TWI422279B - Light emitting diode driving circuit - Google Patents
Light emitting diode driving circuit Download PDFInfo
- Publication number
- TWI422279B TWI422279B TW99117248A TW99117248A TWI422279B TW I422279 B TWI422279 B TW I422279B TW 99117248 A TW99117248 A TW 99117248A TW 99117248 A TW99117248 A TW 99117248A TW I422279 B TWI422279 B TW I422279B
- Authority
- TW
- Taiwan
- Prior art keywords
- transistor switch
- transistor
- coupled
- voltage
- driving circuit
- Prior art date
Links
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
- Led Devices (AREA)
Description
本發明內容是有關於一種驅動電路，且特別是有關於一種發光二極體驅動電路。The present invention relates to a driving circuit, and more particularly to a light emitting diode driving circuit.
對於一般用以驅動發光二極體(LED)的驅動裝置(如：驅動IC)而言，其中的相關電路通常會將流經發光二極體的電流限制於一個固定值。For a drive device (such as a driver IC) that is generally used to drive a light-emitting diode (LED), the associated circuit typically limits the current flowing through the light-emitting diode to a fixed value.
然而，在上述這種電路設計中，當發光二極體發生短路或相關問題時，通常會使與發光二極體耦接之驅動裝置的接腳(pin)處的電壓提高，並因此導致驅動裝置的操作功率上升。However, in such a circuit design as described above, when a short circuit or a related problem occurs in the light emitting diode, the voltage at the pin of the driving device coupled to the light emitting diode is generally increased, and thus the driving is caused. The operating power of the device rises.
如此一來，當發光二極體發生上述問題時，不僅有可能造成驅動裝置的操作功率損耗過大，不利於整體電路的操作，甚至可能造成驅動裝置因操作功率過大而燒毀。As a result, when the above problem occurs in the light-emitting diode, not only the operating power loss of the driving device is excessively large, but also the operation of the overall circuit is disadvantaged, and even the driving device may be burnt due to excessive operating power.
本發明內容之一目的是在提供一種發光二極體驅動電路，藉以於發光二極體發生短路或相關問題時，停止驅動發光二極體，以保護發光二極體及其相關電路。An object of the present invention is to provide a light emitting diode driving circuit for stopping driving a light emitting diode to protect a light emitting diode and related circuits when a short circuit or a related problem occurs in the light emitting diode.
本發明內容之一技術樣態係關於一種發光二極體驅動電路，其包含一第一電晶體開關、一第二電晶體開關以及一第三電晶體開關。第一電晶體開關係用以接收流經至少一發光二極體之一負載電流，並產生相對應負載電流之一負載電壓。第二電晶體開關係用以根據負載電壓導通或關閉。第三電晶體開關串疊耦接於第二電晶體開關和一低位準電壓之間。當負載電壓大於或等於一第一臨界電壓而使得第二電晶體開關和第三電晶體開關導通時，第二電晶體開關產生相對應之一偵測信號用以關閉第一電晶體開關。One aspect of the present invention relates to a light emitting diode driving circuit including a first transistor switch, a second transistor switch, and a third transistor switch. The first transistor-on relationship is for receiving a load current flowing through one of the at least one light-emitting diodes and generating a load voltage corresponding to one of the load currents. The second transistor on relationship is used to turn on or off according to the load voltage. The third transistor switch is coupled in series between the second transistor switch and a low level voltage. When the load voltage is greater than or equal to a first threshold voltage such that the second transistor switch and the third transistor switch are turned on, the second transistor switch generates a corresponding one of the detection signals for turning off the first transistor switch.
依據上述本發明之一實施例，發光二極體驅動電路更包含一分壓單元。分壓單元係用以對負載電壓進行分壓，以產生一操作電壓控制第二電晶體開關。According to an embodiment of the invention described above, the LED driving circuit further comprises a voltage dividing unit. The voltage dividing unit is configured to divide the load voltage to generate an operating voltage to control the second transistor switch.
依據上述本發明之另一實施例，發光二極體驅動電路更包含一第四電晶體開關。第四電晶體開關係用以接收偵測信號而關閉第一電晶體開關。According to another embodiment of the invention described above, the LED driving circuit further includes a fourth transistor switch. The fourth transistor on relationship is configured to receive the detection signal to turn off the first transistor switch.
