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TWI697255B - Dimming controllers and related dimming methods capable of receiving pulse-width-modulation signal and direct-current signal - Google Patents

Dimming controllers and related dimming methods capable of receiving pulse-width-modulation signal and direct-current signal Download PDF

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TWI697255B
TWI697255B TW108115378A TW108115378A TWI697255B TW I697255 B TWI697255 B TW I697255B TW 108115378 A TW108115378 A TW 108115378A TW 108115378 A TW108115378 A TW 108115378A TW I697255 B TWI697255 B TW I697255B
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signal
dimming
pwm
dim
converter
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TW108115378A
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TW202042594A (en
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李俊欣
蘇瑋城
鄭瑞志
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通嘉科技股份有限公司
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Priority to US16/507,778 priority patent/US10667356B2/en
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Abstract

Disclosure provides a dimming controller suitable for the use of dimming a light emitting device. The dimming controller has a dimming node, a signal-type identifier, a selector and an DC-to-PWM converter. The signal-type identifier is connected to the dimming node, a dimming signal on which is of either PWM or DC, to tell whether the dimming signal is of PWM or of DC. The selector is capable of coupled to the dimming node via DC and PWM signal paths. The DC-to-PWM converter converts a DC signal into a PWM signal for dimming the light emitting device. When the signal-type identifier deems the dimming signal as of DC, the signal-type identifier makes the selector select the DC path to connect the dimming node to the DC-to-PWM converter. When the signal-type identifier deems the dimming signal as of PWM, the signal-type identifier makes the selector select the PWM path to connect the dimming node to the DC-to-PWM converter.

Description

可接收脈波寬度調變信號與直流信號的調光控制器與相關之調光方法 Dimming controller capable of receiving pulse width modulation signal and DC signal and related dimming method

本發明係關於一種調光控制器以及相關之調光方法,尤指可以接受不同型態之調光信號的調光控制器以及相關之調光方法。 The invention relates to a dimming controller and related dimming method, in particular to a dimming controller and related dimming method that can receive different types of dimming signals.

良好的發光效率、精簡的元件體積、以及長久的元件壽命,使得發光二極體(LED)廣受照明或背光業界所採用。舉例來說,電腦或電視螢幕中的背光模組,大多數已經從傳統的冷陰極管(Cold Cathode Fluorescent Lamp,CCFL)模組,轉換成LED模組。 Good luminous efficiency, streamlined component size, and long component life have made light-emitting diodes (LEDs) widely used in the lighting or backlight industry. For example, most backlight modules in computers or television screens have been converted from traditional cold cathode tube (Cold Cathode Fluorescent Lamp, CCFL) modules to LED modules.

LED模組往往需要有調整螢幕亮度的功能,因此,LED模組多半具有調光控制器。一般業界有兩種調光方式:脈波寬度調變(pulse-width-modulation,PWM)調光(PWM dimming)、以及類比調光(analog dimming)。PWM調光也有被稱為數位調光。PWM調光採用在邏輯值0與1之間跳躍的一PWM信號,來決定了LED模組處於發光時間對整個循環時間的比例,也就是工作週期(duty cycle);且在發光時間時,LED模組的發光亮度為一固定值;發光時間外的不發光時間,LED模組大致不發光。相對的,採用類比調光(也有稱作電阻式調光)的LED模組,其發光是持續不 間斷的,但是其亮度則是由一直流(direct-current,DC)信號所控制。直流信號也有稱為類比(analog)信號。 LED modules often need to have the function of adjusting the brightness of the screen, so most of the LED modules have dimming controllers. There are two general dimming methods 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 to the light-emitting time to the entire cycle time, that is, the duty cycle; and during the light-emitting time, the LED The light emitting brightness of the module is a fixed value; the LED module does not emit light during the non-lighting time outside the light emitting time. In contrast, LED modules that use analog dimming (also called resistive dimming) have a continuous light emission Intermittent, but its brightness is controlled by a direct-current (DC) signal. DC signals are also called analog signals.

調光控制器最好可以接收直流信號,也可以接收PWM信號,如此可以讓調光控制器獲得較廣泛的應用。 The dimming controller can preferably receive a DC signal or a PWM signal, so that the dimming controller can be widely used.

本發明實施例提供一調光控制器,適用於對一發光元件進行調光。該調光控制器包含有一調光輸入端、一信號辨識器、一選擇器、以及一直流轉PWM轉換器。該調光輸入端可接收一調光信號,其可為直流或是PWM。該信號辨識器連接至該調光輸入端,用以辨識位於該調光輸入端上之該調光信號為直流或是PWM。該選擇器可透過不同之一直流信號路徑以及一PWM信號路徑連接至該調光輸入端,受控於該信號辨識器。該直流轉PWM轉換器耦接至該選擇器,用以將一直流信號,轉換為一PWM信號,用以對該發光元件進行調光。當該信號辨識器認為該調光信號為直流時,該信號辨識器使該選擇器選擇該直流信號路徑,來連接該調光輸入端至該直流轉PWM轉換器。當該信號辨識器認為該調光信號為PWM時,該信號辨識器使該選擇器選擇該PWM信號路徑,來連接該調光輸入端至該直流轉PWM轉換器。 An embodiment of the present invention provides a dimming controller, which is suitable for dimming a light-emitting element. The dimming controller includes a dimming input terminal, a signal identifier, a selector, and a DC converter. The dimming input terminal can receive a dimming signal, which can be DC or PWM. The signal identifier is connected to the dimming input terminal, and is used for identifying whether the dimming signal on the dimming input terminal is DC or PWM. The selector can be connected to the dimming input through a different DC signal path and a PWM signal path, controlled by the signal identifier. The DC-to-PWM converter is coupled to the selector to convert the DC signal into a PWM signal for dimming the light-emitting element. When the signal recognizer considers the dimming signal to be DC, the signal recognizer causes the selector to select the DC signal path to connect the dimming input to the DC-to-PWM converter. When the signal recognizer considers the dimming signal to be PWM, the signal recognizer causes the selector to select the PWM signal path to connect the dimming input to the DC-to-PWM converter.

本發明實施例提供一調光方法,適用於對一發光元件進行調光。該調光方法包含有:接收一調光信號,其可為直流或是PWM;辨識該調光信號為直流或是PWM;提供一直流信號路徑以及一PWM信號路徑;當該調光信號為直流時,選擇該直流信號路徑,用以產生一直流信號;當該調光信號為PWM時,選擇該PWM信號路徑,用以產生該直流信號;以及, 轉換該直流信號,以產生一PWM信號,用以對該發光元件進行調光。 An embodiment of the present invention provides a dimming method, which is suitable for dimming a light-emitting element. The dimming method includes: receiving a dimming signal, which can be DC or PWM; identifying whether the dimming signal is DC or PWM; providing a DC signal path and a PWM signal path; when the dimming signal is DC Select the DC signal path to generate a DC signal; when the dimming signal is PWM, select the PWM signal path to generate the DC signal; and, The DC signal is converted to generate a PWM signal for dimming the light-emitting element.

