signal S DIM In the case of PWM, the signal identifier 12 causes the selector 17b to select the PWM signal path PTH PWM To connect light-adjusting inputThe input DIM to the dc-to-PWM converter 16a.
The DC-to-PWM converter 16a converts the DC signal SD DC Providing corresponding PWM signals SC PWM . In fig. 8, the dc-to-PWM converter 16a includes a signal generator 20 and a comparator 22. The signal generator 20 generates a sawtooth wave S SAW Is provided to an inverting input of comparator 22. Comparator 22 compares direct current signal SD DC And saw tooth wave S SAW To generate PWM signal SC PWM Similar to the function shown in fig. 3. Thus, PWM signal SC PWM Is about a constant value, and is compared with the original dimming signal S DIM Irrespective of the fact that the first and second parts are. Also, PWM signal SC PWM Either for a logical "0" or "1", can be customized as appropriate for the LED driver 14a.
The LED driver 14a in fig. 8 is based on the PWM signal SC PWM The power transistor MNDRV is manufactured to control the current flowing through the light emitting element LT.
Fig. 9 illustrates a dimming method 60c employed by the dimming controller 10c of fig. 8. Some steps of the dimming method 60c are the same as or similar to those of the dimming methods 60a and 60b, and it can be known from the previous descriptions of the dimming methods 60a and 60b, and will not be further described.
In fig. 9, step 68b follows step 67, and the low-pass filter 15 converts the temporary PWM signal SB PWM Generating a corresponding DC signal S DC 。
In FIG. 9, step 70c follows step 68b, and the selector 17b selects the DC signal S DC As a direct current signal SD DC 。
In step 74, the DC-to-PWM converter 16a converts the DC signal SD DC Providing PWM signal SC PWM 。
In step 76, the LED driver 14a generates a PWM signal SC PWM The power transistor MNDRV is manufactured to control the current flowing through the light emitting element LT.
The dimming controller 10c of fig. 8 and the dimming method 60c of fig. 9 have the following advantages. Regardless of the dimming signal S DIM For either DC or PWM, the dimmer controller 10c can generate a corresponding PWM signal SC having a fixed frequency and a fixed logic level PWM To control the current flowing through the light emitting assembly LT.
The multiplexers 26 in the dimming controllers 10a, 10b and 10c are used to select one of the two signals having the same form. The multiplexer 26 in the dimmer controller 10a selects one of the two PWM signals for output. The multiplexer 26 in the dimming controllers 10b and 10c selects one of the two dc signals for output. However, the present invention is not limited thereto, and in some embodiments, the multiplexer 26 may select one of the two signals with different configurations.
Fig. 10 shows a dimmer controller 10d, which in one embodiment may be used as the dimmer controller 10 of fig. 1. The same and similar devices of the dimming controller 10d and the dimming controller 10c have been disclosed in fig. 8 and the corresponding description, and the operation thereof can be known from the previous description related to fig. 8 and 9, and will not be described again. The dimmer controller 10d may have the same functions and benefits as the dimmer controller 10 c.
The low pass filter 15 in the dimmer controller 10c is connected between the multiplexer 26 and the digital buffer 18. Unlike the dimmer controller 10c, the low-pass filter 15 of the dimmer controller 10d is connected between the multiplexer 26 and the comparator 22.
In fig. 10, the selector 17b (including the operational amplifier 24 and the multiplexer 26) can be based on the selection signal S outputted from the signal identifier 12 SEL Select dimming signal S DIM And temporary PWM signal SB PWM One of them is taken as output SD XX To a low pass filter 15, which producesGenerate direct current signal SD DC 。
When the signal identifier 12 considers the dimming signal S DIM In the case of DC, the selector 17b uses the DC signal path PTH DC For generating a DC signal SD DC . At this time, the low-pass filter 15 does not adjust the optical signal S although there may be a delay DIM Has an influence on the voltage level of the voltage, and can faithfully generate and adjust the light signal S DIM DC signal SD with same voltage level DC 。
When the signal identifier 12 considers the dimming signal S DIM In the case of PWM, the selector 17b uses the PWM signal path PTH PWM For generating a DC signal SD DC . At this time, the digital buffer 18 can be regarded as a level shifter (level shifter), no matter what the dimming signal S is DIM The logic level of the logic "1" of (2) may enable the temporary PWM signal SB PWM With a default logic level. While the low-pass filter 15 pairs the temporary PWM signal SB PWM Low-pass filtering to generate corresponding DC signal SD DC 。
Fig. 11 illustrates a dimming method 60d employed by the dimming controller 10d of fig. 10. Some steps of the dimming method 60d are the same as or similar to those of the dimming method 60c, and it can be known from the previous dimming method 60c and the related description, and will not be further described.