依據上述本發明之又一實施例，發光二極體驅動電路更包含一磁滯電晶體。磁滯電晶體串疊耦接於第二電晶體開關和低位準電壓之間，並由偵測信號所控制而導通，以提供一磁滯特性予發光二極體驅動電路。According to still another embodiment of the present invention, the LED driving circuit further includes a hysteresis transistor. The hysteresis transistor is coupled between the second transistor switch and the low level voltage, and is turned on by the detection signal to provide a hysteresis characteristic to the LED driving circuit.
當磁滯電晶體導通，且負載電壓小於或等於一第二臨界電壓而使得第二電晶體開關關閉時，第四電晶體開關關閉。When the hysteresis transistor is turned on and the load voltage is less than or equal to a second threshold voltage such that the second transistor switch is turned off, the fourth transistor switch is turned off.
另外，發光二極體驅動電路可更包含一邏輯控制電路。邏輯控制電路耦接於第二電晶體開關和第四電晶體開關之間，用以接收一脈衝寬度調變信號和偵測信號，並於脈衝寬度調變信號有效時將偵測信號傳送至第四電晶體開關。In addition, the LED driving circuit may further include a logic control circuit. The logic control circuit is coupled between the second transistor switch and the fourth transistor switch for receiving a pulse width modulation signal and a detection signal, and transmitting the detection signal to the first time when the pulse width modulation signal is valid Four transistor switches.
本發明內容之一技術樣態係關於一種發光二極體驅動電路，其包含一第一電晶體開關、一分壓單元、一第二電晶體開關以及一第三電晶體開關。第一電晶體開關之一第一端耦接至少一發光二極體，並於作動時於與發光二極體耦接處產生一負載電壓。分壓單元之一輸入端耦接第一電晶體開關之第一端。第二電晶體開關之一控制端耦接分壓單元之一輸出端，而第二電晶體開關之一第一端電性耦接第一電晶體開關之一控制端。第三電晶體開關之一控制端和一第一端耦接第二電晶體開關之一第二端，而第三電晶體開關之一第二端係用以耦接一低位準電壓。當負載電壓大於或等於一第一臨界電壓時，第二電晶體開關和第三電晶體開關導通，使得第二電晶體開關之第一端拉降至低位準電壓，以關閉第一電晶體開關。One aspect of the present invention relates to a light emitting diode driving circuit including a first transistor switch, a voltage dividing unit, a second transistor switch, and a third transistor switch. The first end of the first transistor switch is coupled to the at least one light emitting diode, and generates a load voltage when coupled to the light emitting diode when the device is activated. One input end of the voltage dividing unit is coupled to the first end of the first transistor switch. One control end of the second transistor switch is coupled to one of the output terminals of the voltage dividing unit, and the first end of the second transistor switch is electrically coupled to one of the control ends of the first transistor switch. One of the control terminals of the third transistor switch is coupled to a second end of the second transistor switch, and the second end of the third transistor switch is coupled to a low level voltage. When the load voltage is greater than or equal to a first threshold voltage, the second transistor switch and the third transistor switch are turned on, so that the first end of the second transistor switch is pulled down to a low level voltage to turn off the first transistor switch .
依據上述本發明之一實施例，發光二極體驅動電路更包含一反相器以及一第四電晶體開關。反相器之一輸入端耦接於第二電晶體開關之第一端。第四電晶體開關之一控制端耦接於反相器之一輸出端，第四電晶體開關之一第一端耦接於第一電晶體開關之控制端，而第四電晶體開關之一第二端耦接於低位準電壓。According to an embodiment of the invention, the LED driving circuit further includes an inverter and a fourth transistor switch. One input end of the inverter is coupled to the first end of the second transistor switch. One control end of the fourth transistor switch is coupled to one of the output ends of the inverter, and the first end of the fourth transistor switch is coupled to the control end of the first transistor switch, and one of the fourth transistor switches The second end is coupled to the low level voltage.