10、10a、10b、10c、10d‧‧‧調光控制器 10, 10a, 10b, 10c, 10d ‧‧‧ dimming controller

12‧‧‧信號辨識器 12‧‧‧Sign Recognizer

14a、14b‧‧‧LED驅動器 14a, 14b ‧‧‧ LED driver

15‧‧‧低通濾波器 15‧‧‧Low-pass filter

16、16a‧‧‧直流轉PWM轉換器 16, 16a‧‧‧DC to PWM converter

17a、17b‧‧‧選擇器 17a, 17b‧‧‧ selector

18‧‧‧數位緩衝器 18‧‧‧Digital buffer

19‧‧‧PWM轉直流轉換器 19‧‧‧PWM to DC converter

20‧‧‧信號產生器 20‧‧‧Signal generator

22‧‧‧比較器 22‧‧‧Comparator

24‧‧‧運算放大器 24‧‧‧Operational amplifier

26‧‧‧多工器 26‧‧‧Multiplexer

28‧‧‧電壓位準轉換器 28‧‧‧Voltage level converter

30‧‧‧運算放大器 30‧‧‧Operational amplifier

31‧‧‧定電流源 31‧‧‧Constant current source

60a、60b、60c‧‧‧調光方法 60a, 60b, 60c ‧‧‧ dimming method

62、64、67、68a、68b、68c、70a、70b、70c、70d、72a、72b、74、76‧‧‧步驟 62, 64, 67, 68a, 68b, 68c, 70a, 70b, 70c, 70d, 72a, 72b, 74, 76‧‧‧

C1‧‧‧電容 C1‧‧‧Capacitance

CS‧‧‧電流偵測端 CS‧‧‧current detection terminal

DIM‧‧‧調光輸入端 DIM‧‧‧Dimming input

DRV‧‧‧驅動端 DRV‧‧‧Drive

FA1、FA2‧‧‧下降緣 FA1, FA2‧‧‧falling edge

GND‧‧‧接地線 GND‧‧‧Ground wire

ISET‧‧‧定電流 I SET ‧‧‧ Constant current

LT‧‧‧發光元件 LT‧‧‧Lighting element

MNDRV‧‧‧功率電晶體 MNDRV‧‧‧Power Transistor

PTHDC‧‧‧直流信號路徑 PTH DC ‧‧‧DC signal path

PTHPWM‧‧‧PWM信號路徑 PTH PWM ‧‧‧PWM signal path

RA1‧‧‧上升緣 RA1‧‧‧Rising edge

RCS‧‧‧電流偵測電阻 RCS‧‧‧Current detection resistor

R1‧‧‧電阻 R1‧‧‧Resistance

RDIM‧‧‧可變電阻 RDIM‧‧‧Variable resistor

SBPWM‧‧‧暫時PWM信號 SB PWM ‧‧‧Temporary PWM signal

SCPWM‧‧‧PWM信號 SC PWM ‧‧‧PWM signal

SDC‧‧‧直流信號 S DC ‧‧‧DC signal

SDIM‧‧‧調光信號 S DIM ‧‧‧ dimming signal

SDIM-PWM‧‧‧PWM信號 S DIM-PWM ‧‧‧PWM signal

SDRV‧‧‧驅動信號 S DRV ‧‧‧ drive signal

SDDC‧‧‧直流信號 SD DC ‧‧‧DC signal

SDXX‧‧‧輸出 SD XX ‧‧‧ output

SPWM‧‧‧PWM信號 S PWM ‧‧‧PWM signal

SSAW‧‧‧鋸齒波 S SAW ‧‧‧Sawtooth wave

SSEL‧‧‧選擇信號 S SEL ‧‧‧selection signal

TDELAY‧‧‧預定延遲 T DELAY ‧‧‧Scheduled delay

VCS‧‧‧電流偵測信號 V CS ‧‧‧ Current detection signal

VDC‧‧‧直流信號 V DC ‧‧‧DC signal

VREF、VREF-L、VREF-H‧‧‧參考電壓 V REF , V REF-L , V REF-H ‧‧‧ reference voltage

第1圖顯示一種依據本發明所實施的調光控制器。 Figure 1 shows a dimming controller implemented in accordance with the present invention.

第2圖顯示一調光控制器,可適用於第1圖中。 Figure 2 shows a dimming controller that can be applied to Figure 1.

第3圖顯示一直流轉為數位PWM之控制轉換單元,舉例顯示調光信號SDIM、鋸齒波SSAW、與PWM信號SPWM的波形。 Figure 3 shows the control conversion unit that has been converted to digital PWM all the time. Examples show the waveforms of dimming signal S DIM , sawtooth wave S SAW , and PWM signal S PWM .

第4圖顯示調光信號SDIM具有兩個下降緣FA1與FA2,以及一個上升緣RA1。 Figure 4 shows that the dimming signal S DIM has two falling edges FA1 and FA2, and one rising edge RA1.

第5圖舉例顯示第2圖之調光控制器所採用的調光方法。 Figure 5 shows an example of the dimming method used by the dimming controller of Figure 2.

第6圖顯示另一調光控制器,可適用於第1圖中。 Figure 6 shows another dimming controller that can be applied to Figure 1.

第7圖舉例顯示第6圖之調光控制器所採用的調光方法。 Figure 7 shows an example of the dimming method used in the dimming controller of Figure 6.

第8圖顯示另一調光控制器,可適用於第1圖中。 Figure 8 shows another dimming controller that can be applied to Figure 1.

第9圖舉例顯示第8圖之調光控制器所採用的調光方法。 Figure 9 shows an example of the dimming method used in the dimming controller of Figure 8.

第10圖顯示另一調光控制器,可適用於第1圖中。 Figure 10 shows another dimming controller that can be applied to Figure 1.

第11圖舉例顯示第10圖之調光控制器所採用的調光方法。 Figure 11 shows an example of the dimming method used in the dimming controller of Figure 10.

在本說明書中,有一些相同的符號,其表示具有相同或是類似之結構、功能、原理的元件,且為業界具有一般知識能力者可以依據本說明書之教導而推知。為說明書之簡潔度考量,相同之符號的元件將不再重述。 In this specification, there are some same symbols, which represent components with the same or similar structure, function, and principle, and those with general knowledge in the industry can infer according to the teaching of this specification. For the sake of brevity of the manual, elements with the same symbol will not be restated.

第1圖顯示一種依據本發明所實施的調光控制器10,透過控 制功率電晶體MNDRV,適用來於對發光元件LT進行調光。 Figure 1 shows a dimming controller 10 implemented according to the present invention The power transistor MNDRV is suitable for dimming the light emitting element LT.

功率電晶體MNDRV可以是一NMOS電晶體,而發光元件LT可以是一個或是數個發光二極體(light-emitting diode,LED)串接或並聯在一起。調光控制器10透過驅動端DRV,提供驅動信號SDRV,來控制功率電晶體MNDRV。驅動信號SDRV可能是一PWM信號,也可能是一DC信號。流經發光元件LT的電流,經過電流偵測電阻RCS,產生電流偵測信號VCS,透過電流偵測端CS,由調光控制器10所接收。調光控制器10從調光輸入端DIM,接收調光信號SDIM,據以產生驅動信號SDRVThe 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 in parallel. The dimming controller 10 provides a driving signal S DRV through the driving terminal DRV to control the power transistor MNDRV. The driving signal S DRV may be a PWM signal or a DC signal. The current flowing through the light-emitting element LT passes through the current detection resistor RCS to generate a current detection signal V CS , which is received by the dimming controller 10 through the current detection terminal CS. The dimming controller 10 receives the dimming signal S DIM from the dimming input terminal DIM, and accordingly generates the driving signal S DRV .

如同第1圖所示,調光控制器10可以接受外界三個不同的信號輸入方式,來進行調光。第一種是外界提供直流信號VDC至調光輸入端DIM,作為調光信號SDIM,而直流信號VDC的電壓準位代表了發光元件LT應產生的平均亮度。第二種是連接一可變電阻RDIM於調光輸入端DIM與一接地線GND之間,稍後將說明可變電阻RDIM的電阻值會轉變為調光輸入端DIM上一直流信號的一電壓準位,其代表了發光元件LT的平均亮度。第三種是外界提供PWM信號SDIM-PWM至調光輸入端DIM,作為調光信號SDIM,而PWM信號SDIM-PWM的工作週期代表了發光元件LT的平均亮度。 As shown in FIG. 1, the dimming controller 10 can accept three different signal input methods from the outside to perform dimming. The first is to provide a DC signal V DC to the dimming input terminal DIM as the dimming signal S DIM , and the voltage level of the DC signal V DC represents the average brightness that the light emitting element LT should produce. The second is to connect a variable resistor RDIM between the dimming input terminal DIM and a ground line GND. The resistance value of the variable resistor RDIM will be converted into a voltage of the DC signal on the dimming input terminal DIM later. Level, which represents the average brightness of the light emitting element LT. The third is that the external provides the PWM signal S DIM-PWM to the dimming input terminal DIM as the dimming signal S DIM , and the duty cycle of the PWM signal S DIM-PWM represents the average brightness of the light emitting element LT.