Unlike the dimming method 60c, in the dimming method 60d, the step 70d follows the step 67, and the selector 17b selects the temporary PWM signal SB PWM As output SD XX 。
Unlike the dimming method 60c, in the dimming method 60d, the step 68c follows the steps 72b and 70d, and the low-pass filter 15 pairs the temporary PWM signal SB PWM Low-pass filtering to generate corresponding DC signal SD CS 。
The foregoing description is only of the preferred embodiments of the invention, and all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (8)
1. A dimming controller adapted to dim a light emitting assembly, comprising:
the light modulation input end receives a light modulation signal, and the light modulation signal is direct current or PWM;
the signal identifier is connected to the dimming input end and used for identifying that the dimming signal positioned on the dimming input end is direct current or PWM;
the selector is connected to the dimming input end through different direct current signal paths and PWM signal paths and is controlled by the signal identifier; and
the direct current-to-PWM converter is coupled to the selector and used for converting a direct current signal into a PWM signal for dimming the light-emitting component;
when the signal identifier considers that the dimming signal is direct current, the signal identifier enables the selector to select the direct current signal path to connect the dimming input end to the direct current-to-PWM converter; and
when the signal identifier considers the dimming signal to be PWM, the signal identifier enables the selector to select the PWM signal path to connect the dimming input end to the direct current-to-PWM converter,
wherein, the dimming controller still contains:
the digital buffer is located on the PWM signal path and is used for generating a temporary PWM signal according to the dimming signal, wherein the temporary PWM signal has a specific logic level.
2. The dimmer controller of claim 1, comprising:
the PWM-to-DC converter is positioned on the PWM signal path and provides the DC signal according to the temporary PWM signal.
3. The dimmer controller of claim 1, further comprising:
the PWM-to-DC converter is connected between the output of the selector and the DC-to-PWM converter and generates the DC signal according to the dimming signal.
4. The dimmer controller of claim 1, the selector comprising:
the unit gain buffer is used for transmitting the dimming signal to the direct current-to-PWM converter when the dimming signal is direct current.
5. The dimming controller of claim 1, the dc-to-PWM converter comprising:
a signal generator for generating a periodic signal; and
the comparator is used for comparing the periodic signal with the direct current signal to generate the PWM signal.
6. A dimming method for dimming a light emitting assembly, comprising:
receiving a dimming signal, wherein the dimming signal is direct current or PWM;
identifying the dimming signal as direct current or PWM;
providing a direct current signal path and a PWM signal path;
when the dimming signal is direct current, selecting the direct current signal path to generate a direct current signal;
when the dimming signal is PWM, selecting the PWM signal path for generating the DC signal;
converting the direct current signal to generate a PWM signal for dimming the light emitting component;
when the dimming signal is PWM, generating a temporary PWM signal according to the dimming signal, wherein the temporary PWM signal has a default logic level; and
the temporary PWM signal is converted to provide the dc signal.
7. The dimming method of claim 6, wherein the step of converting the temporary PWM signal comprises:
the temporary PWM signal is low pass filtered to provide the dc signal.
8. The dimming method of claim 6, comprising:
and providing a unit gain buffer arranged on the direct current signal path and used for providing the direct current signal according to the dimming signal when the dimming signal is direct current.
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| CN117479371A (en) * | 2023-12-26 | 2024-01-30 | 南昌英诺泰克科技有限公司 | Improved intelligent dimming control device |
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| US10091849B2 (en) * | 2016-08-22 | 2018-10-02 | Semiconductor Components Industries, Llc | Hybrid dimming for lighting circuits |
| CN107920402B (en) * | 2016-10-11 | 2019-10-11 | 通用电气照明解决方案有限公司 | A kind of dimming device and lamps and lanterns |
| CN107071982B (en) * | 2017-05-19 | 2018-08-14 | 深圳市晟碟半导体有限公司 | LED drive device and its invariable power light adjusting circuit, light-dimming method |
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