依據上述本發明之另一實施例，發光二極體驅動電路更包含一磁滯電晶體。磁滯電晶體之一控制端耦接於反相器之輸出端，磁滯電晶體之一第一端耦接於第二電晶體開關之第二端，磁滯電晶體之一第二端耦接於低位準電壓。According to another embodiment of the invention described above, the LED driving circuit further includes a hysteresis transistor. One control end of the hysteresis transistor is coupled to the output end of the inverter, and the first end of the hysteresis transistor is coupled to the second end of the second transistor switch, and the second end of the hysteresis transistor is coupled Connected to a low level voltage.
當磁滯電晶體導通，且負載電壓小於或等於一第二臨界電壓時，第二電晶體開關和第四電晶體開關關閉。When the hysteresis transistor is turned on and the load voltage is less than or equal to a second threshold voltage, the second transistor switch and the fourth transistor switch are turned off.
根據本發明之技術內容，應用前述發光二極體驅動電路，可對發光二極體所對應的負載電壓進行偵測，藉以保護發光二極體驅動電路以及整體電路，使其免於發生操作功率過大或燒毀的問題。此外，由於類似上述的保護機制通常是利用複雜的電路或大面積的運算放大器(OP)電路來實現，因此應用前述發光二極體驅動電路可簡化類似的保護機制，節省相關的設計和製作成本。According to the technical content of the present invention, the light-emitting diode driving circuit can be used to detect the load voltage corresponding to the light-emitting diode, thereby protecting the light-emitting diode driving circuit and the whole circuit from operating power. Too big or burned. In addition, since the protection mechanism similar to the above is usually implemented by using a complicated circuit or a large-area operational amplifier (OP) circuit, the application of the foregoing LED driving circuit can simplify a similar protection mechanism and save related design and manufacturing costs. .
下文係舉實施例配合所附圖式作詳細說明，但所提供之實施例並非用以限制本發明所涵蓋的範圍，而結構運作之描述非用以限制其執行之順序，任何由元件重新組合之結構，所產生具有均等功效的裝置，皆為本發明所涵蓋的範圍。其中圖式僅以說明為目的，並未依照原尺寸作圖。The embodiments are described in detail below with reference to the accompanying drawings, but the embodiments are not intended to limit the scope of the invention, and the description of the structure operation is not intended to limit the order of execution, any component recombination The structure, which produces equal devices, is within the scope of the present invention. The drawings are for illustrative purposes only and are not drawn to the original dimensions.
第1圖係依照本發明實施例繪示一種發光二極體驅動電路的示意圖。發光二極體驅動電路100可耦接於至少一發光二極體(LED) 102。在本實施例中，發光二極體驅動電路100耦接於一通道上多個串聯相接的發光二極體(LED) 102，並於操作時驅動上述發光二極體102，使得上述發光二極體102於正常操作時產生負載電流IF。在實作中，上述發光二極體驅動電路100可以一驅動積體電路(IC)來實現。FIG. 1 is a schematic diagram of a light emitting diode driving circuit according to an embodiment of the invention. The LED driving circuit 100 can be coupled to at least one light emitting diode (LED) 102. In this embodiment, the LED driving circuit 100 is coupled to a plurality of LEDs 102 connected in series on a channel, and drives the LEDs 102 during operation to enable the LEDs The pole body 102 generates a load current IF during normal operation. In practice, the above-described LED driving circuit 100 can be implemented by driving an integrated circuit (IC).