換言之,調光信號SDIM可能是一直流信號,也可能是一PWM信號。調光信號SDIM可能是兩種型態其中之一,而這兩種型態是直流與PWM。 In other words, the dimming signal S DIM may be a DC signal or a PWM signal. The dimming signal S DIM may be one of two types, and these two types are DC and PWM.

第2圖顯示一調光控制器10a,在一實施例中,可以作為第1圖中的調光控制器10。調光控制器10a包含有信號辨識器12、直流轉PWM轉換器16、選擇器17a、LED驅動器14a、以及定電流源31。 FIG. 2 shows a dimming controller 10a. In one embodiment, it can be used as the dimming controller 10 in FIG. 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.

直流轉PWM轉換器16是一種型態轉換器。如果調光信號SDIM是一直流信號,直流轉PWM轉換器16可以將其轉換,提供相對應的PWM信號SPWM。第2圖中,直流轉PWM轉換器16包含有信號產生器20、運算放大器24、以及比較器22。請同時參閱第3圖。第3圖顯示調光信號SDIM大約為一直流信號經過一直流轉為數位PWM之控制轉換單元。舉例常用電路如運算放大器24架構為一單位增益緩衝器(Unity-Gain Buffer),把調光信號SDIM的電壓準位重現於比較器22的非反向輸入端。信號產生器20產生鋸齒波SSAW,提供至比較器22的反向輸入端。比較器22比較調光信號SDIM與鋸齒波SSAW,以產生PWM信號SPWM,即如同第3圖所示之功能。 The DC-to-PWM converter 16 is a type converter. If the dimming signal S DIM is a DC signal, the DC-to-PWM converter 16 can convert it 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 also refer to Figure 3. Figure 3 shows that the dimming signal S DIM is approximately a DC-to-DC signal conversion control unit after DC-to-DC conversion. For example, a common circuit such as an operational amplifier 24 is constructed as a Unity-Gain Buffer, and the voltage level of the dimming signal S DIM is reproduced at the non-inverting input terminal of the comparator 22. The signal generator 20 generates a sawtooth wave S SAW and provides it to the inverting input of the comparator 22. The comparator 22 compares the dimming signal S DIM and the sawtooth wave S SAW to generate the PWM signal S PWM , which is the function shown in FIG. 3.

信號辨識器12連接至調光輸入端DIM,用以辨識位於調光輸入端DIM上之調光信號SDIM為直流還是PWM,據以產生選擇信號SSEL,其控制選擇器17a。在第2圖的實施例中,選擇信號SSEL為邏輯上的1時,表示信號辨識器12認為調光信號SDIM是一PWM信號;相反的,當信號辨識器12認為調光信號SDIM是一直流信號時,選擇器17a使選擇信號SSEL為邏輯上的0。 The signal identifier 12 is connected to the dimming input terminal DIM to identify whether the dimming signal S DIM located on the dimming input terminal DIM is DC or PWM, and accordingly generates a selection signal S SEL , which controls the selector 17 a. In the embodiment of FIG. 2, when the selection signal S SEL is logically 1, it indicates that the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal; on the contrary, when the signal recognizer 12 considers the dimming signal S DIM In the case of a DC signal, the selector 17a sets the selection signal S SEL to a logical 0.

在一實施例中,信號辨識器12依據調光信號SDIM的信號緣來決定選擇信號SSEL。請參閱第4圖,其中顯示調光信號SDIM具有兩個下降緣FA1與FA2,以及一個上升緣RA1。信號辨識器12可以依據在一預定時間內,是否有足夠多個下降緣與上升緣,其斜率絕對值都大於一預定值,來產生該選擇信號。舉例來說,如果信號辨識器12發現在8ms中,有超過4個以上的下降緣與上升緣,其斜率絕對值都大於0.1V/us,那就認定調光信號SDIM是一PWM信號,使選擇信號SSEL為邏輯上的1。相反的,如果在8ms中,沒有超過4個斜率絕對值都大於0.1V/us的下降緣與上升緣,那就認定調光信號 SDIM是一直流信號,使選擇信號SSEL為邏輯上的0。 In one embodiment, the signal identifier 12 determines the selection signal S SEL according to the signal edge of the dimming signal S DIM . Please refer to FIG. 4, which shows that the dimming signal S DIM has two falling edges FA1 and FA2, and one rising edge RA1. The signal identifier 12 can generate the selection signal according to whether there are enough falling edges and rising edges within a predetermined time, and the absolute value of the slope is greater than a predetermined value. For example, if the signal recognizer 12 finds that there are more than 4 falling edges and rising edges in 8ms, and the absolute value of the slope is greater than 0.1V/us, then it is considered that the dimming signal S DIM is a PWM signal, The selection signal S SEL is logically 1. On the contrary, if there are no more than 4 falling edges and rising edges whose absolute value of slope is greater than 0.1V/us in 8ms, then the dimming signal S DIM is regarded as a DC signal, so that the selection signal S SEL is logical 0.

舉例來說,第4圖中,信號辨識器12將調光信號SDIM低到跨過參考電壓VREF-H時,視為下降緣FA1的開始。然後比較在預定延遲TDELAY後的調光信號SDIM與參考電壓VREF-L,藉以判別下降緣FA1的斜率絕對值是否大於(VREF-H-VREF-L)/TDELAY。類似的道理,信號辨識器12將調光信號SDIM高到跨過參考電壓VREF-L時,視為上降緣RA1的開始。然後比較在預定延遲TDELAY後的調光信號SDIM與參考電壓VREF-H,藉以判別上升緣RA1的斜率絕對值是否大於(VREF-H-VREF-L)/TDELAY。在另一個實施例中,信號辨識器12也可以依據調光信號SDIM從參考電壓VREF-H變化到參考電壓VREF-L的下降時間,是否大於預定延遲TDELAY,來辨識一下降緣是否陡到足以代表一PWM信號的下降緣。類似的,信號辨識器12也可以依據調光信號SDIM從參考電壓VREF-L變化到參考電壓VREF-H的上升時間,是否大於預定延遲TDELAY,來辨識一上降緣是否陡到足以代表一PWM信號的上降緣。 For example, in FIG. 4, the signal recognizer 12 regards the dimming signal S DIM low to cross the reference voltage V REF-H as the start of the falling edge FA1. Then, the dimming signal S DIM after the predetermined delay T DELAY and the reference voltage V REF-L are compared to determine 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 recognizer 12 regards the dimming signal S DIM high to cross the reference voltage V REF-L as the start of the falling edge RA1. Then, the dimming signal S DIM after the predetermined delay T DELAY and the reference voltage V REF-H are compared to determine 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 recognizer 12 can also recognize a falling edge according to whether the dimming signal S DIM changes from the reference voltage V REF-H to the reference voltage V REF-L during the falling time greater than a predetermined delay T DELAY Whether it is steep enough to represent the falling edge of a PWM signal. Similarly, the signal recognizer 12 can also recognize whether a rising edge is steep according to whether the rise time of the dimming signal S DIM from the reference voltage V REF-L to the reference voltage V REF-H is greater than a predetermined delay T DELAY It is sufficient to represent the rising and falling edges of a PWM signal.

第2圖中的選擇器17a,受控於信號辨識器12,具有二輸入,分別接收PWM信號SPWM以及調光信號SDIM。選擇器17a包含有數位緩衝器18與多工器(multiplexer)26。當信號辨識器12認為調光信號SDIM是一直流信號時,選擇器17a選擇PWM信號SPWM,傳遞至LED驅動器14a。當信號辨識器12認為調光信號SDIM是一PWM信號時,調光信號SDIM經過數位緩衝器18傳遞到多工器26,被其所選擇並傳遞到LED驅動器14a。換言之,多工器26的輸出,如果不是PWM的調光信號SDIM,就是代表直流調光信號SDIM的PWM信號SPWMThe selector 17a in FIG. 2 is controlled by the signal recognizer 12 and has two inputs, respectively receiving the PWM signal S PWM and the dimming signal S DIM . The selector 17a includes a digital buffer 18 and a multiplexer 26. When the signal recognizer 12 considers the dimming signal S DIM to be a DC signal, the selector 17a selects the PWM signal S PWM and transmits it to the LED driver 14a. When the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal, the dimming signal S DIM is transferred to the multiplexer 26 through the digital buffer 18, selected by it, and transferred to the LED driver 14a. In other words, if the output of the multiplexer 26 is not the PWM dimming signal S DIM , it is the PWM signal S PWM representing the DC dimming signal S DIM .

第2圖所顯示的選擇信號SSEL僅僅控制選擇器17a,但本發明 不限於此。舉例來說,在一實施例中,當信號辨識器12認為調光信號SDIM是一PWM信號時,信號辨識器12,透過選擇信號SSEL,使得直流轉PWM轉換器16整個關閉,以節省電能。類似的,當信號辨識器12認為調光信號SDIM是一直流信號時,數位緩衝器18也可以選擇性的被關閉,以節省不必要的耗能。 The selection signal S SEL shown in FIG. 2 only controls the selector 17a, but the present invention is not limited to this. For example, in one embodiment, when the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal, the signal recognizer 12 turns off the DC-to-PWM converter 16 entirely through the selection signal S SEL to save Electrical energy. Similarly, when the signal recognizer 12 considers the dimming signal S DIM to be a DC signal, the digital buffer 18 can also be selectively turned off to save unnecessary power consumption.

LED驅動器14a依據多工器26的輸出,來控制功率電晶體MNDRV,藉以控制流經發光元件LT的電流。當多工器26的輸出為邏輯上的1時,電壓位準轉換器28輸出參考電壓VREF,所以運算放大器30控制功率電晶體MNDRV,使發光元件LT的電流大約為VREF/RCS,其中RCS為電流偵測電阻RCS的電阻值。當多工器26的輸出為邏輯上的0時,電壓位準轉換器28輸出0V,使發光元件LT的電流大約為0。 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 , so 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 , Where R CS is the resistance value of the current detection resistor RCS. When the output of the multiplexer 26 is logically zero, the voltage level converter 28 outputs 0V, so that the current of the light emitting element LT is approximately zero.

定電流源31提供定電流ISET,其流經調光輸入端DIM,可以用以產生直流調光信號SDIM。如果有可變電阻RDIM於調光輸入端DIM與接地線GND之間,定電流ISET可以流經可變電阻RDIM,在調光輸入端DIM產生直流電壓,作為調光信號SDIM。當外界直接提供直流信號VDC或是PWM信號SDIM-PWM來作為調光信號SDIM時,定電流ISET大致不會影響直流信號VDC或是PWM信號SDIM-PWMThe constant current source 31 provides a constant current I SET which flows through the dimming input terminal DIM and can be used to generate a DC dimming signal S DIM . If there is a variable resistor RDIM between the dimming input terminal DIM and the ground line GND, a constant current I SET can flow through the variable resistor RDIM to generate a DC voltage at the dimming input terminal DIM as the dimming signal S DIM . When the DC signal V DC or the PWM signal S DIM-PWM is directly provided by the outside world as the dimming signal S DIM , the constant current I SET does not substantially affect the DC signal V DC or the PWM signal S DIM-PWM .

第5圖舉例顯示第2圖之調光控制器10a所採用的調光方法60a。 FIG. 5 shows an example of the dimming method 60a used by the dimming controller 10a of FIG.

在步驟62,調光控制器10a透過調光輸入端DIM接收調光信號SDIM,其可以是一PWM信號或是一直流信號。 In step 62, the dimming controller 10a receives the dimming signal S DIM through the dimming input terminal DIM , which may be a PWM signal or a DC signal.

步驟64接續步驟62。信號辨識器12辨識位於調光輸入端DIM 上之調光信號SDIM為直流還是PWM,據以產生選擇信號SSEL,其控制選擇器17a。 Step 64 follows step 62. Identification signal recognizer 12 positioned on the modulation dimming input DIM DIM optical signal S DC is PWM, a selection signal is generated according to S SEL, which controls the selector 17a.

步驟68a接續在信號辨識器12認為調光信號SDIM為一直流信號後。直流轉PWM轉換器16轉換調光信號SDIM,提供相對應的PWM信號SPWMStep 68a continues after the signal recognizer 12 considers the dimming signal S DIM to be a DC signal. The DC-to-PWM converter 16 converts the dimming signal S DIM to provide a corresponding PWM signal S PWM .

步驟70a接續步驟68a。選擇器17a選擇PWM信號SPWM,並傳遞至LED驅動器14a,用以驅動發光元件LT。此時,調光信號SDIM透過數位緩衝器18到LED驅動器14a之間的信號路徑被打斷。 Step 70a follows step 68a. The selector 17a selects the PWM signal SPWM and transmits it to the LED driver 14a for driving the light emitting element LT. At this time, the signal path between the dimming signal S DIM through the digital buffer 18 and the LED driver 14a is interrupted.

步驟72a接續在信號辨識器12認為調光信號SDIM為一PWM信號後。選擇器17a選擇調光信號SDIM,並透過數位緩衝器18與多工器26,傳遞至LED驅動器14a,用以驅動發光元件LT。此時,選擇器17a不傳遞PWM信號SPWM至LED驅動器14a。 Step 72a continues after the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal. The selector 17a selects the dimming signal S DIM and transmits it to the LED driver 14a through the digital buffer 18 and the multiplexer 26 for driving the light emitting element LT. At this time, the selector 17a does not pass the PWM signal SPWM to the LED driver 14a.

第2圖之調光控制器10a以及第5圖之調光方法60a有以下的優點。當調光信號SDIM為一直流信號時,可以產生相對應的PWM信號SPWM給LED驅動器14a,用以驅動發光元件LT。當調光信號SDIM為一PWM信號時,調光信號SDIM直接送給LED驅動器14a,可以忠實且精準的反應真正所需要的調光狀態。換言之,不論調光信號SDIM為一直流信號或是一PWM信號,調光控制器10a都可以適當地驅動發光元件LT。 The dimming controller 10a of FIG. 2 and the dimming method 60a of FIG. 5 have the following advantages. When the dimming signal S DIM is a DC signal, a corresponding PWM signal S PWM can be generated to the LED driver 14a for driving the light emitting element LT. When the dimming signal S DIM is a PWM signal, the dimming signal S DIM is directly sent to the LED driver 14a, which can faithfully and accurately reflect the dimming state that is really needed. In other words, regardless of whether the dimming signal S DIM is a DC signal or a PWM signal, the dimming controller 10a can properly drive the light emitting element LT.

第6圖顯示一調光控制器10b,在一實施例中,可以作為第1圖中的調光控制器10。調光控制器10b包含有信號辨識器12、PWM轉直流轉換器19、選擇器17b、LED驅動器14b、以及定電流源31。第6圖中,有一些裝置已經揭露於第2圖中,其操作可以透過先前第2圖之相關解說得知,不 再累述。 FIG. 6 shows a dimming controller 10b. In an embodiment, it can be used as the dimming controller 10 in FIG. 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 exposed in Fig. 2, the operation of which can be known from the previous explanations in Fig. 2. Tell me again.