發光二極體驅動電路100包含運算放大器110、第一電晶體開關120、第二電晶體開關140以及第三電晶體開關150。運算放大器110係用以控制第一電晶體開關120，使得第一電晶體開關120相對應地開啟，並使流經發光二極體102的負載電流IF基本上能維持在一個固定值。第一電晶體開關120係用以接收流經發光二極體102的負載電流IF，並於與發光二極體102耦接處產生相對應負載電流IF的負載電壓LV。第二電晶體開關140係根據負載電壓LV導通或關閉。第三電晶體開關150串疊耦接於第二電晶體開關140和一低位準電壓(如：接地電壓GND)之間。當負載電壓LV大於或等於一第一臨界電壓而使得第二電晶體開關140和第三電晶體開關150導通時，第二電晶體開關140產生相對應之一偵測信號，藉以關閉第一電晶體開關120。The LED driving circuit 100 includes an operational amplifier 110, a first transistor switch 120, a second transistor switch 140, and a third transistor switch 150. The operational amplifier 110 is for controlling the first transistor switch 120 such that the first transistor switch 120 is correspondingly turned on, and the load current IF flowing through the light-emitting diode 102 can be maintained substantially at a fixed value. The first transistor switch 120 is configured to receive a load current IF flowing through the LED 201 and generate a load voltage LV corresponding to the load current IF at a coupling with the LED 102. The second transistor switch 140 is turned on or off according to the load voltage LV. The third transistor switch 150 is coupled in series between the second transistor switch 140 and a low level voltage (eg, ground voltage GND). When the load voltage LV is greater than or equal to a first threshold voltage, causing the second transistor switch 140 and the third transistor switch 150 to be turned on, the second transistor switch 140 generates a corresponding one of the detection signals, thereby turning off the first power. Crystal switch 120.
在本實施例中，運算放大器110具有兩放大器輸入端(即正輸入端和負輸入端)，其中正輸入端係用以接收參考電壓VREF，負輸入端經電阻R1耦接於接地電壓GND。第一電晶體開關120在本實施例中可為NMOS電晶體M1，其中電晶體M1的閘極耦接於運算放大器110的輸出端，其汲極耦接於發光二極體102，以接收負載電流IF，而其源極經電阻R1耦接於接地電壓GND，使得電晶體M1作動時於與發光二極體102耦接處(即電晶體M1的汲極)產生負載電壓LV。In this embodiment, the operational amplifier 110 has two amplifier inputs (ie, a positive input terminal and a negative input terminal), wherein the positive input terminal is configured to receive the reference voltage VREF, and the negative input terminal is coupled to the ground voltage GND via the resistor R1. The first transistor switch 120 can be an NMOS transistor M1 in the embodiment, wherein the gate of the transistor M1 is coupled to the output end of the operational amplifier 110, and the drain is coupled to the LED 102 to receive the load. The current is IF, and the source thereof is coupled to the ground voltage GND via the resistor R1, so that the load voltage LV is generated at the coupling with the light-emitting diode 102 (ie, the drain of the transistor M1) when the transistor M1 is activated.
此外，發光二極體驅動電路100更可包含分壓單元130，其中分壓單元130的輸入端耦接電晶體M1的汲極，分壓單元130的輸出端耦接第二電晶體開關140的控制端。分壓單元130係用以對負載電壓LV進行分壓，以產生一操作電壓CV來控制第二電晶體開關140。In addition, the LED driving circuit 100 further includes a voltage dividing unit 130, wherein the input end of the voltage dividing unit 130 is coupled to the drain of the transistor M1, and the output end of the voltage dividing unit 130 is coupled to the second transistor switch 140. Control terminal. The voltage dividing unit 130 is configured to divide the load voltage LV to generate an operating voltage CV to control the second transistor switch 140.
在本實施例中，分壓單元130可包括電阻R2、R3、R4以及電容C1，其中電阻R2、R3、R4以及電容C1之連接方式如圖所示，於此不再贅述。由圖可知，電阻R2與電晶體M1之汲極耦接的一端可作為分壓單元130的輸入端，而電阻R4與電容C1耦接的一端可作為分壓單元130的輸出端，並耦接於第二電晶體開關140的控制端。在此值得注意的是，本實施例中分壓單元130內的元件僅為例示而已，本領域具通常知識者在不脫離本發明精神和範圍內的情形之下，當可作各種不同的電路設計。In this embodiment, the voltage dividing unit 130 may include resistors R2, R3, and R4 and a capacitor C1. The connections of the resistors R2, R3, and R4 and the capacitor C1 are as shown in the drawing, and details are not described herein. As shown in the figure, one end of the resistor R2 and the drain of the transistor M1 can be used as an input end of the voltage dividing unit 130, and one end of the resistor R4 coupled to the capacitor C1 can be used as an output end of the voltage dividing unit 130 and coupled. At the control end of the second transistor switch 140. It is to be noted that the components in the voltage dividing unit 130 in this embodiment are merely exemplary, and those skilled in the art can make various circuits without departing from the spirit and scope of the present invention. design.