PWM轉直流轉換器19是一種型態轉換器。如果調光信號SDIM是一PWM信號,PWM轉直流轉換器19可以將其轉換,提供相對應的直流信號SDC。第6圖中,PWM轉直流轉換器19包含有數位緩衝器18、電阻R1以及電容C1。數位緩衝器18把調光信號SDIM的邏輯值重現,提供給電阻R1。電阻R1與電容C1構成一低通濾波器,可以產生直流信號SDC,其大約代表了調光信號SDIM的工作週期。 The PWM-to-DC converter 19 is a type converter. If the dimming signal S DIM is a PWM signal, the PWM-to-DC converter 19 can convert it to provide a corresponding DC signal S DC . In FIG. 6, the PWM-to-DC converter 19 includes a digital buffer 18, a resistor R1, and a capacitor C1. The digital buffer 18 reproduces the logic value of the dimming signal S DIM and supplies it to the resistor R1. The resistor R1 and the capacitor C1 form a low-pass filter, which can generate a DC signal S DC , which approximately represents the duty cycle of the dimming signal S DIM .

第6圖中的選擇器17b,受控於信號辨識器12,具有二輸入,分別接收直流信號SDC以及調光信號SDIM。選擇器17b包含有運算放大器24與多工器26。當信號辨識器12認為調光信號SDIM是一直流信號時,運算放大器24,作為一單位增益緩衝器,把調光信號SDIM傳遞至多工器26,其接續傳遞調光信號SDIM至LED驅動器14b。當信號辨識器12認為調光信號SDIM是一PWM信號時,選擇器17b選擇直流信號SDC,並傳遞到LED驅動器14b。換言之,多工器26的輸出,如果不是直流的調光信號SDIM,就是代表PWM調光信號SDIM的直流信號SDCThe selector 17b in FIG. 6 is controlled by the signal recognizer 12 and has two inputs, respectively receiving a DC signal S DC and a dimming signal S DIM . The selector 17b includes an operational amplifier 24 and a multiplexer 26. When the signal recognizer 12 considers the dimming signal S DIM to be a DC signal, the operational amplifier 24 acts as a unity gain buffer to transfer the dimming signal S DIM to the multiplexer 26, which in turn transfers the dimming signal S DIM to the LED Drive 14b. When the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal, the selector 17b selects the DC signal S DC and transmits it to the LED driver 14b. In other words, if the output of the multiplexer 26 is not the DC dimming signal S DIM , it is the DC signal S DC representing the PWM dimming signal S DIM .

LED驅動器14b依據多工器26的輸出,來控制功率電晶體MNDRV,藉以控制流經發光元件LT的電流。舉例來說,當多工器26的輸出之電壓準位為VOUT時,運算放大器30控制功率電晶體MNDRV,使得發光元件LT的電流大約為VOUT/RCSThe 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 , the operational amplifier 30 controls the power transistor MNDRV so that the current of the light emitting element LT is approximately V OUT /R CS .

第7圖舉例顯示第6圖之調光控制器10b所採用的調光方法60b。調光方法60b有一些步驟跟調光方法60a一樣或是相似,可透過先前調光方法60a或調光控制器10a的說明得知,不再累述。 FIG. 7 shows an example of the dimming method 60b used in the dimming controller 10b of FIG. Some steps of the dimming method 60b are the same as or similar to the dimming method 60a, which can be known from the description of the previous dimming method 60a or the dimming controller 10a, and will not be repeated here.

步驟72b接續在信號辨識器12認為調光信號SDIM為一直流信號後。選擇器17b傳遞調光信號SDIM至LED驅動器14b,其據以驅動發光元件LT。 Step 72b continues after the signal recognizer 12 considers the dimming signal S DIM to be a DC signal. The selector 17b transmits the dimming signal S DIM to the LED driver 14b, which drives the light emitting element LT accordingly.

步驟68b接續在信號辨識器12認為調光信號SDIM為一PWM信號後。PWM轉直流轉換器19轉換調光信號SDIM,提供相對應的直流信號SDCStep 68b continues after the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal. The PWM-to-DC converter 19 converts the dimming signal S DIM to provide a corresponding DC signal S DC .

步驟70b接續步驟68b。選擇器17b選擇直流信號SDC,並傳遞至LED驅動器14b,用以驅動發光元件LT。此時,調光信號SDIM透過運算放大器24到LED驅動器14b之間的信號路徑被打斷。 Step 70b follows step 68b. The selector 17b selects the DC signal S DC and transmits it to the LED driver 14b for driving the light emitting element LT. At this time, the signal path between the dimming signal S DIM through the operational amplifier 24 and the LED driver 14b is interrupted.

第6圖所顯示的選擇信號SSEL僅僅控制選擇器17b,但本發明不限於此。舉例來說,在一實施例中,當信號辨識器12認為調光信號SDIM是一PWM信號時,信號辨識器12,透過選擇信號SSEL,使得運算放大器24禁能或是關閉,以節省電能。類似的,當信號辨識器12認為調光信號SDIM是一直流信號時,數位緩衝器18也可以選擇性的被關閉,以節省不必要的耗能。 The selection signal S SEL shown in FIG. 6 only controls the selector 17b, but the present invention is not limited to this. For example, in one embodiment, when the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal, the signal recognizer 12 disables or turns off the operational amplifier 24 through the selection signal S SEL to save Electrical energy. Similarly, when the signal recognizer 12 considers the dimming signal S DIM to be a DC signal, the digital buffer 18 can also be selectively turned off to save unnecessary power consumption.

第6圖之調光控制器10b以及第7圖之調光方法60b有以下的優點。當調光信號SDIM為一直流信號時,可以大約忠實地直接傳遞給LED驅動器14b,用以驅動發光元件LT。當調光信號SDIM為一PWM信號時,PWM轉直流轉換器19產生相對應的直流信號SDC給LED驅動器14b,用以驅動發光元件LT。因此,不論調光信號SDIM為直流或是PWM,調光控制器10b都可以提供適當的直流信號給LED驅動器14b。 The dimming controller 10b of FIG. 6 and the dimming method 60b of FIG. 7 have the following advantages. When the dimming signal S DIM is a DC signal, it can be directly transmitted to the LED driver 14b approximately faithfully for driving the light emitting element LT. When the dimming signal S DIM is a PWM signal, the PWM-to-DC converter 19 generates a corresponding DC signal S DC to the LED driver 14b for driving the light emitting element LT. Therefore, regardless of whether the dimming signal S DIM is DC or PWM, the dimming controller 10b can provide an appropriate DC signal to the LED driver 14b.

本發明並不限於僅僅驅動LED,在其他實施例中,也可以驅 動其他發光裝置。 The invention is not limited to driving only LEDs, in other embodiments, it can also drive Move other light-emitting devices.

第8圖顯示一調光控制器10c,在一實施例中,可以作為第1圖中的調光控制器10。調光控制器10c包含有信號辨識器12、PWM轉直流轉換器19、選擇器17b、直流轉PWM轉換器16a、LED驅動器14a、以及定電流源31。第8圖中,有一些裝置已經揭露於第2圖與第6圖中,其操作可以透過先前第2圖與第6圖之相關解說得知,不再累述。 FIG. 8 shows a dimming controller 10c, which can be used as the dimming controller 10 in FIG. 1 in an embodiment. 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 exposed in Fig. 2 and Fig. 6, the operation of which can be known from the related explanations of Fig. 2 and Fig. 6, and will not be repeated here.

PWM轉直流轉換器19是一種型態轉換器。如果調光信號SDIM是一PWM信號,PWM轉直流轉換器19可以將其轉換,提供相對應的直流信號SDC。第8圖中,PWM轉直流轉換器19包含有數位緩衝器18以及低通濾波器15。數位緩衝器18把調光信號SDIM的邏輯值重現,產生暫時PWM信號SBPWM,提供給電阻R1。低通濾波器15具有電阻R1與電容C1,用以低通濾波暫時PWM信號SBPWM,以產生直流信號SDC,其大約代表了調光信號SDIM的工作週期。 The PWM-to-DC converter 19 is a type converter. If the dimming signal S DIM is a PWM signal, the PWM-to-DC converter 19 can convert it 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 reproduces the logic value of the dimming signal S DIM to generate the temporary PWM signal SB PWM and supplies it to the 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 duty cycle of the dimming signal S DIM .

暫時PWM信號SBPWM的工作週期(duty cycle)會與調光信號SDIM之工作週期一樣,但暫時PWM信號SBPWM的邏輯”1”之邏輯準位不一定與調光信號SDIM的邏輯”1”之邏輯準位一樣。舉例來說,當調光信號SDIM為邏輯”0”時,其邏輯準位為0V;當調光信號SDIM為邏輯”1”時,其邏輯準位可能為1V、3V或5V。而暫時PWM信號SBPWM的邏輯”0”之邏輯準位為0V,而邏輯”1”之邏輯準位一定為預設的5V。所以,數位緩衝器18也可以視為準位移位器(level shifter),不論調光信號SDIM的邏輯”1”之邏輯準位為何,可使得暫時PWM信號SBPWM具有預設的邏輯準位。 The duty cycle of the temporary PWM signal SB PWM will be the same as the duty cycle of the dimming signal S DIM , but the logic level of the logic "1" of the temporary PWM signal SB PWM may not necessarily be the same as the logic level of the dimming signal S DIM The logic level of 1" is the same. For example, when the dimming signal S DIM is logic "0", the logic level is 0V; when the dimming signal S DIM is logic "1", the logic level may be 1V, 3V, or 5V. The logic level of the logic "0" of the temporary PWM signal SB PWM is 0V, and the logic level of the logic "1" must be the preset 5V. Therefore, the digital buffer 18 can also be regarded as a level shifter, regardless of the logic level of the logic "1" of the dimming signal S DIM , the temporary PWM signal SB PWM can have a preset logic level Bit.

第8圖中的選擇器17b,受控於信號辨識器12,具有二輸入, 分別接收直流信號SDC以及調光信號SDIM。選擇器17b包含有運算放大器24與多工器26。當信號辨識器12認為調光信號SDIM是一直流信號時,運算放大器24,作為一單位增益緩衝器,把調光信號SDIM傳遞至多工器26,作為直流信號SDDC,傳遞至直流轉PWM轉換器16a。當信號辨識器12認為調光信號SDIM是一PWM信號時,選擇器17b選擇直流信號SDC,做為直流信號SDDC,傳遞至直流轉PWM轉換器16a。換言之,多工器26的輸出(直流信號SDDC),如果不是直流的調光信號SDIM,就是代表PWM調光信號SDIM的直流信號SDCThe selector 17b in FIG. 8 is controlled by the signal recognizer 12 and has two inputs, respectively receiving the DC signal S DC and the dimming signal S DIM . The selector 17b includes an operational amplifier 24 and a multiplexer 26. When the signal recognizer 12 considers the dimming signal S DIM to be a DC signal, the operational amplifier 24 acts as a unity gain buffer and transfers the dimming signal S DIM to the multiplexer 26 as a DC signal SD DC to the DC converter PWM converter 16a. When the signal recognizer 12 considers the dimming signal S DIM to be a PWM signal, the selector 17b selects the DC signal S DC as the DC signal SD DC and transmits it to the DC-to-PWM converter 16a. In other words, if the output of the multiplexer 26 (DC signal SD DC ) is not the DC dimming signal S DIM , it is the DC signal S DC representing the PWM dimming signal S DIM .

選擇器17b等同透過了不同的直流信號路徑PTHDC以及PWM信號路徑PTHPWM連接到調光輸入端DIM。PWM轉直流轉換器19中的數位緩衝器18與低通濾波器15,都位於PWM信號路徑PTHPWM上。當信號辨識器12認為調光信號SDIM是直流時,信號辨識器12使選擇器17b選擇直流信號路徑PTHDC,來連接調光輸入端DIM至直流轉PWM轉換器16a。當信號辨識器12認為調光信號SDIM是PWM時,信號辨識器12使選擇器17b選擇PWM信號路徑PTHPWM,來連接調光輸入端DIM至直流轉PWM轉換器16a。 The selector 17b is equivalently connected to the dimming input terminal DIM through different DC signal paths PTH DC and PWM signal paths PTH PWM . The digital buffer 18 and the low-pass filter 15 in the PWM-to-DC converter 19 are located on the PWM signal path PTH PWM . When the signal recognizer 12 considers the dimming signal S DIM to be DC, the signal recognizer 12 causes the selector 17b to select the DC signal path PTH DC to connect the dimming input terminal DIM to the DC-to-PWM converter 16a. When the signal recognizer 12 considers the dimming signal S DIM to be PWM, the signal recognizer 12 causes the selector 17b to select the PWM signal path PTH PWM to connect the dimming input terminal DIM to the DC-to-PWM converter 16a.

直流轉PWM轉換器16a用來轉換直流信號SDDC,提供相對應的PWM信號SCPWM。第8圖中,直流轉PWM轉換器16a包含有信號產生器20以及比較器22。信號產生器20產生鋸齒波SSAW,提供至比較器22的反向輸入端。比較器22比較直流信號SDDC與鋸齒波SSAW,以產生PWM信號SCPWM,類似第3圖所示之功能。如此,PWM信號SCPWM的頻率大約就是個定值,與原始的調光信號SDIM無關。而且,PWM信號SCPWM的邏輯準位,不論是對於邏輯上的”0”或”1”,都可以針對LED驅動器14a,適當地加以客制化。 The DC-to-PWM converter 16a is used to convert the DC signal SD DC to provide a corresponding PWM signal 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 and provides it to the inverting input of the comparator 22. The comparator 22 compares the DC signal SD DC with the sawtooth wave S SAW to generate the PWM signal SC PWM , similar to the function shown in FIG. 3. In this way, the frequency of the PWM signal SC PWM is approximately a fixed value, which has nothing to do with the original dimming signal S DIM . In addition, the logic level of the PWM signal SC PWM , whether it is a logical "0" or "1", can be appropriately customized for the LED driver 14a.

第8圖中之LED驅動器14a依據PWM信號SCPWM,制功率電晶體MNDRV,藉以控制流經發光元件LT的電流。 The LED driver 14a in FIG. 8 manufactures a power transistor MNDRV based on the PWM signal SC PWM to control the current flowing through the light emitting element LT.

第9圖舉例顯示第8圖之調光控制器10c所採用的調光方法60c。調光方法60c有一些步驟跟調光方法60a與60b一樣或是相似,可透過先前調光方法60a、60b與相關之說明得知,不再累述。 FIG. 9 shows an example of the dimming method 60c used in the dimming controller 10c of FIG. 8. There are some steps in the dimming method 60c that are the same as or similar to the dimming methods 60a and 60b, which can be known from the previous dimming methods 60a, 60b and related descriptions, and will not be repeated here.

步驟72b接續在信號辨識器12認為調光信號SDIM為一直流信號後。選擇器17b選擇DC信號路徑PTHDC,傳遞調光信號SDIM,作為直流信號SDDCStep 72b continues after the signal recognizer 12 considers the dimming signal S DIM to be a DC signal. The selector 17b selects the DC signal path PTH DC and passes the dimming signal S DIM as the DC signal SD DC .