另一方面，在本實施例中，第二電晶體開關140可為NMOS電晶體M2，其中電晶體M2的閘極耦接於分壓單元130的輸出端(例如：電阻R4與電容C1耦接的一端)，其源極耦接於第三電晶體開關150，而其汲極經一電流源IS耦接於電源電壓VDD，並經由其它元件電性耦接於電晶體M1的閘極，使得電晶體M2導通時可間接控制電晶體M1。第三電晶體開關150在本實施例中可為NMOS電晶體M3，其中電晶體M3的閘極和汲極耦接於電晶體M2的源極，其源極耦接於低位準電壓(如：接地電壓GND)。On the other hand, in the embodiment, the second transistor switch 140 can be an NMOS transistor M2, wherein the gate of the transistor M2 is coupled to the output of the voltage dividing unit 130 (for example, the resistor R4 is coupled to the capacitor C1). The one end is coupled to the third transistor switch 150, and the drain is coupled to the power supply voltage VDD via a current source IS, and is electrically coupled to the gate of the transistor M1 via other components. The transistor M1 can be indirectly controlled when the transistor M2 is turned on. The third transistor switch 150 can be an NMOS transistor M3 in the embodiment, wherein the gate and the drain of the transistor M3 are coupled to the source of the transistor M2, and the source thereof is coupled to the low level voltage (eg: Ground voltage GND).
其次，發光二極體驅動電路100更可包含反相器IV1以及第四電晶體開關160。反相器IV1的輸入端耦接於電晶體M2的汲極，而其輸出端電性耦接於第四電晶體開關160，並用以輸出偵測信號VO，以控制第四電晶體開關160。第四電晶體開關160本實施例中可為NMOS電晶體M4，其中電晶體M4的閘極電性耦接於反相器IV1的輸出端以接收偵測信號VO，其源極耦接於接地電壓GND，而其汲極耦接於電晶體M1的閘極。Secondly, the LED driving circuit 100 further includes an inverter IV1 and a fourth transistor switch 160. The input end of the inverter IV1 is coupled to the drain of the transistor M2, and the output end thereof is electrically coupled to the fourth transistor switch 160 and used to output the detection signal VO to control the fourth transistor switch 160. The fourth transistor switch 160 may be an NMOS transistor M4. The gate of the transistor M4 is electrically coupled to the output of the inverter IV1 to receive the detection signal VO, and the source thereof is coupled to the ground. The voltage is GND, and the drain is coupled to the gate of the transistor M1.
在操作上，當串聯相接的發光二極體102發生短路或相關問題，使得負載電壓LV升高而大於或等於第一臨界電壓(例如：約7V)時，分壓單元130會對負載電壓LV作處理而後產生操作電壓CV。若操作電壓CV大於或等於電晶體M2與電晶體M3之總導通電壓的話，則電晶體M2和電晶體M3會導通，使得節點NX拉降至接地電壓GND，並使得反相器IV1據此產生高位準的偵測信號VO。然後，電晶體M4會根據偵測信號VO導通，使得電晶體M1的閘極拉降至接地電壓GND。如此一來，便可關閉電晶體M1，並使通道上串接的發光二極體102停止作動，以避免因負載電壓LV升高導致發光二極體驅動電路100的功率損耗過大，並保護發光二極體驅動電路100以及整體電路，使其免於發生燒毀的問題。In operation, when the series connected LEDs 102 are short-circuited or related, such that the load voltage LV rises to be greater than or equal to the first threshold voltage (eg, about 7 V), the voltage dividing unit 130 will load voltage The LV is processed to generate an operating voltage CV. If the operating voltage CV is greater than or equal to the total turn-on voltage of the transistor M2 and the transistor M3, the transistor M2 and the transistor M3 are turned on, causing the node NX to be pulled down to the ground voltage GND, and the inverter IV1 is generated accordingly. High level detection signal VO. Then, the transistor M4 is turned on according to the detection signal VO, so that the gate of the transistor M1 is pulled down to the ground voltage GND. In this way, the transistor M1 can be turned off, and the LEDs 102 connected in series on the channel are stopped to avoid excessive power loss of the LED driving circuit 100 due to the increase of the load voltage LV, and the illumination is protected. The diode drive circuit 100 and the overall circuit are protected from the problem of burnout.
此外，發光二極體驅動電路100更可包含磁滯電晶體170，藉此避免當負載電壓LV變化時發光二極體驅動電路100發生誤動作的情況。磁滯電晶體170串疊耦接於電晶體M2和接地電壓GND之間，並由偵測信號VO控制而導通，以提供磁滯(hysteresis)特性予發光二極體驅動電路100。In addition, the LED driving circuit 100 may further include a hysteresis transistor 170, thereby avoiding a malfunction of the LED driving circuit 100 when the load voltage LV changes. The hysteresis transistor 170 is coupled in series between the transistor M2 and the ground voltage GND, and is turned on by the detection signal VO to provide hysteresis characteristics to the LED driving circuit 100.
在本實施例中，磁滯電晶體170可為NMOS電晶體MH，其中電晶體MH的閘極耦接於反相器IV1之輸出端，其汲極耦接於電晶體M2的源極，而其源極耦接於接地電壓GND。In this embodiment, the hysteresis transistor 170 can be an NMOS transistor MH, wherein the gate of the transistor MH is coupled to the output of the inverter IV1, and the drain is coupled to the source of the transistor M2. The source is coupled to the ground voltage GND.
在操作上，當電晶體MH與電晶體M2和M3共同操作時，電晶體MH會提供相對應的磁滯特性予發光二極體驅動電路100。具體而言，依據上述，當負載電壓LV升高而大於或等於第一臨界電壓(例如：約7V)，使得電晶體M2和電晶體M3導通時，節點NX會拉降至接地電壓GND，使得反相器IV1據此產生高位準的偵測信號VO，且電晶體MH根據偵測信號VO導通。In operation, when the transistor MH operates in conjunction with the transistors M2 and M3, the transistor MH provides a corresponding hysteresis characteristic to the LED driving circuit 100. Specifically, according to the above, when the load voltage LV is increased to be greater than or equal to the first threshold voltage (for example, about 7 V), so that the transistor M2 and the transistor M3 are turned on, the node NX is pulled down to the ground voltage GND, so that The inverter IV1 accordingly generates a high level detection signal VO, and the transistor MH is turned on according to the detection signal VO.
接著，若是負載電壓LV從第一臨界電壓(或更高電壓)的位準逐漸減少，則電晶體M3會先行關閉，而電晶體M2和MH此時仍為導通狀態。Then, if the load voltage LV gradually decreases from the level of the first threshold voltage (or higher voltage), the transistor M3 is turned off first, and the transistors M2 and MH are still in an on state at this time.
再者，於電晶體M2和MH仍為導通的情形下，若是負載電壓LV持續減少而小於或等於一第二臨界電壓(例如：約3～3.5V)時，電晶體M2才會因減少後的負載電壓LV或其對應的操作電壓CV關閉，使得電晶體MH和M4相對應關閉。Furthermore, in the case where the transistors M2 and MH are still turned on, if the load voltage LV continues to decrease and is less than or equal to a second threshold voltage (for example, about 3 to 3.5 V), the transistor M2 is reduced. The load voltage LV or its corresponding operating voltage CV is turned off, so that the transistors MH and M4 are correspondingly turned off.
如此一來，便可判斷負載電壓LV是否持續一段時間均高於第二臨界電壓(例如：約3～3.5V)，藉此判斷發光二極體102是否真正發生短路，避免當負載電壓LV並非真正因發光二極體102短路而升高，而僅僅是如脈衝一般瞬間變化時，造成發光二極體驅動電路100發生誤動作的情況。In this way, it can be determined whether the load voltage LV is higher than the second threshold voltage for a period of time (for example, about 3 to 3.5 V), thereby determining whether the light-emitting diode 102 is actually short-circuited, and avoiding when the load voltage LV is not It is true that the light-emitting diode 102 is short-circuited and rises, and only when the pulse changes instantaneously, the light-emitting diode driving circuit 100 malfunctions.