步驟67接續在信號辨識器12認為調光信號SDIM為PWM後。數位緩衝器18把調光信號SDIM的邏輯值重現,產生暫時PWM信號SBPWM,其具有預設的邏輯準位。 Step 67 continues after the signal recognizer 12 considers the dimming signal S DIM to be PWM. The digital buffer 18 reproduces the logic value of the dimming signal S DIM to generate a temporary PWM signal SB PWM with a preset logic level.

第9圖中,步驟68b接續在步驟67後,低通濾波器15轉換暫時PWM信號SBPWM,產生相對應的直流信號SDCIn FIG. 9, step 68b continues after step 67, and the low-pass filter 15 converts the temporary PWM signal SB PWM to generate the corresponding DC signal S DC .

第9圖中,步驟70c接續在步驟68b後,選擇器17b選擇直流信號SDC,作為直流信號SDDCIn FIG. 9, after step 70c continues after step 68b, the selector 17b selects the DC signal S DC as the DC signal SD DC .

步驟74中,直流轉PWM轉換器16a轉換直流信號SDDC,提供PWM信號SCPWMIn step 74, the DC-to-PWM converter 16a converts the DC signal SD DC to provide the PWM signal SC PWM .

步驟76中,LED驅動器14a依據PWM信號SCPWM,制功率電晶體MNDRV,藉以控制流經發光元件LT的電流。 In step 76, the LED driver 14a manufactures a power transistor MNDRV according to the PWM signal SC PWM to control the current flowing through the light emitting element LT.

第8圖之調光控制器10c以及第9圖之調光方法60c有以下的優點。不論調光信號SDIM為直流或是PWM,調光控制器10c都可以產生相對應的具有固定頻率、固定邏輯準位之PWM信號SCPWM,來控制流經發光元 件LT的電流。 The dimming controller 10c of FIG. 8 and the dimming method 60c of FIG. 9 have the following advantages. Regardless of whether the dimming signal S DIM is DC or PWM, the dimming controller 10c can generate a corresponding PWM signal SC PWM with a fixed frequency and a fixed logic level to control the current flowing through the light emitting element LT.

調光控制器10a、10b與10c中的多工器26,都是用來從兩個具有相同型態之信號中,擇一輸出。調光控制器10a中的多工器26是從兩個PWM信號中擇一輸出。調光控制器10b與10c中的多工器26是從兩個直流信號中擇一輸出。但本發明不限於此,在一些實施例中,多工器26可以從兩個不同型態的信號中,擇一輸出。 The multiplexers 26 in the dimming controllers 10a, 10b and 10c are used to select one of two signals with the same type. The multiplexer 26 in the dimming controller 10a outputs one of two PWM signals. The multiplexer 26 in the dimming controllers 10b and 10c outputs one of two DC signals. However, the present invention is not limited to this. In some embodiments, the multiplexer 26 may output one of two different types of signals.

第10圖顯示一調光控制器10d,在一實施例中,可以作為第1圖中的調光控制器10。調光控制器10d與調光控制器10c中,相同與相似之裝置已經揭露於第8圖與對應之說明中,其操作可以透過先前第8圖與第9圖之相關解說得知,不再累述。調光控制器10d可能可以具有與調光控制器10c一樣的功能與好處。 FIG. 10 shows a dimming controller 10d. In one embodiment, it can be used as the dimming controller 10 in FIG. In the dimming controller 10d and the dimming controller 10c, the same and similar devices have been disclosed in FIG. 8 and the corresponding description, and their operation can be known through the related explanations in FIG. 8 and FIG. 9, and no longer Exhaustively. The dimming controller 10d may have the same functions and benefits as the dimming controller 10c.

調光控制器10c中的低通濾波器15連接於多工器26與數位緩衝器18之間。與調光控制器10c所不同的,調光控制器10d中的低通濾波器15,是連接於多工器26與比較器22之間。 The low-pass filter 15 in the dimming controller 10c is connected between the multiplexer 26 and the digital buffer 18. Unlike the dimming controller 10c, the low-pass filter 15 in the dimming controller 10d is connected between the multiplexer 26 and the comparator 22.

第10圖中,選擇器17b(包含有運算放大器24與多工器26),可以依據信號辨識器12所輸出的選擇信號SSEL,選擇調光信號SDIM與暫時PWM信號SBPWM兩者其中之一,當作輸出SDXX,傳送給低通濾波器15,其產生直流信號SDDCIn FIG. 10, the selector 17b (including the operational amplifier 24 and the multiplexer 26) can select both the dimming signal S DIM and the temporary PWM signal SB PWM according to the selection signal S SEL output by the signal recognizer 12 One, as the output SD XX , is transmitted to the low-pass filter 15, which generates the DC signal SD DC .

當信號辨識器12認為調光信號SDIM是直流時,選擇器17b以直流信號路徑PTHDC,用以產生直流信號SDDC。此時,儘管可能有延遲的情形,低通濾波器15並不會對調光信號SDIM的電壓準位有影響,可以忠實的產生與調光信號SDIM具有一樣電壓準位之直流信號SDDCWhen the signal recognizer 12 considers the dimming signal S DIM to be DC, the selector 17b uses the DC signal path PTH DC to generate the DC signal SD DC . At this time, although there may be a delay, the low-pass filter 15 does not affect the voltage level of the dimming signal S DIM , and can faithfully generate a DC signal SD having the same voltage level as the dimming signal S DIM DC .

當信號辨識器12認為調光信號SDIM是PWM時,選擇器17b以PWM信號路徑PTHPWM,用以產生直流信號SDDC。此時,數位緩衝器18可以視為準位移位器(level shifter),不論調光信號SDIM的邏輯”1”之邏輯準位為何,可使得暫時PWM信號SBPWM具有預設的邏輯準位。而低通濾波器15對暫時PWM信號SBPWM進行低通濾波,產生相對應的直流信號SDDCWhen the signal recognizer 12 considers the dimming signal S DIM to be PWM, the selector 17b uses the PWM signal path PTH PWM to generate the DC signal SD DC . At this time, the digital buffer 18 can be regarded as a level shifter, regardless of the logic level of the logic "1" of the dimming signal S DIM , the temporary PWM signal SB PWM can have a preset logic level Bit. The low-pass filter 15 performs low-pass filtering on the temporary PWM signal SB PWM to generate a corresponding DC signal SD DC .

第11圖舉例顯示第10圖之調光控制器10d所採用的調光方法60d。調光方法60d有一些步驟跟調光方法60c一樣或是相似,可透過先前調光方法60c與相關之說明得知,不再累述。 FIG. 11 shows an example of the dimming method 60d used in the dimming controller 10d of FIG. There are some steps in the dimming method 60d that are the same as or similar to the dimming method 60c, which can be known from the previous dimming method 60c and related descriptions, and will not be repeated here.

與調光方法60c不同的,在調光方法60d中,步驟70d接續在步驟67後,選擇器17b選擇暫時PWM信號SBPWM,作為輸出SDXXDifferent from the dimming method 60c, in the dimming method 60d, step 70d is continued after step 67, and the selector 17b selects the temporary PWM signal SB PWM as the output SD XX .

與調光方法60c不同的,在調光方法60d中,步驟68c接續在步驟72b與70d之後,低通濾波器15對暫時PWM信號SBPWM進行低通濾波,產生相對應的直流信號SDDCUnlike the dimming method 60c, in the dimming method 60d, step 68c continues after steps 72b and 70d, the low-pass filter 15 performs low-pass filtering on the temporary PWM signal SB PWM to generate a corresponding DC signal SD DC .

以上所述僅為本發明之較佳實施例,凡依本發明申請專利範圍所做之均等變化與修飾,皆應屬本發明之涵蓋範圍。 The above are only the preferred embodiments of the present invention, and all changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the present invention.