除上述之外，發光二極體驅動電路100可更包含邏輯控制電路180，其中邏輯控制電路180耦接於電晶體M2和電晶體M4之間，用以接收偵測信號VO以及調整發光二極體102亮度之一脈衝寬度調變信號PWM，並於脈衝寬度調變信號PWM有效時將偵測信號VO傳送至電晶體M4。換言之，當脈衝寬度調變信號PWM發出而有效調整發光二極體102之亮度時，邏輯控制電路180才將偵測信號VO傳送至電晶體M4，使得電晶體M1關閉，藉以避免發生誤判而關閉電晶體M1，或發生誤判而關閉發光二極體102的情形。在實作上，邏輯控制電路180可由D型正反器或其它類似的邏輯元件來實現。In addition to the above, the LED driving circuit 100 can further include a logic control circuit 180, wherein the logic control circuit 180 is coupled between the transistor M2 and the transistor M4 for receiving the detection signal VO and adjusting the LED One of the brightness of the body 102 is a pulse width modulation signal PWM, and the detection signal VO is transmitted to the transistor M4 when the pulse width modulation signal PWM is active. In other words, when the pulse width modulation signal PWM is emitted to effectively adjust the brightness of the LED 201, the logic control circuit 180 transmits the detection signal VO to the transistor M4, so that the transistor M1 is turned off to avoid false positives. The transistor M1, or a case where the erroneous determination occurs to turn off the light-emitting diode 102. In practice, logic control circuit 180 can be implemented by a D-type flip-flop or other similar logic element.
由上述本發明之實施例可知，應用前述發光二極體驅動電路100，可對發光二極體102所對應的負載電壓LV進行偵測，藉以保護發光二極體驅動電路100以及整體電路，使其免於發生操作功率過大或燒毀的問題。此外，由於類似上述的保護機制通常是利用複雜的電路或大面積的運算放大器(OP)電路來實現，因此應用前述發光二極體驅動電路100可簡化類似的保護機制，節省相關的設計和製作成本。According to the embodiment of the present invention, the light-emitting diode driving circuit 100 can be used to detect the load voltage LV corresponding to the light-emitting diode 102, thereby protecting the LED driving circuit 100 and the overall circuit. It is exempt from the problem of excessive operating power or burnout. In addition, since the protection mechanism similar to the above is usually implemented by using a complicated circuit or a large-area operational amplifier (OP) circuit, the application of the foregoing LED driving circuit 100 can simplify a similar protection mechanism, saving related design and fabrication. cost.
雖然本發明已以實施方式揭露如上，然其並非用以限定本發明，任何本領域具通常知識者，在不脫離本發明之精神和範圍內，當可作各種之更動與潤飾，因此本發明之保護範圍當視後附之申請專利範圍所界定者為準。The present invention has been disclosed in the above embodiments, but it is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.
100．．．發光二極體驅動電路100. . . Light-emitting diode driving circuit
102．．．發光二極體102. . . Light-emitting diode
110．．．運算放大器110. . . Operational Amplifier
120．．．第一電晶體開關120. . . First transistor switch
130．．．分壓單元130. . . Partition unit
140．．．第二電晶體開關140. . . Second transistor switch
150．．．第三電晶體開關150. . . Third transistor switch
160．．．第四電晶體開關160. . . Fourth transistor switch
170．．．磁滯電晶體170. . . Hysteresis transistor
180．．．邏輯控制電路180. . . Logic control circuit
第1圖係依照本發明實施例繪示一種發光二極體驅動電路的示意圖。FIG. 1 is a schematic diagram of a light emitting diode driving circuit according to an embodiment of the invention.