10c‧‧‧調光控制器 10c‧‧‧ dimming controller

12‧‧‧信號辨識器 12‧‧‧Sign Recognizer

14a‧‧‧LED驅動器 14a‧‧‧LED driver

15‧‧‧低通濾波器 15‧‧‧Low-pass filter

16a‧‧‧直流轉PWM轉換器 16a‧‧‧DC to PWM converter

17b‧‧‧選擇器 17b‧‧‧selector

18‧‧‧數位緩衝器 18‧‧‧Digital buffer

19‧‧‧PWM轉直流轉換器 19‧‧‧PWM to DC converter

20‧‧‧信號產生器 20‧‧‧Signal generator

22‧‧‧比較器 22‧‧‧Comparator

24‧‧‧運算放大器 24‧‧‧Operational amplifier

26‧‧‧多工器 26‧‧‧Multiplexer

31‧‧‧定電流源 31‧‧‧Constant current source

C1‧‧‧電容 C1‧‧‧Capacitance

CS‧‧‧電流偵測端 CS‧‧‧current detection terminal

DIM‧‧‧調光輸入端 DIM‧‧‧Dimming input

DRV‧‧‧驅動端 DRV‧‧‧Drive

ISET‧‧‧定電流 I SET ‧‧‧ Constant current

PTHDC‧‧‧直流信號路徑 PTH DC ‧‧‧DC signal path

PTHPWM‧‧‧PWM信號路徑 PTH PWM ‧‧‧PWM signal path

R1‧‧‧電阻 R1‧‧‧Resistance

SBPWM‧‧‧暫時PWM信號 SB PWM ‧‧‧Temporary PWM signal

SDC‧‧‧直流信號 S DC ‧‧‧DC signal

SDIM‧‧‧調光信號 S DIM ‧‧‧ dimming signal

SDRV‧‧‧驅動信號 S DRV ‧‧‧ drive signal

SDDC‧‧‧直流信號 SD DC ‧‧‧DC signal

SCPWM‧‧‧PWM信號 SC PWM ‧‧‧PWM signal

SSAW‧‧‧鋸齒波 S SAW ‧‧‧Sawtooth wave

SSEL‧‧‧選擇信號 S SEL ‧‧‧selection signal

VCS‧‧‧電流偵測信號 V CS ‧‧‧ Current detection signal

Claims (8)

一種調光控制器,適用於對一發光元件進行調光,包含有:一調光輸入端,可接收一調光信號,其可為直流或是PWM;一信號辨識器,連接至該調光輸入端,用以辨識位於該調光輸入端上之該調光信號為直流或是PWM;一選擇器,可透過不同之一直流信號路徑以及一PWM信號路徑連接至該調光輸入端,該選擇器受控於該信號辨識器;一直流轉PWM轉換器,耦接至該選擇器,用以將一直流信號,轉換為一PWM信號,用以對該發光元件進行調光;以及一PWM轉直流轉換器,連接於該選擇器之一輸出與該直流轉PWM轉換器之間,依據該調光信號,產生該直流信號;其中,當該信號辨識器認為該調光信號為直流時,該信號辨識器使該選擇器選擇該直流信號路徑,來連接該調光輸入端至該PWM轉直流轉換器;以及當該信號辨識器認為該調光信號為PWM時,該信號辨識器使該選擇器選擇該PWM信號路徑,來連接該調光輸入端至該PWM轉直流轉換器。 A dimming controller suitable for dimming a light-emitting element, including: a dimming input terminal, which can receive a dimming signal, which can be DC or PWM; a signal identifier, connected to the dimming The input terminal is used to identify whether the dimming signal on the dimming input terminal is DC or PWM; a selector can be connected to the dimming input terminal through a different DC signal path and a PWM signal path. The selector is controlled by the signal recognizer; a direct current PWM converter, coupled to the selector, is used to convert the direct current signal into a PWM signal for dimming the light emitting element; and a PWM converter The DC converter is connected between one output of the selector and the DC-to-PWM converter, and generates the DC signal according to the dimming signal; wherein, when the signal recognizer considers the dimming signal to be DC, the The signal identifier causes the selector to select the DC signal path to connect the dimming input to the PWM-to-DC converter; and when the signal identifier considers the dimming signal to be PWM, the signal identifier enables the selection The controller selects the PWM signal path to connect the dimming input to the PWM-to-DC converter. 如申請專利範圍第1項之該調光控制器,另包含有:一數位緩衝器,位於該PWM信號路徑上,用以依據該調光信號,產生一暫時PWM信號,其具有一特定邏輯準位,該暫時PWM信號作為該選擇器之一輸入。 For example, the dimming controller of the first patent application scope includes: a digital buffer located on the PWM signal path for generating a temporary PWM signal according to the dimming signal, which has a specific logic criterion Bit, the temporary PWM signal is input as one of the selectors. 如申請專利範圍第1項之該調光控制器,該選擇器包含有: 一單位增益緩衝器,當該調光信號為直流時,用以傳遞該調光信號至該直流轉PWM轉換器。 If the dimming controller of item 1 of the patent application scope, the selector includes: A unity gain buffer is used to transfer the dimming signal to the DC-to-PWM converter when the dimming signal is DC. 如申請專利範圍第1項之該調光控制器,該直流轉PWM轉換器包含有:一信號產生器,用以產生一周期信號;以及一比較器,用以比較該周期信號以及該直流信號,以產生該PWM信號。 As for the dimming controller of claim 1, the DC-to-PWM converter includes: a signal generator for generating a periodic signal; and a comparator for comparing the periodic signal and the DC signal To generate the PWM signal. 一種調光方法,適用於對一發光元件進行調光,包含有:接收一調光信號,其可為直流或是PWM;辨識該調光信號為直流或是PWM;提供一直流信號路徑以及一PWM信號路徑;當該調光信號為直流時,選擇該直流信號路徑,使該調光信號通過一PWM轉直流轉換器,用以產生一直流信號;當該調光信號為PWM時,選擇該PWM信號路徑,使該調光信號通過該PWM轉直流轉換器,用以產生該直流信號;以及轉換該直流信號,以產生一PWM信號,用以對該發光元件進行調光。 A dimming method suitable for dimming a light-emitting element, including: receiving a dimming signal, which can be DC or PWM; identifying whether the dimming signal is DC or PWM; providing a DC signal path and a PWM signal path; when the dimming signal is DC, select the DC signal path to make the dimming signal pass a PWM to DC converter to generate a DC signal; when the dimming signal is PWM, select the The PWM signal path allows the dimming signal to pass through the PWM-to-DC converter to generate the DC signal; and converts the DC signal to generate a PWM signal for dimming the light-emitting element. 如申請專利範圍第5項之該調光方法,包含有:當該調光信號為PWM時,依據該調光信號,產生一暫時PWM信號,其具有一預設的邏輯準位;以及轉換該暫時PWM信號,以提供該直流信號。 For example, the dimming method of claim 5 of the patent scope includes: when the dimming signal is PWM, a temporary PWM signal is generated according to the dimming signal, which has a predetermined logic level; and converting the Temporary PWM signal to provide the DC signal. 如申請專利範圍第6項之該調光方法,其中,該轉換該暫時PWM信號之步驟,包含有:對該暫時PWM信號進行低通濾波,以提供該直流信號。 For example, the dimming method of claim 6, wherein the step of converting the temporary PWM signal includes: performing low-pass filtering on the temporary PWM signal to provide the DC signal. 如申請專利範圍第5項之該調光方法,包含有: 提供一單位增益緩衝器,設於該直流信號路徑上,當該調光信號為直流時,用以依據該調光信號提供該直流信號。 For example, the dimming method in item 5 of the patent application scope includes: A unity gain buffer is provided on the DC signal path. When the dimming signal is DC, it is used to provide the DC signal according to the dimming signal.
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