100．．．發光二極體驅動電路100. . . Light-emitting diode driving circuit
102．．．發光二極體102. . . Light-emitting diode
110．．．運算放大器110. . . Operational Amplifier
120．．．第一電晶體開關120. . . First transistor switch
130．．．分壓單元130. . . Partition unit
140．．．第二電晶體開關140. . . Second transistor switch
150．．．第三電晶體開關150. . . Third transistor switch
160．．．第四電晶體開關160. . . Fourth transistor switch
170．．．磁滯電晶體170. . . Hysteresis transistor
180．．．邏輯控制電路180. . . Logic control circuit
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW99117248A TWI422279B (en) | 2010-05-28 | 2010-05-28 | Light emitting diode driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW99117248A TWI422279B (en) | 2010-05-28 | 2010-05-28 | Light emitting diode driving circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| TW201143517A TW201143517A (en) | 2011-12-01 |
| TWI422279B true TWI422279B (en) | 2014-01-01 |
Family
ID=46765345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| TW99117248A TWI422279B (en) | 2010-05-28 | 2010-05-28 | Light emitting diode driving circuit |
Country Status (1)
| Country | Link |
|---|---|
| TW (1) | TWI422279B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5808496A (en) * | 1993-05-19 | 1998-09-15 | Texas Instruments Incorporated | Low current comparator with hysteresis |
| US20030025465A1 (en) * | 1999-12-23 | 2003-02-06 | Stmicroelectronics, Inc. | LED driver circuit and method |
| US20090021182A1 (en) * | 2006-01-31 | 2009-01-22 | Koninklijke Philips Electronics N.V. | Led driver circuit |
| US7498754B2 (en) * | 2007-04-02 | 2009-03-03 | Supertex, Inc. | Architecture for driving multiple loads at constant current |
| US20090322235A1 (en) * | 2008-06-30 | 2009-12-31 | Shian-Sung Shiu | Led driving circuit, led driving control unit and transistor switch module thereof |
-
2010
- 2010-05-28 TW TW99117248A patent/TWI422279B/en active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5808496A (en) * | 1993-05-19 | 1998-09-15 | Texas Instruments Incorporated | Low current comparator with hysteresis |
| US20030025465A1 (en) * | 1999-12-23 | 2003-02-06 | Stmicroelectronics, Inc. | LED driver circuit and method |
| US20090021182A1 (en) * | 2006-01-31 | 2009-01-22 | Koninklijke Philips Electronics N.V. | Led driver circuit |
| US7498754B2 (en) * | 2007-04-02 | 2009-03-03 | Supertex, Inc. | Architecture for driving multiple loads at constant current |
| US20090322235A1 (en) * | 2008-06-30 | 2009-12-31 | Shian-Sung Shiu | Led driving circuit, led driving control unit and transistor switch module thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201143517A (en) | 2011-12-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101035232B1 (en) | Charge-controlling semiconductor integrated circuit | |
| TWI511610B (en) | Light emitting diode driving apparatus and light emitting diode driving method | |
| TWI523568B (en) | Light emitting diode driving apparatus | |
| JP2007082374A (en) | Protection circuit on reverse connection of power supply | |
| WO2014187018A1 (en) | Short circuit protection circuit and electronic device having same | |
| US8461765B2 (en) | LED driving device | |
| TWI446685B (en) | Redundant power supply control system | |
| TW201304596A (en) | LED driving circuit with open-circuit protection | |
| US10195991B2 (en) | Abnormality detection device | |
| TWI594664B (en) | Light-emitting diode driving device and short protection method for driving device | |
| TWI485948B (en) | Power system and short protection circuit thereof | |
| TWI434621B (en) | Control methods for led chains | |
| TWI422279B (en) | Light emitting diode driving circuit | |
| US20090267520A1 (en) | Lighting control device | |
| TWI442828B (en) | Led drive circuit | |
| TW201031934A (en) | Digital short-circuit detection methods and related circuits | |
| CN104078921B (en) | A kind of controller with short-circuit protection | |
| CN108736877B (en) | Driving circuit | |
| TWI547919B (en) | Control circuit for light emitting diode of display | |
| TWI428056B (en) | Driving circuit used for current-driven device and light emitting device | |
| TWI432093B (en) | Led illumination circuit | |
| TWI827456B (en) | Full-bridge circuit module and circuit system with over-temperature protection mechanism | |
| WO2021128716A1 (en) | Multiplexed output short-circuit protection circuit | |
| TWI641194B (en) | Power device with wiring safety function | |
| TWM644693U (en) | LED short-circuiting protection controller |